求base64编码解码源程序

可以去这里看一看，有完整的解决方案，绝对实用：
http://www.aslike.net

php里面有源代码，复制了一份
/*
   +----------------------------------------------------------------------+
   | PHP HTML Embedded Scripting Language Version 3.0                     |
   +----------------------------------------------------------------------+
   | Copyright (c) 1997-2000 PHP Development Team (See Credits file)      |
   +----------------------------------------------------------------------+
   | This program is free software; you can redistribute it and/or modify |
   | it under the terms of one of the following licenses:                 |
   |                                                                      |
   |  A) the GNU General Public License as published by the Free Software |
   |     Foundation; either version 2 of the License, or (at your option) |
   |     any later version.                                               |
   |                                                                      |
   |  B) the PHP License as published by the PHP Development Team and     |
   |     included in the distribution in the file: LICENSE                |
   |                                                                      |
   | This program is distributed in the hope that it will be useful,      |
   | but WITHOUT ANY WARRANTY; without even the implied warranty of       |
   | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        |
   | GNU General Public License for more details.                         |
   |                                                                      |
   | You should have received a copy of both licenses referred to here.   |
   | If you did not, or have any questions about PHP licensing, please    |
   | contact [email protected].                                                |
   +----------------------------------------------------------------------+
   | Author: Jim Winstead ([email protected])                                  |
   +----------------------------------------------------------------------+
*/
/* $Id: base64.c,v 1.32 2000/01/01 04:31:14 sas Exp $ */#include <string.h>#include "php.h"
#include "internal_functions.h"
#include "base64.h"static char base64_table[] =
{ 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
  'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
  'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
  '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/', '\0'
};
static char base64_pad = '=';unsigned char *_php3_base64_encode(const unsigned char *string, int length, int *ret_length) {
const unsigned char *current = string;
int i = 0;
unsigned char *result = (unsigned char *)emalloc(((length + 3 - length % 3) * 4 / 3 + 1) * sizeof(char)); while (length > 2) { /* keep going until we have less than 24 bits */
result[i++] = base64_table[current[0] >> 2];
result[i++] = base64_table[((current[0] & 0x03) << 4) + (current[1] >> 4)];
result[i++] = base64_table[((current[1] & 0x0f) << 2) + (current[2] >> 6)];
result[i++] = base64_table[current[2] & 0x3f]; current += 3;
length -= 3; /* we just handle 3 octets of data */
} /* now deal with the tail end of things */
if (length != 0) {
result[i++] = base64_table[current[0] >> 2];
if (length > 1) {
result[i++] = base64_table[((current[0] & 0x03) << 4) + (current[1] >> 4)];
result[i++] = base64_table[(current[1] & 0x0f) << 2];
result[i++] = base64_pad;
}
else {
result[i++] = base64_table[(current[0] & 0x03) << 4];
result[i++] = base64_pad;
result[i++] = base64_pad;
}
}
if(ret_length) {
*ret_length = i;
}
result[i] = '\0';
return result;
}/* as above, but backwards. :) */
unsigned char *_php3_base64_decode(const unsigned char *string, int length, int *ret_length) {
const unsigned char *current = string;
int ch, i = 0, j = 0, k;
char *chp; unsigned char *result = (unsigned char *)emalloc((length / 4 * 3 + 1) * sizeof(char));
if (result == NULL) {
return NULL;
} /* run through the whole string, converting as we go */
while ((ch = *current++) != '\0') {
if (ch == base64_pad) break;
chp = strchr(base64_table, ch);
if (chp == NULL) continue;
ch = chp - base64_table; switch(i % 4) {
case 0:
result[j] = ch << 2;
break;
case 1:
result[j++] |= ch >> 4;
result[j] = (ch & 0x0f) << 4;
break;
case 2:
result[j++] |= ch >>2;
result[j] = (ch & 0x03) << 6;
break;
case 3:
result[j++] |= ch;
break;
}
i++;
} k = j;
/* mop things up if we ended on a boundary */
if (ch == base64_pad) {
switch(i % 4) {
case 0:
case 1:
efree(result);
return NULL;
case 2:
k++;
case 3:
result[k++] = 0;
}
}
if(ret_length) {
*ret_length = j;
}
result[k] = '\0';
return result;
}/* {{{ proto string base64_encode(string str)
   Encodes string using MIME base64 algorithm */
void php3_base64_encode(INTERNAL_FUNCTION_PARAMETERS) {
pval *string;
unsigned char *result;
int ret_length;
TLS_VARS; if (ARG_COUNT(ht)!=1 || getParameters(ht,1,&string) == FAILURE) {
WRONG_PARAM_COUNT;
}
convert_to_string(string);
result = _php3_base64_encode(string->value.str.val, string->value.str.len, &ret_length);
if (result != NULL) {
return_value->value.str.val = result;
return_value->value.str.len = ret_length;
return_value->type = IS_STRING;
} else {
RETURN_FALSE;
}
}
/* }}} */
/* {{{ proto string base64_decode(string str)
   Decodes string using MIME base64 algorithm */
void php3_base64_decode(INTERNAL_FUNCTION_PARAMETERS) {
pval *string;
unsigned char *result;
int ret_length;
TLS_VARS; if (ARG_COUNT(ht)!=1 || getParameters(ht,1,&string) == FAILURE) {
WRONG_PARAM_COUNT;
}
convert_to_string(string);
result = _php3_base64_decode(string->value.str.val, string->value.str.len, &ret_length);
if (result != NULL) {
return_value->value.str.val = result;
return_value->value.str.len = ret_length;
return_value->type = IS_STRING;
} else {
RETURN_FALSE;
}
}
/* }}} */
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
*/

告诉你, MS 的 VS.NET 里的 ATL 源代码里就有一个 BASE64编码解码的源代码:)
你在atlmfc目录下搜索一下就可以找到

这里有Base64的中文教程和源代码：http://laoluoc.yeah.net

调试易

求base64编码解码源程序

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