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/* Copyright 2015 The TensorFlow Authors. All Rights Reserved.
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 "tensorflow/core/lib/io/record_writer.h"
#include "tensorflow/core/lib/core/coding.h"
#include "tensorflow/core/lib/hash/crc32c.h"
#include "tensorflow/core/lib/io/compression.h"
#include "tensorflow/core/platform/env.h"
namespace tensorflow {
namespace io {
namespace {
bool IsZlibCompressed(RecordWriterOptions options) {
return options.compression_type == RecordWriterOptions::ZLIB_COMPRESSION;
}
} // namespace
RecordWriterOptions RecordWriterOptions::CreateRecordWriterOptions(
const string& compression_type) {
RecordWriterOptions options;
if (compression_type == "ZLIB") {
options.compression_type = io::RecordWriterOptions::ZLIB_COMPRESSION;
#if defined(IS_SLIM_BUILD)
LOG(ERROR) << "Compression is not supported but compression_type is set."
<< " No compression will be used.";
#else
options.zlib_options = io::ZlibCompressionOptions::DEFAULT();
#endif // IS_SLIM_BUILD
} else if (compression_type == compression::kGzip) {
options.compression_type = io::RecordWriterOptions::ZLIB_COMPRESSION;
#if defined(IS_SLIM_BUILD)
LOG(ERROR) << "Compression is not supported but compression_type is set."
<< " No compression will be used.";
#else
options.zlib_options = io::ZlibCompressionOptions::GZIP();
#endif // IS_SLIM_BUILD
} else if (compression_type != compression::kNone) {
LOG(ERROR) << "Unsupported compression_type:" << compression_type
<< ". No compression will be used.";
}
return options;
}
RecordWriter::RecordWriter(WritableFile* dest,
const RecordWriterOptions& options)
: dest_(dest), options_(options) {
if (IsZlibCompressed(options)) {
// We don't have zlib available on all embedded platforms, so fail.
#if defined(IS_SLIM_BUILD)
LOG(FATAL) << "Zlib compression is unsupported on mobile platforms.";
#else // IS_SLIM_BUILD
ZlibOutputBuffer* zlib_output_buffer = new ZlibOutputBuffer(
dest, options.zlib_options.input_buffer_size,
options.zlib_options.output_buffer_size, options.zlib_options);
Status s = zlib_output_buffer->Init();
if (!s.ok()) {
LOG(FATAL) << "Failed to initialize Zlib inputbuffer. Error: "
<< s.ToString();
}
dest_ = zlib_output_buffer;
#endif // IS_SLIM_BUILD
} else if (options.compression_type == RecordWriterOptions::NONE) {
// Nothing to do
} else {
LOG(FATAL) << "Unspecified compression type :" << options.compression_type;
}
}
RecordWriter::~RecordWriter() {
if (dest_ != nullptr) {
Status s = Close();
if (!s.ok()) {
LOG(ERROR) << "Could not finish writing file: " << s;
}
}
}
Status RecordWriter::WriteRecord(StringPiece data) {
if (dest_ == nullptr) {
return Status(::tensorflow::error::FAILED_PRECONDITION,
"Writer not initialized or previously closed");
}
// Format of a single record:
// uint64 length
// uint32 masked crc of length
// byte data[length]
// uint32 masked crc of data
char header[kHeaderSize];
char footer[kFooterSize];
PopulateHeader(header, data.data(), data.size());
PopulateFooter(footer, data.data(), data.size());
TF_RETURN_IF_ERROR(dest_->Append(StringPiece(header, sizeof(header))));
TF_RETURN_IF_ERROR(dest_->Append(data));
return dest_->Append(StringPiece(footer, sizeof(footer)));
}
Status RecordWriter::Close() {
if (dest_ == nullptr) return Status::OK();
#if !defined(IS_SLIM_BUILD)
if (IsZlibCompressed(options_)) {
Status s = dest_->Close();
delete dest_;
dest_ = nullptr;
return s;
}
#endif // IS_SLIM_BUILD
return Status::OK();
}
Status RecordWriter::Flush() {
if (dest_ == nullptr) {
return Status(::tensorflow::error::FAILED_PRECONDITION,
"Writer not initialized or previously closed");
}
if (IsZlibCompressed(options_)) {
return dest_->Flush();
}
return Status::OK();
}
} // namespace io
} // namespace tensorflow
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