boost/iostreams/filter/gzip.hpp
// (C) Copyright Jonathan Turkanis 2003. // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) // See http://www.boost.org/libs/iostreams for documentation. // Contains the definitions of the class templates gzip_compressor and // gzip_decompressor for reading and writing files in the gzip file format // (RFC 1952). Based in part on work of Jonathan de Halleux; see [...] #ifndef BOOST_IOSTREAMS_GZIP_HPP_INCLUDED #define BOOST_IOSTREAMS_GZIP_HPP_INCLUDED #if defined(_MSC_VER) && (_MSC_VER >= 1020) # pragma once #endif #include <boost/config.hpp> // STATIC_CONSTANT, STDC_NAMESPACE, // DINKUMWARE_STDLIB, __STL_CONFIG_H. #include <algorithm> // min. #include <cstdio> // EOF. #include <cstddef> // size_t. #include <ctime> // std::time_t. #include <memory> // allocator. #include <boost/config.hpp> // Put size_t in std. #include <boost/detail/workaround.hpp> #include <boost/cstdint.hpp> // uint8_t, uint32_t. #include <boost/iostreams/constants.hpp> // buffer size. #include <boost/iostreams/detail/adapter/non_blocking_adapter.hpp> #include <boost/iostreams/detail/adapter/range_adapter.hpp> #include <boost/iostreams/detail/char_traits.hpp> #include <boost/iostreams/detail/ios.hpp> // failure. #include <boost/iostreams/operations.hpp> #include <boost/iostreams/device/back_inserter.hpp> #include <boost/iostreams/filter/zlib.hpp> #include <boost/iostreams/pipeline.hpp> // Must come last. #if defined(BOOST_MSVC) # pragma warning(push) # pragma warning(disable: 4309) // Truncation of constant value. #endif #ifdef BOOST_NO_STDC_NAMESPACE namespace std { using ::time_t; } #endif namespace boost { namespace iostreams { namespace gzip { using namespace boost::iostreams::zlib; // Error codes used by gzip_error. const int zlib_error = 1; const int bad_crc = 2; // Recorded crc doesn't match data. const int bad_length = 3; // Recorded length doesn't match data. const int bad_header = 4; // Malformed header. const int bad_footer = 5; // Malformed footer. namespace magic { // Magic numbers used by gzip header. const int id1 = 0x1f; const int id2 = 0x8b; } // End namespace magic. namespace method { // Codes used for the 'CM' byte of the gzip header. const int deflate = 8; } // End namespace method. namespace flags { // Codes used for the 'FLG' byte of the gzip header. const int text = 1; const int header_crc = 2; const int extra = 4; const int name = 8; const int comment = 16; } // End namespace flags. namespace extra_flags { // Codes used for the 'XFL' byte of the gzip header. const int best_compression = 2; const int best_speed = 4; } // End namespace extra_flags. // Codes used for the 'OS' byte of the gzip header. const int os_fat = 0; const int os_amiga = 1; const int os_vms = 2; const int os_unix = 3; const int os_vm_cms = 4; const int os_atari = 5; const int os_hpfs = 6; const int os_macintosh = 7; const int os_z_system = 8; const int os_cp_m = 9; const int os_tops_20 = 10; const int os_ntfs = 11; const int os_qdos = 12; const int os_acorn = 13; const int os_unknown = 255; } // End namespace gzip. // // Class name: gzip_params. // Description: Subclass of zlib_params with an additional field // representing a file name. // struct gzip_params : zlib_params { // Non-explicit constructor. gzip_params( int level = gzip::default_compression, int method = gzip::deflated, int window_bits = gzip::default_window_bits, int mem_level = gzip::default_mem_level, int strategy = gzip::default_strategy, std::string file_name = "", std::string comment = "", std::time_t mtime = 0 ) : zlib_params(level, method, window_bits, mem_level, strategy), file_name(file_name), mtime(mtime) { } std::string file_name; std::string comment; std::time_t mtime; }; // // Class name: gzip_error. // Description: Subclass of std::ios_base::failure thrown to indicate // zlib errors other than out-of-memory conditions. // class gzip_error : public BOOST_IOSTREAMS_FAILURE { public: explicit gzip_error(int error) : BOOST_IOSTREAMS_FAILURE("gzip error"), error_(error), zlib_error_code_(zlib::okay) { } explicit gzip_error(const zlib_error& e) : BOOST_IOSTREAMS_FAILURE("gzip error"), error_(gzip::zlib_error), zlib_error_code_(e.error()) { } int error() const { return error_; } int zlib_error_code() const { return zlib_error_code_; } private: int error_; int zlib_error_code_; }; // // Template name: gzip_compressor // Description: Model of OutputFilter implementing compression in the // gzip format. // template<typename Alloc = std::allocator<char> > class basic_gzip_compressor : basic_zlib_compressor<Alloc> { private: typedef basic_zlib_compressor<Alloc> base_type; public: typedef char char_type; struct category : dual_use, filter_tag, multichar_tag, closable_tag { }; basic_gzip_compressor( const gzip_params& = gzip::default_compression, int buffer_size = default_device_buffer_size ); template<typename Source> std::streamsize read(Source& src, char_type* s, std::streamsize n) { using namespace std; streamsize result = 0; // Read header. if (!(flags_ & f_header_done)) result += read_string(s, n, header_); // Read body. if (!(flags_ & f_body_done)) { // Read from basic_zlib_filter. streamsize amt = base_type::read(src, s + result, n - result); if (amt != -1) { result += amt; if (amt < n - result) { // Double-check for EOF. amt = base_type::read(src, s + result, n - result); if (amt != -1) result += amt; } } if (amt == -1) prepare_footer(); } // Read footer. if ((flags_ & f_body_done) != 0 && result < n) result += read_string(s + result, n - result, footer_); return result != 0 ? result : -1; } template<typename Sink> std::streamsize write(Sink& snk, const char_type* s, std::streamsize n) { if (!(flags_ & f_header_done)) { std::streamsize amt = static_cast<std::streamsize>(header_.size() - offset_); offset_ += boost::iostreams::write(snk, header_.data() + offset_, amt); if (offset_ == header_.size()) flags_ |= f_header_done; else return 0; } return base_type::write(snk, s, n); } template<typename Sink> void close(Sink& snk, BOOST_IOS::openmode m) { namespace io = boost::iostreams; if (m & BOOST_IOS::out) { // Close zlib compressor. base_type::close(snk, BOOST_IOS::out); if (flags_ & f_header_done) { // Write final fields of gzip file format. write_long(this->crc(), snk); write_long(this->total_in(), snk); } } #if BOOST_WORKAROUND(__GNUC__, == 2) && defined(__STL_CONFIG_H) || \ BOOST_WORKAROUND(BOOST_DINKUMWARE_STDLIB, == 1) \ /**/ footer_.erase(0, std::string::npos); #else footer_.clear(); #endif offset_ = 0; flags_ = 0; } private: static gzip_params normalize_params(gzip_params p); void prepare_footer(); std::streamsize read_string(char* s, std::streamsize n, std::string& str); template<typename Sink> static void write_long(long n, Sink& next) { boost::iostreams::put(next, static_cast<char>(0xFF & n)); boost::iostreams::put(next, static_cast<char>(0xFF & (n >> 8))); boost::iostreams::put(next, static_cast<char>(0xFF & (n >> 16))); boost::iostreams::put(next, static_cast<char>(0xFF & (n >> 24))); } enum flag_type { f_header_done = 1, f_body_done = f_header_done << 1, f_footer_done = f_body_done << 1 }; std::string header_; std::string footer_; std::size_t offset_; int flags_; }; BOOST_IOSTREAMS_PIPABLE(basic_gzip_compressor, 1) typedef basic_gzip_compressor<> gzip_compressor; // // Template name: basic_gzip_decompressor // Description: Model of InputFilter implementing compression in the // gzip format. // template<typename Alloc = std::allocator<char> > class basic_gzip_decompressor : basic_zlib_decompressor<Alloc> { public: typedef char char_type; struct category : multichar_input_filter_tag, closable_tag { }; basic_gzip_decompressor( int window_bits = gzip::default_window_bits, int buffer_size = default_device_buffer_size ); template<typename Source> std::streamsize read(Source& src, char_type* s, std::streamsize n) { if ((flags_ & f_header_read) == 0) { non_blocking_adapter<Source> nb(src); read_header(nb); flags_ |= f_header_read; } if ((flags_ & f_footer_read) != 0) return -1; try { std::streamsize result = 0; std::streamsize amt; if ((amt = base_type::read(src, s, n)) != -1) { result += amt; if (amt < n) { // Double check for EOF. amt = base_type::read(src, s + result, n - result); if (amt != -1) result += amt; } } if (amt == -1) { non_blocking_adapter<Source> nb(src); read_footer(nb); flags_ |= f_footer_read; } return result; } catch (const zlib_error& e) { throw gzip_error(e); } } template<typename Source> void close(Source& src) { try { base_type::close(src, BOOST_IOS::in); flags_ = 0; } catch (const zlib_error& e) { throw gzip_error(e); } } std::string file_name() const { return file_name_; } std::string comment() const { return comment_; } bool text() const { return (flags_ & gzip::flags::text) != 0; } int os() const { return os_; } std::time_t mtime() const { return mtime_; } private: typedef basic_zlib_decompressor<Alloc> base_type; typedef BOOST_IOSTREAMS_CHAR_TRAITS(char) traits_type; static bool is_eof(int c) { return traits_type::eq_int_type(c, EOF); } static gzip_params make_params(int window_bits); template<typename Source> static uint8_t read_uint8(Source& src, int error) { int c; if ((c = boost::iostreams::get(src)) == EOF || c == WOULD_BLOCK) throw gzip_error(error); return static_cast<uint8_t>(traits_type::to_char_type(c)); } template<typename Source> static uint32_t read_uint32(Source& src, int error) { uint8_t b1 = read_uint8(src, error); uint8_t b2 = read_uint8(src, error); uint8_t b3 = read_uint8(src, error); uint8_t b4 = read_uint8(src, error); return b1 + (b2 << 8) + (b3 << 16) + (b4 << 24); } template<typename Source> std::string read_string(Source& src) { std::string result; while (true) { int c; if (is_eof(c = boost::iostreams::get(src))) throw gzip_error(gzip::bad_header); else if (c == 0) return result; else result += static_cast<char>(c); } } template<typename Source> void read_header(Source& src) // Source is non-blocking. { // Reset saved values. #if BOOST_WORKAROUND(__GNUC__, == 2) && defined(__STL_CONFIG_H) || \ BOOST_WORKAROUND(BOOST_DINKUMWARE_STDLIB, == 1) \ /**/ file_name_.erase(0, std::string::npos); comment_.erase(0, std::string::npos); #else file_name_.clear(); comment_.clear(); #endif os_ = gzip::os_unknown; mtime_ = 0; int flags; // Read header, without checking header crc. if ( boost::iostreams::get(src) != gzip::magic::id1 || // ID1. boost::iostreams::get(src) != gzip::magic::id2 || // ID2. is_eof(boost::iostreams::get(src)) || // CM. is_eof(flags = boost::iostreams::get(src)) ) // FLG. { throw gzip_error(gzip::bad_header); } mtime_ = read_uint32(src, gzip::bad_header); // MTIME. read_uint8(src, gzip::bad_header); // XFL. os_ = read_uint8(src, gzip::bad_header); // OS. if (flags & boost::iostreams::gzip::flags::text) flags_ |= f_text; // Skip extra field. (From J. Halleaux; see note at top.) if (flags & gzip::flags::extra) { int length = static_cast<int>( read_uint8(src, gzip::bad_header) + (read_uint8(src, gzip::bad_header) << 8) ); // length is garbage if EOF but the loop below will quit anyway. do { } while (length-- != 0 && !is_eof(boost::iostreams::get(src))); } if (flags & gzip::flags::name) // Read file name. file_name_ = read_string(src); if (flags & gzip::flags::comment) // Read comment. comment_ = read_string(src); if (flags & gzip::flags::header_crc) { // Skip header crc. read_uint8(src, gzip::bad_header); read_uint8(src, gzip::bad_header); } } template<typename Source> void read_footer(Source& src) { typename base_type::string_type footer = this->unconsumed_input(); int c; while (!is_eof(c = boost::iostreams::get(src))) footer += c; detail::range_adapter<input, std::string> rng(footer.begin(), footer.end()); if (read_uint32(rng, gzip::bad_footer) != this->crc()) throw gzip_error(gzip::bad_crc); if (static_cast<int>(read_uint32(rng, gzip::bad_footer)) != this->total_out()) throw gzip_error(gzip::bad_length); } enum flag_type { f_header_read = 1, f_footer_read = f_header_read << 1, f_text = f_footer_read << 1 }; std::string file_name_; std::string comment_; int os_; std::time_t mtime_; int flags_; }; BOOST_IOSTREAMS_PIPABLE(basic_gzip_decompressor, 1) typedef basic_gzip_decompressor<> gzip_decompressor; //------------------Implementation of gzip_compressor-------------------------// template<typename Alloc> basic_gzip_compressor<Alloc>::basic_gzip_compressor (const gzip_params& p, int buffer_size) : base_type(normalize_params(p), buffer_size), offset_(0), flags_(0) { // Calculate gzip header. bool has_name = !p.file_name.empty(); bool has_comment = !p.comment.empty(); std::string::size_type length = 10 + (has_name ? p.file_name.size() + 1 : 0) + (has_comment ? p.comment.size() + 1 : 0); // + 2; // Header crc confuses gunzip. int flags = //gzip::flags::header_crc + (has_name ? gzip::flags::name : 0) + (has_comment ? gzip::flags::comment : 0); int extra_flags = ( p.level == zlib::best_compression ? gzip::extra_flags::best_compression : 0 ) + ( p.level == zlib::best_speed ? gzip::extra_flags::best_speed : 0 ); header_.reserve(length); header_ += gzip::magic::id1; // ID1. header_ += gzip::magic::id2; // ID2. header_ += gzip::method::deflate; // CM. header_ += static_cast<char>(flags); // FLG. header_ += static_cast<char>(0xFF & p.mtime); // MTIME. header_ += static_cast<char>(0xFF & (p.mtime >> 8)); header_ += static_cast<char>(0xFF & (p.mtime >> 16)); header_ += static_cast<char>(0xFF & (p.mtime >> 24)); header_ += static_cast<char>(extra_flags); // XFL. header_ += static_cast<char>(gzip::os_unknown); // OS. if (has_name) { header_ += p.file_name; header_ += '\0'; } if (has_comment) { header_ += p.comment; header_ += '\0'; } } template<typename Alloc> gzip_params basic_gzip_compressor<Alloc>::normalize_params(gzip_params p) { p.noheader = true; p.calculate_crc = true; return p; } template<typename Alloc> void basic_gzip_compressor<Alloc>::prepare_footer() { boost::iostreams::back_insert_device<std::string> out(footer_); write_long(this->crc(), out); write_long(this->total_in(), out); flags_ |= f_body_done; offset_ = 0; } template<typename Alloc> std::streamsize basic_gzip_compressor<Alloc>::read_string (char* s, std::streamsize n, std::string& str) { using namespace std; streamsize avail = static_cast<streamsize>(str.size() - offset_); streamsize amt = (std::min)(avail, n); std::copy( str.data() + offset_, str.data() + offset_ + amt, s ); offset_ += amt; if ( !(flags_ & f_header_done) && offset_ == static_cast<std::size_t>(str.size()) ) { flags_ |= f_header_done; } return amt; } //------------------Implementation of gzip_decompressor-----------------------// template<typename Alloc> basic_gzip_decompressor<Alloc>::basic_gzip_decompressor (int window_bits, int buffer_size) : base_type(make_params(window_bits), buffer_size), os_(gzip::os_unknown), mtime_(0), flags_(0) { } template<typename Alloc> gzip_params basic_gzip_decompressor<Alloc>::make_params(int window_bits) { gzip_params p; p.window_bits = window_bits; p.noheader = true; p.calculate_crc = true; return p; } //----------------------------------------------------------------------------// } } // End namespaces iostreams, boost. #if defined(BOOST_MSVC) # pragma warning(pop) #endif #endif // #ifndef BOOST_IOSTREAMS_GZIP_HPP_INCLUDED