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 void
  77 wxMemoryInputStream::InitFromStream(wxInputStream& stream, wxFileOffset lenFile)
  78 {
  79     if ( lenFile == wxInvalidOffset )
  80         lenFile = stream.GetLength();
  81
  82     if ( lenFile == wxInvalidOffset )
  83     {
  84         m_i_streambuf = NULL;
  85         m_lasterror = wxSTREAM_EOF;
  86         return;
  87     }
  88
  89     const size_t len = wx_truncate_cast(size_t, lenFile);
  90     wxASSERT_MSG( (wxFileOffset)len == lenFile, _T("huge files not supported") );
  91
  92     m_i_streambuf = new wxStreamBuffer(wxStreamBuffer::read);
  93     m_i_streambuf->SetBufferIO(len); // create buffer
  94     stream.Read(m_i_streambuf->GetBufferStart(), len);
  95     m_i_streambuf->SetIntPosition(0); // seek to start pos
  96     m_i_streambuf->Fixed(true);
  97     m_length = stream.LastRead();
  98 }
  99
 100 bool wxMemoryInputStream::CanRead() const
 101 {
 102     return m_i_streambuf->GetIntPosition() != m_length;
 103 }
 104
 105 wxMemoryInputStream::~wxMemoryInputStream()
 106 {
 107     delete m_i_streambuf;
 108 }
 109
 110 char wxMemoryInputStream::Peek()
 111 {
 112     char *buf = (char *)m_i_streambuf->GetBufferStart();
 113     size_t pos = m_i_streambuf->GetIntPosition();
 114     if ( pos == m_length )
 115     {
 116         m_lasterror = wxSTREAM_READ_ERROR;
 117
 118         return 0;
 119     }
 120
 121     return buf[pos];
 122 }
 123
 124 size_t wxMemoryInputStream::OnSysRead(void *buffer, size_t nbytes)
 125 {
 126     size_t pos = m_i_streambuf->GetIntPosition();
 127     if ( pos == m_length )
 128     {
 129         m_lasterror = wxSTREAM_EOF;
 130
 131         return 0;
 132     }
 133
 134     m_i_streambuf->Read(buffer, nbytes);
 135     m_lasterror = wxSTREAM_NO_ERROR;
 136
 137     return m_i_streambuf->GetIntPosition() - pos;
 138 }
 139
 140 wxFileOffset wxMemoryInputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 141 {
 142     return m_i_streambuf->Seek(pos, mode);
 143 }
 144
 145 wxFileOffset wxMemoryInputStream::OnSysTell() const
 146 {
 147     return m_i_streambuf->Tell();
 148 }
 149
 150 // ----------------------------------------------------------------------------
 151 // wxMemoryOutputStream
 152 // ----------------------------------------------------------------------------
 153
 154 wxMemoryOutputStream::wxMemoryOutputStream(void *data, size_t len)
 155 {
 156     m_o_streambuf = new wxStreamBuffer(wxStreamBuffer::write);
 157     if ( data )
 158         m_o_streambuf->SetBufferIO(data, len);
 159     m_o_streambuf->Fixed(false);
 160     m_o_streambuf->Flushable(false);
 161 }
 162
 163 wxMemoryOutputStream::~wxMemoryOutputStream()
 164 {
 165     delete m_o_streambuf;
 166 }
 167
 168 size_t wxMemoryOutputStream::OnSysWrite(const void *buffer, size_t nbytes)
 169 {
 170     size_t oldpos = m_o_streambuf->GetIntPosition();
 171     m_o_streambuf->Write(buffer, nbytes);
 172     size_t newpos = m_o_streambuf->GetIntPosition();
 173
 174     // FIXME can someone please explain what this does? (VZ)
 175     if ( !newpos )
 176         newpos = m_o_streambuf->GetBufferSize();
 177
 178     return newpos - oldpos;
 179 }
 180
 181 wxFileOffset wxMemoryOutputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 182 {
 183     return m_o_streambuf->Seek(pos, mode);
 184 }
 185
 186 wxFileOffset wxMemoryOutputStream::OnSysTell() const
 187 {
 188     return m_o_streambuf->Tell();
 189 }
 190
 191 size_t wxMemoryOutputStream::CopyTo(void *buffer, size_t len) const
 192 {
 193     wxCHECK_MSG( buffer, 0, _T("must have buffer to CopyTo") );
 194
 195     if ( len > GetSize() )
 196         len = GetSize();
 197
 198     memcpy(buffer, m_o_streambuf->GetBufferStart(), len);
 199
 200     return len;
 201 }
 202
 203 #endif // wxUSE_STREAMS