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 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  21 #pragma implementation "mstream.h"
  22 #endif
  23
  24 // For compilers that support precompilation, includes "wx.h".
  25 #include "wx/wxprec.h"
  26
  27 #ifdef __BORLANDC__
  28   #pragma hdrstop
  29 #endif
  30
  31 #if wxUSE_STREAMS
  32
  33 #include <stdlib.h>
  34 #include "wx/stream.h"
  35 #include "wx/mstream.h"
  36
  37 // ============================================================================
  38 // implementation
  39 // ============================================================================
  40
  41 // ----------------------------------------------------------------------------
  42 // wxMemoryInputStream
  43 // ----------------------------------------------------------------------------
  44
  45 wxMemoryInputStream::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
  55 wxMemoryInputStream::~wxMemoryInputStream()
  56 {
  57     delete m_i_streambuf;
  58 }
  59
  60 char wxMemoryInputStream::Peek()
  61 {
  62     char *buf = (char *)m_i_streambuf->GetBufferStart();
  63
  64     return buf[m_i_streambuf->GetIntPosition()];
  65 }
  66
  67 bool wxMemoryInputStream::Eof() const
  68 {
  69     return !m_i_streambuf->GetBytesLeft();
  70 }
  71
  72 size_t wxMemoryInputStream::OnSysRead(void *buffer, size_t nbytes)
  73 {
  74     size_t pos = m_i_streambuf->GetIntPosition();
  75     if ( pos == m_length )
  76     {
  77         m_lasterror = wxSTREAM_EOF;
  78
  79         return 0;
  80     }
  81
  82     m_i_streambuf->Read(buffer, nbytes);
  83     m_lasterror = wxSTREAM_NO_ERROR;
  84
  85     return m_i_streambuf->GetIntPosition() - pos;
  86 }
  87
  88 wxFileOffset wxMemoryInputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
  89 {
  90     return m_i_streambuf->Seek(pos, mode);
  91 }
  92
  93 wxFileOffset wxMemoryInputStream::OnSysTell() const
  94 {
  95     return m_i_streambuf->Tell();
  96 }
  97
  98 // ----------------------------------------------------------------------------
  99 // wxMemoryOutputStream
 100 // ----------------------------------------------------------------------------
 101
 102 wxMemoryOutputStream::wxMemoryOutputStream(void *data, size_t len)
 103 {
 104     m_o_streambuf = new wxStreamBuffer(wxStreamBuffer::write);
 105     if ( data )
 106         m_o_streambuf->SetBufferIO(data, len);
 107     m_o_streambuf->Fixed(false);
 108     m_o_streambuf->Flushable(false);
 109 }
 110
 111 wxMemoryOutputStream::~wxMemoryOutputStream()
 112 {
 113     delete m_o_streambuf;
 114 }
 115
 116 size_t wxMemoryOutputStream::OnSysWrite(const void *buffer, size_t nbytes)
 117 {
 118     size_t oldpos = m_o_streambuf->GetIntPosition();
 119     m_o_streambuf->Write(buffer, nbytes);
 120     size_t newpos = m_o_streambuf->GetIntPosition();
 121
 122     // FIXME can someone please explain what this does? (VZ)
 123     if ( !newpos )
 124         newpos = m_o_streambuf->GetBufferSize();
 125
 126     return newpos - oldpos;
 127 }
 128
 129 wxFileOffset wxMemoryOutputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 130 {
 131     return m_o_streambuf->Seek(pos, mode);
 132 }
 133
 134 wxFileOffset wxMemoryOutputStream::OnSysTell() const
 135 {
 136     return m_o_streambuf->Tell();
 137 }
 138
 139 size_t wxMemoryOutputStream::CopyTo(void *buffer, size_t len) const
 140 {
 141     wxCHECK_MSG( buffer, 0, _T("must have buffer to CopyTo") );
 142
 143     if ( len > GetSize() )
 144         len = GetSize();
 145
 146     memcpy(buffer, m_o_streambuf->GetBufferStart(), len);
 147
 148     return len;
 149 }
 150
 151 #endif // wxUSE_STREAMS