247 lines
8.3 KiB
C++
247 lines
8.3 KiB
C++
#ifndef OSMIUM_IO_GZIP_COMPRESSION_HPP
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#define OSMIUM_IO_GZIP_COMPRESSION_HPP
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/*
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This file is part of Osmium (http://osmcode.org/libosmium).
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Copyright 2013-2015 Jochen Topf <jochen@topf.org> and others (see README).
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Boost Software License - Version 1.0 - August 17th, 2003
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Permission is hereby granted, free of charge, to any person or organization
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obtaining a copy of the software and accompanying documentation covered by
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this license (the "Software") to use, reproduce, display, distribute,
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execute, and transmit the Software, and to prepare derivative works of the
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Software, and to permit third-parties to whom the Software is furnished to
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do so, all subject to the following:
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The copyright notices in the Software and this entire statement, including
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the above license grant, this restriction and the following disclaimer,
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must be included in all copies of the Software, in whole or in part, and
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all derivative works of the Software, unless such copies or derivative
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works are solely in the form of machine-executable object code generated by
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a source language processor.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
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SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
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FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
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ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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DEALINGS IN THE SOFTWARE.
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*/
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/**
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* @file
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*
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* Include this file if you want to read or write gzip-compressed OSM XML
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* files.
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*
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* @attention If you include this file, you'll need to link with `libz`.
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*/
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#include <stdexcept>
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#include <string>
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#include <errno.h>
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#include <zlib.h>
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#include <osmium/io/compression.hpp>
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#include <osmium/io/file_compression.hpp>
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#include <osmium/util/cast.hpp>
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#include <osmium/util/compatibility.hpp>
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namespace osmium {
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/**
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* Exception thrown when there are problems compressing or
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* decompressing gzip files.
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*/
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struct gzip_error : public std::runtime_error {
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int gzip_error_code;
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int system_errno;
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gzip_error(const std::string& what, int error_code) :
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std::runtime_error(what),
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gzip_error_code(error_code),
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system_errno(error_code == Z_ERRNO ? errno : 0) {
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}
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}; // struct gzip_error
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namespace io {
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namespace detail {
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OSMIUM_NORETURN inline void throw_gzip_error(gzFile gzfile, const char* msg, int zlib_error=0) {
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std::string error("gzip error: ");
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error += msg;
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error += ": ";
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int errnum = zlib_error;
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if (zlib_error) {
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error += std::to_string(zlib_error);
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} else {
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error += ::gzerror(gzfile, &errnum);
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}
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throw osmium::gzip_error(error, errnum);
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}
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} // namespace detail
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class GzipCompressor : public Compressor {
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gzFile m_gzfile;
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public:
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explicit GzipCompressor(int fd) :
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Compressor(),
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m_gzfile(::gzdopen(fd, "w")) {
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if (!m_gzfile) {
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detail::throw_gzip_error(m_gzfile, "write initialization failed");
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}
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}
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~GzipCompressor() override final {
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close();
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}
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void write(const std::string& data) override final {
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if (!data.empty()) {
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int nwrite = ::gzwrite(m_gzfile, data.data(), static_cast_with_assert<unsigned int>(data.size()));
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if (nwrite == 0) {
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detail::throw_gzip_error(m_gzfile, "write failed");
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}
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}
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}
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void close() override final {
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if (m_gzfile) {
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int result = ::gzclose(m_gzfile);
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m_gzfile = nullptr;
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if (result != Z_OK) {
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detail::throw_gzip_error(m_gzfile, "write close failed", result);
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}
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}
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}
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}; // class GzipCompressor
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class GzipDecompressor : public Decompressor {
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gzFile m_gzfile;
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public:
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explicit GzipDecompressor(int fd) :
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Decompressor(),
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m_gzfile(::gzdopen(fd, "r")) {
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if (!m_gzfile) {
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detail::throw_gzip_error(m_gzfile, "read initialization failed");
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}
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}
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~GzipDecompressor() override final {
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close();
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}
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std::string read() override final {
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std::string buffer(osmium::io::Decompressor::input_buffer_size, '\0');
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int nread = ::gzread(m_gzfile, const_cast<char*>(buffer.data()), static_cast_with_assert<unsigned int>(buffer.size()));
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if (nread < 0) {
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detail::throw_gzip_error(m_gzfile, "read failed");
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}
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buffer.resize(static_cast<std::string::size_type>(nread));
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return buffer;
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}
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void close() override final {
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if (m_gzfile) {
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int result = ::gzclose(m_gzfile);
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m_gzfile = nullptr;
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if (result != Z_OK) {
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detail::throw_gzip_error(m_gzfile, "read close failed", result);
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}
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}
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}
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}; // class GzipDecompressor
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class GzipBufferDecompressor : public Decompressor {
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const char* m_buffer;
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size_t m_buffer_size;
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z_stream m_zstream;
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public:
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GzipBufferDecompressor(const char* buffer, size_t size) :
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m_buffer(buffer),
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m_buffer_size(size),
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m_zstream() {
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m_zstream.next_in = reinterpret_cast<unsigned char*>(const_cast<char*>(buffer));
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m_zstream.avail_in = static_cast_with_assert<unsigned int>(size);
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int result = inflateInit2(&m_zstream, MAX_WBITS | 32);
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if (result != Z_OK) {
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std::string message("gzip error: decompression init failed: ");
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if (m_zstream.msg) {
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message.append(m_zstream.msg);
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}
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throw osmium::gzip_error(message, result);
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}
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}
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~GzipBufferDecompressor() override final {
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inflateEnd(&m_zstream);
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}
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std::string read() override final {
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std::string output;
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if (m_buffer) {
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const size_t buffer_size = 10240;
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output.append(buffer_size, '\0');
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m_zstream.next_out = reinterpret_cast<unsigned char*>(const_cast<char*>(output.data()));
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m_zstream.avail_out = buffer_size;
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int result = inflate(&m_zstream, Z_SYNC_FLUSH);
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if (result != Z_OK) {
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m_buffer = nullptr;
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m_buffer_size = 0;
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}
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if (result != Z_OK && result != Z_STREAM_END) {
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std::string message("gzip error: inflate failed: ");
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if (m_zstream.msg) {
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message.append(m_zstream.msg);
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}
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throw osmium::gzip_error(message, result);
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}
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output.resize(static_cast<unsigned long>(m_zstream.next_out - reinterpret_cast<const unsigned char*>(output.data())));
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}
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return output;
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}
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}; // class GzipBufferDecompressor
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namespace {
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const bool registered_gzip_compression = osmium::io::CompressionFactory::instance().register_compression(osmium::io::file_compression::gzip,
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[](int fd) { return new osmium::io::GzipCompressor(fd); },
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[](int fd) { return new osmium::io::GzipDecompressor(fd); },
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[](const char* buffer, size_t size) { return new osmium::io::GzipBufferDecompressor(buffer, size); }
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);
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} // anonymous namespace
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} // namespace io
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} // namespace osmium
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#endif // OSMIUM_IO_GZIP_COMPRESSION_HPP
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