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Base64 encode data: Difference between revisions
homemade base64
(→{{header|Erlang}}: Used {{out}} and pre tags for the output) |
(homemade base64) |
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Compile with
<pre>gcc -lresolv -o base64encode base64encode.c</pre>
===Manual implementation===
The following reads standard input and writes base64-encoded stream to standard output, e.g. <tt>./a.out <some_random_file >/dev/null</tt> if you don't want to see the output. It gives identical output as the common <tt>base64</tt> utility program, though much less efficiently.
<lang c>#include <stdio.h>
#include <unistd.h>
typedef unsigned long UL;
int main(void)
{
const char *alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
unsigned char c[4];
UL u, len, w = 0;
do {
c[1] = c[2] = 0;
if (!(len = read(fileno(stdin), c, 3))) break;
u = (UL)c[0]<<16 | (UL)c[1]<<8 | (UL)c[2];
putchar(alpha[u>>18]);
putchar(alpha[u>>12 & 63]);
putchar(len < 2 ? '=' : alpha[u>>6 & 63]);
putchar(len < 3 ? '=' : alpha[u & 63]);
if (++w == 19) w = 0, putchar('\n');
} while (len == 3);
if (w) putchar('\n');
return 0;
}</lang>
=={{header|D}}==
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