iflytoplinuxsdk_ptdv1/core/utils/base64.hpp

/**
 * Copyright (c) 2017 Baidu.com, Inc. All Rights Reserved
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 *
 * @author baidu aip
 */
#ifndef __AIP_BASE64_H__
#define __AIP_BASE64_H__

#include <iostream>
#include <string>

namespace iflytop {

static const std::string base64_chars =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "abcdefghijklmnopqrstuvwxyz"
    "0123456789+/";

static inline bool is_base64(const char c) { return (isalnum(c) || (c == '+') || (c == '/')); }

static inline std::string base64_encode(const char* bytes_to_encode, unsigned int in_len) {
  std::string   ret;
  int           i = 0;
  int           j = 0;
  unsigned char char_array_3[3];
  unsigned char char_array_4[4];

  while (in_len--) {
    char_array_3[i++] = *(bytes_to_encode++);
    if (i == 3) {
      char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
      char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
      char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
      char_array_4[3] = char_array_3[2] & 0x3f;

      for (i = 0; (i < 4); i++) {
        ret += base64_chars[char_array_4[i]];
      }
      i = 0;
    }
  }

  if (i) {
    for (j = i; j < 3; j++) {
      char_array_3[j] = '\0';
    }

    char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
    char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
    char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
    char_array_4[3] = char_array_3[2] & 0x3f;

    for (j = 0; (j < i + 1); j++) {
      ret += base64_chars[char_array_4[j]];
    }

    while ((i++ < 3)) {
      ret += '=';
    }
  }

  return ret;
}

static inline std::vector<uint8_t> base64_decode(std::string const& encoded_string) {
  int                  in_len = (int)encoded_string.size();
  int                  i      = 0;
  int                  j      = 0;
  int                  in_    = 0;
  unsigned char        char_array_4[4], char_array_3[3];
  std::vector<uint8_t> ret;

  while (in_len-- && (encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {
    char_array_4[i++] = encoded_string[in_];
    in_++;
    if (i == 4) {
      for (i = 0; i < 4; i++) char_array_4[i] = base64_chars.find(char_array_4[i]);

      char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
      char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
      char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

      for (i = 0; (i < 3); i++) {
        // ret += char_array_3[i];
        ret.push_back(char_array_3[i]);
      }
      i = 0;
    }
  }

  if (i) {
    for (j = i; j < 4; j++) char_array_4[j] = 0;

    for (j = 0; j < 4; j++) char_array_4[j] = base64_chars.find(char_array_4[j]);

    char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
    char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
    char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

    for (j = 0; (j < i - 1); j++) {
      // ret += char_array_3[j];
      ret.push_back(char_array_3[j]);
    }
  }

  return ret;
}

}  // namespace iflytop
#endif