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//
// MCBase64.c
// mailcore2
//
// Created by DINH Viêt Hoà on 7/30/13.
// Copyright (c) 2013 MailCore. All rights reserved.
//
#include "MCBase64.h"
#include <stdlib.h>
#define CHAR64(c) (((c) < 0 || (c) > 127) ? -1 : index_64[(c)])
static char index_64[128] = {
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, -1,-1,-1,63,
52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1,-1,-1,-1,
-1, 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,-1, -1,-1,-1,-1,
-1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1
};
static char basis_64[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
char * MCEncodeBase64(const char * in, int len)
{
char * output, * tmp;
unsigned char oval;
int out_len;
const unsigned char * uin = (const unsigned char *) in;
out_len = ((len + 2) / 3 * 4) + 1;
if ((len > 0) && (in == NULL))
return NULL;
output = malloc(out_len);
if (!output)
return NULL;
tmp = output;
while (len >= 3) {
*tmp++ = basis_64[uin[0] >> 2];
*tmp++ = basis_64[((uin[0] << 4) & 0x30) | (uin[1] >> 4)];
*tmp++ = basis_64[((uin[1] << 2) & 0x3c) | (uin[2] >> 6)];
*tmp++ = basis_64[uin[2] & 0x3f];
uin += 3;
len -= 3;
}
if (len > 0) {
*tmp++ = basis_64[uin[0] >> 2];
oval = (uin[0] << 4) & 0x30;
if (len > 1) oval |= uin[1] >> 4;
*tmp++ = basis_64[oval];
*tmp++ = (len < 2) ? '=' : basis_64[(uin[1] << 2) & 0x3c];
*tmp++ = '=';
}
*tmp = '\0';
return output;
}
char * MCDecodeBase64(const char * in, int len, int * p_outlen)
{
char * output, * out;
int i, c1, c2, c3, c4;
int max_out_len;
max_out_len = ((len + 3) * 4 / 3) + 1;
output = malloc(max_out_len);
if (output == NULL)
return NULL;
out = output;
if (in[0] == '+' && in[1] == ' ')
in += 2;
for (i = 0; i < (len / 4); i++) {
c1 = in[0];
c2 = in[1];
c3 = in[2];
c4 = in[3];
if (CHAR64(c1) == -1 || CHAR64(c2) == -1 ||
(c3 != '=' && CHAR64(c3) == -1) ||
(c4 != '=' && CHAR64(c4) == -1)) {
free(out);
return NULL;
}
in += 4;
*output++ = (CHAR64(c1) << 2) | (CHAR64(c2) >> 4);
if (c3 != '=') {
*output++ = ((CHAR64(c2) << 4) & 0xf0) | (CHAR64(c3) >> 2);
if (c4 != '=') {
*output++ = ((CHAR64(c3) << 6) & 0xc0) | CHAR64(c4);
}
}
}
*output = 0;
if (p_outlen != NULL) {
*p_outlen = (int) (output - out);
}
return out;
}
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