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 #pragma once
30 
31 // standard C++ with new header file names and std:: namespace
32 #include <iostream>
33 #include <fstream>
34 #include <zlib.h>
35 
36 #ifdef GZSTREAM_NAMESPACE
37 namespace GZSTREAM_NAMESPACE {
38 #endif
39 
40 // ----------------------------------------------------------------------------
41 // Internal classes to implement gzstream. See below for user classes.
42 // ----------------------------------------------------------------------------
43 
44 class gzstreambuf : public std::streambuf {
45 private:
46     static const int bufferSize = 47+256;    // size of data buff
47     // totals 512 bytes under g++ for igzstream at the end.
48 
49     gzFile           file;               // file handle for compressed file
50     char             buffer[bufferSize]; // data buffer
51     char             opened;             // open/close state of stream
52     int              mode;               // I/O mode
53 
54     int flush_buffer();
55 public:
gzstreambuf()56     gzstreambuf() : opened(0) {
57         setp( buffer, buffer + (bufferSize-1));
58         setg( buffer + 4,     // beginning of putback area
59               buffer + 4,     // read position
60               buffer + 4);    // end position
61         // ASSERT: both input & output capabilities will not be used together
62     }
is_open()63     int is_open() { return opened; }
64     gzstreambuf* open( const char* name, int open_mode);
65     gzstreambuf* close();
~gzstreambuf()66     ~gzstreambuf() { close(); }
67 
68     virtual int     overflow( int c = EOF) override;
69     virtual int     underflow() override;
70     virtual int     sync() override;
71 };
72 
73 class gzstreambase : virtual public std::ios {
74 protected:
75     gzstreambuf buf;
76 public:
gzstreambase()77     gzstreambase() { init(&buf); }
78     gzstreambase( const char* name, int open_mode);
79     ~gzstreambase();
80     void open( const char* name, int open_mode);
81     void close();
rdbuf()82     gzstreambuf* rdbuf() { return &buf; }
83 };
84 
85 // ----------------------------------------------------------------------------
86 // User classes. Use igzstream and ogzstream analogously to ifstream and
87 // ofstream respectively. They read and write files based on the gz*
88 // function interface of the zlib. Files are compatible with gzip compression.
89 // ----------------------------------------------------------------------------
90 
91 class igzstream : public gzstreambase, public std::istream {
92 public:
igzstream()93     igzstream() : std::istream( &buf) {}
94     igzstream( const char* name, int open_mode = std::ios::in)
gzstreambase(name,open_mode)95         : gzstreambase( name, open_mode), std::istream( &buf) {}
rdbuf()96     gzstreambuf* rdbuf() { return gzstreambase::rdbuf(); }
97     void open( const char* name, int open_mode = std::ios::in) {
98         gzstreambase::open( name, open_mode);
99     }
100 };
101 
102 class ogzstream : public gzstreambase, public std::ostream {
103 public:
ogzstream()104     ogzstream() : std::ostream( &buf) {}
105     ogzstream( const char* name, int mode = std::ios::out)
gzstreambase(name,mode)106         : gzstreambase( name, mode), std::ostream( &buf) {}
rdbuf()107     gzstreambuf* rdbuf() { return gzstreambase::rdbuf(); }
108     void open( const char* name, int open_mode = std::ios::out) {
109         gzstreambase::open( name, open_mode);
110     }
111 };
112 
113 #ifdef GZSTREAM_NAMESPACE
114 } // namespace GZSTREAM_NAMESPACE
115 #endif
116 
117 // ============================================================================
118 // EOF //
119 
120