src/common/mstream.cpp

   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:      $Id$
   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 <stdlib.h>
  30 #include "wx/stream.h"
  31 #include "wx/mstream.h"
  32
  33 // ============================================================================
  34 // implementation
  35 // ============================================================================
  36
  37 // ----------------------------------------------------------------------------
  38 // wxMemoryInputStream
  39 // ----------------------------------------------------------------------------
  40
  41 wxMemoryInputStream::wxMemoryInputStream(const void *data, size_t len)
  42 {
  43     m_i_streambuf = new wxStreamBuffer(wxStreamBuffer::read);
  44     m_i_streambuf->SetBufferIO((void *)data, len); // const_cast
  45     m_i_streambuf->SetIntPosition(0); // seek to start pos
  46     m_i_streambuf->Fixed(true);
  47
  48     m_length = len;
  49 }
  50
  51 wxMemoryInputStream::wxMemoryInputStream(const wxMemoryOutputStream& stream)
  52 {
  53     const wxFileOffset lenFile = stream.GetLength();
  54     if ( lenFile == wxInvalidOffset )
  55     {
  56         m_i_streambuf = NULL;
  57         m_lasterror = wxSTREAM_EOF;
  58         return;
  59     }
  60
  61     const size_t len = wx_truncate_cast(size_t, lenFile);
  62     wxASSERT_MSG( len == lenFile + size_t(0), _T("huge files not supported") );
  63
  64     m_i_streambuf = new wxStreamBuffer(wxStreamBuffer::read);
  65     m_i_streambuf->SetBufferIO(len); // create buffer
  66     stream.CopyTo(m_i_streambuf->GetBufferStart(), len);
  67     m_i_streambuf->SetIntPosition(0); // seek to start pos
  68     m_i_streambuf->Fixed(true);
  69     m_length = len;
  70 }
  71
  72 wxMemoryInputStream::~wxMemoryInputStream()
  73 {
  74     delete m_i_streambuf;
  75 }
  76
  77 char wxMemoryInputStream::Peek()
  78 {
  79     char *buf = (char *)m_i_streambuf->GetBufferStart();
  80     size_t pos = m_i_streambuf->GetIntPosition();
  81     if ( pos == m_length )
  82     {
  83         m_lasterror = wxSTREAM_READ_ERROR;
  84
  85         return 0;
  86     }
  87
  88     return buf[pos];
  89 }
  90
  91 size_t wxMemoryInputStream::OnSysRead(void *buffer, size_t nbytes)
  92 {
  93     size_t pos = m_i_streambuf->GetIntPosition();
  94     if ( pos == m_length )
  95     {
  96         m_lasterror = wxSTREAM_EOF;
  97
  98         return 0;
  99     }
 100
 101     m_i_streambuf->Read(buffer, nbytes);
 102     m_lasterror = wxSTREAM_NO_ERROR;
 103
 104     return m_i_streambuf->GetIntPosition() - pos;
 105 }
 106
 107 wxFileOffset wxMemoryInputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 108 {
 109     return m_i_streambuf->Seek(pos, mode);
 110 }
 111
 112 wxFileOffset wxMemoryInputStream::OnSysTell() const
 113 {
 114     return m_i_streambuf->Tell();
 115 }
 116
 117 // ----------------------------------------------------------------------------
 118 // wxMemoryOutputStream
 119 // ----------------------------------------------------------------------------
 120
 121 wxMemoryOutputStream::wxMemoryOutputStream(void *data, size_t len)
 122 {
 123     m_o_streambuf = new wxStreamBuffer(wxStreamBuffer::write);
 124     if ( data )
 125         m_o_streambuf->SetBufferIO(data, len);
 126     m_o_streambuf->Fixed(false);
 127     m_o_streambuf->Flushable(false);
 128 }
 129
 130 wxMemoryOutputStream::~wxMemoryOutputStream()
 131 {
 132     delete m_o_streambuf;
 133 }
 134
 135 size_t wxMemoryOutputStream::OnSysWrite(const void *buffer, size_t nbytes)
 136 {
 137     size_t oldpos = m_o_streambuf->GetIntPosition();
 138     m_o_streambuf->Write(buffer, nbytes);
 139     size_t newpos = m_o_streambuf->GetIntPosition();
 140
 141     // FIXME can someone please explain what this does? (VZ)
 142     if ( !newpos )
 143         newpos = m_o_streambuf->GetBufferSize();
 144
 145     return newpos - oldpos;
 146 }
 147
 148 wxFileOffset wxMemoryOutputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 149 {
 150     return m_o_streambuf->Seek(pos, mode);
 151 }
 152
 153 wxFileOffset wxMemoryOutputStream::OnSysTell() const
 154 {
 155     return m_o_streambuf->Tell();
 156 }
 157
 158 size_t wxMemoryOutputStream::CopyTo(void *buffer, size_t len) const
 159 {
 160     wxCHECK_MSG( buffer, 0, _T("must have buffer to CopyTo") );
 161
 162     if ( len > GetSize() )
 163         len = GetSize();
 164
 165     memcpy(buffer, m_o_streambuf->GetBufferStart(), len);
 166
 167     return len;
 168 }
 169
 170 #endif // wxUSE_STREAMS