Hex dump: Difference between revisions

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@@ Line 64: / Line 64: @@
 Other hexdump/xxd features and a command line interface to your program are optional.
+=={{header|C}}==
+<syntaxhighlight lang="c">#include <ctype.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#define BYTES_HEX 16
+#define BYTES_BIN 6
+static void print_hex(const char* data, long count) {
+    long i = 0;
+    for (; i < count; ++i) {
+        if (i % 8 == 0)
+            putchar(' ');
+        printf(" %02x", (unsigned char)data[i]);
+    }
+    for (; i < BYTES_HEX; ++i) {
+        if (i % 8 == 0)
+            putchar(' ');
+        printf("   ");
+    }
+}
+static void print_binary(const char* data, long count) {
+    long i = 0;
+    putchar(' ');
+    for (; i < count; ++i) {
+        unsigned char c = data[i];
+        putchar(' ');
+        for (unsigned char m = 1 << 7; m != 0; m >>= 1)
+            putchar((c & m) ? '1' : '0');
+    }
+    for (; i < BYTES_BIN; ++i)
+        printf("         ");
+}
+static void print_chars(const char* data, long count) {
+    for (long i = 0; i < count; ++i) {
+        unsigned char c = data[i];
+        putchar(isprint(c) ? c : '.');
+    }
+}
+static bool string_to_long(const char* str, long* value) {
+    char* eptr;
+    long result = strtol(str, &eptr, 0);
+    if (errno || *eptr || result < 0)
+        return false;
+    *value = result;
+    return true;
+}
+static void usage(const char* program) {
+    fprintf(stderr, "usage: %s [-b] [-s skip] [-n length] filename\n", program);
+}
+int main(int argc, char** argv) {
+    long offset = 0;
+    long max_length = LONG_MAX;
+    bool binary = false;
+    int i = 1;
+    for (; i < argc && argv[i][0] == '-'; ++i) {
+        switch (argv[i][1]) {
+        case 's':
+            if (++i == argc) {
+                usage(argv[0]);
+                return EXIT_FAILURE;
+            }
+            if (!string_to_long(argv[i], &offset)) {
+                fprintf(stderr, "Invalid skip '%s'.\n", argv[i]);
+                return EXIT_FAILURE;
+            }
+            break;
+        case 'n':
+            if (++i == argc) {
+                usage(argv[0]);
+                return EXIT_FAILURE;
+            }
+            if (!string_to_long(argv[i], &max_length)) {
+                fprintf(stderr, "Invalid length '%s'.\n", argv[i]);
+                return EXIT_FAILURE;
+            }
+            break;
+        case 'b':
+            binary = true;
+            break;
+        default:
+            usage(argv[0]);
+            return EXIT_FAILURE;
+        }
+    }
+    if (i + 1 != argc) {
+        usage(argv[0]);
+        return EXIT_FAILURE;
+    }
+    FILE* fp = fopen(argv[i], "rb");
+    if (!fp) {
+        perror(argv[i]);
+        return EXIT_FAILURE;
+    }
+    if (fseek(fp, 0, SEEK_END)) {
+        perror("fseek");
+        fclose(fp);
+        return EXIT_FAILURE;
+    }
+    long max_offset = ftell(fp);
+    if (offset > max_offset)
+        offset = max_offset;
+    if (fseek(fp, offset, SEEK_SET)) {
+        perror("fseek");
+        fclose(fp);
+        return EXIT_FAILURE;
+    }
+    char data[BYTES_HEX];
+    const long max_count = binary ? BYTES_BIN : BYTES_HEX;
+    for (long length = 0; length <= max_length;) {
+        printf("%08lx", offset);
+        long count = fread(data, 1, max_count, fp);
+        if (count > max_length - length)
+            count = max_length - length;
+        if (count == 0) {
+            putchar('\n');
+            break;
+        }
+        if (binary)
+            print_binary(data, count);
+        else
+            print_hex(data, count);
+        printf("  |");
+        print_chars(data, count);
+        printf("|\n");
+        offset += count;
+        length += count;
+    }
+    fclose(fp);
+    return EXIT_SUCCESS;
+}</syntaxhighlight>
+{{out}}
+Hexadecimal output:
+<pre>
+00000000  ff fe 52 00 6f 00 73 00  65 00 74 00 74 00 61 00  |..R.o.s.e.t.t.a.|
+00000010  20 00 43 00 6f 00 64 00  65 00 20 00 69 00 73 00  | .C.o.d.e. .i.s.|
+00000020  20 00 61 00 20 00 70 00  72 00 6f 00 67 00 72 00  | .a. .p.r.o.g.r.|
+00000030  61 00 6d 00 6d 00 69 00  6e 00 67 00 20 00 63 00  |a.m.m.i.n.g. .c.|
+00000040  68 00 72 00 65 00 73 00  74 00 6f 00 6d 00 61 00  |h.r.e.s.t.o.m.a.|
+00000050  74 00 68 00 79 00 20 00  73 00 69 00 74 00 65 00  |t.h.y. .s.i.t.e.|
+00000060  20 00 3d d8 00 de 2e 00                           | .=.....|
+00000068
+</pre>
+Binary output:
+<pre>
+00000000  11111111 11111110 01010010 00000000 01101111 00000000  |..R.o.|
+00000006  01110011 00000000 01100101 00000000 01110100 00000000  |s.e.t.|
+0000000c  01110100 00000000 01100001 00000000 00100000 00000000  |t.a. .|
+00000012  01000011 00000000 01101111 00000000 01100100 00000000  |C.o.d.|
+00000018  01100101 00000000 00100000 00000000 01101001 00000000  |e. .i.|
+0000001e  01110011 00000000 00100000 00000000 01100001 00000000  |s. .a.|
+00000024  00100000 00000000 01110000 00000000 01110010 00000000  | .p.r.|
+0000002a  01101111 00000000 01100111 00000000 01110010 00000000  |o.g.r.|
+00000030  01100001 00000000 01101101 00000000 01101101 00000000  |a.m.m.|
+00000036  01101001 00000000 01101110 00000000 01100111 00000000  |i.n.g.|
+0000003c  00100000 00000000 01100011 00000000 01101000 00000000  | .c.h.|
+00000042  01110010 00000000 01100101 00000000 01110011 00000000  |r.e.s.|
+00000048  01110100 00000000 01101111 00000000 01101101 00000000  |t.o.m.|
+0000004e  01100001 00000000 01110100 00000000 01101000 00000000  |a.t.h.|
+00000054  01111001 00000000 00100000 00000000 01110011 00000000  |y. .s.|
+0000005a  01101001 00000000 01110100 00000000 01100101 00000000  |i.t.e.|
+00000060  00100000 00000000 00111101 11011000 00000000 11011110  | .=...|
+00000066  00101110 00000000                                      |..|
+00000068
+</pre>
 =={{header|FreeBASIC}}==