1/////////////////////////////////////////////////////////////////////////////
2// Name:        src/common/mstream.cpp
3// Purpose:     "Memory stream" classes
4// Author:      Guilhem Lavaux
5// Modified by: VZ (23.11.00): general code review
6// Created:     04/01/98
7// RCS-ID:      $Id: mstream.cpp 39001 2006-05-03 21:50:35Z ABX $
8// Copyright:   (c) Guilhem Lavaux
9// Licence:     wxWindows licence
10/////////////////////////////////////////////////////////////////////////////
11
12// ============================================================================
13// declarations
14// ============================================================================
15
16// ----------------------------------------------------------------------------
17// headers
18// ----------------------------------------------------------------------------
19
20// For compilers that support precompilation, includes "wx.h".
21#include "wx/wxprec.h"
22
23#ifdef __BORLANDC__
24    #pragma hdrstop
25#endif
26
27#if wxUSE_STREAMS
28
29#include "wx/mstream.h"
30
31#ifndef   WX_PRECOMP
32    #include  "wx/stream.h"
33#endif  //WX_PRECOMP
34
35#include <stdlib.h>
36
37// ============================================================================
38// implementation
39// ============================================================================
40
41// ----------------------------------------------------------------------------
42// wxMemoryInputStream
43// ----------------------------------------------------------------------------
44
45wxMemoryInputStream::wxMemoryInputStream(const void *data, size_t len)
46{
47    m_i_streambuf = new wxStreamBuffer(wxStreamBuffer::read);
48    m_i_streambuf->SetBufferIO((void *)data, len); // const_cast
49    m_i_streambuf->SetIntPosition(0); // seek to start pos
50    m_i_streambuf->Fixed(true);
51
52    m_length = len;
53}
54
55wxMemoryInputStream::wxMemoryInputStream(const wxMemoryOutputStream& stream)
56{
57    const wxFileOffset lenFile = stream.GetLength();
58    if ( lenFile == wxInvalidOffset )
59    {
60        m_i_streambuf = NULL;
61        m_lasterror = wxSTREAM_EOF;
62        return;
63    }
64
65    const size_t len = wx_truncate_cast(size_t, lenFile);
66    wxASSERT_MSG( len == lenFile + size_t(0), _T("huge files not supported") );
67
68    m_i_streambuf = new wxStreamBuffer(wxStreamBuffer::read);
69    m_i_streambuf->SetBufferIO(len); // create buffer
70    stream.CopyTo(m_i_streambuf->GetBufferStart(), len);
71    m_i_streambuf->SetIntPosition(0); // seek to start pos
72    m_i_streambuf->Fixed(true);
73    m_length = len;
74}
75
76wxMemoryInputStream::~wxMemoryInputStream()
77{
78    delete m_i_streambuf;
79}
80
81char wxMemoryInputStream::Peek()
82{
83    char *buf = (char *)m_i_streambuf->GetBufferStart();
84    size_t pos = m_i_streambuf->GetIntPosition();
85    if ( pos == m_length )
86    {
87        m_lasterror = wxSTREAM_READ_ERROR;
88
89        return 0;
90    }
91
92    return buf[pos];
93}
94
95size_t wxMemoryInputStream::OnSysRead(void *buffer, size_t nbytes)
96{
97    size_t pos = m_i_streambuf->GetIntPosition();
98    if ( pos == m_length )
99    {
100        m_lasterror = wxSTREAM_EOF;
101
102        return 0;
103    }
104
105    m_i_streambuf->Read(buffer, nbytes);
106    m_lasterror = wxSTREAM_NO_ERROR;
107
108    return m_i_streambuf->GetIntPosition() - pos;
109}
110
111wxFileOffset wxMemoryInputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
112{
113    return m_i_streambuf->Seek(pos, mode);
114}
115
116wxFileOffset wxMemoryInputStream::OnSysTell() const
117{
118    return m_i_streambuf->Tell();
119}
120
121// ----------------------------------------------------------------------------
122// wxMemoryOutputStream
123// ----------------------------------------------------------------------------
124
125wxMemoryOutputStream::wxMemoryOutputStream(void *data, size_t len)
126{
127    m_o_streambuf = new wxStreamBuffer(wxStreamBuffer::write);
128    if ( data )
129        m_o_streambuf->SetBufferIO(data, len);
130    m_o_streambuf->Fixed(false);
131    m_o_streambuf->Flushable(false);
132}
133
134wxMemoryOutputStream::~wxMemoryOutputStream()
135{
136    delete m_o_streambuf;
137}
138
139size_t wxMemoryOutputStream::OnSysWrite(const void *buffer, size_t nbytes)
140{
141    size_t oldpos = m_o_streambuf->GetIntPosition();
142    m_o_streambuf->Write(buffer, nbytes);
143    size_t newpos = m_o_streambuf->GetIntPosition();
144
145    // FIXME can someone please explain what this does? (VZ)
146    if ( !newpos )
147        newpos = m_o_streambuf->GetBufferSize();
148
149    return newpos - oldpos;
150}
151
152wxFileOffset wxMemoryOutputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
153{
154    return m_o_streambuf->Seek(pos, mode);
155}
156
157wxFileOffset wxMemoryOutputStream::OnSysTell() const
158{
159    return m_o_streambuf->Tell();
160}
161
162size_t wxMemoryOutputStream::CopyTo(void *buffer, size_t len) const
163{
164    wxCHECK_MSG( buffer, 0, _T("must have buffer to CopyTo") );
165
166    if ( len > GetSize() )
167        len = GetSize();
168
169    memcpy(buffer, m_o_streambuf->GetBufferStart(), len);
170
171    return len;
172}
173
174#endif // wxUSE_STREAMS
175