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base64.c
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base64.c
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#include <string.h>
#include "include/base64.h"
static const unsigned char pr2six[256] = {
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
64, 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, 64, 64, 64, 64, 63,
64, 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, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64};
static const char b6[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
int BDL(const char *bufcoded)
{
size_t nbytesdecoded;
register const unsigned char *bufin;
register size_t nprbytes;
bufin = (const unsigned char *)bufcoded;
while (pr2six[*(bufin++)] <= 63)
;
nprbytes = (size_t)(bufin - (const unsigned char *)bufcoded) - 1;
nbytesdecoded = ((nprbytes + 3) / 4) * 3;
return (int)(nbytesdecoded + 1);
}
int BEL(int len)
{
return ((len + 2) / 3 * 4) + 1;
}
int BD(char *bufplain, const char *bufcoded)
{
register const unsigned char *bufin;
register unsigned char *bufout;
register size_t nprbytes;
bufin = (const unsigned char *)bufcoded;
while (pr2six[*(bufin++)] <= 63)
;
nprbytes = (bufin - (const unsigned char *)bufcoded) - 1;
bufout = (unsigned char *)bufplain;
bufin = (const unsigned char *)bufcoded;
while (nprbytes > 4)
{
*(bufout++) = (unsigned char)(pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
*(bufout++) = (unsigned char)(pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
*(bufout++) = (unsigned char)(pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
bufin += 4;
nprbytes -= 4;
}
if (nprbytes > 1)
*(bufout++) = (unsigned char)(pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
if (nprbytes > 2)
*(bufout++) = (unsigned char)(pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
if (nprbytes > 3)
*(bufout++) = (unsigned char)(pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
*(bufout++) = '\0';
return 0; /* unused */
}
int BE(char *encoded, const char *string, int len)
{
int i;
char *p = encoded;
for (i = 0; i < len - 2; i += 3)
{
*p++ = b6[(string[i] >> 2) & 0x3F];
*p++ = b6[((string[i] & 0x3) << 4) | ((int)(string[i + 1] & 0xF0) >> 4)];
*p++ = b6[((string[i + 1] & 0xF) << 2) | ((int)(string[i + 2] & 0xC0) >> 6)];
*p++ = b6[string[i + 2] & 0x3F];
}
if (i < len)
{
*p++ = b6[(string[i] >> 2) & 0x3F];
if (i == (len - 1))
{
*p++ = b6[((string[i] & 0x3) << 4)];
}
else
{
*p++ = b6[((string[i] & 0x3) << 4) | ((int)(string[i + 1] & 0xF0) >> 4)];
*p++ = b6[((string[i + 1] & 0xF) << 2)];
}
}
*p++ = '\0';
return 0; /* unused */
}