tomcrypt/base64.c
2010-06-16 12:37:49 +02:00

112 lines
3.4 KiB
C

/* compliant base64 code donated by Wayne Scott (wscott@bitmover.com) */
#include "mycrypt.h"
#ifdef BASE64
static const char *codes =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const unsigned char map[256] = {
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255,
255, 254, 255, 255, 255, 0, 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255,
255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
49, 50, 51, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255 };
int base64_encode(const unsigned char *in, unsigned long len,
unsigned char *out, unsigned long *outlen)
{
unsigned long i, len2, leven;
unsigned char *p;
_ARGCHK(in != NULL);
_ARGCHK(out != NULL);
_ARGCHK(outlen != NULL);
/* valid output size ? */
len2 = 4 * ((len + 2) / 3);
if (*outlen < len2 + 1) {
return CRYPT_BUFFER_OVERFLOW;
}
p = out;
leven = 3*(len / 3);
for (i = 0; i < leven; i += 3) {
*p++ = codes[in[0] >> 2];
*p++ = codes[((in[0] & 3) << 4) + (in[1] >> 4)];
*p++ = codes[((in[1] & 0xf) << 2) + (in[2] >> 6)];
*p++ = codes[in[2] & 0x3f];
in += 3;
}
/* Pad it if necessary... */
if (i < len) {
unsigned a = in[0];
unsigned b = (i+1 < len) ? in[1] : 0;
unsigned c = 0;
*p++ = codes[a >> 2];
*p++ = codes[((a & 3) << 4) + (b >> 4)];
*p++ = (i+1 < len) ? codes[((b & 0xf) << 2) + (c >> 6)] : '=';
*p++ = '=';
}
/* append a NULL byte */
*p = '\0';
/* return ok */
*outlen = p - out;
return CRYPT_OK;
}
int base64_decode(const unsigned char *in, unsigned long len,
unsigned char *out, unsigned long *outlen)
{
unsigned long t, x, y, z;
unsigned char c;
int g = 3;
_ARGCHK(in != NULL);
_ARGCHK(out != NULL);
_ARGCHK(outlen != NULL);
for (x = y = z = t = 0; x < len; x++) {
c = map[in[x]];
if (c == 255) continue;
if (c == 254) { c = 0; g--; }
t = (t<<6)|c;
if (++y == 4) {
if (z + g > *outlen) goto error;
out[z++] = (unsigned char)((t>>16)&255);
if (g > 1) out[z++] = (unsigned char)((t>>8)&255);
if (g > 2) out[z++] = (unsigned char)(t&255);
y = t = 0;
}
}
if (y != 0) {
return CRYPT_INVALID_PACKET;
}
*outlen = z;
return CRYPT_OK;
error:
return CRYPT_BUFFER_OVERFLOW;
}
#endif