#include#includeconst char * base64char = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; char * base64_encode( const unsigned char * originChar, char * base64, int originlength )//base64编码{ int i, j; unsigned char current; for ( i = 0, j = 0 ; i < originlength ; i += 3 ) { current = (originChar[i] >> 2) ; current &= (unsigned char)0x3F; base64[j++] = base64char[(int)current]; current = ( (unsigned char)(originChar[i] << 4 ) ) & ( (unsigned char)0x30 ) ; if ( i + 1 >= originlength ) { base64[j++] = base64char[(int)current]; base64[j++] = '='; base64[j++] = '='; break; } current |= ( (unsigned char)(originChar[i+1] >> 4) ) & ( (unsigned char) 0x0F ); base64[j++] = base64char[(int)current]; current = ( (unsigned char)(originChar[i+1] << 2) ) & ( (unsigned char)0x3C ) ; if ( i + 2 >= originlength ) { base64[j++] = base64char[(int)current]; base64[j++] = '='; break; } current |= ( (unsigned char)(originChar[i+2] >> 6) ) & ( (unsigned char) 0x03 ); base64[j++] = base64char[(int)current]; current = ( (unsigned char)originChar[i+2] ) & ( (unsigned char)0x3F ) ; base64[j++] = base64char[(int)current]; } base64[j] = ''; return base64;}int base64_decode( const char * base64, unsigned char * originChar )//base64解码{ int i, j; unsigned char k; unsigned char temp[4]; for ( i = 0, j = 0; base64[i] != '' ; i += 4 ) { memset( temp, 0xFF, sizeof(temp) ); for ( k = 0 ; k < 64 ; k ++ ) { if ( base64char[k] == base64[i] ) temp[0]= k; } for ( k = 0 ; k < 64 ; k ++ ) { if ( base64char[k] == base64[i+1] ) temp[1]= k; } for ( k = 0 ; k < 64 ; k ++ ) { if ( base64char[k] == base64[i+2] ) temp[2]= k; } for ( k = 0 ; k < 64 ; k ++ ) { if ( base64char[k] == base64[i+3] ) temp[3]= k; } originChar[j++] = ((unsigned char)(((unsigned char)(temp[0] << 2))&0xFC)) | ((unsigned char)((unsigned char)(temp[1]>>4)&0x03)); if ( base64[i+2] == '=' ) break; originChar[j++] = ((unsigned char)(((unsigned char)(temp[1] << 4))&0xF0)) | ((unsigned char)((unsigned char)(temp[2]>>2)&0x0F)); if ( base64[i+3] == '=' ) break; originChar[j++] = ((unsigned char)(((unsigned char)(temp[2] << 6))&0xF0)) | ((unsigned char)(temp[3]&0x3F)); } return j;}int main(){ char *buff = "12345678"; int len = sizeof(buff); char base64[len*4/3+2]; char baes64[len*4/3+2]; base64_encode(buff,base64,len); printf("base64 = %sn",base64); base64_decode(base64,baes64); printf("baes64 = %sn",baes64); return 0;}
原文链接：https://blog.csdn.net/lly_3485390095/article/details/107043753