网络传输经常用base64编码的数据,因此我们需要将其解码成正常字符集合。
base64.h
1 #ifdef __cplusplus 2 extern "C" { 3 #endif 4 5 char * base64_encode( const unsigned char * bindata, char * base64, int binlength ); 6 int base64_decode( const char * base64, unsigned char * bindata ); 7 8 #ifdef __cplusplus 9 } 10 #endif
base64.c
1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <string.h> 4 #include "base64.h" 5 6 #ifndef MAX_PATH 7 #define MAX_PATH 256 8 #endif 9 10 const char * base64char = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 11 12 char * base64_encode( const unsigned char * bindata, char * base64, int binlength ) 13 { 14 int i, j; 15 unsigned char current; 16 17 for ( i = 0, j = 0 ; i < binlength ; i += 3 ) 18 { 19 current = (bindata[i] >> 2) ; 20 current &= (unsigned char)0x3F; 21 base64[j++] = base64char[(int)current]; 22 23 current = ( (unsigned char)(bindata[i] << 4 ) ) & ( (unsigned char)0x30 ) ; 24 if ( i + 1 >= binlength ) 25 { 26 base64[j++] = base64char[(int)current]; 27 base64[j++] = '='; 28 base64[j++] = '='; 29 break; 30 } 31 current |= ( (unsigned char)(bindata[i+1] >> 4) ) & ( (unsigned char) 0x0F ); 32 base64[j++] = base64char[(int)current]; 33 34 current = ( (unsigned char)(bindata[i+1] << 2) ) & ( (unsigned char)0x3C ) ; 35 if ( i + 2 >= binlength ) 36 { 37 base64[j++] = base64char[(int)current]; 38 base64[j++] = '='; 39 break; 40 } 41 current |= ( (unsigned char)(bindata[i+2] >> 6) ) & ( (unsigned char) 0x03 ); 42 base64[j++] = base64char[(int)current]; 43 44 current = ( (unsigned char)bindata[i+2] ) & ( (unsigned char)0x3F ) ; 45 base64[j++] = base64char[(int)current]; 46 } 47 base64[j] = '