libziparchive/zip_writer.cc - LeafOS-Project/android_system_core - Gitiles

 /*
  * 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.
  */

 #include "entry_name_utils-inl.h"
 #include "zip_archive_common.h"
 #include "ziparchive/zip_writer.h"

 #include <utils/Log.h>

 #include <sys/param.h>

 #include <cassert>
 #include <cstdio>
 #include <memory>
 #include <vector>
 #include <zlib.h>
 #define DEF_MEM_LEVEL 8                // normally in zutil.h?

 #if !defined(powerof2)
 #define powerof2(x) ((((x)-1)&(x))==0)
 #endif

 /* Zip compression methods we support */
 enum {
   kCompressStored     = 0,        // no compression
   kCompressDeflated   = 8,        // standard deflate
 };

 // Size of the output buffer used for compression.
 static const size_t kBufSize = 32768u;

 // No error, operation completed successfully.
 static const int32_t kNoError = 0;

 // The ZipWriter is in a bad state.
 static const int32_t kInvalidState = -1;

 // There was an IO error while writing to disk.
 static const int32_t kIoError = -2;

 // The zip entry name was invalid.
 static const int32_t kInvalidEntryName = -3;

 // An error occurred in zlib.
 static const int32_t kZlibError = -4;

 // The start aligned function was called with the aligned flag.
 static const int32_t kInvalidAlign32Flag = -5;

 // The alignment parameter is not a power of 2.
 static const int32_t kInvalidAlignment = -6;

 static const char* sErrorCodes[] = {
     "Invalid state",
     "IO error",
     "Invalid entry name",
     "Zlib error",
 };

 const char* ZipWriter::ErrorCodeString(int32_t error_code) {
   if (error_code < 0 && (-error_code) < static_cast<int32_t>(arraysize(sErrorCodes))) {
     return sErrorCodes[-error_code];
   }
   return nullptr;
 }

 static void DeleteZStream(z_stream* stream) {
   deflateEnd(stream);
   delete stream;
 }

 ZipWriter::ZipWriter(FILE* f) : file_(f), current_offset_(0), state_(State::kWritingZip),
                                 z_stream_(nullptr, DeleteZStream), buffer_(kBufSize) {
 }

 ZipWriter::ZipWriter(ZipWriter&& writer) : file_(writer.file_),
                                            current_offset_(writer.current_offset_),
                                            state_(writer.state_),
                                            files_(std::move(writer.files_)),
                                            z_stream_(std::move(writer.z_stream_)),
                                            buffer_(std::move(writer.buffer_)){
   writer.file_ = nullptr;
   writer.state_ = State::kError;
 }

 ZipWriter& ZipWriter::operator=(ZipWriter&& writer) {
   file_ = writer.file_;
   current_offset_ = writer.current_offset_;
   state_ = writer.state_;
   files_ = std::move(writer.files_);
   z_stream_ = std::move(writer.z_stream_);
   buffer_ = std::move(writer.buffer_);
   writer.file_ = nullptr;
   writer.state_ = State::kError;
   return *this;
 }

 int32_t ZipWriter::HandleError(int32_t error_code) {
   state_ = State::kError;
   z_stream_.reset();
   return error_code;
 }

 int32_t ZipWriter::StartEntry(const char* path, size_t flags) {
   uint32_t alignment = 0;
   if (flags & kAlign32) {
     flags &= ~kAlign32;
     alignment = 4;
   }
   return StartAlignedEntryWithTime(path, flags, time_t(), alignment);
 }

 int32_t ZipWriter::StartAlignedEntry(const char* path, size_t flags, uint32_t alignment) {
   return StartAlignedEntryWithTime(path, flags, time_t(), alignment);
 }

 int32_t ZipWriter::StartEntryWithTime(const char* path, size_t flags, time_t time) {
   uint32_t alignment = 0;
   if (flags & kAlign32) {
     flags &= ~kAlign32;
     alignment = 4;
   }
   return StartAlignedEntryWithTime(path, flags, time, alignment);
 }

 static void ExtractTimeAndDate(time_t when, uint16_t* out_time, uint16_t* out_date) {
   /* round up to an even number of seconds */
   when = static_cast<time_t>((static_cast<unsigned long>(when) + 1) & (~1));

   struct tm* ptm;
 #if !defined(_WIN32)
     struct tm tm_result;
     ptm = localtime_r(&when, &tm_result);
 #else
     ptm = localtime(&when);
 #endif

   int year = ptm->tm_year;
   if (year < 80) {
     year = 80;
   }

   *out_date = (year - 80) << 9 | (ptm->tm_mon + 1) << 5 | ptm->tm_mday;
   *out_time = ptm->tm_hour << 11 | ptm->tm_min << 5 | ptm->tm_sec >> 1;
 }

 int32_t ZipWriter::StartAlignedEntryWithTime(const char* path, size_t flags,
                                              time_t time, uint32_t alignment) {
   if (state_ != State::kWritingZip) {
     return kInvalidState;
   }

   if (flags & kAlign32) {
     return kInvalidAlign32Flag;
   }

   if (powerof2(alignment) == 0) {
     return kInvalidAlignment;
   }

   FileInfo fileInfo = {};
   fileInfo.path = std::string(path);
   fileInfo.local_file_header_offset = current_offset_;

   if (!IsValidEntryName(reinterpret_cast<const uint8_t*>(fileInfo.path.data()),
                        fileInfo.path.size())) {
     return kInvalidEntryName;
   }

   LocalFileHeader header = {};
   header.lfh_signature = LocalFileHeader::kSignature;

   // Set this flag to denote that a DataDescriptor struct will appear after the data,
   // containing the crc and size fields.
   header.gpb_flags |= kGPBDDFlagMask;

   if (flags & ZipWriter::kCompress) {
     fileInfo.compression_method = kCompressDeflated;

     int32_t result = PrepareDeflate();
     if (result != kNoError) {
       return result;
     }
   } else {
     fileInfo.compression_method = kCompressStored;
   }
   header.compression_method = fileInfo.compression_method;

   ExtractTimeAndDate(time, &fileInfo.last_mod_time, &fileInfo.last_mod_date);
   header.last_mod_time = fileInfo.last_mod_time;
   header.last_mod_date = fileInfo.last_mod_date;

   header.file_name_length = fileInfo.path.size();

   off64_t offset = current_offset_ + sizeof(header) + fileInfo.path.size();
   std::vector<char> zero_padding;
   if (alignment != 0 && (offset & (alignment - 1))) {
     // Pad the extra field so the data will be aligned.
     uint16_t padding = alignment - (offset % alignment);
     header.extra_field_length = padding;
     offset += padding;
     zero_padding.resize(padding);
     memset(zero_padding.data(), 0, zero_padding.size());
   }

   if (fwrite(&header, sizeof(header), 1, file_) != 1) {
     return HandleError(kIoError);
   }

   if (fwrite(path, sizeof(*path), fileInfo.path.size(), file_) != fileInfo.path.size()) {
     return HandleError(kIoError);
   }

   if (header.extra_field_length != 0 &&
       fwrite(zero_padding.data(), 1, header.extra_field_length, file_)
       != header.extra_field_length) {
     return HandleError(kIoError);
   }

   files_.emplace_back(std::move(fileInfo));

   current_offset_ = offset;
   state_ = State::kWritingEntry;
   return kNoError;
 }

 int32_t ZipWriter::PrepareDeflate() {
   assert(state_ == State::kWritingZip);

   // Initialize the z_stream for compression.
   z_stream_ = std::unique_ptr<z_stream, void(*)(z_stream*)>(new z_stream(), DeleteZStream);

 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wold-style-cast"
   int zerr = deflateInit2(z_stream_.get(), Z_BEST_COMPRESSION, Z_DEFLATED, -MAX_WBITS,
                           DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY);
 #pragma GCC diagnostic pop

   if (zerr != Z_OK) {
     if (zerr == Z_VERSION_ERROR) {
       ALOGE("Installed zlib is not compatible with linked version (%s)", ZLIB_VERSION);
       return HandleError(kZlibError);
     } else {
       ALOGE("deflateInit2 failed (zerr=%d)", zerr);
       return HandleError(kZlibError);
     }
   }

   z_stream_->next_out = buffer_.data();
   z_stream_->avail_out = buffer_.size();
   return kNoError;
 }

 int32_t ZipWriter::WriteBytes(const void* data, size_t len) {
   if (state_ != State::kWritingEntry) {
     return HandleError(kInvalidState);
   }

   FileInfo& currentFile = files_.back();
   int32_t result = kNoError;
   if (currentFile.compression_method & kCompressDeflated) {
     result = CompressBytes(&currentFile, data, len);
   } else {
     result = StoreBytes(&currentFile, data, len);
   }

   if (result != kNoError) {
     return result;
   }

   currentFile.crc32 = crc32(currentFile.crc32, reinterpret_cast<const Bytef*>(data), len);
   currentFile.uncompressed_size += len;
   return kNoError;
 }

 int32_t ZipWriter::StoreBytes(FileInfo* file, const void* data, size_t len) {
   assert(state_ == State::kWritingEntry);

   if (fwrite(data, 1, len, file_) != len) {
     return HandleError(kIoError);
   }
   file->compressed_size += len;
   current_offset_ += len;
   return kNoError;
 }

 int32_t ZipWriter::CompressBytes(FileInfo* file, const void* data, size_t len) {
   assert(state_ == State::kWritingEntry);
   assert(z_stream_);
   assert(z_stream_->next_out != nullptr);
   assert(z_stream_->avail_out != 0);

   // Prepare the input.
   z_stream_->next_in = reinterpret_cast<const uint8_t*>(data);
   z_stream_->avail_in = len;

   while (z_stream_->avail_in > 0) {
     // We have more data to compress.
     int zerr = deflate(z_stream_.get(), Z_NO_FLUSH);
     if (zerr != Z_OK) {
       return HandleError(kZlibError);
     }

     if (z_stream_->avail_out == 0) {
       // The output is full, let's write it to disk.
       size_t write_bytes = z_stream_->next_out - buffer_.data();
       if (fwrite(buffer_.data(), 1, write_bytes, file_) != write_bytes) {
         return HandleError(kIoError);
       }
       file->compressed_size += write_bytes;
       current_offset_ += write_bytes;

       // Reset the output buffer for the next input.
       z_stream_->next_out = buffer_.data();
       z_stream_->avail_out = buffer_.size();
     }
   }
   return kNoError;
 }

 int32_t ZipWriter::FlushCompressedBytes(FileInfo* file) {
   assert(state_ == State::kWritingEntry);
   assert(z_stream_);
   assert(z_stream_->next_out != nullptr);
   assert(z_stream_->avail_out != 0);

   // Keep deflating while there isn't enough space in the buffer to
   // to complete the compress.
   int zerr;
   while ((zerr = deflate(z_stream_.get(), Z_FINISH)) == Z_OK) {
     assert(z_stream_->avail_out == 0);
     size_t write_bytes = z_stream_->next_out - buffer_.data();
     if (fwrite(buffer_.data(), 1, write_bytes, file_) != write_bytes) {
       return HandleError(kIoError);
     }
     file->compressed_size += write_bytes;
     current_offset_ += write_bytes;

     z_stream_->next_out = buffer_.data();
     z_stream_->avail_out = buffer_.size();
   }
   if (zerr != Z_STREAM_END) {
     return HandleError(kZlibError);
   }

   size_t write_bytes = z_stream_->next_out - buffer_.data();
   if (write_bytes != 0) {
     if (fwrite(buffer_.data(), 1, write_bytes, file_) != write_bytes) {
       return HandleError(kIoError);
     }
     file->compressed_size += write_bytes;
     current_offset_ += write_bytes;
   }
   z_stream_.reset();
   return kNoError;
 }

 int32_t ZipWriter::FinishEntry() {
   if (state_ != State::kWritingEntry) {
     return kInvalidState;
   }

   FileInfo& currentFile = files_.back();
   if (currentFile.compression_method & kCompressDeflated) {
     int32_t result = FlushCompressedBytes(&currentFile);
     if (result != kNoError) {
       return result;
     }
   }

   const uint32_t sig = DataDescriptor::kOptSignature;
   if (fwrite(&sig, sizeof(sig), 1, file_) != 1) {
     state_ = State::kError;
     return kIoError;
   }

   DataDescriptor dd = {};
   dd.crc32 = currentFile.crc32;
   dd.compressed_size = currentFile.compressed_size;
   dd.uncompressed_size = currentFile.uncompressed_size;
   if (fwrite(&dd, sizeof(dd), 1, file_) != 1) {
     return HandleError(kIoError);
   }

   current_offset_ += sizeof(DataDescriptor::kOptSignature) + sizeof(dd);
   state_ = State::kWritingZip;
   return kNoError;
 }

 int32_t ZipWriter::Finish() {
   if (state_ != State::kWritingZip) {
     return kInvalidState;
   }

   off64_t startOfCdr = current_offset_;
   for (FileInfo& file : files_) {
     CentralDirectoryRecord cdr = {};
     cdr.record_signature = CentralDirectoryRecord::kSignature;
     cdr.gpb_flags |= kGPBDDFlagMask;
     cdr.compression_method = file.compression_method;
     cdr.last_mod_time = file.last_mod_time;
     cdr.last_mod_date = file.last_mod_date;
     cdr.crc32 = file.crc32;
     cdr.compressed_size = file.compressed_size;
     cdr.uncompressed_size = file.uncompressed_size;
     cdr.file_name_length = file.path.size();
     cdr.local_file_header_offset = file.local_file_header_offset;
     if (fwrite(&cdr, sizeof(cdr), 1, file_) != 1) {
       return HandleError(kIoError);
     }

     if (fwrite(file.path.data(), 1, file.path.size(), file_) != file.path.size()) {
       return HandleError(kIoError);
     }

     current_offset_ += sizeof(cdr) + file.path.size();
   }

   EocdRecord er = {};
   er.eocd_signature = EocdRecord::kSignature;
   er.disk_num = 0;
   er.cd_start_disk = 0;
   er.num_records_on_disk = files_.size();
   er.num_records = files_.size();
   er.cd_size = current_offset_ - startOfCdr;
   er.cd_start_offset = startOfCdr;

   if (fwrite(&er, sizeof(er), 1, file_) != 1) {
     return HandleError(kIoError);
   }

   if (fflush(file_) != 0) {
     return HandleError(kIoError);
   }

   current_offset_ += sizeof(er);
   state_ = State::kDone;
   return kNoError;
 }
	/*
	* 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.
	*/

	#include "entry_name_utils-inl.h"
	#include "zip_archive_common.h"
	#include "ziparchive/zip_writer.h"

	#include <utils/Log.h>

	#include <sys/param.h>

	#include <cassert>
	#include <cstdio>
	#include <memory>
	#include <vector>
	#include <zlib.h>
	#define DEF_MEM_LEVEL 8 // normally in zutil.h?

	#if !defined(powerof2)
	#define powerof2(x) ((((x)-1)&(x))==0)
	#endif

	/* Zip compression methods we support */
	enum {
	kCompressStored = 0, // no compression
	kCompressDeflated = 8, // standard deflate
	};

	// Size of the output buffer used for compression.
	static const size_t kBufSize = 32768u;

	// No error, operation completed successfully.
	static const int32_t kNoError = 0;

	// The ZipWriter is in a bad state.
	static const int32_t kInvalidState = -1;

	// There was an IO error while writing to disk.
	static const int32_t kIoError = -2;

	// The zip entry name was invalid.
	static const int32_t kInvalidEntryName = -3;

	// An error occurred in zlib.
	static const int32_t kZlibError = -4;

	// The start aligned function was called with the aligned flag.
	static const int32_t kInvalidAlign32Flag = -5;

	// The alignment parameter is not a power of 2.
	static const int32_t kInvalidAlignment = -6;

	static const char* sErrorCodes[] = {
	"Invalid state",
	"IO error",
	"Invalid entry name",
	"Zlib error",
	};

	const char* ZipWriter::ErrorCodeString(int32_t error_code) {
	if (error_code < 0 && (-error_code) < static_cast<int32_t>(arraysize(sErrorCodes))) {
	return sErrorCodes[-error_code];
	}
	return nullptr;
	}

	static void DeleteZStream(z_stream* stream) {
	deflateEnd(stream);
	delete stream;
	}

	ZipWriter::ZipWriter(FILE* f) : file_(f), current_offset_(0), state_(State::kWritingZip),
	z_stream_(nullptr, DeleteZStream), buffer_(kBufSize) {
	}

	ZipWriter::ZipWriter(ZipWriter&& writer) : file_(writer.file_),
	current_offset_(writer.current_offset_),
	state_(writer.state_),
	files_(std::move(writer.files_)),
	z_stream_(std::move(writer.z_stream_)),
	buffer_(std::move(writer.buffer_)){
	writer.file_ = nullptr;
	writer.state_ = State::kError;
	}

	ZipWriter& ZipWriter::operator=(ZipWriter&& writer) {
	file_ = writer.file_;
	current_offset_ = writer.current_offset_;
	state_ = writer.state_;
	files_ = std::move(writer.files_);
	z_stream_ = std::move(writer.z_stream_);
	buffer_ = std::move(writer.buffer_);
	writer.file_ = nullptr;
	writer.state_ = State::kError;
	return *this;
	}

	int32_t ZipWriter::HandleError(int32_t error_code) {
	state_ = State::kError;
	z_stream_.reset();
	return error_code;
	}

	int32_t ZipWriter::StartEntry(const char* path, size_t flags) {
	uint32_t alignment = 0;
	if (flags & kAlign32) {
	flags &= ~kAlign32;
	alignment = 4;
	}
	return StartAlignedEntryWithTime(path, flags, time_t(), alignment);
	}

	int32_t ZipWriter::StartAlignedEntry(const char* path, size_t flags, uint32_t alignment) {
	return StartAlignedEntryWithTime(path, flags, time_t(), alignment);
	}

	int32_t ZipWriter::StartEntryWithTime(const char* path, size_t flags, time_t time) {
	uint32_t alignment = 0;
	if (flags & kAlign32) {
	flags &= ~kAlign32;
	alignment = 4;
	}
	return StartAlignedEntryWithTime(path, flags, time, alignment);
	}

	static void ExtractTimeAndDate(time_t when, uint16_t* out_time, uint16_t* out_date) {
	/* round up to an even number of seconds */
	when = static_cast<time_t>((static_cast<unsigned long>(when) + 1) & (~1));

	struct tm* ptm;
	#if !defined(_WIN32)
	struct tm tm_result;
	ptm = localtime_r(&when, &tm_result);
	#else
	ptm = localtime(&when);
	#endif

	int year = ptm->tm_year;
	if (year < 80) {
	year = 80;
	}

	*out_date = (year - 80) << 9 \| (ptm->tm_mon + 1) << 5 \| ptm->tm_mday;
	*out_time = ptm->tm_hour << 11 \| ptm->tm_min << 5 \| ptm->tm_sec >> 1;
	}

	int32_t ZipWriter::StartAlignedEntryWithTime(const char* path, size_t flags,
	time_t time, uint32_t alignment) {
	if (state_ != State::kWritingZip) {
	return kInvalidState;
	}

	if (flags & kAlign32) {
	return kInvalidAlign32Flag;
	}

	if (powerof2(alignment) == 0) {
	return kInvalidAlignment;
	}

	FileInfo fileInfo = {};
	fileInfo.path = std::string(path);
	fileInfo.local_file_header_offset = current_offset_;

	if (!IsValidEntryName(reinterpret_cast<const uint8_t*>(fileInfo.path.data()),
	fileInfo.path.size())) {
	return kInvalidEntryName;
	}

	LocalFileHeader header = {};
	header.lfh_signature = LocalFileHeader::kSignature;

	// Set this flag to denote that a DataDescriptor struct will appear after the data,
	// containing the crc and size fields.
	header.gpb_flags \|= kGPBDDFlagMask;

	if (flags & ZipWriter::kCompress) {
	fileInfo.compression_method = kCompressDeflated;

	int32_t result = PrepareDeflate();
	if (result != kNoError) {
	return result;
	}
	} else {
	fileInfo.compression_method = kCompressStored;
	}
	header.compression_method = fileInfo.compression_method;

	ExtractTimeAndDate(time, &fileInfo.last_mod_time, &fileInfo.last_mod_date);
	header.last_mod_time = fileInfo.last_mod_time;
	header.last_mod_date = fileInfo.last_mod_date;

	header.file_name_length = fileInfo.path.size();

	off64_t offset = current_offset_ + sizeof(header) + fileInfo.path.size();
	std::vector<char> zero_padding;
	if (alignment != 0 && (offset & (alignment - 1))) {
	// Pad the extra field so the data will be aligned.
	uint16_t padding = alignment - (offset % alignment);
	header.extra_field_length = padding;
	offset += padding;
	zero_padding.resize(padding);
	memset(zero_padding.data(), 0, zero_padding.size());
	}

	if (fwrite(&header, sizeof(header), 1, file_) != 1) {
	return HandleError(kIoError);
	}

	if (fwrite(path, sizeof(*path), fileInfo.path.size(), file_) != fileInfo.path.size()) {
	return HandleError(kIoError);
	}

	if (header.extra_field_length != 0 &&
	fwrite(zero_padding.data(), 1, header.extra_field_length, file_)
	!= header.extra_field_length) {
	return HandleError(kIoError);
	}

	files_.emplace_back(std::move(fileInfo));

	current_offset_ = offset;
	state_ = State::kWritingEntry;
	return kNoError;
	}

	int32_t ZipWriter::PrepareDeflate() {
	assert(state_ == State::kWritingZip);

	// Initialize the z_stream for compression.
	z_stream_ = std::unique_ptr<z_stream, void()(z_stream)>(new z_stream(), DeleteZStream);

	#pragma GCC diagnostic push
	#pragma GCC diagnostic ignored "-Wold-style-cast"
	int zerr = deflateInit2(z_stream_.get(), Z_BEST_COMPRESSION, Z_DEFLATED, -MAX_WBITS,
	DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY);
	#pragma GCC diagnostic pop

	if (zerr != Z_OK) {
	if (zerr == Z_VERSION_ERROR) {
	ALOGE("Installed zlib is not compatible with linked version (%s)", ZLIB_VERSION);
	return HandleError(kZlibError);
	} else {
	ALOGE("deflateInit2 failed (zerr=%d)", zerr);
	return HandleError(kZlibError);
	}
	}

	z_stream_->next_out = buffer_.data();
	z_stream_->avail_out = buffer_.size();
	return kNoError;
	}

	int32_t ZipWriter::WriteBytes(const void* data, size_t len) {
	if (state_ != State::kWritingEntry) {
	return HandleError(kInvalidState);
	}

	FileInfo& currentFile = files_.back();
	int32_t result = kNoError;
	if (currentFile.compression_method & kCompressDeflated) {
	result = CompressBytes(&currentFile, data, len);
	} else {
	result = StoreBytes(&currentFile, data, len);
	}

	if (result != kNoError) {
	return result;
	}

	currentFile.crc32 = crc32(currentFile.crc32, reinterpret_cast<const Bytef*>(data), len);
	currentFile.uncompressed_size += len;
	return kNoError;
	}

	int32_t ZipWriter::StoreBytes(FileInfo* file, const void* data, size_t len) {
	assert(state_ == State::kWritingEntry);

	if (fwrite(data, 1, len, file_) != len) {
	return HandleError(kIoError);
	}
	file->compressed_size += len;
	current_offset_ += len;
	return kNoError;
	}

	int32_t ZipWriter::CompressBytes(FileInfo* file, const void* data, size_t len) {
	assert(state_ == State::kWritingEntry);
	assert(z_stream_);
	assert(z_stream_->next_out != nullptr);
	assert(z_stream_->avail_out != 0);

	// Prepare the input.
	z_stream_->next_in = reinterpret_cast<const uint8_t*>(data);
	z_stream_->avail_in = len;

	while (z_stream_->avail_in > 0) {
	// We have more data to compress.
	int zerr = deflate(z_stream_.get(), Z_NO_FLUSH);
	if (zerr != Z_OK) {
	return HandleError(kZlibError);
	}

	if (z_stream_->avail_out == 0) {
	// The output is full, let's write it to disk.
	size_t write_bytes = z_stream_->next_out - buffer_.data();
	if (fwrite(buffer_.data(), 1, write_bytes, file_) != write_bytes) {
	return HandleError(kIoError);
	}
	file->compressed_size += write_bytes;
	current_offset_ += write_bytes;

	// Reset the output buffer for the next input.
	z_stream_->next_out = buffer_.data();
	z_stream_->avail_out = buffer_.size();
	}
	}
	return kNoError;
	}

	int32_t ZipWriter::FlushCompressedBytes(FileInfo* file) {
	assert(state_ == State::kWritingEntry);
	assert(z_stream_);
	assert(z_stream_->next_out != nullptr);
	assert(z_stream_->avail_out != 0);

	// Keep deflating while there isn't enough space in the buffer to
	// to complete the compress.
	int zerr;
	while ((zerr = deflate(z_stream_.get(), Z_FINISH)) == Z_OK) {
	assert(z_stream_->avail_out == 0);
	size_t write_bytes = z_stream_->next_out - buffer_.data();
	if (fwrite(buffer_.data(), 1, write_bytes, file_) != write_bytes) {
	return HandleError(kIoError);
	}
	file->compressed_size += write_bytes;
	current_offset_ += write_bytes;

	z_stream_->next_out = buffer_.data();
	z_stream_->avail_out = buffer_.size();
	}
	if (zerr != Z_STREAM_END) {
	return HandleError(kZlibError);
	}

	size_t write_bytes = z_stream_->next_out - buffer_.data();
	if (write_bytes != 0) {
	if (fwrite(buffer_.data(), 1, write_bytes, file_) != write_bytes) {
	return HandleError(kIoError);
	}
	file->compressed_size += write_bytes;
	current_offset_ += write_bytes;
	}
	z_stream_.reset();
	return kNoError;
	}

	int32_t ZipWriter::FinishEntry() {
	if (state_ != State::kWritingEntry) {
	return kInvalidState;
	}

	FileInfo& currentFile = files_.back();
	if (currentFile.compression_method & kCompressDeflated) {
	int32_t result = FlushCompressedBytes(&currentFile);
	if (result != kNoError) {
	return result;
	}
	}

	const uint32_t sig = DataDescriptor::kOptSignature;
	if (fwrite(&sig, sizeof(sig), 1, file_) != 1) {
	state_ = State::kError;
	return kIoError;
	}

	DataDescriptor dd = {};
	dd.crc32 = currentFile.crc32;
	dd.compressed_size = currentFile.compressed_size;
	dd.uncompressed_size = currentFile.uncompressed_size;
	if (fwrite(&dd, sizeof(dd), 1, file_) != 1) {
	return HandleError(kIoError);
	}

	current_offset_ += sizeof(DataDescriptor::kOptSignature) + sizeof(dd);
	state_ = State::kWritingZip;
	return kNoError;
	}

	int32_t ZipWriter::Finish() {
	if (state_ != State::kWritingZip) {
	return kInvalidState;
	}

	off64_t startOfCdr = current_offset_;
	for (FileInfo& file : files_) {
	CentralDirectoryRecord cdr = {};
	cdr.record_signature = CentralDirectoryRecord::kSignature;
	cdr.gpb_flags \|= kGPBDDFlagMask;
	cdr.compression_method = file.compression_method;
	cdr.last_mod_time = file.last_mod_time;
	cdr.last_mod_date = file.last_mod_date;
	cdr.crc32 = file.crc32;
	cdr.compressed_size = file.compressed_size;
	cdr.uncompressed_size = file.uncompressed_size;
	cdr.file_name_length = file.path.size();
	cdr.local_file_header_offset = file.local_file_header_offset;
	if (fwrite(&cdr, sizeof(cdr), 1, file_) != 1) {
	return HandleError(kIoError);
	}

	if (fwrite(file.path.data(), 1, file.path.size(), file_) != file.path.size()) {
	return HandleError(kIoError);
	}

	current_offset_ += sizeof(cdr) + file.path.size();
	}

	EocdRecord er = {};
	er.eocd_signature = EocdRecord::kSignature;
	er.disk_num = 0;
	er.cd_start_disk = 0;
	er.num_records_on_disk = files_.size();
	er.num_records = files_.size();
	er.cd_size = current_offset_ - startOfCdr;
	er.cd_start_offset = startOfCdr;

	if (fwrite(&er, sizeof(er), 1, file_) != 1) {
	return HandleError(kIoError);
	}

	if (fflush(file_) != 0) {
	return HandleError(kIoError);
	}

	current_offset_ += sizeof(er);
	state_ = State::kDone;
	return kNoError;
	}