1 /*
2  * Copyright (C) 2021 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "android-base/hex.h"
18 
19 #include "android-base/logging.h"
20 
21 namespace android {
22 namespace base {
23 
HexString(const void * bytes,size_t len)24 std::string HexString(const void* bytes, size_t len) {
25   CHECK(bytes != nullptr || len == 0) << bytes << " " << len;
26 
27   // b/132916539: Doing this the 'C way', std::setfill triggers ubsan implicit conversion
28   const uint8_t* bytes8 = static_cast<const uint8_t*>(bytes);
29   const char chars[] = "0123456789abcdef";
30   std::string result;
31   result.resize(len * 2);
32 
33   for (size_t i = 0; i < len; i++) {
34     result[2 * i] = chars[bytes8[i] >> 4];
35     result[2 * i + 1] = chars[bytes8[i] & 0xf];
36   }
37 
38   return result;
39 }
40 
41 }  // namespace base
42 }  // namespace android
43