bionic/linker/linker_sleb128.h
Dmitriy Ivanov 18870d350c Always use signed leb128 decoder
Relocation packer no longer encodes relocation tables
  using unsigned leb128: https://android-review.googlesource.com/147745

Bug: http://b/18051137
Change-Id: I620b7188e5f3dd9d5123431aa1fc7feca76be607
2015-04-22 13:29:42 -07:00

59 lines
1.5 KiB
C++

/*
* Copyright (C) 2015 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 _LINKER_SLEB128_H
#define _LINKER_SLEB128_H
#include <stdint.h>
// Helper classes for decoding LEB128, used in packed relocation data.
// http://en.wikipedia.org/wiki/LEB128
class sleb128_decoder {
public:
sleb128_decoder(const uint8_t* buffer, size_t count)
: current_(buffer), end_(buffer+count) { }
size_t pop_front() {
size_t value = 0;
static const size_t size = CHAR_BIT * sizeof(value);
size_t shift = 0;
uint8_t byte;
do {
if (current_ >= end_) {
__libc_fatal("sleb128_decoder ran out of bounds");
}
byte = *current_++;
value |= (static_cast<size_t>(byte & 127) << shift);
shift += 7;
} while (byte & 128);
if (shift < size && (byte & 64)) {
value |= -(static_cast<size_t>(1) << shift);
}
return value;
}
private:
const uint8_t* current_;
const uint8_t* const end_;
};
#endif // __LINKER_SLEB128_H