base64.h 파일
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#ifndef _BASE64_H_
#define _BASE64_H_
#ifdef __cplusplus
extern "C" {
#endif
int Base64encode_len(int len);
int Base64encode(char * coded_dst, const char *plain_src,int len_plain_src);
int Base64decode_len(const char * coded_src);
int Base64decode(char * plain_dst, const char *coded_src);
#ifdef __cplusplus
}
#endif
#endif //_BASE64_H_
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base64.c
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#include <string.h>
#include "base64.h"
/* aaaack but it's fast and const should make it shared text page. */
static const unsigned char pr2six[256] =
{
/* ASCII table */
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, 64, 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, 64,
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
};
int Base64decode_len(const char *bufcoded)
{
int nbytesdecoded;
register const unsigned char *bufin;
register int nprbytes;
bufin = (const unsigned char *) bufcoded;
while (pr2six[*(bufin++)] <= 63);
nprbytes = (bufin - (const unsigned char *) bufcoded) - 1;
nbytesdecoded = ((nprbytes + 3) / 4) * 3;
return nbytesdecoded + 1;
}
int Base64decode(char *bufplain, const char *bufcoded)
{
int nbytesdecoded;
register const unsigned char *bufin;
register unsigned char *bufout;
register int nprbytes;
bufin = (const unsigned char *) bufcoded;
while (pr2six[*(bufin++)] <= 63);
nprbytes = (bufin - (const unsigned char *) bufcoded) - 1;
nbytesdecoded = ((nprbytes + 3) / 4) * 3;
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;
}
/* Note: (nprbytes == 1) would be an error, so just ingore that case */
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';
nbytesdecoded -= (4 - nprbytes) & 3;
return nbytesdecoded;
}
static const char basis_64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
int Base64encode_len(int len)
{
return ((len + 2) / 3 * 4) + 1;
}
int Base64encode(char *encoded, const char *string, int len)
{
int i;
char *p;
p = encoded;
for (i = 0; i < len - 2; i += 3) {
*p++ = basis_64[(string[i] >> 2) & 0x3F];
*p++ = basis_64[((string[i] & 0x3) << 4) | ((int) (string[i + 1] & 0xF0) >> 4)];
*p++ = basis_64[((string[i + 1] & 0xF) << 2) | ((int) (string[i + 2] & 0xC0) >> 6)];
*p++ = basis_64[string[i + 2] & 0x3F];
}
if (i < len) {
*p++ = basis_64[(string[i] >> 2) & 0x3F];
if (i == (len - 1)) {
*p++ = basis_64[((string[i] & 0x3) << 4)];
*p++ = '=';
}
else {
*p++ = basis_64[((string[i] & 0x3) << 4) | ((int) (string[i + 1] & 0xF0) >> 4)];
*p++ = basis_64[((string[i + 1] & 0xF) << 2)];
}
*p++ = '=';
}
*p++ = '\0';
return p - encoded;
}
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