lz4diff/lz4patch.cc - SHIFTPHONES/android_system_update_engine - Gitiles

 //
 // Copyright (C) 2021 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.
 //

 #include "lz4patch.h"

 #include <endian.h>
 #include <unistd.h>
 #include <fcntl.h>

 #include <algorithm>
 #include <string_view>

 #include <bsdiff/bspatch.h>
 #include <bsdiff/memory_file.h>
 #include <bsdiff/file.h>
 #include <puffin/memory_stream.h>

 #include "android-base/strings.h"
 #include "lz4diff/lz4diff.h"
 #include "lz4diff/lz4diff.pb.h"
 #include "lz4diff_compress.h"
 #include "lz4diff_format.h"
 #include "puffin/puffpatch.h"
 #include "update_engine/common/hash_calculator.h"
 #include "update_engine/common/utils.h"

 namespace chromeos_update_engine {

 namespace {

 template <typename T>
 constexpr void BigEndianToHost(T& t) {
   static_assert(std::is_integral_v<T>);
   static_assert(sizeof(t) == 4 || sizeof(t) == 8 || sizeof(t) == 2);
   if constexpr (sizeof(t) == 4) {
     t = be32toh(t);
   } else if constexpr (sizeof(t) == 8) {
     t = be64toh(t);
   } else if constexpr (sizeof(t) == 2) {
     t = be16toh(t);
   }
 }

 // In memory representation of an LZ4Diff patch, it's not marked as packed
 // because parsing isn't as simple as reinterpret_cast<> any way.
 struct Lz4diffPatch {
   char magic[kLz4diffMagic.size()];
   uint32_t version;
   uint32_t pb_header_size;  // size of protobuf message
   Lz4diffHeader pb_header;
   std::string_view inner_patch;
 };

 // Utility class to interact with puffin API. C++ does not have standard
 // Read/Write trait. So everybody invent their own file descriptor wrapper.
 class StringViewStream : public puffin::StreamInterface {
  public:
   ~StringViewStream() override = default;

   bool GetSize(uint64_t* size) const override {
     *size = read_memory_.size();
     return true;
   }

   bool GetOffset(uint64_t* offset) const override {
     *offset = offset_;
     return true;
   }

   bool Seek(uint64_t offset) override {
     TEST_AND_RETURN_FALSE(open_);
     uint64_t size;
     GetSize(&size);
     TEST_AND_RETURN_FALSE(offset <= size);
     offset_ = offset;
     return true;
   }

   bool Read(void* buffer, size_t length) override {
     TEST_AND_RETURN_FALSE(open_);
     TEST_AND_RETURN_FALSE(offset_ + length <= read_memory_.size());
     memcpy(buffer, read_memory_.data() + offset_, length);
     offset_ += length;
     return true;
   }

   bool Write(const void* buffer, size_t length) override {
     LOG(ERROR) << "Unsupported operation " << __FUNCTION__;
     return false;
   }

   bool Close() override {
     open_ = false;
     return true;
   }

   constexpr StringViewStream(std::string_view read_memory)
       : read_memory_(read_memory) {
     CHECK(!read_memory.empty());
   }

  private:
   // The memory buffer for reading.
   std::string_view read_memory_;

   // The current offset.
   uint64_t offset_{};
   bool open_{true};
 };

 bool ParseLz4DifffPatch(std::string_view patch_data, Lz4diffPatch* output) {
   CHECK_NE(output, nullptr);
   if (!android::base::StartsWith(patch_data, kLz4diffMagic)) {
     LOG(ERROR) << "Invalid lz4diff magic: "
                << HexEncode(patch_data.substr(0, kLz4diffMagic.size()))
                << ", expected: " << HexEncode(kLz4diffMagic);
     return false;
   }
   Lz4diffPatch& patch = *output;
   std::memcpy(patch.magic, patch_data.data(), kLz4diffMagic.size());
   std::memcpy(&patch.version,
               patch_data.data() + kLz4diffMagic.size(),
               sizeof(patch.version));
   BigEndianToHost(patch.version);
   if (patch.version != kLz4diffVersion) {
     LOG(ERROR) << "Unsupported lz4diff version: " << patch.version
                << ", supported version: " << kLz4diffVersion;
     return false;
   }
   std::memcpy(&patch.pb_header_size,
               patch_data.data() + kLz4diffMagic.size() + sizeof(patch.version),
               sizeof(patch.pb_header_size));
   BigEndianToHost(patch.pb_header_size);
   TEST_AND_RETURN_FALSE(patch.pb_header.ParseFromArray(
       patch_data.data() + kLz4diffHeaderSize, patch.pb_header_size));
   patch.inner_patch =
       patch_data.substr(kLz4diffHeaderSize + patch.pb_header_size);
   return true;
 }

 bool bspatch(std::string_view input_data,
              std::string_view patch_data,
              Blob* output) {
   CHECK_NE(output, nullptr);
   output->clear();
   CHECK_GT(patch_data.size(), 0UL);
   int err =
       bsdiff::bspatch(reinterpret_cast<const uint8_t*>(input_data.data()),
                       input_data.size(),
                       reinterpret_cast<const uint8_t*>(patch_data.data()),
                       patch_data.size(),
                       [output](const uint8_t* data, size_t size) -> size_t {
                         output->insert(output->end(), data, data + size);
                         return size;
                       });
   return err == 0;
 }

 bool puffpatch(std::string_view input_data,
                std::string_view patch_data,
                Blob* output) {
   return puffin::PuffPatch(std::make_unique<StringViewStream>(input_data),
                            puffin::MemoryStream::CreateForWrite(output),
                            reinterpret_cast<const uint8_t*>(patch_data.data()),
                            patch_data.size());
 }

 std::vector<CompressedBlock> ToCompressedBlockVec(
     const google::protobuf::RepeatedPtrField<CompressedBlockInfo>& rpf) {
   std::vector<CompressedBlock> ret;
   ret.reserve(rpf.size());
   for (const auto& block : rpf) {
     auto& info = ret.emplace_back();
     info.compressed_length = block.compressed_length();
     info.uncompressed_length = block.uncompressed_length();
     info.uncompressed_offset = block.uncompressed_offset();
   }
   return ret;
 }

 bool HasPosfixPatches(const Lz4diffPatch& patch) {
   for (const auto& info : patch.pb_header.dst_info().block_info()) {
     if (!info.postfix_bspatch().empty()) {
       return true;
     }
   }
   return false;
 }

 size_t GetCompressedSize(
     const google::protobuf::RepeatedPtrField<CompressedBlockInfo>& info) {
   size_t compressed_size = 0;
   for (const auto& block : info) {
     compressed_size += block.compressed_length();
   }
   return compressed_size;
 }

 size_t GetDecompressedSize(
     const google::protobuf::RepeatedPtrField<CompressedBlockInfo>& info) {
   size_t decompressed_size = 0;
   for (const auto& block : info) {
     decompressed_size += block.uncompressed_length();
   }
   return decompressed_size;
 }

 bool ApplyInnerPatch(Blob decompressed_src,
                      const Lz4diffPatch& patch,
                      Blob* decompressed_dst) {
   switch (patch.pb_header.inner_type()) {
     case InnerPatchType::BSDIFF:
       TEST_AND_RETURN_FALSE(bspatch(
           ToStringView(decompressed_src), patch.inner_patch, decompressed_dst));
       break;
     case InnerPatchType::PUFFDIFF:
       TEST_AND_RETURN_FALSE(puffpatch(
           ToStringView(decompressed_src), patch.inner_patch, decompressed_dst));
       break;
     default:
       LOG(ERROR) << "Unsupported patch type: " << patch.pb_header.inner_type();
       return false;
   }
   return true;
 }

 // TODO(zhangkelvin) Rewrite this in C++ 20 coroutine once that's available.
 // Hand coding CPS is not fun.
 bool Lz4Patch(std::string_view src_data,
               const Lz4diffPatch& patch,
               const SinkFunc& sink) {
   auto decompressed_src = TryDecompressBlob(
       src_data,
       ToCompressedBlockVec(patch.pb_header.src_info().block_info()),
       patch.pb_header.src_info().zero_padding_enabled());
   TEST_AND_RETURN_FALSE(!decompressed_src.empty());
   Blob decompressed_dst;
   const auto decompressed_dst_size =
       GetDecompressedSize(patch.pb_header.dst_info().block_info());
   decompressed_dst.reserve(decompressed_dst_size);

   ApplyInnerPatch(std::move(decompressed_src), patch, &decompressed_dst);

   if (!HasPosfixPatches(patch)) {
     return TryCompressBlob(
         ToStringView(decompressed_dst),
         ToCompressedBlockVec(patch.pb_header.dst_info().block_info()),
         patch.pb_header.dst_info().zero_padding_enabled(),
         patch.pb_header.dst_info().algo(),
         sink);
   }
   auto postfix_patcher =
       [&sink,
        block_idx = 0,
        &dst_block_info = patch.pb_header.dst_info().block_info()](
           const uint8_t* data, size_t size) mutable -> size_t {
     if (block_idx >= dst_block_info.size()) {
       return sink(data, size);
     }
     const auto& block_info = dst_block_info[block_idx];
     TEST_EQ(size, block_info.compressed_length());
     DEFER { block_idx++; };
     if (block_info.postfix_bspatch().empty()) {
       return sink(data, size);
     }
     if (!block_info.sha256_hash().empty()) {
       Blob actual_hash;
       TEST_AND_RETURN_FALSE(
           HashCalculator::RawHashOfBytes(data, size, &actual_hash));
       if (ToStringView(actual_hash) != block_info.sha256_hash()) {
         LOG(ERROR) << "Block " << block_info
                    << " is corrupted. This usually means the patch generator "
                       "used a different version of LZ4, or an incompatible LZ4 "
                       "patch generator was used, or LZ4 produces different "
                       "output on different platforms. Expected hash: "
                    << HexEncode(block_info.sha256_hash())
                    << ", actual hash: " << HexEncode(actual_hash);
         return 0;
       }
     }
     Blob fixed_block;
     TEST_AND_RETURN_FALSE(
         bspatch(std::string_view(reinterpret_cast<const char*>(data), size),
                 block_info.postfix_bspatch(),
                 &fixed_block));
     return sink(fixed_block.data(), fixed_block.size());
   };

   return TryCompressBlob(
       ToStringView(decompressed_dst),
       ToCompressedBlockVec(patch.pb_header.dst_info().block_info()),
       patch.pb_header.dst_info().zero_padding_enabled(),
       patch.pb_header.dst_info().algo(),
       postfix_patcher);
 }

 bool Lz4Patch(std::string_view src_data,
               const Lz4diffPatch& patch,
               Blob* output) {
   Blob blob;
   const auto output_size =
       GetCompressedSize(patch.pb_header.dst_info().block_info());
   blob.reserve(output_size);
   TEST_AND_RETURN_FALSE(Lz4Patch(
       src_data, patch, [&blob](const uint8_t* data, size_t size) -> size_t {
         blob.insert(blob.end(), data, data + size);
         return size;
       }));
   *output = std::move(blob);
   return true;
 }

 }  // namespace

 bool Lz4Patch(std::string_view src_data,
               std::string_view patch_data,
               Blob* output) {
   Lz4diffPatch patch;
   TEST_AND_RETURN_FALSE(ParseLz4DifffPatch(patch_data, &patch));
   return Lz4Patch(src_data, patch, output);
 }

 bool Lz4Patch(std::string_view src_data,
               std::string_view patch_data,
               const SinkFunc& sink) {
   Lz4diffPatch patch;
   TEST_AND_RETURN_FALSE(ParseLz4DifffPatch(patch_data, &patch));
   return Lz4Patch(src_data, patch, sink);
 }

 bool Lz4Patch(const Blob& src_data, const Blob& patch_data, Blob* output) {
   return Lz4Patch(ToStringView(src_data), ToStringView(patch_data), output);
 }

 std::ostream& operator<<(std::ostream& out, const CompressionAlgorithm& info) {
   out << "Algo {type: " << info.Type_Name(info.type());
   if (info.level() != 0) {
     out << ", level: " << info.level();
   }
   out << "}";

   return out;
 }

 std::ostream& operator<<(std::ostream& out, const CompressionInfo& info) {
   out << "CompressionInfo {block_info: " << info.block_info()
       << ", algo: " << info.algo() << "}";
   return out;
 }

 std::ostream& operator<<(std::ostream& out, const Lz4diffHeader& header) {
   out << "Lz4diffHeader {src_info: " << header.src_info()
       << ", dst_info: " << header.dst_info() << "}";
   return out;
 }

 }  // namespace chromeos_update_engine
	//
	// Copyright (C) 2021 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.
	//

	#include "lz4patch.h"

	#include <endian.h>
	#include <unistd.h>
	#include <fcntl.h>

	#include <algorithm>
	#include <string_view>

	#include <bsdiff/bspatch.h>
	#include <bsdiff/memory_file.h>
	#include <bsdiff/file.h>
	#include <puffin/memory_stream.h>

	#include "android-base/strings.h"
	#include "lz4diff/lz4diff.h"
	#include "lz4diff/lz4diff.pb.h"
	#include "lz4diff_compress.h"
	#include "lz4diff_format.h"
	#include "puffin/puffpatch.h"
	#include "update_engine/common/hash_calculator.h"
	#include "update_engine/common/utils.h"

	namespace chromeos_update_engine {

	namespace {

	template <typename T>
	constexpr void BigEndianToHost(T& t) {
	static_assert(std::is_integral_v<T>);
	static_assert(sizeof(t) == 4 \|\| sizeof(t) == 8 \|\| sizeof(t) == 2);
	if constexpr (sizeof(t) == 4) {
	t = be32toh(t);
	} else if constexpr (sizeof(t) == 8) {
	t = be64toh(t);
	} else if constexpr (sizeof(t) == 2) {
	t = be16toh(t);
	}
	}

	// In memory representation of an LZ4Diff patch, it's not marked as packed
	// because parsing isn't as simple as reinterpret_cast<> any way.
	struct Lz4diffPatch {
	char magic[kLz4diffMagic.size()];
	uint32_t version;
	uint32_t pb_header_size; // size of protobuf message
	Lz4diffHeader pb_header;
	std::string_view inner_patch;
	};

	// Utility class to interact with puffin API. C++ does not have standard
	// Read/Write trait. So everybody invent their own file descriptor wrapper.
	class StringViewStream : public puffin::StreamInterface {
	public:
	~StringViewStream() override = default;

	bool GetSize(uint64_t* size) const override {
	*size = read_memory_.size();
	return true;
	}

	bool GetOffset(uint64_t* offset) const override {
	*offset = offset_;
	return true;
	}

	bool Seek(uint64_t offset) override {
	TEST_AND_RETURN_FALSE(open_);
	uint64_t size;
	GetSize(&size);
	TEST_AND_RETURN_FALSE(offset <= size);
	offset_ = offset;
	return true;
	}

	bool Read(void* buffer, size_t length) override {
	TEST_AND_RETURN_FALSE(open_);
	TEST_AND_RETURN_FALSE(offset_ + length <= read_memory_.size());
	memcpy(buffer, read_memory_.data() + offset_, length);
	offset_ += length;
	return true;
	}

	bool Write(const void* buffer, size_t length) override {
	LOG(ERROR) << "Unsupported operation " << __FUNCTION__;
	return false;
	}

	bool Close() override {
	open_ = false;
	return true;
	}

	constexpr StringViewStream(std::string_view read_memory)
	: read_memory_(read_memory) {
	CHECK(!read_memory.empty());
	}

	private:
	// The memory buffer for reading.
	std::string_view read_memory_;

	// The current offset.
	uint64_t offset_{};
	bool open_{true};
	};

	bool ParseLz4DifffPatch(std::string_view patch_data, Lz4diffPatch* output) {
	CHECK_NE(output, nullptr);
	if (!android::base::StartsWith(patch_data, kLz4diffMagic)) {
	LOG(ERROR) << "Invalid lz4diff magic: "
	<< HexEncode(patch_data.substr(0, kLz4diffMagic.size()))
	<< ", expected: " << HexEncode(kLz4diffMagic);
	return false;
	}
	Lz4diffPatch& patch = *output;
	std::memcpy(patch.magic, patch_data.data(), kLz4diffMagic.size());
	std::memcpy(&patch.version,
	patch_data.data() + kLz4diffMagic.size(),
	sizeof(patch.version));
	BigEndianToHost(patch.version);
	if (patch.version != kLz4diffVersion) {
	LOG(ERROR) << "Unsupported lz4diff version: " << patch.version
	<< ", supported version: " << kLz4diffVersion;
	return false;
	}
	std::memcpy(&patch.pb_header_size,
	patch_data.data() + kLz4diffMagic.size() + sizeof(patch.version),
	sizeof(patch.pb_header_size));
	BigEndianToHost(patch.pb_header_size);
	TEST_AND_RETURN_FALSE(patch.pb_header.ParseFromArray(
	patch_data.data() + kLz4diffHeaderSize, patch.pb_header_size));
	patch.inner_patch =
	patch_data.substr(kLz4diffHeaderSize + patch.pb_header_size);
	return true;
	}

	bool bspatch(std::string_view input_data,
	std::string_view patch_data,
	Blob* output) {
	CHECK_NE(output, nullptr);
	output->clear();
	CHECK_GT(patch_data.size(), 0UL);
	int err =
	bsdiff::bspatch(reinterpret_cast<const uint8_t*>(input_data.data()),
	input_data.size(),
	reinterpret_cast<const uint8_t*>(patch_data.data()),
	patch_data.size(),
	[output](const uint8_t* data, size_t size) -> size_t {
	output->insert(output->end(), data, data + size);
	return size;
	});
	return err == 0;
	}

	bool puffpatch(std::string_view input_data,
	std::string_view patch_data,
	Blob* output) {
	return puffin::PuffPatch(std::make_unique<StringViewStream>(input_data),
	puffin::MemoryStream::CreateForWrite(output),
	reinterpret_cast<const uint8_t*>(patch_data.data()),
	patch_data.size());
	}

	std::vector<CompressedBlock> ToCompressedBlockVec(
	const google::protobuf::RepeatedPtrField<CompressedBlockInfo>& rpf) {
	std::vector<CompressedBlock> ret;
	ret.reserve(rpf.size());
	for (const auto& block : rpf) {
	auto& info = ret.emplace_back();
	info.compressed_length = block.compressed_length();
	info.uncompressed_length = block.uncompressed_length();
	info.uncompressed_offset = block.uncompressed_offset();
	}
	return ret;
	}

	bool HasPosfixPatches(const Lz4diffPatch& patch) {
	for (const auto& info : patch.pb_header.dst_info().block_info()) {
	if (!info.postfix_bspatch().empty()) {
	return true;
	}
	}
	return false;
	}

	size_t GetCompressedSize(
	const google::protobuf::RepeatedPtrField<CompressedBlockInfo>& info) {
	size_t compressed_size = 0;
	for (const auto& block : info) {
	compressed_size += block.compressed_length();
	}
	return compressed_size;
	}

	size_t GetDecompressedSize(
	const google::protobuf::RepeatedPtrField<CompressedBlockInfo>& info) {
	size_t decompressed_size = 0;
	for (const auto& block : info) {
	decompressed_size += block.uncompressed_length();
	}
	return decompressed_size;
	}

	bool ApplyInnerPatch(Blob decompressed_src,
	const Lz4diffPatch& patch,
	Blob* decompressed_dst) {
	switch (patch.pb_header.inner_type()) {
	case InnerPatchType::BSDIFF:
	TEST_AND_RETURN_FALSE(bspatch(
	ToStringView(decompressed_src), patch.inner_patch, decompressed_dst));
	break;
	case InnerPatchType::PUFFDIFF:
	TEST_AND_RETURN_FALSE(puffpatch(
	ToStringView(decompressed_src), patch.inner_patch, decompressed_dst));
	break;
	default:
	LOG(ERROR) << "Unsupported patch type: " << patch.pb_header.inner_type();
	return false;
	}
	return true;
	}

	// TODO(zhangkelvin) Rewrite this in C++ 20 coroutine once that's available.
	// Hand coding CPS is not fun.
	bool Lz4Patch(std::string_view src_data,
	const Lz4diffPatch& patch,
	const SinkFunc& sink) {
	auto decompressed_src = TryDecompressBlob(
	src_data,
	ToCompressedBlockVec(patch.pb_header.src_info().block_info()),
	patch.pb_header.src_info().zero_padding_enabled());
	TEST_AND_RETURN_FALSE(!decompressed_src.empty());
	Blob decompressed_dst;
	const auto decompressed_dst_size =
	GetDecompressedSize(patch.pb_header.dst_info().block_info());
	decompressed_dst.reserve(decompressed_dst_size);

	ApplyInnerPatch(std::move(decompressed_src), patch, &decompressed_dst);

	if (!HasPosfixPatches(patch)) {
	return TryCompressBlob(
	ToStringView(decompressed_dst),
	ToCompressedBlockVec(patch.pb_header.dst_info().block_info()),
	patch.pb_header.dst_info().zero_padding_enabled(),
	patch.pb_header.dst_info().algo(),
	sink);
	}
	auto postfix_patcher =
	[&sink,
	block_idx = 0,
	&dst_block_info = patch.pb_header.dst_info().block_info()](
	const uint8_t* data, size_t size) mutable -> size_t {
	if (block_idx >= dst_block_info.size()) {
	return sink(data, size);
	}
	const auto& block_info = dst_block_info[block_idx];
	TEST_EQ(size, block_info.compressed_length());
	DEFER { block_idx++; };
	if (block_info.postfix_bspatch().empty()) {
	return sink(data, size);
	}
	if (!block_info.sha256_hash().empty()) {
	Blob actual_hash;
	TEST_AND_RETURN_FALSE(
	HashCalculator::RawHashOfBytes(data, size, &actual_hash));
	if (ToStringView(actual_hash) != block_info.sha256_hash()) {
	LOG(ERROR) << "Block " << block_info
	<< " is corrupted. This usually means the patch generator "
	"used a different version of LZ4, or an incompatible LZ4 "
	"patch generator was used, or LZ4 produces different "
	"output on different platforms. Expected hash: "
	<< HexEncode(block_info.sha256_hash())
	<< ", actual hash: " << HexEncode(actual_hash);
	return 0;
	}
	}
	Blob fixed_block;
	TEST_AND_RETURN_FALSE(
	bspatch(std::string_view(reinterpret_cast<const char*>(data), size),
	block_info.postfix_bspatch(),
	&fixed_block));
	return sink(fixed_block.data(), fixed_block.size());
	};

	return TryCompressBlob(
	ToStringView(decompressed_dst),
	ToCompressedBlockVec(patch.pb_header.dst_info().block_info()),
	patch.pb_header.dst_info().zero_padding_enabled(),
	patch.pb_header.dst_info().algo(),
	postfix_patcher);
	}

	bool Lz4Patch(std::string_view src_data,
	const Lz4diffPatch& patch,
	Blob* output) {
	Blob blob;
	const auto output_size =
	GetCompressedSize(patch.pb_header.dst_info().block_info());
	blob.reserve(output_size);
	TEST_AND_RETURN_FALSE(Lz4Patch(
	src_data, patch, [&blob](const uint8_t* data, size_t size) -> size_t {
	blob.insert(blob.end(), data, data + size);
	return size;
	}));
	*output = std::move(blob);
	return true;
	}

	} // namespace

	bool Lz4Patch(std::string_view src_data,
	std::string_view patch_data,
	Blob* output) {
	Lz4diffPatch patch;
	TEST_AND_RETURN_FALSE(ParseLz4DifffPatch(patch_data, &patch));
	return Lz4Patch(src_data, patch, output);
	}

	bool Lz4Patch(std::string_view src_data,
	std::string_view patch_data,
	const SinkFunc& sink) {
	Lz4diffPatch patch;
	TEST_AND_RETURN_FALSE(ParseLz4DifffPatch(patch_data, &patch));
	return Lz4Patch(src_data, patch, sink);
	}

	bool Lz4Patch(const Blob& src_data, const Blob& patch_data, Blob* output) {
	return Lz4Patch(ToStringView(src_data), ToStringView(patch_data), output);
	}

	std::ostream& operator<<(std::ostream& out, const CompressionAlgorithm& info) {
	out << "Algo {type: " << info.Type_Name(info.type());
	if (info.level() != 0) {
	out << ", level: " << info.level();
	}
	out << "}";

	return out;
	}

	std::ostream& operator<<(std::ostream& out, const CompressionInfo& info) {
	out << "CompressionInfo {block_info: " << info.block_info()
	<< ", algo: " << info.algo() << "}";
	return out;
	}

	std::ostream& operator<<(std::ostream& out, const Lz4diffHeader& header) {
	out << "Lz4diffHeader {src_info: " << header.src_info()
	<< ", dst_info: " << header.dst_info() << "}";
	return out;
	}

	} // namespace chromeos_update_engine