C语言实现base64编码,base64解码

jopen 5年前

C语言实现base64编码,base64解码。

char *base64_encode(char *binData, char *base64, int binLength)  {          int i = 0;          int j = 0;          int current = 0;          for (i = 0; i < binLength; i += 3) {                     //获取第一个6位                  current = (*(binData+i) >> 2) & 0x3F;                  *(base64 + j++) = base64char[current];                     //获取第二个6位的前两位                  current = (*(binData+i) << 4) & 0x30;                     //如果只有一个字符,那么需要做特殊处理                  if (binLength <= (i+1)) {                          *(base64 + j++) = base64char[current];                          *(base64 + j++) = '=';                          *(base64 + j++) = '=';                          break;                  }                     //获取第二个6位的后四位                  current |= (*(binData+i+1) >> 4 ) & 0xf;                  *(base64 + j++) = base64char[current];                  //获取第三个6位的前四位                  current = (*(binData+i+1) << 2 ) & 0x3c;                  if (binLength <= (i+2)) {                          *(base64 + j++) = base64char[current];                          *(base64 + j++) = '=';                          break;                  }                     //获取第三个6位的后两位                  current |= (*(binData+i+2) >> 6) & 0x03;                  *(base64 + j++) = base64char[current];                     //获取第四个6位                  current = *(binData+i+2) & 0x3F;                  *(base64 + j++) = base64char[current];          }          *(base64+j) = '\0';             return base64;  }              char *base64_decode(char const *base64Str, char *debase64Str, int encodeStrLen)  {          int i = 0;          int j = 0;          int k = 0;          char temp[4] = "";             for (i = 0; i < encodeStrLen; i += 4) {                  for (j = 0; j < 64 ; j++) {                          if (*(base64Str + i) == base64char[j]) {                                  temp[0] = j;                          }                  }                     for (j = 0; j < 64 ; j++) {                          if (*(base64Str + i + 1) == base64char[j]) {                                  temp[1] = j;                          }                  }                        for (j = 0; j < 64 ; j++) {                          if (*(base64Str + i + 2) == base64char[j]) {                                  temp[2] = j;                          }                  }                        for (j = 0; j < 64 ; j++) {                          if (*(base64Str + i + 3) == base64char[j]) {                                  temp[3] = j;                          }                  }                     *(debase64Str + k++) = ((temp[0] << 2) & 0xFC) | ((temp[1]>>4) & 0x03);                  if ( *(base64Str + i + 2)  == '=' )                          break;                     *(debase64Str + k++) = ((temp[1] << 4) & 0xF0) | ((temp[2]>>2) & 0x0F);                  if ( *(base64Str + i + 3) == '=' )                          break;                     *(debase64Str + k++) = ((temp[2] << 6) & 0xF0) | (temp[3] & 0x3F);          }          return debase64Str;  }