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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.
#include "packer.h"
#include <vector>
#include "debug.h"
#include "delta_encoder.h"
#include "elf_traits.h"
#include "sleb128.h"
namespace relocation_packer {
// Pack relocations into a group encoded packed representation.
template <typename ELF>
void RelocationPacker<ELF>::PackRelocations(const std::vector<typename ELF::Rela>& relocations,
std::vector<uint8_t>* packed) {
// Run-length encode.
std::vector<typename ELF::Addr> packed_words;
RelocationDeltaCodec<ELF> codec;
codec.Encode(relocations, &packed_words);
// If insufficient data do nothing.
if (packed_words.empty())
return;
Sleb128Encoder<typename ELF::Addr> sleb128_encoder;
std::vector<uint8_t> sleb128_packed;
sleb128_encoder.EnqueueAll(packed_words);
sleb128_encoder.GetEncoding(&sleb128_packed);
packed->push_back('A');
packed->push_back('P');
packed->push_back('S');
packed->push_back('2');
packed->insert(packed->end(), sleb128_packed.begin(), sleb128_packed.end());
}
// Unpack relative relocations from a run-length encoded packed
// representation.
template <typename ELF>
void RelocationPacker<ELF>::UnpackRelocations(
const std::vector<uint8_t>& packed,
std::vector<typename ELF::Rela>* relocations) {
std::vector<typename ELF::Addr> packed_words;
CHECK(packed.size() > 4 &&
packed[0] == 'A' &&
packed[1] == 'P' &&
packed[2] == 'S' &&
packed[3] == '2');
Sleb128Decoder<typename ELF::Addr> decoder(packed, 4);
decoder.DequeueAll(&packed_words);
RelocationDeltaCodec<ELF> codec;
codec.Decode(packed_words, relocations);
}
template class RelocationPacker<ELF32_traits>;
template class RelocationPacker<ELF64_traits>;
} // namespace relocation_packer
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