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89 lines
2.6 KiB
89 lines
2.6 KiB
// Copyright 2017 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "bsdiff/diff_encoder.h"
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#include <vector>
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#include "bsdiff/logging.h"
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namespace {
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// The maximum positive number that we should encode. A number larger than this
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// for unsigned fields will be interpreted as a negative value and thus a
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// corrupt patch.
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const uint64_t kMaxEncodedUint64Value = (1ULL << 63) - 1;
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} // namespace
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namespace bsdiff {
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bool DiffEncoder::Init() {
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return patch_->Init(new_size_);
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}
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bool DiffEncoder::AddControlEntry(const ControlEntry& entry) {
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if (entry.diff_size > kMaxEncodedUint64Value) {
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LOG(ERROR) << "Encoding value out of range " << entry.diff_size;
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return false;
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}
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if (entry.extra_size > kMaxEncodedUint64Value) {
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LOG(ERROR) << "Encoding value out of range " << entry.extra_size;
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return false;
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}
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// entry.diff_size + entry.extra_size don't overflow in uint64_t since we
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// checked the kMaxEncodedUint64Value limit before.
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if (entry.diff_size + entry.extra_size > new_size_ - written_output_) {
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LOG(ERROR) << "Wrote more output than the declared new_size";
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return false;
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}
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if (entry.diff_size > 0 &&
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(old_pos_ < 0 ||
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static_cast<uint64_t>(old_pos_) + entry.diff_size > old_size_)) {
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LOG(ERROR) << "The pointer in the old stream [" << old_pos_ << ", "
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<< (static_cast<uint64_t>(old_pos_) + entry.diff_size)
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<< ") is out of bounds [0, " << old_size_ << ")";
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return false;
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}
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// Pass down the control entry.
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if (!patch_->AddControlEntry(entry))
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return false;
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// Generate the diff stream.
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std::vector<uint8_t> diff(entry.diff_size);
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for (uint64_t i = 0; i < entry.diff_size; ++i) {
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diff[i] = new_buf_[written_output_ + i] - old_buf_[old_pos_ + i];
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}
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if (!patch_->WriteDiffStream(diff.data(), diff.size())) {
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LOG(ERROR) << "Writing " << diff.size() << " bytes to the diff stream";
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return false;
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}
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if (!patch_->WriteExtraStream(new_buf_ + written_output_ + entry.diff_size,
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entry.extra_size)) {
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LOG(ERROR) << "Writing " << entry.extra_size
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<< " bytes to the extra stream";
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return false;
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}
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old_pos_ += entry.diff_size + entry.offset_increment;
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written_output_ += entry.diff_size + entry.extra_size;
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return true;
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}
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bool DiffEncoder::Close() {
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if (written_output_ != new_size_) {
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LOG(ERROR) << "Close() called but not all the output was written";
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return false;
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}
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return patch_->Close();
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}
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} // namespace bsdiff
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