libdexfile/dex/base64_test_util.h

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * 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.
 */

#ifndef ART_LIBDEXFILE_DEX_BASE64_TEST_UTIL_H_
#define ART_LIBDEXFILE_DEX_BASE64_TEST_UTIL_H_

#include <stdint.h>
#include <stdlib.h>

#include <memory>
#include <vector>

#include <android-base/logging.h>

namespace art {

static inline uint8_t* DecodeBase64(const char* src, size_t* dst_size) {
  static const uint8_t kBase64Map[256] = {
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255,  62, 255, 255, 255,  63,
    52,  53,  54,  55,  56,  57,  58,  59,  60,  61, 255, 255,
    255, 254, 255, 255, 255,   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, 255, 255, 255, 255, 255,
    255,  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, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255
  };

  CHECK(dst_size != nullptr);
  std::vector<uint8_t> tmp;
  uint32_t t = 0, y = 0;
  int g = 3;
  for (size_t i = 0; src[i] != '\0'; ++i) {
    uint8_t c = kBase64Map[src[i] & 0xFF];
    if (c == 255) continue;
    // the final = symbols are read and used to trim the remaining bytes
    if (c == 254) {
      c = 0;
      // prevent g < 0 which would potentially allow an overflow later
      if (--g < 0) {
        *dst_size = 0;
        return nullptr;
      }
    } else if (g != 3) {
      // we only allow = to be at the end
      *dst_size = 0;
      return nullptr;
    }
    t = (t << 6) | c;
    if (++y == 4) {
      tmp.push_back((t >> 16) & 255);
      if (g > 1) {
        tmp.push_back((t >> 8) & 255);
      }
      if (g > 2) {
        tmp.push_back(t & 255);
      }
      y = t = 0;
    }
  }
  if (y != 0) {
    *dst_size = 0;
    return nullptr;
  }
  std::unique_ptr<uint8_t[]> dst(new uint8_t[tmp.size()]);
  *dst_size = tmp.size();
  std::copy(tmp.begin(), tmp.end(), dst.get());
  return dst.release();
}

}  // namespace art

#endif  // ART_LIBDEXFILE_DEX_BASE64_TEST_UTIL_H_