ext/gzstream/gzstream.cc

   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.C
  21 // Revision      : $Revision: 1.7 $
  22 // Revision_date : $Date: 2003/01/08 14:41:27 $
  23 // Author(s)     : Deepak Bandyopadhyay, Lutz Kettner
  24 //
  25 // Standard streambuf implementation following Nicolai Josuttis, "The
  26 // Standard C++ Library".
  27 // ============================================================================
  28
  29 #include <gzstream.hh>
  30 #include <iostream>
  31 #include <string.h>  // for memcpy
  32
  33 #ifdef GZSTREAM_NAMESPACE
  34 namespace GZSTREAM_NAMESPACE {
  35 #endif
  36
  37 // ----------------------------------------------------------------------------
  38 // Internal classes to implement gzstream. See header file for user classes.
  39 // ----------------------------------------------------------------------------
  40
  41 // --------------------------------------
  42 // class gzstreambuf:
  43 // --------------------------------------
  44
  45 gzstreambuf* gzstreambuf::open( const char* name, int open_mode) {
  46     if ( is_open())
  47         return (gzstreambuf*)0;
  48     mode = open_mode;
  49     // no append nor read/write mode
  50     if ((mode & std::ios::ate) || (mode & std::ios::app)
  51         || ((mode & std::ios::in) && (mode & std::ios::out)))
  52         return (gzstreambuf*)0;
  53     char  fmode[10];
  54     char* fmodeptr = fmode;
  55     if ( mode & std::ios::in)
  56         *fmodeptr++ = 'r';
  57     else if ( mode & std::ios::out)
  58         *fmodeptr++ = 'w';
  59     *fmodeptr++ = 'b';
  60     *fmodeptr = '\0';
  61     file = gzopen( name, fmode);
  62     if (file == 0)
  63         return (gzstreambuf*)0;
  64     opened = 1;
  65     return this;
  66 }
  67
  68 gzstreambuf * gzstreambuf::close() {
  69     if ( is_open()) {
  70         sync();
  71         opened = 0;
  72         if ( gzclose( file) == Z_OK)
  73             return this;
  74     }
  75     return (gzstreambuf*)0;
  76 }
  77
  78 int gzstreambuf::underflow() { // used for input buffer only
  79     if ( gptr() && ( gptr() < egptr()))
  80         return * reinterpret_cast<unsigned char *>( gptr());
  81
  82     if ( ! (mode & std::ios::in) || ! opened)
  83         return EOF;
  84     // Josuttis' implementation of inbuf
  85     int n_putback = gptr() - eback();
  86     if ( n_putback > 4)
  87         n_putback = 4;
  88     memcpy( buffer + (4 - n_putback), gptr() - n_putback, n_putback);
  89
  90     int num = gzread( file, buffer+4, bufferSize-4);
  91     if (num <= 0) // ERROR or EOF
  92         return EOF;
  93
  94     // reset buffer pointers
  95     setg( buffer + (4 - n_putback),   // beginning of putback area
  96           buffer + 4,                 // read position
  97           buffer + 4 + num);          // end of buffer
  98
  99     // return next character
 100     return *reinterpret_cast<unsigned char *>(gptr());
 101 }
 102
 103 int gzstreambuf::flush_buffer() {
 104     // Separate the writing of the buffer from overflow() and
 105     // sync() operation.
 106     int w = pptr() - pbase();
 107     if ( gzwrite( file, pbase(), w) != w)
 108         return EOF;
 109     pbump( -w);
 110     return w;
 111 }
 112
 113 int gzstreambuf::overflow( int c) { // used for output buffer only
 114     if ( ! ( mode & std::ios::out) || ! opened)
 115         return EOF;
 116     if (c != EOF) {
 117         *pptr() = c;
 118         pbump(1);
 119     }
 120     if ( flush_buffer() == EOF)
 121         return EOF;
 122     return c;
 123 }
 124
 125 int gzstreambuf::sync() {
 126     // Changed to use flush_buffer() instead of overflow( EOF)
 127     // which caused improper behavior with std::endl and flush(),
 128     // bug reported by Vincent Ricard.
 129     if ( pptr() && pptr() > pbase()) {
 130         if ( flush_buffer() == EOF)
 131             return -1;
 132     }
 133     return 0;
 134 }
 135
 136 // --------------------------------------
 137 // class gzstreambase:
 138 // --------------------------------------
 139
 140 gzstreambase::gzstreambase( const char* name, int mode) {
 141     init( &buf);
 142     open( name, mode);
 143 }
 144
 145 gzstreambase::~gzstreambase() {
 146     buf.close();
 147 }
 148
 149 void gzstreambase::open( const char* name, int open_mode) {
 150     if ( ! buf.open( name, open_mode))
 151         clear( rdstate() | std::ios::badbit);
 152 }
 153
 154 void gzstreambase::close() {
 155     if ( buf.is_open())
 156         if ( ! buf.close())
 157             clear( rdstate() | std::ios::badbit);
 158 }
 159
 160 #ifdef GZSTREAM_NAMESPACE
 161 } // namespace GZSTREAM_NAMESPACE
 162 #endif
 163
 164 // ============================================================================
 165 // EOF //