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-rw-r--r--src/substream.cpp109
1 files changed, 109 insertions, 0 deletions
diff --git a/src/substream.cpp b/src/substream.cpp
new file mode 100644
index 0000000..ddb31b4
--- /dev/null
+++ b/src/substream.cpp
@@ -0,0 +1,109 @@
1/*
2 * Copyright (C) 2007-2008 Xagasoft, All rights reserved.
3 *
4 * This file is part of the libbu++ library and is released under the
5 * terms of the license contained in the file LICENSE.
6 */
7
8#include "bu/substream.h"
9
10Bu::SubStream::SubStream( Bu::Stream &rNext, long iSize ) :
11 Bu::Filter( rNext ),
12 iStart( 0 ),
13 iPos( 0 ),
14 iSize( iSize )
15{
16 iStart = rNext.tell();
17}
18
19Bu::SubStream::~SubStream()
20{
21}
22
23size_t Bu::SubStream::read( void *pBuf, size_t nBytes )
24{
25 if( (long)nBytes > iSize-iPos )
26 nBytes = iSize-iPos;
27 nBytes = rNext.read( pBuf, nBytes );
28 iPos += nBytes;
29 return nBytes;
30}
31
32size_t Bu::SubStream::write( const void *pBuf, size_t nBytes )
33{
34 if( (long)nBytes > iSize-iPos )
35 nBytes = iSize-iPos;
36 nBytes = rNext.write( pBuf, nBytes );
37 iPos += nBytes;
38 return nBytes;
39}
40
41void Bu::SubStream::start()
42{
43 // doesn't mean anything...
44}
45
46size_t Bu::SubStream::stop()
47{
48 // doesn't mean anything...
49 return 0;
50}
51
52void Bu::SubStream::close()
53{
54 // don't do anything? maybe...
55}
56
57long Bu::SubStream::tell()
58{
59 return iPos;
60}
61
62void Bu::SubStream::seek( long offset )
63{
64 if( iPos+offset < 0 )
65 offset = -iPos;
66 else if( iPos+offset > iSize )
67 offset = iSize-iPos;
68 rNext.seek( offset );
69 iPos += offset;
70}
71
72void Bu::SubStream::setPos( long pos )
73{
74 if( pos < 0 )
75 pos = 0;
76 else if( pos > iSize )
77 pos = iSize;
78 iPos = pos;
79 pos += iStart;
80 rNext.setPos( pos );
81}
82
83void Bu::SubStream::setPosEnd( long pos )
84{
85 if( iSize-pos < 0 )
86 pos = 0;
87 else if( iSize-pos > iSize )
88 pos = iSize;
89 else
90 pos = iSize-pos;
91 iPos = pos;
92 rNext.setPos( iStart+pos );
93}
94
95bool Bu::SubStream::isEos()
96{
97 return rNext.isEos() || iPos == iSize;
98}
99
100bool Bu::SubStream::canRead()
101{
102 return rNext.canRead() && (iPos < iSize);
103}
104
105bool Bu::SubStream::canWrite()
106{
107 return rNext.canWrite() && (iPos < iSize);
108}
109