243 lines
7.9 KiB
C++
243 lines
7.9 KiB
C++
// ============================================================================
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// gzstream, C++ iostream classes wrapping the zlib compression library.
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// Copyright (C) 2001 Deepak Bandyopadhyay, Lutz Kettner
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2.1 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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// ============================================================================
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//
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// File : gzstream.h
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// Revision : Revision: 1.5
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// Revision_date : Date: 2002/04/26 23:30:15
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// Author(s) : Deepak Bandyopadhyay, Lutz Kettner
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//
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// Matthew Walker made changes to fix a bug with igzstream. Previously, if
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// a call was made to igzstream with a filename that disn't exist, no error
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// would be reported. This has been fixed.
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//
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// Standard streambuf implementation following Nicolai Josuttis, "The
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// Standard C++ Library".
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// ============================================================================
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#ifndef GZSTREAM_H
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#define GZSTREAM_H
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// standard C++ with new header file names and std:: namespace
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#include <iostream>
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#include <fstream>
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#include <zlib.h>
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#ifdef GZSTREAM_NAMESPACE
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namespace GZSTREAM_NAMESPACE {
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#endif
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// ----------------------------------------------------------------------------
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// Internal classes to implement gzstream. See below for user classes.
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// ----------------------------------------------------------------------------
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class gzstreambuf : public std::streambuf {
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private:
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static const int bufferSize = 47+256; // size of data buff
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// totals 512 bytes under g++ for igzstream at the end.
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gzFile file; // file handle for compressed file
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char buffer[bufferSize]; // data buffer
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char opened; // open/close state of stream
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int mode; // I/O mode
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int flush_buffer();
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public:
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inline gzstreambuf() : opened(0) {
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setp( buffer, buffer + (bufferSize-1));
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setg( buffer + 4, // beginning of putback area
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buffer + 4, // read position
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buffer + 4); // end position
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// ASSERT: both input & output capabilities will not be used together
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}
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inline int is_open() { return opened; }
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inline gzstreambuf* open( const char* name, int open_mode);
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inline gzstreambuf* close();
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inline ~gzstreambuf() { close(); }
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virtual int overflow( int c = EOF);
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virtual int underflow();
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virtual int sync();
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};
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class gzstreambase : virtual public std::ios {
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protected:
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gzstreambuf buf;
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public:
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inline gzstreambase() { init(&buf); }
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inline gzstreambase( const char* name, int open_mode);
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inline ~gzstreambase();
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inline void open( const char* name, int open_mode);
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inline void close();
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inline gzstreambuf* rdbuf() { return &buf; }
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};
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// ----------------------------------------------------------------------------
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// User classes. Use igzstream and ogzstream analogously to ifstream and
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// ofstream respectively. They read and write files based on the gz*
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// function interface of the zlib. Files are compatible with gzip compression.
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// ----------------------------------------------------------------------------
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class igzstream : public std::istream, public gzstreambase {
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public:
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inline igzstream() : std::istream( &buf) {}
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inline igzstream( const char* name, int open_mode = std::ios::in)
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: std::istream( &buf), gzstreambase( name, open_mode) {}
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inline gzstreambuf* rdbuf() { return gzstreambase::rdbuf(); }
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inline void open( const char* name, int open_mode = std::ios::in) {
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gzstreambase::open( name, open_mode);
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}
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};
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class ogzstream : public std::ostream, public gzstreambase {
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public:
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inline ogzstream() : std::ostream( &buf) {}
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inline ogzstream( const char* name, int mode = std::ios::out)
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: std::ostream( &buf), gzstreambase( name, mode) {}
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inline gzstreambuf* rdbuf() { return gzstreambase::rdbuf(); }
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inline void open( const char* name, int open_mode = std::ios::out) {
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gzstreambase::open( name, open_mode);
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}
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};
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inline gzstreambuf* gzstreambuf::open( const char* name, int open_mode) {
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if ( is_open())
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return (gzstreambuf*)0;
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mode = open_mode;
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// no append nor read/write mode
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if ((mode & std::ios::ate) || (mode & std::ios::app)
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|| ((mode & std::ios::in) && (mode & std::ios::out)))
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return (gzstreambuf*)0;
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char fmode[10];
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char* fmodeptr = fmode;
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if ( mode & std::ios::in)
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*fmodeptr++ = 'r';
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else if ( mode & std::ios::out)
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*fmodeptr++ = 'w';
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*fmodeptr++ = 'b';
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*fmodeptr = '\0';
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file = gzopen( name, fmode);
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if (file == 0)
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return (gzstreambuf*)0;
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opened = 1;
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return this;
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}
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inline gzstreambuf * gzstreambuf::close() {
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if ( is_open()) {
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sync();
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opened = 0;
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if ( gzclose( file) == Z_OK)
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return this;
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}
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return (gzstreambuf*)0;
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}
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inline int gzstreambuf::underflow() { // used for input buffer only
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if ( gptr() && ( gptr() < egptr()))
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return * reinterpret_cast<unsigned char *>( gptr());
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if ( ! (mode & std::ios::in) || ! opened)
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return EOF;
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// Josuttis' implementation of inbuf
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int n_putback = gptr() - eback();
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if ( n_putback > 4)
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n_putback = 4;
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memcpy( buffer + (4 - n_putback), gptr() - n_putback, n_putback);
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int num = gzread( file, buffer+4, bufferSize-4);
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if (num <= 0) // ERROR or EOF
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return EOF;
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// reset buffer pointers
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setg( buffer + (4 - n_putback), // beginning of putback area
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buffer + 4, // read position
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buffer + 4 + num); // end of buffer
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// return next character
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return * reinterpret_cast<unsigned char *>( gptr());
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}
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inline int gzstreambuf::flush_buffer() {
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// Separate the writing of the buffer from overflow() and
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// sync() operation.
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int w = pptr() - pbase();
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if ( gzwrite( file, pbase(), w) != w)
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return EOF;
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pbump( -w);
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return w;
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}
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inline int gzstreambuf::overflow( int c) { // used for output buffer only
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if ( ! ( mode & std::ios::out) || ! opened)
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return EOF;
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if (c != EOF) {
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*pptr() = c;
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pbump(1);
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}
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if ( flush_buffer() == EOF)
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return EOF;
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return c;
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}
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inline int gzstreambuf::sync() {
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// Changed to use flush_buffer() instead of overflow( EOF)
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// which caused improper behavior with std::endl and flush(),
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// bug reported by Vincent Ricard.
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if ( pptr() && pptr() > pbase()) {
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if ( flush_buffer() == EOF)
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return -1;
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}
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return 0;
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}
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// --------------------------------------
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// class gzstreambase:
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// --------------------------------------
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inline gzstreambase::gzstreambase( const char* name, int mode) {
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init( &buf);
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open( name, mode);
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}
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inline gzstreambase::~gzstreambase() {
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buf.close();
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}
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inline void gzstreambase::open( const char* name, int open_mode) {
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if ( ! buf.open( name, open_mode))
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clear( rdstate() | std::ios::badbit);
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}
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inline void gzstreambase::close() {
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if ( buf.is_open())
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if ( ! buf.close())
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clear( rdstate() | std::ios::badbit);
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}
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#ifdef GZSTREAM_NAMESPACE
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} // namespace GZSTREAM_NAMESPACE
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#endif
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#endif // GZSTREAM_H
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// ============================================================================
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// EOF //
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