复制代码 代码如下:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
static const char b64_table[65] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char reverse_table[128] =
{
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 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
};
unsigned char *base64_encode(unsigned char *bindata,size_t inlen,unsigned char **out,size_t *outlen)
{
size_t _outlen = *outlen;
unsigned char *_out = NULL;
size_t out_pos = 0;
if(NULL == *out)
{
_outlen = (inlen / 3 + (inlen%3 != 0)) * 4 + 1;
_out = malloc(_outlen);
}
else
{
_outlen = *outlen;
_out = *out;
}
memset(_out,'=',_outlen);
_out[_outlen-1] = 0;
unsigned int bits_collected = 0;
unsigned int accumulator = 0;
for(int i = 0; i < inlen; i++)
{
accumulator = (accumulator << 8) | (bindata[i] & 0xffu);
bits_collected += 8;
while (bits_collected >= 6)
{
bits_collected -= 6;
_out[out_pos++] = b64_table[(accumulator >> bits_collected) & 0x3fu];
}
}
if(bits_collected >= 6)
{
if(NULL == *out)
{
free(_out);
}
return NULL;
}
if (bits_collected > 0)
{
// Any trailing bits that are missing.
accumulator <<= 6 - bits_collected;
_out[out_pos++] = b64_table[accumulator & 0x3fu];
}
*outlen = _outlen;
*out = _out;
return _out;
}
unsigned char *base64_decode(unsigned char *bindata,size_t inlen,unsigned char **out,size_t *outlen)
{
size_t _outlen = *outlen;
unsigned char *_out = NULL;
int bits_collected = 0;
unsigned int accumulator = 0;
size_t out_pos = 0;
if(NULL == *out)
{
_outlen = inlen;
_out = malloc(_outlen);
}
else
{
_outlen = *outlen;
_out = *out;
}
int c = 0;
for(int i = 0; i < inlen; i++)
{
c = bindata[i];
if (isspace(c) || c == '=')
{
// Skip whitespace and padding. Be liberal in what you accept.
continue;
}
if ((c > 127) || (c < 0) || (reverse_table[c] > 63))
{
return NULL;
}
accumulator = (accumulator << 6) | reverse_table[c];
bits_collected += 6;
if (bits_collected >= 8)
{
bits_collected -= 8;
_out[out_pos++] = (char)((accumulator >> bits_collected) & 0xffu);
}
}
*outlen = _outlen;
*out = _out;
return _out;
}
int main(int argc,char *argv[])
{
unsigned char *str = argv[1];
unsigned char *out = 0;
size_t len = 0;
printf("%sn",base64_encode(str,strlen(str),&out,&len));
unsigned char *_out = 0;
size_t _len = 0;
printf("%sn",base64_decode(out,strlen(out),&_out,&_len));
return 0;
}
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