ASCII art diagram converter
You are encouraged to solve this task according to the task description, using any language you may know.
Given the RFC 1035 message diagram from Section 4.1.1 (Header section format) as a string: http://www.ietf.org/rfc/rfc1035.txt
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Where (every column of the table is 1 bit):
ID is 16 bits QR = Query (0) or Response (1) Opcode = Four bits defining kind of query: 0: a standard query (QUERY) 1: an inverse query (IQUERY) 2: a server status request (STATUS) 3-15: reserved for future use AA = Authoritative Answer bit TC = Truncation bit RD = Recursion Desired bit RA = Recursion Available bit Z = Reserved RCODE = Response code QC = Question Count ANC = Answer Count AUC = Authority Count ADC = Additional Count
Write a function, member function, class or template that accepts a similar multi-line string as input to define a data structure or something else able to decode or store a header with that specified bit structure.
If your language has macros, introspection, code generation, or powerful enough templates, then accept such string at compile-time to define the header data structure statically.
Such "Header" function or template should accept a table with 8, 16, 32 or 64 columns, and any number of rows. For simplicity the only allowed symbols to define the table are + - | (plus, minus, pipe), and whitespace. Lines of the input string composed just of whitespace should be ignored. Leading and trailing whitespace in the input string should be ignored, as well as before and after each table row. The box for each bit of the diagram takes four chars "+--+". The code should perform a little of validation of the input string, but for brevity a full validation is not required.
Bonus: perform a thoroughly validation of the input string.
AArch64 Assembly
<lang AArch64 Assembly> /* ARM assembly AARCH64 Raspberry PI 3B or android 64 bits */ /* program asciiDiagram64.s */
/*******************************************/ /* Constantes file */ /*******************************************/ /* for this file see task include a file in language AArch64 assembly*/ .include "../includeConstantesARM64.inc"
/*******************************************/ /* Structures */ /********************************************/ /* Structure result */
.struct 0
res_name: //
.struct res_name + 8
res_startzone: //
.struct res_startzone + 8
res_endzone: //
.struct res_endzone + 8
res_size: //
.struct res_size + 8
res_end:
/*********************************/ /* Initialized data */ /*********************************/ .data szMessDiagram: .asciz "Display diagramm :\n" szMessValBin: .asciz "\nBinary Value :\n" szMessValZone: .asciz "\nZones values : \n" szMessResultTab: .asciz "Name @ start @ end @ size @ \n" szMessSplitZone: .asciz "Name @ value : @ \n"
szMessErrSep: .asciz "Error : no séparator in first position of line.\n" szMessErrlong: .asciz "Error : string hexa size not multiple to 4. \n" szCarriageReturn: .asciz "\n"
szLine1: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+"
.equ LGLINE, . - szLine1
szLine2: .asciz "| ID |" szLine3: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+" szLine4: .asciz "|QR| Opcode |AA|TC|RD|RA| Z | RCODE |" szLine5: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+" szLine6: .asciz "| QDCOUNT |" szLine7: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+" szLine8: .asciz "| ANCOUNT |" szLine9: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+" szLine10: .asciz "| NSCOUNT |" szLine11: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+" szLine12: .asciz "| ARCOUNT |" szLine13: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+"
.equ NBLINES, (. - szLine1) / LGLINE
bSeparator: .byte '|'
szValueHex: .asciz "78477bbf5496e12e1bf169a4" szValueHexTest: .asciz "0ABCDEFabcdef123" /*********************************/ /* UnInitialized data */ /*********************************/ .bss sZoneConv: .skip 24 tbZones: .skip res_end * NBLINES * 5 sBuffer: .skip 100 /*********************************/ /* code section */ /*********************************/ .text .global main main: // entry of program
ldr x0,qAdrszMessDiagram bl affichageMess ldr x1,qAdrszLine1 mov x3,#LGLINE mov x2,#0
1: // display diagram lines
madd x0,x2,x3,x1 bl affichageMess ldr x0,qAdrszCarriageReturn bl affichageMess add x2,x2,#1 cmp x2,#NBLINES blt 1b ldr x0,qAdrszLine1 // first line address of diagram bl decode // decode the diagram mov x8,x0 // save result number mov x3,#0 // indice mov x4,#res_end // one result size ldr x5,qAdrtbZones // table result address
2:
madd x6,x3,x4,x5 // compute result offset ldr x1,[x6,#res_name] // zone name ldr x0,qAdrszMessResultTab bl strInsertAtCharInc // insertion in message mov x7,x0 ldr x0,[x6,#res_startzone] ldr x1,qAdrsZoneConv bl conversion10 // call decimal conversion mov x0,x7 ldr x1,qAdrsZoneConv // insert value conversion in message bl strInsertAtCharInc mov x7,x0 ldr x0,[x6,#res_endzone] ldr x1,qAdrsZoneConv // else display odd message bl conversion10 // call decimal conversion mov x0,x7 ldr x1,qAdrsZoneConv // insert value conversion in message bl strInsertAtCharInc mov x7,x0 ldr x0,[x6,#res_size] ldr x1,qAdrsZoneConv // else display odd message bl conversion10 // call decimal conversion mov x0,x7 ldr x1,qAdrsZoneConv // insert value conversion in message bl strInsertAtCharInc mov x7,x0 bl affichageMess bl libererPlace // liberation heap area add x3,x3,#1 cmp x3,x8 blt 2b ldr x0,qAdrtbZones ldr x1,qAdrszValueHex //ldr x1,qAdrszValueHexTest bl extractValue // convert string value hexa in binary string mov x7,x0 // string binary address ldr x0,qAdrszMessValZone bl affichageMess mov x0,x7 ldr x1,qAdrtbZones mov x2,x8 // result number bl splitZone
100: // standard end of the program
mov x0, #0 // return code mov x8, #EXIT // request to exit program svc #0 // perform the system call
qAdrszCarriageReturn: .quad szCarriageReturn qAdrszMessResultTab: .quad szMessResultTab qAdrszMessDiagram: .quad szMessDiagram qAdrszMessValZone: .quad szMessValZone qAdrsZoneConv: .quad sZoneConv qAdrszLine1: .quad szLine1 qAdrszValueHex: .quad szValueHex qAdrszValueHexTest: .quad szValueHexTest /***************************************************/ /* decode lines */ /***************************************************/ // x0 contains diagram address // x0 return result counter decode:
stp x1,lr,[sp,-16]! // save registres stp x2,x3,[sp,-16]! // save registres stp x4,x5,[sp,-16]! // save registres stp x6,x7,[sp,-16]! // save registres mov x5,x0 mov x7,#LGLINE // size line diagram ldr x3,qAdrbSeparator // séparator ldrb w3,[x3] ldr x1,qAdrtbZones // result table address mov x2,#0 // result counter mov x6,#1 // line 2
1:
madd x0,x6,x7,x5 // compute line offset ldrb w4,[x0] // load one byte cmp w4,w3 // separator ? bne 99f // no -> error bl decodeOneLine // decode a line mov x2,x0 // new result number add x6,x6,#2 // new line cmp x6,#NBLINES // end ? blt 1b mov x0,x2 // return result counter b 100f
99:
ldr x0,qAdrszMessErrSep bl affichageMess mov x0,#-1
100:
ldp x6,x7,[sp],16 // restaur des 2 registres ldp x4,x5,[sp],16 // restaur des 2 registres ldp x2,x3,[sp],16 // restaur des 2 registres ldp x1,lr,[sp],16 // restaur des 2 registres ret
qAdrbSeparator: .quad bSeparator qAdrszMessErrSep: .quad szMessErrSep qAdrtbZones: .quad tbZones /***************************************************/ /* decode one line */ /***************************************************/ // x0 contains line diagram address // x1 contains table result // x2 contains result number // x3 contains séparator // x0 return new result number decodeOneLine:
stp x1,lr,[sp,-16]! // save registres stp x2,x3,[sp,-16]! // save registres stp x4,x5,[sp,-16]! // save registres stp x6,x7,[sp,-16]! // save registres stp x8,x9,[sp,-16]! // save registres stp x10,x11,[sp,-16]! // save registres stp x12,x13,[sp,-16]! // save registres mov x11,x0 // save address diagram mov x7,x1 // save address table result mov x4,x2 // save result counter mov x0,#0 // zone size mov x5,#-1 // name text begin address mov x6,x3 // séparator mov x8,#res_end mov x10,#0 // zone start mov x12,#1 // character indice
1:
ldrb w1,[x11,x12] // load one byte cmp w1,#0 // line end ? beq 10f cmp w1,w6 // separator ? beq 3f cmp w1,#' ' // space ? bne 2f cmp x5,#0 // text name found ? mov x1,#0 blt 11f strb w1,[x11,x12] // yes -> 0 final text
11:
add x0,x0,#1 // increment zone size add x12,x12,#1 // new byte b 1b // and loop
2:
cmp x5,#0 // text name found ? add x1,x11,x12 // no -> start zone csel x5,x1,x5,lt add x0,x0,#1 // increment zone size add x12,x12,#1 // new byte b 1b // and loop
3: // separator
cmp x5,#0 // zone name ? blt 31f mov x1,#0 strb w1,[x11,x12] // yes -> 0 final
31:
madd x9,x4,x8,x7 // compute result offset str x5,[x9,#res_name] // store address start name add x0,x0,#1 // compute zone size cmp x0,#3 mov x1,#2 mov x5,#3 csel x1,x5,x1,gt udiv x2,x0,x1 // / by size characters zone str x2,[x9,#res_size] cmp x4,#0 // first result ? csel x10,xzr,x10,eq beq 4f sub x10,x9,x8 // else start zone = prev end zone + 1 ldr x10,[x10,#res_endzone] add x10,x10,#1
4:
str x10,[x9,#res_startzone] add x10,x10,x2 // end zone = start zone + size - 1 sub x10,x10,#1 str x10,[x9,#res_endzone] add x4,x4,#1 // increment counter result mov x0,#0 // raz size zone add x10,x10,#1 // next byte mov x5,#-1 // no text name add x12,x12,#1 // next byte b 1b // and loop
10:
mov x0,x4 // return result counter
100:
ldp x12,x13,[sp],16 // restaur des 2 registres ldp x10,x11,[sp],16 // restaur des 2 registres ldp x8,x9,[sp],16 // restaur des 2 registres ldp x6,x7,[sp],16 // restaur des 2 registres ldp x4,x5,[sp],16 // restaur des 2 registres ldp x2,x3,[sp],16 // restaur des 2 registres ldp x1,lr,[sp],16 // restaur des 2 registres ret
/***************************************************/ /* convert strinh value hexa in binary string */ /***************************************************/ // x0 contains diagram address // x1 contains string hex value extractValue:
stp x1,lr,[sp,-16]! // save registres stp x2,x3,[sp,-16]! // save registres stp x4,x5,[sp,-16]! // save registres stp x6,x7,[sp,-16]! // save registres stp x8,x9,[sp,-16]! // save registres mov x5,x0 // save address ldr x0,qAdrszMessValBin bl affichageMess mov x6,x1 // save address string hexa mov x2,#0 mov x3,#0
1: // compute string size
ldrb w4,[x1,x2] // load byte cmp w4,#0 // end string ? cinc x2,x2,ne bne 1b lsr x8,x2,#2 // control if multiple of 4 lsl x3,x8,#2 cmp x3,x2 bne 99f // no -> error lsl x0,x2,#3 // compute size string * 8 add x0,x0,#1 // zero final bl reserverPlace // reserve array on the heap mov x7,x0 // address of heap array mov x1,x0 // for routine mov x0,x6 // address string value hexa bl conversionBin // conversion string hexa -> binary mov x0,x7 bl affichageMess ldr x0,qAdrszCarriageReturn bl affichageMess mov x0,x7 // return address string binary b 100f
99:
ldr x0,qAdrszMessErrlong bl affichageMess mov x0,#-1
100:
ldp x8,x9,[sp],16 // restaur des 2 registres ldp x6,x7,[sp],16 // restaur des 2 registres ldp x4,x5,[sp],16 // restaur des 2 registres ldp x2,x3,[sp],16 // restaur des 2 registres ldp x1,lr,[sp],16 // restaur des 2 registres ret
qAdrszMessValBin: .quad szMessValBin qAdrszMessErrlong: .quad szMessErrlong /***************************************************/ /* decode lines */ /***************************************************/ // x0 contains address string binary // x1 contains table zones address // x2 contains result number splitZone:
stp x1,lr,[sp,-16]! // save registres stp x2,x3,[sp,-16]! // save registres stp x4,x5,[sp,-16]! // save registres stp x6,x7,[sp,-16]! // save registres stp x8,x9,[sp,-16]! // save registres stp x10,x11,[sp,-16]! // save registres stp x12,x13,[sp,-16]! // save registres mov x5,x0 mov x6,x1 mov x3,#0 // indice table mov x4,#0 // indice string mov x8,#res_end
1: // loop
madd x7,x3,x8,x6 // compute result offset ldr x0,[x7,#res_startzone] ldr x1,[x7,#res_size] // zone size ldr x12,qAdrsBuffer mov x9,#0 add x0,x0,x5
2: // copy bytes
ldrb w10,[x0,x9] strb w10,[x12,x9] add x9,x9,#1 cmp x9,x1 // zone size maxi ? blt 2b // no -> loop mov x10,#0 // 0 final strb w10,[x12,x9] // dislay name and value ldr x0,qAdrszMessSplitZone ldr x1,[x7,#res_name] bl strInsertAtCharInc mov x1,x12 bl strInsertAtCharInc bl affichageMess bl libererPlace add x3,x3,#1 cmp x3,x2 // end result ? blt 1b // no -> loop
100:
ldp x12,x13,[sp],16 // restaur des 2 registres ldp x10,x11,[sp],16 // restaur des 2 registres ldp x8,x9,[sp],16 // restaur des 2 registres ldp x6,x7,[sp],16 // restaur des 2 registres ldp x4,x5,[sp],16 // restaur des 2 registres ldp x2,x3,[sp],16 // restaur des 2 registres ldp x1,lr,[sp],16 // restaur des 2 registres ret
qAdrszMessSplitZone: .quad szMessSplitZone qAdrsBuffer: .quad sBuffer /***************************************************/ /* conversion chaine hexa en */ /***************************************************/ // x0 contains string address // x1 contains buffer address conversionBin:
stp x1,lr,[sp,-16]! // save registres stp x2,x3,[sp,-16]! // save registres stp x4,x5,[sp,-16]! // save registres stp x6,x7,[sp,-16]! // save registres stp x8,x9,[sp,-16]! // save registres mov x2,#0 mov x3,#0
1:
ldrb w4,[x0,x2] cmp w4,#0 // string end beq 10f subs w4,w4,#0x30 // conversion digits blt 5f cmp w4,#10 blt 2f // digits 0 à 9 OK cmp w4,#18 // < A ? blt 5f cmp w4,#24 sub w5,w4,#8 // letters A-F csel w4,w5,w4,lt blt 2f cmp w4,#49 // < a ? blt 5f cmp w4,#54 // > f ? bgt 5f sub w4,w4,#39 // letters a-f
2: // x4 contains value on right 4 bits
mov x5,#0 add x3,x3,#4 // size ' bits sub x7,x3,#1 // store indice
3:
tst x4,#1 // test first right bit mov x6,#48 // character '0' mov x8,#49 // character '1' csel x6,x8,x6,ne lsr x4,x4,1 strb w6,[x1,x7] // character -> display zone sub x7,x7,#1 // prev position add x5,x5,#1 // next bit cmp x5,#4 // end ? blt 3b
5: // loop to next byte
add x2,x2,#1 b 1b
10:
mov x6,#0 strb w6,[x1,x3] // zéro final
100:
ldp x8,x9,[sp],16 // restaur des 2 registres ldp x6,x7,[sp],16 // restaur des 2 registres ldp x4,x5,[sp],16 // restaur des 2 registres ldp x2,x3,[sp],16 // restaur des 2 registres ldp x1,lr,[sp],16 // restaur des 2 registres ret
/********************************************************/ /* File Include fonctions */ /********************************************************/ /* for this file see task include a file in language AArch64 assembly */ .include "../includeARM64.inc" </lang>
- Output:
Display diagramm : +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ Name ID start 0 end 15 size 16 Name QR start 16 end 16 size 1 Name Opcode start 17 end 20 size 4 Name AA start 21 end 21 size 1 Name TC start 22 end 22 size 1 Name RD start 23 end 23 size 1 Name RA start 24 end 24 size 1 Name Z start 25 end 27 size 3 Name RCODE start 28 end 31 size 4 Name QDCOUNT start 32 end 47 size 16 Name ANCOUNT start 48 end 63 size 16 Name NSCOUNT start 64 end 79 size 16 Name ARCOUNT start 80 end 95 size 16 Binary Value : 011110000100011101111011101111110101010010010110111000010010111000011011111100010110100110100100 Zones values : Name ID value : 0111100001000111 Name QR value : 0 Name Opcode value : 1111 Name AA value : 0 Name TC value : 1 Name RD value : 1 Name RA value : 1 Name Z value : 011 Name RCODE value : 1111 Name QDCOUNT value : 0101010010010110 Name ANCOUNT value : 1110000100101110 Name NSCOUNT value : 0001101111110001 Name ARCOUNT value : 0110100110100100
ARM Assembly
<lang ARM Assembly> /* ARM assembly Raspberry PI or android 32 bits */ /* program asciiDiagram.s */
/* REMARK 1 : this program use routines in a include file
see task Include a file language arm assembly for the routine affichageMess conversion10 see at end of this program the instruction include */
/* for constantes see task include a file in arm assembly */ /************************************/ /* Constantes */ /************************************/ .include "../constantes.inc"
/*******************************************/ /* Structures */ /********************************************/ /* Structure result */
.struct 0
res_name: //
.struct res_name + 4
res_startzone: //
.struct res_startzone + 4
res_endzone: //
.struct res_endzone + 4
res_size: //
.struct res_size + 4
res_end:
/*********************************/ /* Initialized data */ /*********************************/ .data szMessDiagram: .asciz "Display diagramm :\n" szMessValBin: .asciz "\nBinary Value :\n" szMessValZone: .asciz "\nZones values : \n" szMessResultTab: .asciz "Name @ start @ end @ size @ \n" szMessSplitZone: .asciz "Name @ value : @ \n"
szMessErrSep: .asciz "Error : no séparator in first position of line.\n" szMessErrlong: .asciz "Error : string hexa size not multiple to 4. \n" szCarriageReturn: .asciz "\n"
szLine1: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+"
.equ LGLINE, . - szLine1
szLine2: .asciz "| ID |" szLine3: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+" szLine4: .asciz "|QR| Opcode |AA|TC|RD|RA| Z | RCODE |" szLine5: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+" szLine6: .asciz "| QDCOUNT |" szLine7: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+" szLine8: .asciz "| ANCOUNT |" szLine9: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+" szLine10: .asciz "| NSCOUNT |" szLine11: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+" szLine12: .asciz "| ARCOUNT |" szLine13: .asciz "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+"
.equ NBLINES, (. - szLine1) / LGLINE
bSeparator: .byte '|'
szValueHex: .asciz "78477bbf5496e12e1bf169a4" szValueHexTest: .asciz "0ABCDEFabcdef123" /*********************************/ /* UnInitialized data */ /*********************************/ .bss sZoneConv: .skip 24 tbZones: .skip res_end * NBLINES * 5 sBuffer: .skip 100 /*********************************/ /* code section */ /*********************************/ .text .global main main: @ entry of program
ldr r0,iAdrszMessDiagram bl affichageMess ldr r1,iAdrszLine1 mov r3,#LGLINE mov r2,#0
1: @ display diagram lines
mla r0,r2,r3,r1 bl affichageMess ldr r0,iAdrszCarriageReturn bl affichageMess add r2,r2,#1 cmp r2,#NBLINES blt 1b ldr r0,iAdrszLine1 @ first line address of diagram bl decode @ decode the diagram mov r8,r0 @ save result number mov r3,#0 @ indice mov r4,#res_end @ one result size ldr r5,iAdrtbZones @ table result address
2:
mla r6,r3,r4,r5 @ compute result offset ldr r1,[r6,#res_name] @ zone name ldr r0,iAdrszMessResultTab bl strInsertAtCharInc @ insertion in message mov r7,r0 ldr r0,[r6,#res_startzone] ldr r1,iAdrsZoneConv bl conversion10 @ call decimal conversion mov r0,r7 ldr r1,iAdrsZoneConv @ insert value conversion in message bl strInsertAtCharInc mov r7,r0 ldr r0,[r6,#res_endzone] ldr r1,iAdrsZoneConv @ else display odd message bl conversion10 @ call decimal conversion mov r0,r7 ldr r1,iAdrsZoneConv @ insert value conversion in message bl strInsertAtCharInc mov r7,r0 ldr r0,[r6,#res_size] ldr r1,iAdrsZoneConv @ else display odd message bl conversion10 @ call decimal conversion mov r0,r7 ldr r1,iAdrsZoneConv @ insert value conversion in message bl strInsertAtCharInc mov r7,r0 bl affichageMess bl libererPlace @ liberation heap area add r3,r3,#1 cmp r3,r8 blt 2b ldr r0,iAdrtbZones ldr r1,iAdrszValueHex //ldr r1,iAdrszValueHexTest bl extractValue @ convert string value hexa in binary string mov r7,r0 @ string binary address ldr r0,iAdrszMessValZone bl affichageMess mov r0,r7 ldr r1,iAdrtbZones mov r2,r8 @ result number bl splitZone
100: @ standard end of the program
mov r0, #0 @ return code mov r7, #EXIT @ request to exit program svc #0 @ perform the system call
iAdrszCarriageReturn: .int szCarriageReturn iAdrszMessResultTab: .int szMessResultTab iAdrszMessDiagram: .int szMessDiagram iAdrszMessValZone: .int szMessValZone iAdrsZoneConv: .int sZoneConv iAdrszLine1: .int szLine1 iAdrszValueHex: .int szValueHex iAdrszValueHexTest: .int szValueHexTest /***************************************************/ /* decode lines */ /***************************************************/ // r0 contains diagram address // r0 return result counter decode:
push {r1-r7,lr} @ save registers mov r5,r0 mov r7,#LGLINE @ size line diagram ldr r3,iAdrbSeparator @ séparator ldrb r3,[r3] ldr r1,iAdrtbZones @ result table address mov r2,#0 @ result counter mov r6,#1 @ line 2
1:
mla r0,r6,r7,r5 @ compute line offset ldrb r4,[r0] @ load one byte cmp r4,r3 @ separator ? bne 99f @ no -> error bl decodeOneLine @ decode a line mov r2,r0 @ new result number add r6,r6,#2 @ new line cmp r6,#NBLINES @ end ? blt 1b mov r0,r2 @ return result counter b 100f
99:
ldr r0,iAdrszMessErrSep bl affichageMess mov r0,#-1
100:
pop {r1-r7,lr} @ restaur registers bx lr @ return
iAdrbSeparator: .int bSeparator iAdrszMessErrSep: .int szMessErrSep iAdrtbZones: .int tbZones /***************************************************/ /* decode one line */ /***************************************************/ // r0 contains line diagram address // r1 contains table result // r2 contains result number // r3 contains séparator // r0 return new result number decodeOneLine:
push {r1-r12,lr} @ save registers mov r11,r0 @ save address diagram mov r7,r1 @ save address table result mov r4,r2 @ save result counter mov r0,#0 @ zone size mov r5,#-1 @ name text begin address mov r6,r3 @ séparator mov r8,#res_end mov r10,#0 @ zone start mov r12,#1 @ character indice
1:
ldrb r1,[r11,r12] @ load one byte cmp r1,#0 @ line end ? beq 10f cmp r1,r6 @ separator ? beq 3f cmp r1,#' ' @ space ? bne 2f cmp r5,#0 @ text name found ? mov r1,#0 strgeb r1,[r11,r12] @ yes -> 0 final text add r0,r0,#1 @ increment zone size add r12,r12,#1 @ new byte b 1b @ and loop
2:
cmp r5,#0 @ text name found ? addlt r5,r11,r12 @ no -> start zone add r0,r0,#1 @ increment zone size add r12,r12,#1 @ new byte b 1b @ and loop
3: @ separator
cmp r5,#0 @ zone name ? mov r1,#0 strgeb r1,[r11,r12] @ yes -> 0 final mla r9,r4,r8,r7 @ compute result offset str r5,[r9,#res_name] @ store address start name add r0,r0,#1 @ compute zone size cmp r0,#3 movle r1,#2 movgt r1,#3 bl division @ / by size characters zone str r2,[r9,#res_size] cmp r4,#0 @ first result ? moveq r10,#0 @ yes -> start zone = 0 beq 4f sub r10,r9,r8 @ else start zone = prev end zone + 1 ldr r10,[r10,#res_endzone] add r10,r10,#1
4:
str r10,[r9,#res_startzone] add r10,r10,r2 @ end zone = start zone + size - 1 sub r10,r10,#1 str r10,[r9,#res_endzone] add r4,r4,#1 @ increment counter result mov r0,#0 @ raz size zone add r10,r10,#1 @ next byte mov r5,#-1 @ no text name add r12,r12,#1 @ next byte b 1b @ and loop
10:
mov r0,r4 @ return result counter
100:
pop {r1-r12,lr} @ restaur registers bx lr @ return
/***************************************************/ /* convert strinh value hexa in binary string */ /***************************************************/ // r0 contains diagram address // r1 contains string hex value extractValue:
push {r1-r8,lr} @ save registers mov r5,r0 @ save address ldr r0,iAdrszMessValBin bl affichageMess mov r6,r1 @ save address string hexa mov r2,#0 mov r3,#0
1: @ compute string size
ldrb r4,[r1,r2] @ load byte cmp r4,#0 @ end string ? addne r2,r2,#1 bne 1b lsr r8,r2,#2 @ control if multiple of 4 lsl r3,r8,#2 cmp r3,r2 bne 99f @ no -> error lsl r0,r2,#3 @ compute size string * 8 add r0,r0,#1 @ zero final bl reserverPlace @ reserve array on the heap mov r7,r0 @ address of heap array mov r1,r0 @ for routine mov r0,r6 @ address string value hexa bl conversionBin @ conversion string hexa -> binary mov r0,r7 bl affichageMess ldr r0,iAdrszCarriageReturn bl affichageMess mov r0,r7 @ return address string binary b 100f
99:
ldr r0,iAdrszMessErrlong bl affichageMess mov r0,#-1
100:
pop {r1-r8,lr} @ restaur registers bx lr @ return
iAdrszMessValBin: .int szMessValBin iAdrszMessErrlong: .int szMessErrlong /***************************************************/ /* decode lines */ /***************************************************/ // r0 contains address string binary // r1 contains table zones address // r2 contains result number splitZone:
push {r1-r12,lr} @ save registers mov r5,r0 mov r6,r1 mov r3,#0 @ indice table mov r4,#0 @ indice string mov r8,#res_end
1: @ loop
mla r7,r3,r8,r6 @ compute result offset ldr r0,[r7,#res_startzone] ldr r1,[r7,#res_size] @ zone size ldr r12,iAdrsBuffer mov r9,#0 add r0,r0,r5
2: @ copy bytes
ldrb r10,[r0,r9] strb r10,[r12,r9] add r9,r9,#1 cmp r9,r1 @ zone size maxi ? blt 2b @ no -> loop mov r10,#0 @ 0 final str r10,[r12,r9] @ dislay name and value ldr r0,iAdrszMessSplitZone ldr r1,[r7,#res_name] bl strInsertAtCharInc mov r1,r12 bl strInsertAtCharInc bl affichageMess bl libererPlace add r3,r3,#1 cmp r3,r2 @ end result ? blt 1b @ no -> loop
100:
pop {r1-r12,lr} @ restaur registers bx lr @ return
iAdrszMessSplitZone: .int szMessSplitZone iAdrsBuffer: .int sBuffer /***************************************************/ /* conversion chaine hexa en */ /***************************************************/ // r0 contains string address // r1 contains buffer address conversionBin:
push {r2-r7,lr} @ save registers mov r2,#0 mov r3,#0
1:
ldrb r4,[r0,r2] cmp r4,#0 @ string end beq 10f subs r4,r4,#0x30 @ conversion digits blt 5f cmp r4,#10 blt 2f @ digits 0 à 9 OK cmp r4,#18 @ < A ? blt 5f //vidregtit inter cmp r4,#24 sublt r4,r4,#8 @ letters A-F blt 2f cmp r4,#49 @ < a ? blt 5f cmp r4,#54 @ > f ? bgt 5f sub r4,r4,#39 @ letters a-f
2: @ r4 contains value on right 4 bits
mov r5,#0 add r3,r3,#4 @ size bits sub r7,r3,#1 @ store indice
3:
lsrs r4,#1 @ right bit in carry movcc r6,#48 @ flag carry off character '0' movcs r6,#49 @ flag carry on character '1' strb r6,[r1,r7] @ character -> display zone sub r7,r7,#1 @ prev position add r5,r5,#1 @ next bit cmp r5,#4 @ end ? blt 3b
5: @ loop to next byte
add r2,r2,#1 b 1b
10:
mov r6,#0 strb r6,[r1,r3] @ zéro final
100:
pop {r2-r7,lr} @ restaur registers bx lr @ return
/***************************************************/ /* ROUTINES INCLUDE */ /***************************************************/ .include "../affichage.inc" </lang>
- Output:
Display diagramm : +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ Name ID start 0 end 15 size 16 Name QR start 16 end 16 size 1 Name Opcode start 17 end 20 size 4 Name AA start 21 end 21 size 1 Name TC start 22 end 22 size 1 Name RD start 23 end 23 size 1 Name RA start 24 end 24 size 1 Name Z start 25 end 27 size 3 Name RCODE start 28 end 31 size 4 Name QDCOUNT start 32 end 47 size 16 Name ANCOUNT start 48 end 63 size 16 Name NSCOUNT start 64 end 79 size 16 Name ARCOUNT start 80 end 95 size 16 Binary Value : 011110000100011101111011101111110101010010010110111000010010111000011011111100010110100110100100 Zones values : Name ID value : 0111100001000111 Name QR value : 0 Name Opcode value : 1111 Name AA value : 0 Name TC value : 1 Name RD value : 1 Name RA value : 1 Name Z value : 011 Name RCODE value : 1111 Name QDCOUNT value : 0101010010010110 Name ANCOUNT value : 1110000100101110 Name NSCOUNT value : 0001101111110001 Name ARCOUNT value : 0110100110100100
C
interpret text diagram as data structure <lang C>
- include <stdlib.h>
- include <stdio.h>
- include <string.h>
enum { MAX_ROWS=14, MAX_NAMES=20, NAME_SZ=80 };
char *Lines[MAX_ROWS] = {
" +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+", " | ID |", " +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+", " |QR| Opcode |AA|TC|RD|RA| Z | RCODE |", " +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+", " | QDCOUNT |", " +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+", " | ANCOUNT |", " +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+", " | NSCOUNT |", " +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+", " | ARCOUNT |", " +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+"
}; typedef struct {
unsigned bit3s; unsigned mask; unsigned data; char A[NAME_SZ+2];
}NAME_T; NAME_T names[MAX_NAMES]; unsigned idx_name; enum{ID,BITS,QDCOUNT,ANCOUNT,NSCOUNT,ARCOUNT,MAX_HDR}; unsigned header[MAX_HDR]; // for test unsigned idx_hdr;
int bit_hdr(char *pLine); int bit_names(char *pLine); void dump_names(void); void make_test_hdr(void);
int main(void){
char *p1; int rv; printf("Extract meta-data from bit-encoded text form\n"); make_test_hdr(); idx_name = 0; for( int i=0; i<MAX_ROWS;i++ ){ p1 = Lines[i]; if( p1==NULL ) break; if( rv = bit_hdr(Lines[i]), rv>0) continue; if( rv = bit_names(Lines[i]),rv>0) continue; //printf("%s, %d\n",p1, numbits ); } dump_names();
}
int bit_hdr(char *pLine){ // count the '+--'
char *p1 = strchr(pLine,'+'); if( p1==NULL ) return 0; int numbits=0; for( int i=0; i<strlen(p1)-1; i+=3 ){ if( p1[i] != '+' || p1[i+1] != '-' || p1[i+2] != '-' ) return 0; numbits++; } return numbits;
}
int bit_names(char *pLine){ // count the bit-group names
char *p1,*p2 = pLine, tmp[80]; unsigned sz=0, maskbitcount = 15; while(1){ p1 = strchr(p2,'|'); if( p1==NULL ) break; p1++; p2 = strchr(p1,'|'); if( p2==NULL ) break; sz = p2-p1; tmp[sz] = 0; // set end of string int k=0; for(int j=0; j<sz;j++){ // strip spaces
if( p1[j] > ' ') tmp[k++] = p1[j];
} tmp[k]= 0; sz++; NAME_T *pn = &names[idx_name++]; strcpy(&pn->A[0], &tmp[0]); pn->bit3s = sz/3; if( pn->bit3s < 16 ){
for( int i=0; i<pn->bit3s; i++){ pn->mask |= 1 << maskbitcount--; } pn->data = header[idx_hdr] & pn->mask; unsigned m2 = pn->mask; while( (m2 & 1)==0 ){ m2>>=1; pn->data >>= 1; } if( pn->mask == 0xf ) idx_hdr++;
} else{
pn->data = header[idx_hdr++];
} } return sz;
}
void dump_names(void){ // print extracted names and bits
NAME_T *pn; printf("-name-bits-mask-data-\n"); for( int i=0; i<MAX_NAMES; i++ ){ pn = &names[i]; if( pn->bit3s < 1 ) break; printf("%10s %2d X%04x = %u\n",pn->A, pn->bit3s, pn->mask, pn->data); } puts("bye..");
}
void make_test_hdr(void){
header[ID] = 1024; header[QDCOUNT] = 12; header[ANCOUNT] = 34; header[NSCOUNT] = 56; header[ARCOUNT] = 78; // QR OP AA TC RD RA Z RCODE // 1 0110 1 0 1 0 000 1010 // 1011 0101 0000 1010 // B 5 0 A header[BITS] = 0xB50A;
} </lang>
- Output:
Extract meta-data from bit-encoded text form -name-bits-mask-data- ID 16 X0000 = 1024 QR 1 X8000 = 1 Opcode 4 X7800 = 6 AA 1 X0400 = 1 TC 1 X0200 = 0 RD 1 X0100 = 1 RA 1 X0080 = 0 Z 3 X0070 = 0 RCODE 4 X000f = 10 QDCOUNT 16 X0000 = 12 ANCOUNT 16 X0000 = 34 NSCOUNT 16 X0000 = 56 ARCOUNT 16 X0000 = 78 bye..
C++
Uses C++20
The ASCII diagram is parsed at compile time into a data structure that is used at runtime to encode and decode the fields.
<lang cpp>#include <array>
- include <bitset>
- include <iostream>
using namespace std;
struct FieldDetails {string_view Name; int NumBits;};
// parses the ASCII diagram and returns the field name, bit sizes, and the // total byte size template <const char *T> consteval auto ParseDiagram() {
// trim the ASCII diagram text constexpr string_view rawArt(T); constexpr auto firstBar = rawArt.find("|"); constexpr auto lastBar = rawArt.find_last_of("|"); constexpr auto art = rawArt.substr(firstBar, lastBar - firstBar); static_assert(firstBar < lastBar, "ASCII Table has no fields"); // make an array for all of the fields constexpr auto numFields = count(rawArt.begin(), rawArt.end(), '|') - count(rawArt.begin(), rawArt.end(), '\n') / 2; array<FieldDetails, numFields> fields; // parse the diagram bool isValidDiagram = true; int startDiagramIndex = 0; int totalBits = 0; for(int i = 0; i < numFields; ) { auto beginningBar = art.find("|", startDiagramIndex); auto endingBar = art.find("|", beginningBar + 1); auto field = art.substr(beginningBar + 1, endingBar - beginningBar - 1); if(field.find("-") == field.npos) { int numBits = (field.size() + 1) / 3; auto nameStart = field.find_first_not_of(" "); auto nameEnd = field.find_last_not_of(" "); if (nameStart > nameEnd || nameStart == string_view::npos) { // the table cannot be parsed isValidDiagram = false; field = ""sv; } else { field = field.substr(nameStart, 1 + nameEnd - nameStart); } fields[i++] = FieldDetails {field, numBits}; totalBits += numBits; } startDiagramIndex = endingBar; } int numRawBytes = isValidDiagram ? (totalBits - 1) / 8 + 1 : 0; return make_pair(fields, numRawBytes);
}
// encode the values of the fields into a raw data array template <const char *T> auto Encode(auto inputValues) {
constexpr auto parsedDiagram = ParseDiagram<T>(); static_assert(parsedDiagram.second > 0, "Invalid ASCII talble"); array<unsigned char, parsedDiagram.second> data;
int startBit = 0; int i = 0; for(auto value : inputValues) { const auto &field = parsedDiagram.first[i++]; int remainingValueBits = field.NumBits; while(remainingValueBits > 0) { // pack the bits from an input field into the data array auto [fieldStartByte, fieldStartBit] = div(startBit, 8); int unusedBits = 8 - fieldStartBit; int numBitsToEncode = min({unusedBits, 8, field.NumBits}); int divisor = 1 << (remainingValueBits - numBitsToEncode); unsigned char bitsToEncode = value / divisor; data[fieldStartByte] <<= numBitsToEncode; data[fieldStartByte] |= bitsToEncode; value %= divisor; startBit += numBitsToEncode; remainingValueBits -= numBitsToEncode; } } return data;
}
// decode the raw data into the format of the ASCII diagram template <const char *T> void Decode(auto data) {
cout << "Name Bit Pattern\n"; cout << "======= ================\n"; constexpr auto parsedDiagram = ParseDiagram<T>(); static_assert(parsedDiagram.second > 0, "Invalid ASCII talble");
int startBit = 0; for(const auto& field : parsedDiagram.first) { // unpack the bits from the data into a single field auto [fieldStartByte, fieldStartBit] = div(startBit, 8); unsigned char firstByte = data[fieldStartByte]; firstByte <<= fieldStartBit; firstByte >>= fieldStartBit; int64_t value = firstByte; auto endBit = startBit + field.NumBits; auto [fieldEndByte, fieldEndBit] = div(endBit, 8); fieldEndByte = min(fieldEndByte, (int)(ssize(data) - 1)); for(int index = fieldStartByte + 1; index <= fieldEndByte; index++) { value <<= 8; value += data[index]; } value >>= fieldEndBit; startBit = endBit; cout << field.Name << string_view(" ", (7 - field.Name.size())) << " " << string_view(bitset<64>(value).to_string()).substr(64 - field.NumBits, 64) << "\n"; }
}
int main(void) {
static constexpr char art[] = R"( +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+)"; // using the table above, encode the data below auto rawData = Encode<art> (initializer_list<int64_t> { 30791, 0, 15, 0, 1, 1, 1, 3, 15, 21654, 57646, 7153, 27044 }); cout << "Raw encoded data in hex:\n"; for (auto v : rawData) printf("%.2X", v); cout << "\n\n"; cout << "Decoded raw data:\n"; Decode<art>(rawData);
}</lang>
- Output:
Raw encoded data in hex: 78477BBF5496E12E1BF169A4 Decoded raw data: Name Bit Pattern ======= ================ ID 0100011101111011 QR 1 Opcode 0011 AA 0 TC 0 RD 1 RA 1 Z 011 RCODE 0100 QDCOUNT 1001011011100001 ANCOUNT 0010111000011011 NSCOUNT 1111000101101001 ARCOUNT 0110100110100100
An invalid table will cause a compilation error - here the ANCOUNT field is missing. <lang cpp> static constexpr char missingFieldArt[] = R"(
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+)";
</lang>
GCC 11 gives this error
- Output:
../ascii-art-diagram-converter.cpp: In instantiation of 'void Decode(auto:12) [with const char* T = (& missingFieldArt); auto:12 = std::array<unsigned char, 12>]': ../ascii-art-diagram-converter.cpp:181:36: required from here ../ascii-art-diagram-converter.cpp:98:40: error: static assertion failed: Invalid ASCII talble 98 | static_assert(parsedDiagram.second > 0, "Invalid ASCII talble"); | ~~~~~~~~~~~~~~~~~~~~~^~~ ../ascii-art-diagram-converter.cpp:98:40: note: '(((int)parsedDiagram.std::pair<std::array<FieldDetails, 13>, int>::second) > 0)' evaluates to false
D
This solution generates anonymous struct code at compile-time, that can be mixed-in inside a struct or class. <lang d>string makeStructFromDiagram(in string rawDiagram) pure @safe {
import std.conv: text; import std.format: format; import std.string: strip, splitLines, indexOf; import std.array: empty, popFront;
static void commitCurrent(ref uint anonCount, ref uint totalBits, ref size_t currentBits, ref string code, ref string currentName) pure @safe { if (currentBits) { code ~= "\t";
currentName = currentName.strip; if (currentName.empty) { anonCount++; currentName = "anonymous_field_" ~ anonCount.text; }
string type; if (currentBits == 1) type = "bool"; else if (currentBits <= ubyte.sizeof * 8) type = "ubyte"; else if (currentBits <= ushort.sizeof * 8) type = "ushort"; else if (currentBits <= uint.sizeof * 8) type = "uint"; else if (currentBits <= ulong.sizeof * 8) type = "ulong"; //else if (currentBits <= ucent.sizeof * 8) // type = "ucent"; else assert(0, "Too many bits for the item " ~ currentName);
immutable byteOffset = totalBits / 8; immutable bitOffset = totalBits % 8;
// Getter: code ~= "@property " ~ type ~ " " ~ currentName ~ "() const pure nothrow @safe {\n"; code ~= "\t\t"; if (currentBits == 1) { code ~= format("return (_payload[%d] & (1 << (7-%d))) ? true : false;", byteOffset, bitOffset); } else if (currentBits < 8) { auto mask = (1 << currentBits) - 1; mask <<= 7 - bitOffset - currentBits + 1; code ~= format("return (_payload[%d] & 0b%08b) >> %d;", byteOffset, mask, 7 - bitOffset - currentBits + 1); } else { assert(currentBits % 8 == 0); assert(bitOffset == 0); code ~= type ~ " v = 0;\n\t\t";
code ~= "version(LittleEndian) {\n\t\t"; foreach (immutable i; 0 .. currentBits / 8) code ~= "\tv |= (cast(" ~ type ~ ") _payload[" ~ text(byteOffset + i) ~ "]) << (" ~ text((currentBits / 8) - i - 1) ~ " * 8);\n\t\t"; code ~= "} else static assert(0);\n\t\t"; code ~= "return v;"; } code ~= "\n"; code ~= "\t}\n\t";
// Setter: code ~= "@property void " ~ currentName ~ "(in " ~ type ~ " value) pure nothrow @safe {\n"; code ~= "\t\t"; if (currentBits < 8) { auto mask = (1 << currentBits) - 1; mask <<= 7 - bitOffset - currentBits + 1; code ~= format("_payload[%d] &= ~0b%08b;\n\t\t", byteOffset, mask); code ~= "assert(value < " ~ text(1 << currentBits) ~ ");\n\t\t"; code~=format("_payload[%d] |= cast(ubyte) value << %d;", byteOffset, 7 - bitOffset - currentBits + 1); } else { assert(currentBits % 8 == 0); assert(bitOffset == 0);
code ~= "version(LittleEndian) {\n\t\t"; foreach (immutable i; 0 .. currentBits / 8) code ~= "\t_payload[" ~ text(byteOffset + i) ~ "] = (value >> (" ~ text((currentBits / 8) - i - 1) ~ " * 8) & 0xff);\n\t\t"; code ~= "} else static assert(0);"; }
code ~= "\n"; code ~= "\t}\n"; totalBits += currentBits; }
currentBits = 0; currentName = null; }
enum C : char { pipe='|', cross='+' } enum cWidth = 3; // Width of a bit cell in the table. immutable diagram = rawDiagram.strip;
size_t bitCountPerRow = 0, currentBits; uint anonCount = 0, totalBits; string currentName; string code = "struct {\n"; // Anonymous.
foreach (line; diagram.splitLines) { assert(!line.empty); line = line.strip; if (line[0] == C.cross) { commitCurrent(anonCount, totalBits, currentBits, code, currentName); if (bitCountPerRow == 0) bitCountPerRow = (line.length - 1) / cWidth; else assert(bitCountPerRow == (line.length - 1) / cWidth); } else { // A field of some sort. while (line.length > 2) { assert(line[0] != '/', "Variable length data not supported"); assert(line[0] == C.pipe, "Malformed table"); line.popFront; const idx = line[0 .. $ - 1].indexOf(C.pipe); if (idx != -1) { const field = line[0 .. idx]; line = line[idx .. $];
commitCurrent(anonCount, totalBits, currentBits, code, currentName); currentName = field; currentBits = (field.length + 1) / cWidth; commitCurrent(anonCount, totalBits, currentBits, code, currentName); } else { // The full row or a continuation of the last. currentName ~= line[0 .. $ - 1]; // At this point, line does not include the first // C.pipe, but the length will include the last. currentBits += line.length / cWidth;
line = line[$ .. $]; } } } }
// Using bytes to avoid endianness issues. // hopefully the compiler will optimize it, otherwise // maybe we could specialize the properties more. code ~= "\n\tprivate ubyte[" ~ text((totalBits + 7) / 8) ~ "] _payload;\n";
return code ~ "}";
}
void main() { // Testing.
import std.stdio;
enum diagram = " +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+";
// To debug the code generation: //pragma(msg, diagram.makeStructFromDiagram);
// Usage. static struct Header { mixin(diagram.makeStructFromDiagram); }
Header h; h.ID = 10; h.RA = true; h.ARCOUNT = 255; h.Opcode = 7;
// See the byte representation to test the setter's details. h._payload.writeln;
// Test the getters: assert(h.ID == 10); assert(h.RA == true); assert(h.ARCOUNT == 255); assert(h.Opcode == 7);
}</lang>
- Output:
[0, 10, 56, 128, 0, 0, 0, 0, 0, 0, 0, 255]
Static support for BigEndian is easy to add.
It also supports larger values like this, that is 32 bits long:
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ThirtyTwo | | | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Go
<lang go>package main
import (
"fmt" "log" "math/big" "strings"
)
type result struct {
name string size int start int end int
}
func (r result) String() string {
return fmt.Sprintf("%-7s %2d %3d %3d", r.name, r.size, r.start, r.end)
}
func validate(diagram string) []string {
var lines []string for _, line := range strings.Split(diagram, "\n") { line = strings.Trim(line, " \t") if line != "" { lines = append(lines, line) } } if len(lines) == 0 { log.Fatal("diagram has no non-empty lines!") } width := len(lines[0]) cols := (width - 1) / 3 if cols != 8 && cols != 16 && cols != 32 && cols != 64 { log.Fatal("number of columns should be 8, 16, 32 or 64") } if len(lines)%2 == 0 { log.Fatal("number of non-empty lines should be odd") } if lines[0] != strings.Repeat("+--", cols)+"+" { log.Fatal("incorrect header line") } for i, line := range lines { if i == 0 { continue } else if i%2 == 0 { if line != lines[0] { log.Fatal("incorrect separator line") } } else if len(line) != width { log.Fatal("inconsistent line widths") } else if line[0] != '|' || line[width-1] != '|' { log.Fatal("non-separator lines must begin and end with '|'") } } return lines
}
func decode(lines []string) []result {
fmt.Println("Name Bits Start End") fmt.Println("======= ==== ===== ===") start := 0 width := len(lines[0]) var results []result for i, line := range lines { if i%2 == 0 { continue } line := line[1 : width-1] for _, name := range strings.Split(line, "|") { size := (len(name) + 1) / 3 name = strings.TrimSpace(name) res := result{name, size, start, start + size - 1} results = append(results, res) fmt.Println(res) start += size } } return results
}
func unpack(results []result, hex string) {
fmt.Println("\nTest string in hex:") fmt.Println(hex) fmt.Println("\nTest string in binary:") bin := hex2bin(hex) fmt.Println(bin) fmt.Println("\nUnpacked:\n") fmt.Println("Name Size Bit pattern") fmt.Println("======= ==== ================") for _, res := range results { fmt.Printf("%-7s %2d %s\n", res.name, res.size, bin[res.start:res.end+1]) }
}
func hex2bin(hex string) string {
z := new(big.Int) z.SetString(hex, 16) return fmt.Sprintf("%0*b", 4*len(hex), z)
}
func main() {
const diagram = ` +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ ` lines := validate(diagram) fmt.Println("Diagram after trimming whitespace and removal of blank lines:\n") for _, line := range lines { fmt.Println(line) } fmt.Println("\nDecoded:\n") results := decode(lines) hex := "78477bbf5496e12e1bf169a4" // test string unpack(results, hex)
}</lang>
- Output:
Diagram after trimming whitespace and removal of blank lines: +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ Decoded: Name Bits Start End ======= ==== ===== === ID 16 0 15 QR 1 16 16 Opcode 4 17 20 AA 1 21 21 TC 1 22 22 RD 1 23 23 RA 1 24 24 Z 3 25 27 RCODE 4 28 31 QDCOUNT 16 32 47 ANCOUNT 16 48 63 NSCOUNT 16 64 79 ARCOUNT 16 80 95 Test string in hex: 78477bbf5496e12e1bf169a4 Test string in binary: 011110000100011101111011101111110101010010010110111000010010111000011011111100010110100110100100 Unpacked: Name Size Bit pattern ======= ==== ================ ID 16 0111100001000111 QR 1 0 Opcode 4 1111 AA 1 0 TC 1 1 RD 1 1 RA 1 1 Z 3 011 RCODE 4 1111 QDCOUNT 16 0101010010010110 ANCOUNT 16 1110000100101110 NSCOUNT 16 0001101111110001 ARCOUNT 16 0110100110100100
J
<lang J>require'strings'
soul=: -. {. normalize=: [:soul' ',dltb;._2
mask=: 0: _1} '+' = {. partition=: '|' = mask #"1 soul labels=: ;@(([: <@}: <@dltb;._1)"1~ '|'&=)@soul names=: ;:^:(0 = L.)
unpacker=:1 :0
p=. , partition normalize m p #.;.1 (8#2) ,@:#: ]
)
packer=:1 :0
w=. -#;.1 ,partition normalize m _8 (#.\ ;) w ({. #:)&.> ]
)
getter=:1 :0
nm=. labels normalize m (nm i. names@[) { ]
)
setter=:1 :0
q=. ' n=. q,~q,;:inv labels normalize m 1 :('(',n,' i.&names m)}')
)
starter=:1 :0
0"0 labels normalize m
)</lang>
Sample definition (note the deliberate introduction of extraneous whitespace in locations the task requires us to ignore it.
<lang j>sample=: 0 :0
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
)
unpack=: sample unpacker pack=: sample packer get=: sample getter set=: sample setter start=: sample starter</lang>
Example data for sample definition:
<lang J>
4095 13 5 6144 4096 'ID Opcode RCODE ARCOUNT QDCOUNT' set start
4095 0 13 0 0 0 0 0 5 4096 0 0 6144
pack 4095 13 5 6144 4096 'ID Opcode RCODE ARCOUNT QDCOUNT' set start
15 255 104 5 16 0 0 0 0 0 24 0
unpack 0 10 56 128 0 0 0 0 0 0 0 255
10 0 7 0 0 0 1 0 0 0 0 0 255
'Opcode' get unpack 0 10 56 128 0 0 0 0 0 0 0 255
7</lang>
In other words:
- unpack converts an octet sequence to the corresponding numeric sequence
- pack converts a numeric sequence to the corresponding octet sequence
- get extracts named elements from the numeric sequence
- set updates named elements in the numeric sequence
- start represents the default "all zeros" sequence which may be used to derive other sequences
Note that this implementation assumes that the ascii diagram represents the native word width on a single line, and assumes well formed data.
Java
Separate methods to validate, display, decode ASCII art, and decode hex value.
<lang Java> import java.math.BigInteger; import java.util.ArrayList; import java.util.LinkedHashMap; import java.util.List; import java.util.Map;
public class AsciiArtDiagramConverter {
private static final String TEST = "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+\r\n" + "| ID |\r\n" + "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+\r\n" + "|QR| Opcode |AA|TC|RD|RA| Z | RCODE |\r\n" + "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+\r\n" + "| QDCOUNT |\r\n" + "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+\r\n" + "| ANCOUNT |\r\n" + "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+\r\n" + "| NSCOUNT |\r\n" + "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+\r\n" + "| ARCOUNT |\r\n" + "+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+";
public static void main(String[] args) { validate(TEST); display(TEST); Map<String,List<Integer>> asciiMap = decode(TEST); displayMap(asciiMap); displayCode(asciiMap, "78477bbf5496e12e1bf169a4"); }
private static void displayCode(Map<String,List<Integer>> asciiMap, String hex) { System.out.printf("%nTest string in hex:%n%s%n%n", hex);
String bin = new BigInteger(hex,16).toString(2);
// Zero pad in front as needed int length = 0; for ( String code : asciiMap.keySet() ) { List<Integer> pos = asciiMap.get(code); length += pos.get(1) - pos.get(0) + 1; } while ( length > bin.length() ) { bin = "0" + bin; } System.out.printf("Test string in binary:%n%s%n%n", bin);
System.out.printf("Name Size Bit Pattern%n"); System.out.printf("-------- ----- -----------%n"); for ( String code : asciiMap.keySet() ) { List<Integer> pos = asciiMap.get(code); int start = pos.get(0); int end = pos.get(1); System.out.printf("%-8s %2d %s%n", code, end-start+1, bin.substring(start, end+1)); }
}
private static void display(String ascii) { System.out.printf("%nDiagram:%n%n"); for ( String s : TEST.split("\\r\\n") ) { System.out.println(s); } }
private static void displayMap(Map<String,List<Integer>> asciiMap) { System.out.printf("%nDecode:%n%n");
System.out.printf("Name Size Start End%n"); System.out.printf("-------- ----- ----- -----%n"); for ( String code : asciiMap.keySet() ) { List<Integer> pos = asciiMap.get(code); System.out.printf("%-8s %2d %2d %2d%n", code, pos.get(1)-pos.get(0)+1, pos.get(0), pos.get(1)); }
}
private static Map<String,List<Integer>> decode(String ascii) { Map<String,List<Integer>> map = new LinkedHashMap<>(); String[] split = TEST.split("\\r\\n"); int size = split[0].indexOf("+", 1) - split[0].indexOf("+"); int length = split[0].length() - 1; for ( int i = 1 ; i < split.length ; i += 2 ) { int barIndex = 1; String test = split[i]; int next; while ( barIndex < length && (next = test.indexOf("|", barIndex)) > 0 ) { // List is start and end of code. List<Integer> startEnd = new ArrayList<>(); startEnd.add((barIndex/size) + (i/2)*(length/size)); startEnd.add(((next-1)/size) + (i/2)*(length/size)); String code = test.substring(barIndex, next).replace(" ", ""); map.put(code, startEnd); // Next bar barIndex = next + 1; } }
return map; }
private static void validate(String ascii) { String[] split = TEST.split("\\r\\n"); if ( split.length % 2 != 1 ) { throw new RuntimeException("ERROR 1: Invalid number of input lines. Line count = " + split.length); } int size = 0; for ( int i = 0 ; i < split.length ; i++ ) { String test = split[i]; if ( i % 2 == 0 ) { // Start with +, an equal number of -, end with + if ( ! test.matches("^\\+([-]+\\+)+$") ) { throw new RuntimeException("ERROR 2: Improper line format. Line = " + test); } if ( size == 0 ) { int firstPlus = test.indexOf("+"); int secondPlus = test.indexOf("+", 1); size = secondPlus - firstPlus; } if ( ((test.length()-1) % size) != 0 ) { throw new RuntimeException("ERROR 3: Improper line format. Line = " + test); } // Equally spaced splits of +, - for ( int j = 0 ; j < test.length()-1 ; j += size ) { if ( test.charAt(j) != '+' ) { throw new RuntimeException("ERROR 4: Improper line format. Line = " + test); } for ( int k = j+1 ; k < j + size ; k++ ) { if ( test.charAt(k) != '-' ) { throw new RuntimeException("ERROR 5: Improper line format. Line = " + test); } } } } else { // Vertical bar, followed by optional spaces, followed by name, followed by optional spaces, followed by vdrtical bar if ( ! test.matches("^\\|(\\s*[A-Za-z]+\\s*\\|)+$") ) { throw new RuntimeException("ERROR 6: Improper line format. Line = " + test); } for ( int j = 0 ; j < test.length()-1 ; j += size ) { for ( int k = j+1 ; k < j + size ; k++ ) { // Vertical bar only at boundaries if ( test.charAt(k) == '|' ) { throw new RuntimeException("ERROR 7: Improper line format. Line = " + test); } } }
} } }
} </lang>
- Output:
Diagram: +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ Decode: Name Size Start End -------- ----- ----- ----- ID 16 0 15 QR 1 16 16 Opcode 4 17 20 AA 1 21 21 TC 1 22 22 RD 1 23 23 RA 1 24 24 Z 3 25 27 RCODE 4 28 31 QDCOUNT 16 32 47 ANCOUNT 16 48 63 NSCOUNT 16 64 79 ARCOUNT 16 80 95 Test string in hex: 78477bbf5496e12e1bf169a4 Test string in binary: 011110000100011101111011101111110101010010010110111000010010111000011011111100010110100110100100 Name Size Bit Pattern -------- ----- ----------- ID 16 0111100001000111 QR 1 0 Opcode 4 1111 AA 1 0 TC 1 1 RD 1 1 RA 1 1 Z 3 011 RCODE 4 1111 QDCOUNT 16 0101010010010110 ANCOUNT 16 1110000100101110 NSCOUNT 16 0001101111110001 ARCOUNT 16 0110100110100100
JavaScript
<lang javascript>// ------------------------------------------------------------[ Boilerplate ]-- const trimWhitespace = s => s.trim(); const isNotEmpty = s => s !== ; const stringLength = s => s.length; const hexToBin4 = s => parseInt(s, 16).toString(2).padStart(4, '0'); const concatHexToBin = (binStr, hexStr) => binStr.concat(, hexToBin4(hexStr)); const alignRight = n => s => `${s}`.padStart(n, ' '); const alignLeft = n => s => `${s}`.padEnd(n, ' '); const repeatChar = c => n => c.padStart(n, c); const joinWith = c => arr => arr.join(c); const joinNl = joinWith('\n'); const joinSp = joinWith(' ');
const printDiagramInfo = map => {
const pName = alignLeft(8); const p5 = alignRight(5); const line = repeatChar('-'); const res = []; res.push(joinSp([pName('Name'), p5('Size'), p5('Start'), p5('End')])); res.push(joinSp([line(8), line(5), line(5), line(5)])); [...map.values()].forEach(({label, bitLength, start, end}) => { res.push(joinSp([pName(label), p5(bitLength), p5(start), p5(end)])); }) return res;
}
// -------------------------------------------------------------------[ Main ]-- const parseDiagram = dia => {
const arr = dia.split('\n').map(trimWhitespace).filter(isNotEmpty);
const hLine = arr[0]; const bitTokens = hLine.split('+').map(trimWhitespace).filter(isNotEmpty); const bitWidth = bitTokens.length; const bitTokenWidth = bitTokens[0].length;
const fields = arr.filter(e => e !== hLine); const allFields = fields.reduce((p, c) => [...p, ...c.split('|')], []) .filter(isNotEmpty);
const lookupMap = Array(bitWidth).fill().reduce((p, c, i) => { const v = i + 1; const stringWidth = (v * bitTokenWidth) + (v - 1); p.set(stringWidth, v); return p; }, new Map())
const fieldMetaMap = allFields.reduce((p, e, i) => { const bitLength = lookupMap.get(e.length); const label = trimWhitespace(e); const start = i ? p.get(i - 1).end + 1 : 0; const end = start - 1 + bitLength; p.set(i, {label, bitLength, start, end}) return p; }, new Map());
const pName = alignLeft(8); const pBit = alignRight(5); const pPat = alignRight(18); const line = repeatChar('-'); const nl = '\n'; return hexStr => { const binString = [...hexStr].reduce(concatHexToBin, );
const res = printDiagramInfo(fieldMetaMap); res.unshift(joinNl(['Diagram:', ...arr, nl])); res.push(joinNl([nl, 'Test string in hex:', hexStr])); res.push(joinNl(['Test string in binary:', binString, nl])); res.push(joinSp([pName('Name'), pBit('Size'), pPat('Pattern')])); res.push(joinSp([line(8), line(5), line(18)]));
[...fieldMetaMap.values()].forEach(({label, bitLength, start, end}) => { res.push(joinSp( [pName(label), pBit(bitLength), pPat(binString.substr(start, bitLength))])) }) return joinNl(res); }
}
// --------------------------------------------------------------[ Run tests ]--
const dia = ` +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ `;
const parser = parseDiagram(dia);
parser('78477bbf5496e12e1bf169a4');</lang>
- Output:
Diagram: +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ Name Size Start End -------- ----- ----- ----- ID 16 0 15 QR 1 16 16 Opcode 4 17 20 AA 1 21 21 TC 1 22 22 RD 1 23 23 RA 1 24 24 Z 3 25 27 RCODE 4 28 31 QDCOUNT 16 32 47 ANCOUNT 16 48 63 NSCOUNT 16 64 79 ARCOUNT 16 80 95 Test string in hex: 78477bbf5496e12e1bf169a4 Test string in binary: 011110000100011101111011101111110101010010010110111000010010111000011011111100010110100110100100 Name Size Pattern -------- ----- ------------------ ID 16 0111100001000111 QR 1 0 Opcode 4 1111 AA 1 0 TC 1 1 RD 1 1 RA 1 1 Z 3 011 RCODE 4 1111 QDCOUNT 16 0101010010010110 ANCOUNT 16 1110000100101110 NSCOUNT 16 0001101111110001 ARCOUNT 16 0110100110100100
Julia
The validator() function can be customized. The one used only checks length. <lang julia>diagram = """
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+"""
testhexdata = "78477bbf5496e12e1bf169a4"
struct BitField
name::String bits::Int fieldstart::Int fieldend::Int
end
function diagramtostruct(txt)
bitfields = Vector{BitField}() lines = map(strip, split(txt, "\n")) for row in 1:2:length(lines)-1 nbits = sum(x -> x == '+', lines[row]) - 1 fieldpos = findall(x -> x == '|', lines[row + 1]) bitaccum = div(row, 2) * nbits for (i, field) in enumerate(fieldpos[1:end-1]) endfield = fieldpos[i + 1] bitsize = div(endfield - field, 3) bitlabel = strip(lines[row + 1][field+1:endfield-1]) bitstart = div(field - 1, 3) + bitaccum bitend = bitstart + bitsize - 1 push!(bitfields, BitField(bitlabel, bitsize, bitstart, bitend)) end end bitfields
end
binbyte(c) = string(parse(UInt8, c, base=16), base=2, pad=8) hextobinary(s) = reduce(*, map(binbyte, map(x -> s[x:x+1], 1:2:length(s)-1))) validator(binstring, fields) = length(binstring) == sum(x -> x.bits, fields)
function bitreader(bitfields, hexdata)
println("\nEvaluation of hex data $hexdata as bitfields:") println("Name Size Bits\n------- ---- ----------------") b = hextobinary(hexdata) @assert(validator(b, bitfields)) for bf in bitfields pat = b[bf.fieldstart+1:bf.fieldend+1] println(rpad(bf.name, 9), rpad(bf.bits, 6), lpad(pat, 16)) end
end
const decoded = diagramtostruct(diagram)
println("Diagram as bit fields:\nName Bits Start End\n------ ---- ----- ---") for bf in decoded
println(rpad(bf.name, 8), rpad(bf.bits, 6), rpad(bf.fieldstart, 6), lpad(bf.fieldend, 4))
end
bitreader(decoded, testhexdata)
</lang>
- Output:
Diagram as bit fields: Name Bits Start End ------ ---- ----- --- ID 16 0 15 QR 1 16 16 Opcode 4 17 20 AA 1 21 21 TC 1 22 22 RD 1 23 23 RA 1 24 24 Z 3 25 27 RCODE 4 28 31 QDCOUNT 16 32 47 ANCOUNT 16 48 63 NSCOUNT 16 64 79 ARCOUNT 16 80 95 Evaluation of hex data 78477bbf5496e12e1bf169a4 as bitfields: Name Size Bits ------- ---- ---------------- ID 16 0111100001000111 QR 1 0 Opcode 4 1111 AA 1 0 TC 1 1 RD 1 1 RA 1 1 Z 3 011 RCODE 4 1111 QDCOUNT 16 0101010010010110 ANCOUNT 16 1110000100101110 NSCOUNT 16 0001101111110001 ARCOUNT 16 0110100110100100
Lua
Provided mainly to illustrate the string-parsing aspect, not necessarily the bit-structure aspect... <lang lua>local function validate(diagram)
local lines = {} for s in diagram:gmatch("[^\r\n]+") do s = s:match("^%s*(.-)%s*$") if s~="" then lines[#lines+1]=s end end -- "a little of validation".."for brevity" assert(#lines>0, "FAIL: no non-empty lines") assert(#lines%2==1, "FAIL: even number of lines") return lines
end
local function parse(lines)
local schema, offset = {}, 0 for i = 2,#lines,2 do for part in lines[i]:gmatch("\|([^\|]+)") do schema[#schema+1] = { name=part:match("^%s*(.-)%s*$"), numbits=(#part+1)/3, offset=offset } offset = offset + (#part+1)/3 end end return schema
end
local diagram = [[
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
]] -- extra whitespace added for testing
local schema = parse(validate(diagram)) print("NAME NUMBITS OFFSET") print("-------- -------- --------") for i = 1,#schema do
local item = schema[i] print(string.format("%-8s %8d %8d", item.name, item.numbits, item.offset))
end</lang>
- Output:
NAME NUMBITS OFFSET -------- -------- -------- ID 16 0 QR 1 16 Opcode 4 17 AA 1 21 TC 1 22 RD 1 23 RA 1 24 Z 3 25 RCODE 4 28 QDCOUNT 16 32 ANCOUNT 16 48 NSCOUNT 16 64 ARCOUNT 16 80
Nim
The program is composed of three parts.
In the first part, a parser takes a diagram (string composed of lines) and produce a raw structure which describes the fields. The parser may be executed at compile time (if the input string is a constant) or at runtime. It performs a full validation of the structure, detecting syntax errors and structure errors.
The second part of the module produces a type declaration from the raw structure. This operation is done at compile time by calling a macro which constructs an abstract syntax tree to represent the structure. Nim describes bit fields in a way not very different of the C way by specifying the field length in a pragma, for instance “{.bitsize: 5.}.
After the type declaration has been produced, it is possible to declare variables and work with them as if the structure had been explicitly described using Nim syntax rather than using ASCII-art diagram.
The third part of the module produces a description at runtime. As Nim is statically typed, it is not possible to produce a new type and declare variables of this type. So, starting from the raw structure built by the parser, we produce a structure containing a storage area and a table of field positions and we provide two procedures to get and set a field value. These procedures uses masks and logical operations to read and write the values.
So, the behavior when using structures built at compile time and structure built at runtime is different. For a variable “s”, reading the content of field “f” is done using the normal syntax “s.f” in the first case and using “s.get("f")” in the second case.
Of course, the second mechanism may be used for all cases. The first mechanism is mainly interesting to show how it is possible, using Nim powerful macro system, to create a type ex nihilo.
<lang Nim>import macros import strutils import tables
const Diagram = """
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+"""
- Exceptions.
type
# Exceptions. SyntaxError = object of CatchableError StructureError = object of CatchableError FieldError = object of CatchableError
- ---------------------------------------------------------------------------------------------------
proc raiseException(exc: typedesc; linenum: int; message: string) =
## Raise an exception with a message including the line number. raise newException(exc, "Line $1: $2".format(linenum, message))
- Parser.
type
# Allowed tokens. Token = enum tkSpace, tkPlus, tkMinus2, tkVLine, tkIdent, tkEnd, tkError
# Lexer description. Lexer = object line: string # Line to parse. linenum: int # Line number. pos: int # Current position. token: Token # Current token. value: string # Associated value (for tkIdent).
# Description of a field. Field = tuple[name: string, length: int]
# Description of fields in a row. RowFields = seq[Field]
# Structure to describe fields. RawStructure = object size: int # Size of a row in bits. rows: seq[RowFields] # List of rows.
- ---------------------------------------------------------------------------------------------------
proc getNextToken(lexer: var Lexer) =
## Search next toke/* Nim */ n and update lexer state accordingly.
doAssert(lexer.pos < lexer.line.high)
inc lexer.pos let ch = lexer.line[lexer.pos] case ch
of ' ': lexer.token = tkSpace
of '+': lexer.token = tkPlus
of '-': inc lexer.pos lexer.token = if lexer.line[lexer.pos] == '-': tkMinus2 else: tkError
of '|': lexer.token = tkVLine
of Letters: # Beginning of an identifier. lexer.value = $ch inc lexer.pos while lexer.pos < lexer.line.high and lexer.line[lexer.pos] in IdentChars: lexer.value.add(lexer.line[lexer.pos]) inc lexer.pos dec lexer.pos lexer.token = tkIdent
of '\n': # End of the line. lexer.token = tkEnd
else: lexer.token = tkError
- ---------------------------------------------------------------------------------------------------
proc initLexer(line: string; linenum: int): Lexer =
## Initialize a lexer.
result.line = line & '\n' # Add a sentinel. result.linenum = linenum result.pos = -1
- ---------------------------------------------------------------------------------------------------
proc parseSepLine(lexer: var Lexer): int =
## Parse a separation line. Return the corresponding size in bits.
lexer.getNextToken() while lexer.token != tkEnd: if lexer.token != tkMinus2: raiseException(SyntaxError, lexer.linenum, "“--” expected") lexer.getNextToken() if lexer.token != tkPlus: raiseException(SyntaxError, lexer.linenum, "“+” expected") inc result lexer.getNextToken()
- ---------------------------------------------------------------------------------------------------
proc parseFieldLine(lexer: var Lexer; structure: var RawStructure) =
## Parse a field description line and update the structure accordingly.
var rowFields: RowFields # List of fields. var prevpos = 0 # Previous position. var size = 0 # Total size.
lexer.getNextToken() while lexer.token != tkEnd:
# Parse a field. while lexer.token == tkSpace: lexer.getNextToken() if lexer.token != tkIdent: raiseException(SyntaxError, lexer.linenum, "Identifier expected") let id = lexer.value lexer.getNextToken() while lexer.token == tkSpace: lexer.getNextToken() if lexer.token != tkVLine: raiseException(SyntaxError, lexer.linenum, "“|” expected") if lexer.pos mod 3 != 0: raiseException(SyntaxError, lexer.linenum, "wrong position for “|”")
# Build a field description. let fieldLength = (lexer.pos - prevpos) div 3 rowFields.add((id, fieldLength)) inc size, fieldLength prevpos = lexer.pos lexer.getNextToken()
# Add the row fields description to the structure. if size != structure.size: raiseException(StructureError, lexer.linenum, "total size of fields doesn’t fit") structure.rows.add(rowFields)
- ---------------------------------------------------------------------------------------------------
proc parseLine(line: string; linenum: Positive; structure: var RawStructure) =
## Parse a line.
# Eliminate spaces at beginning and at end, and ignore empty lines. let line = line.strip() if line.len == 0: return
var lexer = initLexer(line, linenum) lexer.getNextToken()
if lexer.token == tkPlus: # Separator line. let size = parseSepLine(lexer) if size notin {8, 16, 32, 64}: raiseException(StructureError, linenum, "wrong structure size; got $1, expected 8, 16, 32 or 64".format(size)) if structure.size > 0: # Not the first separation line. if size != structure.size: raiseException(StructureError, linenum, "inconsistent size; got $1, expected $2".format(size, structure.size)) else: structure.size = size
elif lexer.token == tkVLine: # Fields description line. parseFieldLine(lexer, structure)
else: raiseException(SyntaxError, linenum, "“+” or “|” expected")
- ---------------------------------------------------------------------------------------------------
proc parse(diagram: string): RawStructure =
## Parse a diagram describing a structure.
var linenum = 0 for line in diagram.splitLines(): inc linenum parseLine(line, linenum, result)
- Generation of a structure type at compile time.
- Access to fields is done directly without getter or setter.
macro createStructType*(diagram, typeName: static string): untyped =
## Create a type from "diagram" whose name is given by "typeName".
# C types to use as units. const Ctypes = {8: "cuchar", 16: "cushort", 32: "cuint", 64: "culong"}.toTable
# Check that the type name is a valid identifier. if not typeName.validIdentifier(): error("Invalid type name: " & typeName) return
# Parse the diagram. var struct: RawStructure try: struct = parse(diagram) except SyntaxError, StructureError: error(getCurrentExceptionMsg()) return
# Build the beginning: "type <typeName> = object". # For now, the list of fields is empty. let ctype = Ctypes[struct.size] let recList = newNimNode(nnkRecList) result = nnkStmtList.newTree( nnkTypeSection.newTree( nnkTypeDef.newTree( ident(typeName), newEmptyNode(), nnkObjectTy.newTree( newEmptyNode(), newEmptyNode(), recList))))
# Add the fields. for row in struct.rows: if row.len == 1: # Single field in a unit. No need to specify the length. recList.add(newIdentDefs( nnkPostfix.newTree( ident("*"), ident(row[0].name)), ident(ctype))) else: # Several fields. Use pragma "bitsize". for field in row: let fieldNode = nnkPragmaExpr.newTree( nnkPostfix.newTree( ident("*"), ident(field.name)), nnkPragma.newTree( nnkExprColonExpr.newTree( ident("bitsize"), newIntLitNode(field.length)))) recList.add(newIdentDefs(fieldNode, ident(ctype)))
- Generation of a structure at runtime.
- Access to fields must be done via a specific getter or setter.
type
# Unit to use. Unit = enum unit8, unit16, unit32, unit64
# Position of a field in a unit. FieldPosition = tuple[row, start, length: int]
# Description of the structure. Structure* = object names: seq[string] # Original names. positions: Table[string, FieldPosition] # Mapping name (in lower case) => Position. # Storage. case unit: Unit: of unit8: s8: seq[uint8] of unit16: s16: seq[uint16] of unit32: s32: seq[uint32] of unit64: s64: seq[uint64]
- ---------------------------------------------------------------------------------------------------
proc createStructVar*(diagram: string): Structure =
## Create a variable for the structure described by "diagram".
var rawStruct = parse(diagram)
# Allocate the storage for the structure. case rawStruct.size of 8: result = Structure(unit: unit8) result.s8.setLen(rawStruct.rows.len) of 16: result = Structure(unit: unit16) result.s16.setLen(rawStruct.rows.len) of 32: result = Structure(unit: unit32) result.s32.setLen(rawStruct.rows.len) of 64: result = Structure(unit: unit64) result.s64.setLen(rawStruct.rows.len) else: raise newException(ValueError, "Internal error")
# Build the table mapping field names to positions. for i, row in rawStruct.rows: var offset = 0 for field in row: result.names.add(field.name) result.positions[field.name.toLower] = (row: i, start: offset, length: field.length) inc offset, field.length
- ---------------------------------------------------------------------------------------------------
proc get*(struct: Structure; fieldName: string): uint64 =
## Return the value of field "fieldName" in a structure. ## The value type is "uint64" and should be converted to another type if needed.
# Get the position of the field. var row, start, length: int try: (row, start, length) = struct.positions[fieldName.toLower] except KeyError: raise newException(FieldError, "Invalid field: " & fieldName)
let mask = 1 shl length - 1 let endpos = start + length - 1
case struct.unit of unit8: result = (struct.s8[row] and mask.uint8 shl (7 - endpos)) shr (7 - endpos) of unit16: result = (struct.s16[row] and mask.uint16 shl (15 - endpos)) shr (15 - endpos) of unit32: result = (struct.s32[row] and mask.uint32 shl (31 - endpos)) shr (31 - endpos) of unit64: result = (struct.s64[row] and mask.uint64 shl (63 - endpos)) shr (63 - endpos)
- ---------------------------------------------------------------------------------------------------
proc set*(struct: var Structure; fieldName: string; value: SomeInteger) =
## Set the value of the field "fieldName" in a structure.
# Get the position of the field. var row, start, length: int try: (row, start, length) = struct.positions[fieldName.toLower] except KeyError: raise newException(FieldError, "Invalid field: " & fieldName)
let mask = 1 shl length - 1 let endpos = start + length - 1 let value = value and mask # Make sure that the value fits in the field.
case struct.unit of unit8: struct.s8[row] = struct.s8[row] and not (mask.uint8 shl (7 - endpos)) or (value.uint8 shl (7 - endpos)) of unit16: struct.s16[row] = struct.s16[row] and not (mask.uint16 shl (15 - endpos)) or (value.uint16 shl (15 - endpos)) of unit32: struct.s32[row] = struct.s32[row] and not (mask.uint32 shl (31 - endpos)) or (value.uint32 shl (31 - endpos)) of unit64: struct.s64[row] = struct.s64[row] and not (mask.uint64 shl (63 - endpos)) or (value.uint64 shl (63 - endpos))
- ---------------------------------------------------------------------------------------------------
iterator fields*(struct: Structure): uint64 =
## Yield the values of the successive fields of a structure
for name in struct.positions.keys: yield struct.get(name)
- ---------------------------------------------------------------------------------------------------
iterator fieldPairs*(struct: Structure): tuple[key: string, val: uint64] =
## Yield names and values of the successive fields of a structure
for name in struct.names: yield (name, struct.get(name))
- ---------------------------------------------------------------------------------------------------
proc `$`*(struct: Structure): string =
## Produce a representation of a structure.
result = "(" for name in struct.names: result.addSep(", ", 1) result.add(name & ": " & $struct.get(name)) result.add(')')
- ---------------------------------------------------------------------------------------------------
proc toHex(struct: Structure): string =
## Return the hexadecimal representation of a structure.
case struct.unit of unit8: for row in struct.s8: result.add(row.toHex(2)) of unit16: for row in struct.s16: result.add(row.toHex(4)) of unit32: for row in struct.s32: result.add(row.tohex(8)) of unit64: for row in struct.s64: result.add(row.toHex(16))
- ———————————————————————————————————————————————————————————————————————————————————————————————————
when isMainModule:
# Creation of a structure at compile time. # ----------------------------------------
# Create the type "Header" to represent the structure described by "Diagram". createStructType(Diagram, "Header")
# Declare a variable of type Header and initialize its fields. var header1 = Header(ID: 30791, QR: 0, Opcode: 15, AA: 0, TC: 1, RD: 1, RA: 1, Z: 3, RCODE:15, QDCOUNT: 21654, ANCOUNT: 57646, NSCOUNT: 7153, ARCOUNT: 27044) echo "Header from a structure defined at compile time:" echo header1 echo ""
# Of course, it is possible to loop on the fields. echo "Same fields/values retrieved with an iterator:" for name, value in header1.fieldPairs: echo name, ": ", value echo ""
# Hexadecimal representation. var h = "" var p = cast[ptr UncheckedArray[typeof(header1.ID)]](addr(header1)) for i in 0..<(sizeof(header1) div sizeof(typeof(header1.ID))): h.add(p[i].toHex(4)) echo "Hexadecimal representation: ", h echo ""
# Creation of a structure at runtime. # -----------------------------------
# Declare a variable initalized with the structure created at runtime. var header2 = createStructVar(Diagram)
header2.set("ID", 30791) header2.set("QR", 0) header2.set("Opcode", 15) header2.set("AA", 0) header2.set("TC", 1) header2.set("RD", 1) header2.set("RA", 1) header2.set("Z", 3) header2.set("RCODE", 15) header2.set("QDCOUNT", 21654) header2.set("ANCOUNT", 57646) header2.set("NSCOUNT", 7153) header2.set("ARCOUNT", 27044)
echo "Header from a structure defined at runtime: " echo header2 echo ""
# List fields using the "fieldPairs" iterator. echo "Same fields/values retrieved with an iterator:" for name, val in header2.fieldPairs(): echo name, ": ", val echo ""
# Hexadecimal representation. echo "Hexadecimal representation: ", header2.toHex()</lang>
- Output:
Header from a structure defined at compile time: (ID: 30791, QR: 0, Opcode: 15, AA: 0, TC: 1, RD: 1, RA: 1, Z: 3, RCODE: 15, QDCOUNT: 21654, ANCOUNT: 57646, NSCOUNT: 7153, ARCOUNT: 27044) Same fields/values retrieved with an iterator: ID: 30791 QR: 0 Opcode: 15 AA: 0 TC: 1 RD: 1 RA: 1 Z: 3 RCODE: 15 QDCOUNT: 21654 ANCOUNT: 57646 NSCOUNT: 7153 ARCOUNT: 27044 Hexadecimal representation: 7847F7DE5496E12E1BF169A4 Header from a structure defined at runtime: (ID: 30791, QR: 0, Opcode: 15, AA: 0, TC: 1, RD: 1, RA: 1, Z: 3, RCODE: 15, QDCOUNT: 21654, ANCOUNT: 57646, NSCOUNT: 7153, ARCOUNT: 27044) Same fields/values retrieved with an iterator: ID: 30791 QR: 0 Opcode: 15 AA: 0 TC: 1 RD: 1 RA: 1 Z: 3 RCODE: 15 QDCOUNT: 21654 ANCOUNT: 57646 NSCOUNT: 7153 ARCOUNT: 27044 Hexadecimal representation: 78477BBF5496E12E1BF169A4
Ol
<lang scheme> (import (owl parse))
(define format " +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+") (define (subA x) (- x #\A -1))
(define whitespace (byte-if (lambda (x) (has? '(#\newline #\return #\+ #\- #\|) x)))) (define maybe-whitespaces (greedy* whitespace))
(define format-parser
(let-parse* ( (key (greedy* (let-parse* ( (* maybe-whitespaces) (sp1 (greedy* (imm #\space))) (name (greedy+ (byte-if (lambda (x) (or (<= #\A x #\Z) (<= #\a x #\z)))))) (sp2 (greedy* (imm #\space)))) (cons (/ (+ (length sp1) (length name) (length sp2) 1) 3) (list->string name))))) (* maybe-whitespaces)) key))
(define table (parse format-parser (str-iter format) #f #f #f)) (unless table
(print "Invalid template. Exiting.") (halt 1))
(print "table structure:" format) (print "is encoded as " table " ")
(define (decode table data)
(let loop ((table (reverse table)) (bits data) (out #null)) (if (null? table) out else (define name (cdar table)) (define width (caar table)) (define val (band bits (- (<< 1 width) 1)))
(loop (cdr table) (>> bits width) (cons (cons name val) out)))))
(define binary-input-data #b011110000100011101111011101111110101010010010110111000010010111000011011111100010110100110100100) (print "decoding input data " binary-input-data)
(define datastructure (decode table binary-input-data))
(print) (print "parsed datastructure:") (for-each (lambda (x)
(print (car x) " == " (cdr x) " (" (number->string (cdr x) 2) ")")) datastructure)
</lang>
- Output:
$ ol ascii_art_diagram_converter.scm table structure: +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ is encoded as ((16 . ID) (1 . QR) (4 . Opcode) (1 . AA) (1 . TC) (1 . RD) (1 . RA) (3 . Z) (4 . RCODE) (16 . QDCOUNT) (16 . ANCOUNT) (16 . NSCOUNT) (16 . ARCOUNT)) decoding input data 37224619292254864697109604772 parsed datastructure: ID == 30791 (111100001000111) QR == 0 (0) Opcode == 15 (1111) AA == 0 (0) TC == 1 (1) RD == 1 (1) RA == 1 (1) Z == 3 (11) RCODE == 15 (1111) QDCOUNT == 21654 (101010010010110) ANCOUNT == 57646 (1110000100101110) NSCOUNT == 7153 (1101111110001) ARCOUNT == 27044 (110100110100100)
Perl
<lang perl>#!/usr/bin/perl
use strict; use warnings;
$_ = <<END;
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
END
my $template; my @names; while( /\| *(\w+) */g )
{ printf "%10s is %2d bits\n", $1, my $length = length($&) / 3; push @names, $1; $template .= "A$length "; }
my $input = '78477bbf5496e12e1bf169a4'; # as hex
my %datastructure; @datastructure{ @names } = unpack $template, unpack 'B*', pack 'H*', $input;
print "\ntemplate = $template\n\n"; use Data::Dump 'dd'; dd 'datastructure', \%datastructure;</lang>
- Output:
ID is 16 bits QR is 1 bits Opcode is 4 bits AA is 1 bits TC is 1 bits RD is 1 bits RA is 1 bits Z is 3 bits RCODE is 4 bits QDCOUNT is 16 bits ANCOUNT is 16 bits NSCOUNT is 16 bits ARCOUNT is 16 bits template = A16 A1 A4 A1 A1 A1 A1 A3 A4 A16 A16 A16 A16 ( "datastructure", { AA => 0, ANCOUNT => 1110000100101110, ARCOUNT => "0110100110100100", ID => "0111100001000111", NSCOUNT => "0001101111110001", Opcode => 1111, QDCOUNT => "0101010010010110", QR => 0, RA => 1, RCODE => 1111, RD => 1, TC => 1, Z => "011", }, )
Phix
Should work on any width, but didn't actually test, or verify width is 8/16/32/64. <lang Phix>function interpret(sequence lines)
if remainder(length(lines),2)!=1 then crash("missing header/footer?") end if string l1 = lines[1] integer w = length(l1) integer bits = (w-1)/3 -- sug: check this is 8/16/32/64 if l1!=join(repeat("+",bits+1),"--") then crash("malformed header?") end if sequence res = {} integer offset = 0 for i=1 to length(lines) do string li = lines[i] if remainder(i,2) then if li!=l1 then crash("missing separator (line %d)?",{i}) end if else if li[1]!='|' or li[w]!='|' then crash("missing separator on line %d",{i}) end if integer k = 1 while true do integer l = find('|',li,k+1) string desc = trim(li[k+1..l-1]) {k,l} = {l,(l-k)/3} res = append(res,{desc,l,offset}) offset += l if k=w then exit end if end while end if end for res = append(res,{"total",0,offset}) return res
end function
procedure unpack(string data, sequence res)
if length(data)*8!=res[$][3] then crash("wrong length") end if string bin = "" for i=1 to length(data) do bin &= sprintf("%08b",data[i]) end for printf(1,"\n\nTest bit string:\n%s\n\nUnpacked:\n",{bin}) for i=1 to length(res)-1 do {string name, integer bits, integer offset} = res[i] printf(1,"%7s, %02d bits: %s\n",{name,bits,bin[offset+1..offset+bits]}) end for
end procedure
function trimskip(string diagram) -- -- split's ",no_empty:=true)" is not quite enough here. -- Note that if copy/paste slips in any tab characters, -- it will most likely trigger a length mismatch error. --
sequence lines = split(diagram,'\n') integer prevlli = 0 for i=length(lines) to 1 by -1 do string li = trim(lines[i]) integer lli = length(li) if lli then if prevlli=0 then prevlli = lli elsif lli!=prevlli then crash("mismatching lengths") end if lines[i] = li else lines[i..i] = {} end if end for return lines
end function
constant diagram = """
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
"""
sequence lines = trimskip(diagram) sequence res = interpret(lines) printf(1,"--Name-- Size Offset\n") for i=1 to length(res) do
printf(1," %-7s %2d %5d\n",res[i])
end for
unpack(x"78477bbf5496e12e1bf169a4",res)</lang>
- Output:
--Name-- Size Offset ID 16 0 QR 1 16 Opcode 4 17 AA 1 21 TC 1 22 RD 1 23 RA 1 24 Z 3 25 RCODE 4 28 QDCOUNT 16 32 ANCOUNT 16 48 NSCOUNT 16 64 ARCOUNT 16 80 total 0 96 Test bit string: 011110000100011101111011101111110101010010010110111000010010111000011011111100010110100110100100 Unpacked: ID, 16 bits: 0111100001000111 QR, 01 bits: 0 Opcode, 04 bits: 1111 AA, 01 bits: 0 TC, 01 bits: 1 RD, 01 bits: 1 RA, 01 bits: 1 Z, 03 bits: 011 RCODE, 04 bits: 1111 QDCOUNT, 16 bits: 0101010010010110 ANCOUNT, 16 bits: 1110000100101110 NSCOUNT, 16 bits: 0001101111110001 ARCOUNT, 16 bits: 0110100110100100
Python
<lang python> """ http://rosettacode.org/wiki/ASCII_art_diagram_converter
Python example based off Go example:
http://rosettacode.org/wiki/ASCII_art_diagram_converter#Go
"""
def validate(diagram):
# trim empty lines rawlines = diagram.splitlines() lines = [] for line in rawlines: if line != : lines.append(line) # validate non-empty lines if len(lines) == 0: print('diagram has no non-empty lines!') return None width = len(lines[0]) cols = (width - 1) // 3 if cols not in [8, 16, 32, 64]: print('number of columns should be 8, 16, 32 or 64') return None if len(lines)%2 == 0: print('number of non-empty lines should be odd') return None if lines[0] != (('+--' * cols)+'+'): print('incorrect header line') return None
for i in range(len(lines)): line=lines[i] if i == 0: continue elif i%2 == 0: if line != lines[0]: print('incorrect separator line') return None elif len(line) != width: print('inconsistent line widths') return None elif line[0] != '|' or line[width-1] != '|': print("non-separator lines must begin and end with '|'") return None return lines
"""
results is list of lists like:
[[name, bits, start, end],...
"""
def decode(lines):
print("Name Bits Start End") print("======= ==== ===== ===") startbit = 0 results = [] for line in lines: infield=False for c in line: if not infield and c == '|': infield = True spaces = 0 name = elif infield: if c == ' ': spaces += 1 elif c != '|': name += c else: bits = (spaces + len(name) + 1) // 3 endbit = startbit + bits - 1 print('{0:7} {1:2d} {2:2d} {3:2d}'.format(name, bits, startbit, endbit)) reslist = [name, bits, startbit, endbit] results.append(reslist) spaces = 0 name = startbit += bits return results
def unpack(results, hex):
print("\nTest string in hex:") print(hex) print("\nTest string in binary:") bin = f'{int(hex, 16):0>{4*len(hex)}b}' print(bin) print("\nUnpacked:\n") print("Name Size Bit pattern") print("======= ==== ================") for r in results: name = r[0] size = r[1] startbit = r[2] endbit = r[3] bitpattern = bin[startbit:endbit+1] print('{0:7} {1:2d} {2:16}'.format(name, size, bitpattern))
diagram = """
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ID |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|QR| Opcode |AA|TC|RD|RA| Z | RCODE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| QDCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ANCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| NSCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ARCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
"""
lines = validate(diagram)
if lines == None:
print("No lines returned")
else:
print(" ") print("Diagram after trimming whitespace and removal of blank lines:") print(" ") for line in lines: print(line) print(" ") print("Decoded:") print(" ")
results = decode(lines) # test string hex = "78477bbf5496e12e1bf169a4" unpack(results, hex)
</lang>
- Output:
Diagram after trimming whitespace and removal of blank lines: +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ Decoded: Name Bits Start End ======= ==== ===== === ID 16 0 15 QR 1 16 16 Opcode 4 17 20 AA 1 21 21 TC 1 22 22 RD 1 23 23 RA 1 24 24 Z 3 25 27 RCODE 4 28 31 QDCOUNT 16 32 47 ANCOUNT 16 48 63 NSCOUNT 16 64 79 ARCOUNT 16 80 95 Test string in hex: 78477bbf5496e12e1bf169a4 Test string in binary: 011110000100011101111011101111110101010010010110111000010010111000011011111100010110100110100100 Unpacked: Name Size Bit pattern ======= ==== ================ ID 16 0111100001000111 QR 1 0 Opcode 4 1111 AA 1 0 TC 1 1 RD 1 1 RA 1 1 Z 3 011 RCODE 4 1111 QDCOUNT 16 0101010010010110 ANCOUNT 16 1110000100101110 NSCOUNT 16 0001101111110001 ARCOUNT 16 0110100110100100
Racket
Three files:
ascii-art-parser.rkt
: provides the functionascii-art->struct
, which converts ASCII art from a string (or input port) to a list of word-number, bit range and idascii-art-reader.rkt
: uses this to provide a sytntaxdefine-ascii-art-structure
which defines a structure using the art worktest-ascci-art-reader.rkt
: gives it all a rigourousish going over
Note that if you want to extend the word width too 32-bits (or more) add multiples of eight bit blocks horizontally (i.e. --+--+--+--+--+--+--+--+
). IMO Having the diagrams 16-bits wide reflects the choice of a 16-bit word as the natural word size of the interface. If it were 32 or 64, the blocks would have to be wider.
ascii-art-parser.rkt
Note that this is in the racket/base
language so it doesn't overburden the modules that import it, especially since they're at the suntax phase.
<lang racket>#lang racket/base
(require (only-in racket/list drop-right)
(only-in racket/string string-trim))
(provide ascii-art->struct)
- reads ascii art from a string or input-port
- returns
- list of (word-number highest-bit lowest-bit name-symbol)
- bits per word
(define (ascii-art->struct art)
(define art-inport (cond [(string? art) (open-input-string art)] [(input-port? art) art] [else (raise-argument-error 'ascii-art->struct "(or/c string? input-port?)" art)])) (define lines (for/list ((l (in-port (lambda (p) (define pk (peek-char p)) (case pk ((#\+ #\|) (read-line p)) (else eof))) art-inport))) l)) (when (null? lines) (error 'ascii-art->struct "no lines")) (define bit-re #px"[|+]([^|+]*)") (define cell-re #px"[|]([^|]*)")
(define bit-boundaries (regexp-match-positions* bit-re (car lines)))
(define bits/word (sub1 (length bit-boundaries)))
(unless (zero? (modulo bits/word 8)) (error 'ascii-art->struct "diagram is not a multiple of 8 bits wide"))
(define-values (pos->bit-start# pos->bit-end#) (for/fold ((s# (hash)) (e# (hash))) ((box (in-range bits/word)) (boundary (in-list bit-boundaries))) (define bit (- bits/word box 1)) (values (hash-set s# (car boundary) bit) (hash-set e# (cdr boundary) bit))))
(define fields (apply append (for/list ((line-number (in-naturals)) (line (in-list lines)) #:when (odd? line-number)) (define word (quotient line-number 2)) (define cell-positions (regexp-match-positions* cell-re line)) (define cell-contents (regexp-match* cell-re line)) (for/list ((cp (in-list (drop-right cell-positions 1))) (cnt (in-list cell-contents))) (define cell-start-bit (hash-ref pos->bit-start# (car cp))) (define cell-end-bit (hash-ref pos->bit-end# (cdr cp))) (list word cell-start-bit cell-end-bit (string->symbol (string-trim (substring cnt 1)))))))) (values fields bits/word))</lang>
ascii-art-reader.rkt
<lang racket>#lang racket
(require (for-syntax "ascii-art-parser.rkt"))
(require (for-syntax racket/syntax))
(provide (all-defined-out))
(define-syntax (define-ascii-art-structure stx)
(syntax-case stx () [(_ id art) (let*-values (((all-fields bits/word) (ascii-art->struct (syntax-e #'art)))) (with-syntax ((bytes->id (format-id stx "bytes->~a" #'id)) (id->bytes (format-id stx "~a->bytes" #'id)) (word-size (add1 (car (for/last ((f all-fields)) f)))) (fld-ids (map cadddr all-fields))
(fld-setters (cons #'id (for/list ((fld (in-list all-fields))) (let* ((bytes/word (quotient bits/word 8)) (start-byte (let ((word-no (car fld))) (* word-no bytes/word)))) `(bitwise-bit-field (integer-bytes->integer bs #f (system-big-endian?) ,start-byte ,(+ start-byte bytes/word)) ,(caddr fld) ,(add1 (cadr fld)))))))
(set-fields-bits (list* 'begin (for/list ((fld (in-list all-fields))) (define val (cadddr fld)) (define start-bit (cadr fld)) (define end-bit (caddr fld)) (define start-byte (let ((word-no (car fld))) (* word-no (quotient bits/word 8)))) (define fld-bit-width (- start-bit end-bit -1)) (define aligned?/width (and (= end-bit 0) (= (modulo start-bit 8) 7) (quotient fld-bit-width 8))) (case aligned?/width [(2 4) `(integer->integer-bytes ,val ,aligned?/width #f (system-big-endian?) rv ,start-byte)] [else (define the-byte (+ start-byte (quotient end-bit 8))) `(bytes-set! rv ,the-byte (bitwise-ior (arithmetic-shift (bitwise-bit-field ,val 0 ,fld-bit-width) ,(modulo end-bit 8)) (bytes-ref rv ,the-byte)))]))))) #`(begin (struct id fld-ids #:mutable)
(define (bytes->id bs) fld-setters)
(define (id->bytes art-in) (match-define (id #,@#'fld-ids) art-in) (define rv (make-bytes (* word-size #,(quotient bits/word 8)))) set-fields-bits rv))))]))</lang>
test-ascii-art-reader.rkt
<lang racket>#lang racket
(require "ascii-art-reader.rkt")
(require "ascii-art-parser.rkt")
(require tests/eli-tester)
(define rfc-1035-header-art
#<<EOS
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ EOS
)
(define-values (rslt rslt-b/w) (ascii-art->struct rfc-1035-header-art))
(test
rslt-b/w => 16 rslt => '((0 15 0 ID) (1 15 15 QR) (1 14 11 Opcode) (1 10 10 AA) (1 9 9 TC) (1 8 8 RD) (1 7 7 RA) (1 6 4 Z) (1 3 0 RCODE) (2 15 0 QDCOUNT) (3 15 0 ANCOUNT) (4 15 0 NSCOUNT) (5 15 0 ARCOUNT)))
(define-ascii-art-structure rfc-1035-header #<<EOS +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ EOS
)
(define h-bytes
(bytes-append (integer->integer-bytes #x1234 2 #f) (integer->integer-bytes #x5678 2 #f) (integer->integer-bytes #x9abc 2 #f) (integer->integer-bytes #xdef0 2 #f) (integer->integer-bytes #xfedc 2 #f) (integer->integer-bytes #xba98 2 #f)))
(define h-bytes~
(bytes-append (integer->integer-bytes #x1234 2 #f (not (system-big-endian?))) (integer->integer-bytes #x5678 2 #f (not (system-big-endian?))) (integer->integer-bytes #x9abc 2 #f (not (system-big-endian?))) (integer->integer-bytes #xdef0 2 #f (not (system-big-endian?))) (integer->integer-bytes #xfedc 2 #f (not (system-big-endian?))) (integer->integer-bytes #xba98 2 #f (not (system-big-endian?)))))
(define h (bytes->rfc-1035-header h-bytes)) (define bytes-h (rfc-1035-header->bytes h))
(define h~ (bytes->rfc-1035-header h-bytes~)) (define bytes-h~ (rfc-1035-header->bytes h~))
(test
(rfc-1035-header-ID h) => #x1234 (rfc-1035-header-ARCOUNT h) => #xBA98 (rfc-1035-header-RCODE h) => 8 (rfc-1035-header-ID h~) => #x3412 (rfc-1035-header-ARCOUNT h~) => #x98BA (rfc-1035-header-RCODE h~) => 6 h-bytes => bytes-h h-bytes~ => bytes-h~)
(set-rfc-1035-header-RA! h 0)
(set-rfc-1035-header-Z! h 7) (test
(rfc-1035-header-Z (bytes->rfc-1035-header (rfc-1035-header->bytes h))) => 7 (rfc-1035-header-RA (bytes->rfc-1035-header (rfc-1035-header->bytes h))) => 0)
(set-rfc-1035-header-Z! h 15) ;; naughty -- might splat RA (test
(rfc-1035-header-Z (bytes->rfc-1035-header (rfc-1035-header->bytes h))) => 7 (rfc-1035-header-RA (bytes->rfc-1035-header (rfc-1035-header->bytes h))) => 0)</lang>
- Output:
Nothing much to see... all tests pass
Raku
(formerly Perl 6)
<lang perl6>grammar RFC1025 {
rule TOP { <.line-separator> [<line> <.line-separator>]+ } rule line-separator { <.ws> '+--'+ '+' } token line { <.ws> '|' +%% <field> } token field { \s* <label> \s* } token label { \w+[\s+\w+]* }
}
sub bits ($item) { ($item.chars + 1) div 3 }
sub deconstruct ($bits, %struct) {
map { $bits.substr(.<from>, .<bits>) }, @(%struct<fields>);
}
sub interpret ($header) {
my $datagram = RFC1025.parse($header); my %struct; for $datagram.<line> -> $line { FIRST %struct<line-width> = $line.&bits; state $from = 0; %struct<fields>.push: %(:bits(.&bits), :ID(.<label>.Str), :from($from.clone), :to(($from+=.&bits)-1)) for $line<field>; } %struct
}
use experimental :pack;
my $diagram = q:to/END/;
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
END
my %structure = interpret($diagram);
say 'Line width: ', %structure<line-width>, ' bits'; printf("Name: %7s, bit count: %2d, bit %2d to bit %2d\n", .<ID>, .<bits>, .<from>, .<to>) for @(%structure<fields>); say "\nGenerate a random 12 byte \"header\""; say my $buf = Buf.new((^0xFF .roll) xx 12); say "\nShow it converted to a bit string"; say my $bitstr = $buf.unpack('C*')».fmt("%08b").join; say "\nAnd unpack it"; printf("%7s, %02d bits: %s\n", %structure<fields>[$_]<ID>, %structure<fields>[$_]<bits>,
deconstruct($bitstr, %structure)[$_]) for ^@(%structure<fields>);</lang>
- Output:
Line width: 16 bits Name: ID, bit count: 16, bit 0 to bit 15 Name: QR, bit count: 1, bit 16 to bit 16 Name: Opcode, bit count: 4, bit 17 to bit 20 Name: AA, bit count: 1, bit 21 to bit 21 Name: TC, bit count: 1, bit 22 to bit 22 Name: RD, bit count: 1, bit 23 to bit 23 Name: RA, bit count: 1, bit 24 to bit 24 Name: Z, bit count: 3, bit 25 to bit 27 Name: RCODE, bit count: 4, bit 28 to bit 31 Name: QDCOUNT, bit count: 16, bit 32 to bit 47 Name: ANCOUNT, bit count: 16, bit 48 to bit 63 Name: NSCOUNT, bit count: 16, bit 64 to bit 79 Name: ARCOUNT, bit count: 16, bit 80 to bit 95 Generate a random 12 byte "header" Buf:0x<78 47 7b bf 54 96 e1 2e 1b f1 69 a4> Show it converted to a bit string 011110000100011101111011101111110101010010010110111000010010111000011011111100010110100110100100 And unpack it ID, 16 bits: 0111100001000111 QR, 01 bits: 0 Opcode, 04 bits: 1111 AA, 01 bits: 0 TC, 01 bits: 1 RD, 01 bits: 1 RA, 01 bits: 1 Z, 03 bits: 011 RCODE, 04 bits: 1111 QDCOUNT, 16 bits: 0101010010010110 ANCOUNT, 16 bits: 1110000100101110 NSCOUNT, 16 bits: 0001101111110001 ARCOUNT, 16 bits: 0110100110100100
REXX
Some code was added to the REXX program to validate the input file. <lang rexx>/*REXX program interprets an ASCII art diagram for names and their bit length(s).*/ numeric digits 100 /*be able to handle large numbers. */ er= '***error*** illegal input txt' /*a literal used for error messages. */ parse arg iFID test . /*obtain optional input─FID & test─data*/ if iFID== | iFID=="," then iFID= 'ASCIIART.TXT' /*use the default iFID.*/ if test== | test=="," then test= 'cafe8050800000808080000a' /* " " " data.*/ w= 0; wb= 0; !.= 0; $= /*W (max width name), bits, names. */ @.= 0; @.0= 1 /*!.α is structure bit position. */
/* [↓] read the input text file (iFID)*/ do j=1 while lines(iFID)\==0; q= linein(iFID); say '■■■■■text►'q q= strip(q); if q== then iterate /*strip leading and trailing blanks. */ _L= left(q, 1); _R= right(q, 1) /*get extreme left and right characters*/ /* [↓] is this record an "in-between"?*/ if _L=='+' then do; if verify(q, '+-')\==0 then say er "(invalid grid):" q iterate /*skip this record, it's a single "+". */ end if _L\=='|' | _R\=="|" then do; say er '(boundary): ' q; iterate end do until q=='|'; parse var q '|' x "|" -1 q /*parse record for names.*/ n= strip(x); w= max(w, length(n) ); if n== then leave /*is N null?*/ if words(n)\==1 then do; say er '(invalid name): ' n; iterate j end /* [↑] add more name validations. */ $$= $; nn= n; upper $$ n /*$$ and N could be a mixed─case name.*/ if wordpos(nn, $$)\==0 then do; say er '(dup name):' n; iterate j end $= $ n /*add the N (name) to the $ list. */ #= words($); !.#= (length(x) + 1) % 3 /*assign the number of bits for N. */ wb= max(wb, !.#) /*max # of bits; # names prev. to this.*/ prev= # - 1; @.#= @.prev + !.prev /*number of names previous to this name*/ end /*until*/ end /*j*/
say if j==1 then do; say er ' (file not found): ' iFID; exit 12
end do k=1 for words($) say right( word($, k), w)right(!.k, 4) "bits, bit position:"right(@.k, 5) end /*k*/
say /* [↓] Any (hex) data to test? */ L= length(test); if L==0 then exit /*stick a fork in it, we're all done. */ bits= x2b(test) /*convert test data to a bit string. */ wm= length( x2d( b2x( copies(1, wb) ) ) ) + 1 /*used for displaying max width numbers*/ say 'test (hex)=' test " length=" L 'hexadecimal digits.' say
do r=1 by 8+8 to L*4; _1= substr(bits, r, 8, 0); _2= substr(bits, r+8, 8, 0) say 'test (bit)=' _1 _2 " hex=" lower( b2x(_1) ) lower( b2x(_2) ) end /*r*/
say
do m=1 for words($) /*show some hexadecimal strings──►term.*/ _= lower( b2x( substr( bits, @.m, !.m) )) /*show the hex string in lowercase. */ say right( word($, m), w+2) ' decimal='right( x2d(_), wm) " hex=" _ end /*m*/
exit 0 /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ lower: l= 'abcdefghijklmnopqrstuvwxyz'; u=l; upper u; return translate( arg(1), l, u)</lang>
- output when using the default input:
■■■■■text► ■■■■■text► ■■■■■text► +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ ■■■■■text► | ID | ■■■■■text► +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ ■■■■■text► |QR| Opcode |AA|TC|RD|RA| Z | RCODE | ■■■■■text► +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ ■■■■■text► | QDCOUNT | ■■■■■text► +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ ■■■■■text► | ANCOUNT | ■■■■■text► +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ ■■■■■text► | NSCOUNT | ■■■■■text► +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ ■■■■■text► | ARCOUNT | ■■■■■text► +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ ■■■■■text► ■■■■■text► ID 16 bits, bit position: 1 QR 1 bits, bit position: 17 OPCODE 4 bits, bit position: 18 AA 1 bits, bit position: 22 TC 1 bits, bit position: 23 RD 1 bits, bit position: 24 RA 1 bits, bit position: 25 Z 3 bits, bit position: 26 RCODE 4 bits, bit position: 29 QDCOUNT 16 bits, bit position: 33 ANCOUNT 16 bits, bit position: 49 NSCOUNT 16 bits, bit position: 65 ARCOUNT 16 bits, bit position: 81 test (hex)= cafe8050800000808080000a length= 24 hexadecimal digits. test (bit)= 11001010 11111110 hex= ca fe test (bit)= 10000000 01010000 hex= 80 50 test (bit)= 10000000 00000000 hex= 80 00 test (bit)= 00000000 10000000 hex= 00 80 test (bit)= 10000000 10000000 hex= 80 80 test (bit)= 00000000 00001010 hex= 00 0A ID decimal= 51966 hex= cafe QR decimal= 1 hex= 1 OPCODE decimal= 0 hex= 0 AA decimal= 0 hex= 0 TC decimal= 0 hex= 0 RD decimal= 0 hex= 0 RA decimal= 0 hex= 0 Z decimal= 5 hex= 5 RCODE decimal= 0 hex= 0 QDCOUNT decimal= 32768 hex= 8000 ANCOUNT decimal= 128 hex= 0080 NSCOUNT decimal= 32896 hex= 8080 ARCOUNT decimal= 10 hex= 000a
Rust
The solution implements a few additional features:
- The input is thoroughly validated.
- The width is intentionally not restricted, therefore diagrams of any width can be processed.
- The parser allows omitting border for fields that occupy multiple full lines.
- Fields can wrap over an end of a line.
- When extracting field values, truncated input is recognized and unfilled fields are reported.
See the output below the source code.
<lang Rust>use std::{borrow::Cow, io::Write};
pub type Bit = bool;
- [derive(Clone, Debug)]
pub struct Field {
name: String, from: usize, to: usize,
}
impl Field {
pub fn new(name: String, from: usize, to: usize) -> Self { assert!(from < to); Self { name, from, to } }
pub fn name(&self) -> &str { &self.name }
pub fn from(&self) -> usize { self.from }
pub fn to(&self) -> usize { self.to }
pub fn size(&self) -> usize { self.to - self.from }
pub fn extract_bits<'a>( &self, bytes: &'a [u8], ) -> Option<impl Iterator<Item = (usize, Bit)> + 'a> { if self.to <= bytes.len() * 8 { Some((self.from..self.to).map(move |index| { let byte = bytes[index / 8]; let bit_index = 7 - (index % 8); let bit_value = (byte >> bit_index) & 1 == 1; (index, bit_value) })) } else { None } }
fn extend(&mut self, new_to: usize) { assert!(self.to <= new_to); self.to = new_to; }
}
trait Consume: Iterator {
fn consume(&mut self, value: Self::Item) -> Result<Self::Item, Option<Self::Item>> where Self::Item: PartialEq, { match self.next() { Some(v) if v == value => Ok(v), Some(v) => Err(Some(v)), None => Err(None), } }
}
impl<T: Iterator> Consume for T {}
- [derive(Clone, Copy, Debug)]
enum ParserState {
Uninitialized, ExpectBorder, ExpectField, AllowEmpty,
}
- [derive(Clone, Copy, Debug)]
pub enum ParserError {
ParsingFailed, UnexpectedEnd, InvalidBorder, WrongLineWidth, FieldExpected, BadField,
}
- [derive(Debug)]
pub(crate) struct Parser {
state: Option<ParserState>, width: usize, from: usize, fields: Vec<Field>,
}
impl Parser {
#[allow(clippy::new_without_default)] pub fn new() -> Self { Self { state: Some(ParserState::Uninitialized), width: 0, from: 0, fields: Vec::new(), } }
pub fn accept(&mut self, line: &str) -> Result<(), ParserError> { if let Some(state) = self.state.take() { let line = line.trim();
if !line.is_empty() { self.state = Some(match state { ParserState::Uninitialized => self.parse_border(line)?, ParserState::ExpectBorder => self.accept_border(line)?, ParserState::ExpectField => self.parse_fields(line)?, ParserState::AllowEmpty => self.extend_field(line)?, }); }
Ok(()) } else { Err(ParserError::ParsingFailed) } }
pub fn finish(self) -> Result<Vec<Field>, ParserError> { match self.state { Some(ParserState::ExpectField) => Ok(self.fields), _ => Err(ParserError::UnexpectedEnd), } }
fn parse_border(&mut self, line: &str) -> Result<ParserState, ParserError> { self.width = Parser::border_columns(line).map_err(|_| ParserError::InvalidBorder)?; Ok(ParserState::ExpectField) }
fn accept_border(&mut self, line: &str) -> Result<ParserState, ParserError> { match Parser::border_columns(line) { Ok(width) if width == self.width => Ok(ParserState::ExpectField), Ok(_) => Err(ParserError::WrongLineWidth), Err(_) => Err(ParserError::InvalidBorder), } }
fn parse_fields(&mut self, line: &str) -> Result<ParserState, ParserError> { let mut slots = line.split('|'); // The first split result is the space outside of the schema slots.consume("").map_err(|_| ParserError::FieldExpected)?; let mut remaining_width = self.width * Parser::COLUMN_WIDTH; let mut fields_found = 0;
loop { match slots.next() { Some(slot) if slot.is_empty() => { // The only empty slot is the last one if slots.next().is_some() || remaining_width != 0 { return Err(ParserError::BadField); }
break; }
Some(slot) => { let slot_width = slot.chars().count() + 1; // Include the slot separator if remaining_width < slot_width || slot_width % Parser::COLUMN_WIDTH != 0 { return Err(ParserError::BadField); }
let name = slot.trim();
if name.is_empty() { return Err(ParserError::BadField); }
// An actual field slot confirmed remaining_width -= slot_width; fields_found += 1; let from = self.from; let to = from + slot_width / Parser::COLUMN_WIDTH; // If the slot belongs to the same field as the last one, just extend it if let Some(f) = self.fields.last_mut().filter(|f| f.name() == name) { f.extend(to); } else { self.fields.push(Field::new(name.to_string(), from, to)); }
self.from = to; }
_ => return Err(ParserError::BadField), } }
Ok(if fields_found == 1 { ParserState::AllowEmpty } else { ParserState::ExpectBorder }) }
fn extend_field(&mut self, line: &str) -> Result<ParserState, ParserError> { let mut slots = line.split('|'); // The first split result is the space outside of the schema if slots.consume("").is_ok() { if let Some(slot) = slots.next() { if slots.consume("").is_ok() { let slot_width = slot.chars().count() + 1; let remaining_width = self.width * Parser::COLUMN_WIDTH; if slot_width == remaining_width && slot.chars().all(|c| c == ' ') { self.from += self.width; self.fields.last_mut().unwrap().extend(self.from); return Ok(ParserState::AllowEmpty); } } } }
self.accept_border(line) }
const COLUMN_WIDTH: usize = 3;
fn border_columns(line: &str) -> Result<usize, Option<char>> { let mut chars = line.chars();
// Read the first cell, which is mandatory chars.consume('+')?; chars.consume('-')?; chars.consume('-')?; chars.consume('+')?; let mut width = 1;
loop { match chars.consume('-') { Err(Some(c)) => return Err(Some(c)), Err(None) => return Ok(width), Ok(_) => {} }
chars.consume('-')?; chars.consume('+')?; width += 1; } }
}
pub struct Fields(pub Vec<Field>);
- [derive(Clone, Debug)]
pub struct ParseFieldsError {
pub line: Option<String>, pub kind: ParserError,
}
impl ParseFieldsError {
fn new(line: Option<String>, kind: ParserError) -> Self { Self { line, kind } }
}
impl std::str::FromStr for Fields {
type Err = ParseFieldsError;
fn from_str(s: &str) -> Result<Self, Self::Err> { let mut parser = Parser::new(); for line in s.lines() { parser .accept(line) .map_err(|e| ParseFieldsError::new(Some(line.to_string()), e))?; }
parser .finish() .map(Fields) .map_err(|e| ParseFieldsError::new(None, e)) }
}
impl Fields {
pub fn print_schema(&self, f: &mut dyn Write) -> std::io::Result<()> { writeln!(f, "Name Bits Start End")?; writeln!(f, "=================================")?; for field in self.0.iter() { writeln!( f, "{:<12} {:>5} {:>3} {:>3}", field.name(), field.size(), field.from(), field.to() - 1 // Range is exclusive, but display it as inclusive )?; } writeln!(f) }
pub fn print_decode(&self, f: &mut dyn Write, bytes: &[u8]) -> std::io::Result<()> { writeln!(f, "Input (hexadecimal octets): {:x?}", bytes)?; writeln!(f)?; writeln!(f, "Name Size Bit pattern")?; writeln!(f, "=================================")?; for field in self.0.iter() { writeln!( f, "{:<12} {:>5} {}", field.name(), field.size(), field .extract_bits(&bytes) .map(|it| it.fold(String::new(), |mut acc, (index, bit)| { // Instead of simple collect, let's print it rather with // byte boundaries visible as spaces if index % 8 == 0 && !acc.is_empty() { acc.push(' '); } acc.push(if bit { '1' } else { '0' }); acc })) .map(Cow::Owned) .unwrap_or_else(|| Cow::Borrowed("N/A")) )?; }
writeln!(f) }
}
fn normalize(diagram: &str) -> String {
diagram .lines() .map(|line| line.trim()) .filter(|line| !line.is_empty()) .fold(String::new(), |mut acc, x| { if !acc.is_empty() { acc.push('\n'); }
acc.push_str(x); acc })
}
fn main() {
let diagram = r" +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | OVERSIZED | | | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | OVERSIZED | unused | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ ";
let data = b"\x78\x47\x7b\xbf\x54\x96\xe1\x2e\x1b\xf1\x69\xa4\xab\xcd\xef\xfe\xdc";
// Normalize and print the input, there is no need and no requirement to // generate it from the parsed representation let diagram = normalize(diagram); println!("{}", diagram); println!();
match diagram.parse::<Fields>() { Ok(fields) => { let mut stdout = std::io::stdout(); fields.print_schema(&mut stdout).ok(); fields.print_decode(&mut stdout, data).ok(); }
Err(ParseFieldsError { line: Some(line), kind: e, }) => eprintln!("Invalid input: {:?}\n{}", e, line),
Err(ParseFieldsError { line: _, kind: e, }) => eprintln!("Could not parse the input: {:?}", e), }
}</lang>
- Output:
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | OVERSIZED | | | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | OVERSIZED | unused | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ Name Bits Start End ================================= ID 16 0 15 QR 1 16 16 Opcode 4 17 20 AA 1 21 21 TC 1 22 22 RD 1 23 23 RA 1 24 24 Z 3 25 27 RCODE 4 28 31 QDCOUNT 16 32 47 ANCOUNT 16 48 63 NSCOUNT 16 64 79 ARCOUNT 16 80 95 OVERSIZED 36 96 131 unused 12 132 143 Input (hexadecimal octets): [78, 47, 7b, bf, 54, 96, e1, 2e, 1b, f1, 69, a4, ab, cd, ef, fe, dc] Name Size Bit pattern ================================= ID 16 01111000 01000111 QR 1 0 Opcode 4 1111 AA 1 0 TC 1 1 RD 1 1 RA 1 1 Z 3 011 RCODE 4 1111 QDCOUNT 16 01010100 10010110 ANCOUNT 16 11100001 00101110 NSCOUNT 16 00011011 11110001 ARCOUNT 16 01101001 10100100 OVERSIZED 36 10101011 11001101 11101111 11111110 1101 unused 12 N/A
Tcl
This is a nice task to illustrate a couple of important concepts in Tcl:
* using dictionaries, taking advantage of their ordering properties * the binary command * using (semi-)structured text as part of your source code
In this implementation, parse produces a dictionary from names to bit-lengths. encode and decode use these to produce appropriate binary format strings, and then do what they say on the tin. As implemented, this is limited to unsigned numeric values in fields. Supporting unsigned values, strings and enums would require parsing a more complex annotation than only the ASCII art packet structure, but ought not take much more code. <lang Tcl> namespace eval asciipacket {
proc assert {expr} { ;# for "static" assertions that throw nice errors if {![uplevel 1 [list expr $expr]]} { raise {ASSERT ERROR} "{$expr} {[subst -noc $expr]}" } }
proc b2h {data} { ;# format a binary string in hex digits binary scan $data H* hex; set hex }
proc parse {s} { set result {} ;# we will return a dictionary set s [string trim $s] ;# remove whitespace set s [split $s \n] ;# split into lines set s [lmap x $s {string trim $x}] ;# trim whitespace from each line set s [lassign $s border0] ;# pop off top border row ;# calculate chars per row, chars per bit set rowlen [llength [string map {+ \ } $border0]] set bitlen [expr {([string length $border0] - 1) / $rowlen}] assert {$bitlen * $rowlen + 1 == [string length $border0]}
foreach {row border} $s { assert {$border eq $border0} set row [string trim $row |] foreach field [split $row |] { set len [string length |$field] assert {$len % $bitlen == 0} set name [string trim $field] set nbits [expr {$len / $bitlen}] assert {![dict exists $result $name]} dict set result $name $nbits } } return $result }
proc encode {schema values} { set bincodes {1 B 8 c 16 S 32 W} ;# see binary(n) set binfmt "" ;# format string set binargs "" ;# positional args dict for {name bitlen} $schema { set val [dict get $values $name] if {[dict exists $bincodes $bitlen]} { set fmt "[dict get $bincodes $bitlen]" } else { set val [format %0${bitlen}b $val] set fmt "B${bitlen}" } append binfmt $fmt lappend binargs $val } binary format $binfmt {*}$binargs }
proc decode {schema data} { set result {} ;# we will return a dict set bincodes {1 B 8 c 16 S 32 W} ;# see binary(n) set binfmt "" ;# format string set binargs "" ;# positional args dict for {name bitlen} $schema { if {[dict exists $bincodes $bitlen]} { set fmt "[dict get $bincodes $bitlen]u" ;# note unsigned } else { set fmt "B${bitlen}" } append binfmt $fmt lappend binargs $name } binary scan $data $binfmt {*}$binargs foreach _ $binargs { dict set result $_ [set $_] } return $result }
} </lang> And here is how to use it with the original test data: <lang Tcl> proc test {} {
set header { +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ }
set schema [asciipacket::parse $header] set values { ID 0xcafe QR 1 Opcode 5 AA 1 TC 0 RD 0 RA 1 Z 4 RCODE 8 QDCOUNT 0x00a5 ANCOUNT 0x0a50 NSCOUNT 0xa500 ARCOUNT 0x500a } set pkt [asciipacket::encode $schema $values] puts "encoded packet (hex): [asciipacket::b2h $pkt]" array set decoded [asciipacket::decode $schema $pkt] parray decoded
} test </lang>
- Output:
encoded packet (hex): cafe805080000080808000a50a50a500500a decoded(AA) = 1 decoded(ANCOUNT) = 2640 decoded(ARCOUNT) = 20490 decoded(ID) = 51966 decoded(NSCOUNT) = 42240 decoded(Opcode) = 0101 decoded(QDCOUNT) = 165 decoded(QR) = 1 decoded(RA) = 1 decoded(RCODE) = 1000 decoded(RD) = 0 decoded(TC) = 0 decoded(Z) = 100
Wren
<lang ecmascript>import "/dynamic" for Tuple import "/fmt" for Fmt import "/big" for BigInt
var Result = Tuple.create("Result", ["name", "size", "start", "end"])
var validate = Fn.new { |diagram|
var lines = [] for (line in diagram.split("\n")) { line = line.trim(" \t") if (line != "") lines.add(line) } if (lines.count == 0) Fiber.abort("diagram has no non-empty lines!") var width = lines[0].count var cols = ((width - 1) / 3).floor if (cols != 8 && cols != 16 && cols != 32 && cols != 64) { Fiber.abort("number of columns should be 8, 16, 32 or 64") } if (lines.count%2 == 0) { Fiber.abort("number of non-empty lines should be odd") } if (lines[0] != "+--" * cols + "+") Fiber.abort("incorrect header line") var i = 0 for (line in lines) { if (i == 0) { continue } else if (i%2 == 0) { if (line != lines[0]) Fiber.abort("incorrect separator line") } else if (line.count != width) { Fiber.abort("inconsistent line widths") } else if (line[0] != "|" || line[width-1] != "|") { Fiber.abort("non-separator lines must begin and end with '|'") } i = i + 1 } return lines
}
var decode = Fn.new { |lines|
System.print("Name Bits Start End") System.print("======= ==== ===== ===") var start = 0 var width = lines[0].count var results = [] var i = 0 for (line in lines) { if (i%2 == 0) { i = i + 1 continue } line = line[1...width-1] for (name in line.split("|")) { var size = ((name.count + 1) / 3).floor name = name.trim() var r = Result.new(name, size, start, start + size - 1) results.add(r) Fmt.print("$-7s $2d $3d $3d", r.name, r.size, r.start, r.end) start = start + size } i = i + 1 } return results
}
var hex2bin = Fn.new { |hex|
var z = BigInt.fromBaseString(hex, 16) return Fmt.swrite("$0%(4*hex.count)s", z.toBaseString(2))
}
var unpack = Fn.new { |results, hex|
System.print("\nTest string in hex:") System.print(hex) System.print("\nTest string in binary:") var bin = hex2bin.call(hex) System.print(bin) System.print("\nUnpacked:\n") System.print("Name Size Bit pattern") System.print("======= ==== ================") for (res in results) { Fmt.print("$-7s $2d $s", res.name, res.size, bin[res.start..res.end]) }
}
var diagram = """
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
""" var lines = validate.call(diagram) System.print("Diagram after trimming whitespace and removal of blank lines:\n") for (line in lines) System.print(line) System.print("\nDecoded:\n") var results = decode.call(lines) var hex = "78477bbf5496e12e1bf169a4" // test string unpack.call(results, hex)</lang>
- Output:
Diagram after trimming whitespace and removal of blank lines: +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z | RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ Decoded: Name Bits Start End ======= ==== ===== === ID 16 0 15 QR 1 16 16 Opcode 4 17 20 AA 1 21 21 TC 1 22 22 RD 1 23 23 RA 1 24 24 Z 3 25 27 RCODE 4 28 31 QDCOUNT 16 32 47 ANCOUNT 16 48 63 NSCOUNT 16 64 79 ARCOUNT 16 80 95 Test string in hex: 78477bbf5496e12e1bf169a4 Test string in binary: 011110000100011101111011101111110101010010010110111000010010111000011011111100010110100110100100 Unpacked: Name Size Bit pattern ======= ==== ================ ID 16 0111100001000111 QR 1 0 Opcode 4 1111 AA 1 0 TC 1 1 RD 1 1 RA 1 1 Z 3 011 RCODE 4 1111 QDCOUNT 16 0101010010010110 ANCOUNT 16 1110000100101110 NSCOUNT 16 0001101111110001 ARCOUNT 16 0110100110100100