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     size_t pos = m_i_streambuf->GetIntPosition();
  64     if ( pos == m_length )
  65     {
  66         m_lasterror = wxSTREAM_READ_ERROR;
  67
  68         return 0;
  69     }
  70
  71     return buf[pos];
  72 }
  73
  74 bool wxMemoryInputStream::Eof() const
  75 {
  76     return !m_i_streambuf->GetBytesLeft();
  77 }
  78
  79 size_t wxMemoryInputStream::OnSysRead(void *buffer, size_t nbytes)
  80 {
  81     size_t pos = m_i_streambuf->GetIntPosition();
  82     if ( pos == m_length )
  83     {
  84         m_lasterror = wxSTREAM_EOF;
  85
  86         return 0;
  87     }
  88
  89     m_i_streambuf->Read(buffer, nbytes);
  90     m_lasterror = wxSTREAM_NO_ERROR;
  91
  92     return m_i_streambuf->GetIntPosition() - pos;
  93 }
  94
  95 wxFileOffset wxMemoryInputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
  96 {
  97     return m_i_streambuf->Seek(pos, mode);
  98 }
  99
 100 wxFileOffset wxMemoryInputStream::OnSysTell() const
 101 {
 102     return m_i_streambuf->Tell();
 103 }
 104
 105 // ----------------------------------------------------------------------------
 106 // wxMemoryOutputStream
 107 // ----------------------------------------------------------------------------
 108
 109 wxMemoryOutputStream::wxMemoryOutputStream(void *data, size_t len)
 110 {
 111     m_o_streambuf = new wxStreamBuffer(wxStreamBuffer::write);
 112     if ( data )
 113         m_o_streambuf->SetBufferIO(data, len);
 114     m_o_streambuf->Fixed(false);
 115     m_o_streambuf->Flushable(false);
 116 }
 117
 118 wxMemoryOutputStream::~wxMemoryOutputStream()
 119 {
 120     delete m_o_streambuf;
 121 }
 122
 123 size_t wxMemoryOutputStream::OnSysWrite(const void *buffer, size_t nbytes)
 124 {
 125     size_t oldpos = m_o_streambuf->GetIntPosition();
 126     m_o_streambuf->Write(buffer, nbytes);
 127     size_t newpos = m_o_streambuf->GetIntPosition();
 128
 129     // FIXME can someone please explain what this does? (VZ)
 130     if ( !newpos )
 131         newpos = m_o_streambuf->GetBufferSize();
 132
 133     return newpos - oldpos;
 134 }
 135
 136 wxFileOffset wxMemoryOutputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 137 {
 138     return m_o_streambuf->Seek(pos, mode);
 139 }
 140
 141 wxFileOffset wxMemoryOutputStream::OnSysTell() const
 142 {
 143     return m_o_streambuf->Tell();
 144 }
 145
 146 size_t wxMemoryOutputStream::CopyTo(void *buffer, size_t len) const
 147 {
 148     wxCHECK_MSG( buffer, 0, _T("must have buffer to CopyTo") );
 149
 150     if ( len > GetSize() )
 151         len = GetSize();
 152
 153     memcpy(buffer, m_o_streambuf->GetBufferStart(), len);
 154
 155     return len;
 156 }
 157
 158 #endif // wxUSE_STREAMS