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Diffstat (limited to 'decoder/gzstream.h')
| -rw-r--r-- | decoder/gzstream.h | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/decoder/gzstream.h b/decoder/gzstream.h new file mode 100644 index 00000000..ad9785fd --- /dev/null +++ b/decoder/gzstream.h @@ -0,0 +1,121 @@ +// ============================================================================ +// gzstream, C++ iostream classes wrapping the zlib compression library. +// Copyright (C) 2001 Deepak Bandyopadhyay, Lutz Kettner +// +// This library is free software; you can redistribute it and/or +// modify it under the terms of the GNU Lesser General Public +// License as published by the Free Software Foundation; either +// version 2.1 of the License, or (at your option) any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public +// License along with this library; if not, write to the Free Software +// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA +// ============================================================================ +// +// File : gzstream.h +// Revision : $Revision: 1.1 $ +// Revision_date : $Date: 2006/03/30 04:05:52 $ +// Author(s) : Deepak Bandyopadhyay, Lutz Kettner +// +// Standard streambuf implementation following Nicolai Josuttis, "The +// Standard C++ Library". +// ============================================================================ + +#ifndef GZSTREAM_H +#define GZSTREAM_H 1 + +// standard C++ with new header file names and std:: namespace +#include <iostream> +#include <fstream> +#include <zlib.h> + +#ifdef GZSTREAM_NAMESPACE +namespace GZSTREAM_NAMESPACE { +#endif + +// ---------------------------------------------------------------------------- +// Internal classes to implement gzstream. See below for user classes. +// ---------------------------------------------------------------------------- + +class gzstreambuf : public std::streambuf { +private: + static const int bufferSize = 47+256; // size of data buff + // totals 512 bytes under g++ for igzstream at the end. + + gzFile file; // file handle for compressed file + char buffer[bufferSize]; // data buffer + char opened; // open/close state of stream + int mode; // I/O mode + + int flush_buffer(); +public: + gzstreambuf() : opened(0) { + setp( buffer, buffer + (bufferSize-1)); + setg( buffer + 4, // beginning of putback area + buffer + 4, // read position + buffer + 4); // end position + // ASSERT: both input & output capabilities will not be used together + } + int is_open() { return opened; } + gzstreambuf* open( const char* name, int open_mode); + gzstreambuf* close(); + ~gzstreambuf() { close(); } + + virtual int overflow( int c = EOF); + virtual int underflow(); + virtual int sync(); +}; + +class gzstreambase : virtual public std::ios { +protected: + gzstreambuf buf; +public: + gzstreambase() { init(&buf); } + gzstreambase( const char* name, int open_mode); + ~gzstreambase(); + void open( const char* name, int open_mode); + void close(); + gzstreambuf* rdbuf() { return &buf; } +}; + +// ---------------------------------------------------------------------------- +// User classes. Use igzstream and ogzstream analogously to ifstream and +// ofstream respectively. They read and write files based on the gz* +// function interface of the zlib. Files are compatible with gzip compression. +// ---------------------------------------------------------------------------- + +class igzstream : public gzstreambase, public std::istream { +public: + igzstream() : std::istream( &buf) {} + igzstream( const char* name, int open_mode = std::ios::in) + : gzstreambase( name, open_mode), std::istream( &buf) {} + gzstreambuf* rdbuf() { return gzstreambase::rdbuf(); } + void open( const char* name, int open_mode = std::ios::in) { + gzstreambase::open( name, open_mode); + } +}; + +class ogzstream : public gzstreambase, public std::ostream { +public: + ogzstream() : std::ostream( &buf) {} + ogzstream( const char* name, int mode = std::ios::out) + : gzstreambase( name, mode), std::ostream( &buf) {} + gzstreambuf* rdbuf() { return gzstreambase::rdbuf(); } + void open( const char* name, int open_mode = std::ios::out) { + gzstreambase::open( name, open_mode); + } +}; + +#ifdef GZSTREAM_NAMESPACE +} // namespace GZSTREAM_NAMESPACE +#endif + +#endif // GZSTREAM_H +// ============================================================================ +// EOF // + |