ext/gzstream/gzstream.hh

   1 // ============================================================================
   2 // gzstream, C++ iostream classes wrapping the zlib compression library.
   3 // Copyright (C) 2001  Deepak Bandyopadhyay, Lutz Kettner
   4 //
   5 // This library is free software; you can redistribute it and/or
   6 // modify it under the terms of the GNU Lesser General Public
   7 // License as published by the Free Software Foundation; either
   8 // version 2.1 of the License, or (at your option) any later version.
   9 //
  10 // This library is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 // Lesser General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU Lesser General Public
  16 // License along with this library; if not, write to the Free Software
  17 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 // ============================================================================
  19 //
  20 // File          : gzstream.h
  21 // Revision      : $Revision: 1.5 $
  22 // Revision_date : $Date: 2002/04/26 23:30:15 $
  23 // Author(s)     : Deepak Bandyopadhyay, Lutz Kettner
  24 //
  25 // Standard streambuf implementation following Nicolai Josuttis, "The
  26 // Standard C++ Library".
  27 // ============================================================================
  28
  29 #ifndef GZSTREAM_H
  30 #define GZSTREAM_H 1
  31
  32 // standard C++ with new header file names and std:: namespace
  33 #include <iostream>
  34 #include <fstream>
  35 #include <zlib.h>
  36
  37 #ifdef GZSTREAM_NAMESPACE
  38 namespace GZSTREAM_NAMESPACE {
  39 #endif
  40
  41 // ----------------------------------------------------------------------------
  42 // Internal classes to implement gzstream. See below for user classes.
  43 // ----------------------------------------------------------------------------
  44
  45 class gzstreambuf : public std::streambuf {
  46 private:
  47     static const int bufferSize = 47+256;    // size of data buff
  48     // totals 512 bytes under g++ for igzstream at the end.
  49
  50     gzFile           file;               // file handle for compressed file
  51     char             buffer[bufferSize]; // data buffer
  52     char             opened;             // open/close state of stream
  53     int              mode;               // I/O mode
  54
  55     int flush_buffer();
  56 public:
  57     gzstreambuf() : opened(0) {
  58         setp( buffer, buffer + (bufferSize-1));
  59         setg( buffer + 4,     // beginning of putback area
  60               buffer + 4,     // read position
  61               buffer + 4);    // end position
  62         // ASSERT: both input & output capabilities will not be used together
  63     }
  64     int is_open() { return opened; }
  65     gzstreambuf* open( const char* name, int open_mode);
  66     gzstreambuf* close();
  67     ~gzstreambuf() { close(); }
  68
  69     virtual int     overflow( int c = EOF);
  70     virtual int     underflow();
  71     virtual int     sync();
  72 };
  73
  74 class gzstreambase : virtual public std::ios {
  75 protected:
  76     gzstreambuf buf;
  77 public:
  78     gzstreambase() { init(&buf); }
  79     gzstreambase( const char* name, int open_mode);
  80     ~gzstreambase();
  81     int is_open() { return buf.is_open(); }
  82     void open( const char* name, int open_mode);
  83     void close();
  84     gzstreambuf* rdbuf() { return &buf; }
  85 };
  86
  87 // ----------------------------------------------------------------------------
  88 // User classes. Use igzstream and ogzstream analogously to ifstream and
  89 // ofstream respectively. They read and write files based on the gz*
  90 // function interface of the zlib. Files are compatible with gzip compression.
  91 // ----------------------------------------------------------------------------
  92
  93 class igzstream : public gzstreambase, public std::istream {
  94 public:
  95     igzstream() : std::istream( &buf) {}
  96     igzstream( const char* name, int open_mode = std::ios::in)
  97         : gzstreambase( name, open_mode | std::ios::in), std::istream( &buf) {}
  98     gzstreambuf* rdbuf() { return gzstreambase::rdbuf(); }
  99     void open( const char* name, int open_mode = std::ios::in) {
 100         gzstreambase::open( name, open_mode);
 101     }
 102 };
 103
 104 class ogzstream : public gzstreambase, public std::ostream {
 105 public:
 106     ogzstream() : std::ostream( &buf) {}
 107     ogzstream( const char* name, int mode = std::ios::out)
 108         : gzstreambase( name, mode | std::ios::out), std::ostream( &buf) {}
 109     gzstreambuf* rdbuf() { return gzstreambase::rdbuf(); }
 110     void open( const char* name, int open_mode = std::ios::out) {
 111         gzstreambase::open( name, open_mode);
 112     }
 113 };
 114
 115 #ifdef GZSTREAM_NAMESPACE
 116 } // namespace GZSTREAM_NAMESPACE
 117 #endif
 118
 119 #endif // GZSTREAM_H
 120 // ============================================================================
 121 // EOF //
 122