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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// SLEB128 encoder and decoder for packed relative relocations.
// Packed relocations consist of a large number of relatively small
// integer values. Encoding these as LEB128 saves space.
// For more on LEB128 see
#include <stdint.h>
#include <unistd.h>
#include <vector>
#include "elf_traits.h"
namespace relocation_packer {
// Encode packed words as a signed LEB128 byte stream.
template<typename int_t>
class Sleb128Encoder {
// Explicit (but empty) constructor and destructor, for chromium-style.
// Add a value to the encoding stream.
// |value| is the signed int to add.
void Enqueue(int_t value);
// Add a vector of values to the encoding stream.
// |values| is the vector of signed ints to add.
void EnqueueAll(const std::vector<int_t>& values);
// Retrieve the encoded representation of the values.
// |encoding| is the returned vector of encoded data.
void GetEncoding(std::vector<uint8_t>* encoding) { *encoding = encoding_; }
// Growable vector holding the encoded LEB128 stream.
std::vector<uint8_t> encoding_;
// Decode a LEB128 byte stream to produce packed words.
template <typename int_t>
class Sleb128Decoder {
// Create a new decoder for the given encoded stream.
// |encoding| is the vector of encoded data.
explicit Sleb128Decoder(const std::vector<uint8_t>& encoding, size_t start_with);
// Explicit (but empty) destructor, for chromium-style.
// Retrieve the next value from the encoded stream.
int_t Dequeue();
// Retrieve all remaining values from the encoded stream.
// |values| is the vector of decoded data.
void DequeueAll(std::vector<int_t>* values);
// Encoded LEB128 stream.
std::vector<uint8_t> encoding_;
// Cursor indicating the current stream retrieval point.
size_t cursor_;
} // namespace relocation_packer