/*
 * Copyright (C) 2021 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.
 */

#include "android-base/hex.h"

#include "android-base/logging.h"

namespace android {
namespace base {

std::string HexString(const void* bytes, size_t len) {
  CHECK(bytes != nullptr || len == 0) << bytes << " " << len;

  // b/132916539: Doing this the 'C way', std::setfill triggers ubsan implicit conversion
  const uint8_t* bytes8 = static_cast<const uint8_t*>(bytes);
  const char chars[] = "0123456789abcdef";
  std::string result;
  result.resize(len * 2);

  for (size_t i = 0; i < len; i++) {
    result[2 * i] = chars[bytes8[i] >> 4];
    result[2 * i + 1] = chars[bytes8[i] & 0xf];
  }

  return result;
}

}  // namespace base
}  // namespace android