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 "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
  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(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
  76 wxMemoryInputStream::~wxMemoryInputStream()
  77 {
  78     delete m_i_streambuf;
  79 }
  80
  81 char 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
  95 size_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
 111 wxFileOffset wxMemoryInputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 112 {
 113     return m_i_streambuf->Seek(pos, mode);
 114 }
 115
 116 wxFileOffset wxMemoryInputStream::OnSysTell() const
 117 {
 118     return m_i_streambuf->Tell();
 119 }
 120
 121 // ----------------------------------------------------------------------------
 122 // wxMemoryOutputStream
 123 // ----------------------------------------------------------------------------
 124
 125 wxMemoryOutputStream::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
 134 wxMemoryOutputStream::~wxMemoryOutputStream()
 135 {
 136     delete m_o_streambuf;
 137 }
 138
 139 size_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
 152 wxFileOffset wxMemoryOutputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 153 {
 154     return m_o_streambuf->Seek(pos, mode);
 155 }
 156
 157 wxFileOffset wxMemoryOutputStream::OnSysTell() const
 158 {
 159     return m_o_streambuf->Tell();
 160 }
 161
 162 size_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