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| /*base64.c*/
| #include "base64.h"
|
| char* base64_encode(const char* str)
| {
| long len;
| long str_len;
| char* res;
| int i, j;
| //¶¨Òåbase64±àÂë±í
| const char* base64_table = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
|
| //¼ÆËã¾¹ýbase64±àÂëºóµÄ×Ö·û´®³¤¶È
| str_len = strlen(str);
| if (str_len % 3 == 0)
| len = str_len / 3 * 4;
| else
| len = (str_len / 3 + 1) * 4;
|
| res =( char*) malloc(sizeof( char) * len + 1);
| res[len] = '\0';
|
| //ÒÔ3¸ö8λ×Ö·ûΪһ×é½øÐбàÂë
| for (i = 0, j = 0; i < len - 2; j += 3, i += 4)
| {
| res[i] = base64_table[str[j] >> 2]; //È¡³öµÚÒ»¸ö×Ö·ûµÄÇ°6λ²¢ÕÒ³ö¶ÔÓ¦µÄ½á¹û×Ö·û
| res[i + 1] = base64_table[(str[j] & 0x3) << 4 | (str[j + 1] >> 4)]; //½«µÚÒ»¸ö×Ö·ûµÄºóλÓëµÚ¶þ¸ö×Ö·ûµÄÇ°4λ½øÐÐ×éºÏ²¢ÕÒµ½¶ÔÓ¦µÄ½á¹û×Ö·û
| res[i + 2] = base64_table[(str[j + 1] & 0xf) << 2 | (str[j + 2] >> 6)]; //½«µÚ¶þ¸ö×Ö·ûµÄºó4λÓëµÚÈý¸ö×Ö·ûµÄÇ°2λ×éºÏ²¢ÕÒ³ö¶ÔÓ¦µÄ½á¹û×Ö·û
| res[i + 3] = base64_table[str[j + 2] & 0x3f]; //È¡³öµÚÈý¸ö×Ö·ûµÄºó6λ²¢ÕÒ³ö½á¹û×Ö·û
| }
|
| switch (str_len % 3)
| {
| case 1:
| res[i - 2] = '=';
| res[i - 1] = '=';
| break;
| case 2:
| res[i - 1] = '=';
| break;
| }
|
| return res;
| }
|
| char* base64_decode(const char* code)
| {
| //¸ù¾Ýbase64±í£¬ÒÔ×Ö·ûÕÒµ½¶ÔÓ¦µÄÊ®½øÖÆÊý¾Ý
| int table[] = { 0,0,0,0,0,0,0,0,0,0,0,0,
| 0,0,0,0,0,0,0,0,0,0,0,0,
| 0,0,0,0,0,0,0,0,0,0,0,0,
| 0,0,0,0,0,0,0,62,0,0,0,
| 63,52,53,54,55,56,57,58,
| 59,60,61,0,0,0,0,0,0,0,0,
| 1,2,3,4,5,6,7,8,9,10,11,12,
| 13,14,15,16,17,18,19,20,21,
| 22,23,24,25,0,0,0,0,0,0,26,
| 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
| };
| long len;
| long str_len;
| char* res;
| int i, j;
|
| //¼ÆËã½âÂëºóµÄ×Ö·û´®³¤¶È
| len = strlen(code);
| //ÅжϱàÂëºóµÄ×Ö·û´®ºóÊÇ·ñÓÐ=
| if (strstr(code, "=="))
| str_len = len / 4 * 3 - 2;
| else if (strstr(code, "="))
| str_len = len / 4 * 3 - 1;
| else
| str_len = len / 4 * 3;
|
| res = ( char*)malloc(sizeof( char) * str_len + 1);
| res[str_len] = '\0';
|
| //ÒÔ4¸ö×Ö·ûΪһλ½øÐнâÂë
| for (i = 0, j = 0; i < len - 2; j += 3, i += 4)
| {
| res[j] = ((unsigned char)table[code[i]]) << 2 | (((unsigned char)table[code[i + 1]]) >> 4); //È¡³öµÚÒ»¸ö×Ö·û¶ÔÓ¦base64±íµÄÊ®½øÖÆÊýµÄÇ°6λÓëµÚ¶þ¸ö×Ö·û¶ÔÓ¦base64±íµÄÊ®½øÖÆÊýµÄºó2λ½øÐÐ×éºÏ
| res[j + 1] = (((unsigned char)table[code[i + 1]]) << 4) | (((unsigned char)table[code[i + 2]]) >> 2); //È¡³öµÚ¶þ¸ö×Ö·û¶ÔÓ¦base64±íµÄÊ®½øÖÆÊýµÄºó4λÓëµÚÈý¸ö×Ö·û¶ÔÓ¦bas464±íµÄÊ®½øÖÆÊýµÄºó4λ½øÐÐ×éºÏ
| res[j + 2] = (((unsigned char)table[code[i + 2]]) << 6) | ((unsigned char)table[code[i + 3]]); //È¡³öµÚÈý¸ö×Ö·û¶ÔÓ¦base64±íµÄÊ®½øÖÆÊýµÄºó2λÓëµÚ4¸ö×Ö·û½øÐÐ×éºÏ
| }
|
| return res;
|
| }
|
|
