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 IMPLEMENT_ABSTRACT_CLASS(wxMemoryInputStream, wxInputStream)
  46
  47 wxMemoryInputStream::wxMemoryInputStream(const void *data, size_t len)
  48 {
  49     m_i_streambuf = new wxStreamBuffer(wxStreamBuffer::read);
  50     m_i_streambuf->SetBufferIO((void *)data, len); // const_cast
  51     m_i_streambuf->SetIntPosition(0); // seek to start pos
  52     m_i_streambuf->Fixed(true);
  53
  54     m_length = len;
  55 }
  56
  57 wxMemoryInputStream::wxMemoryInputStream(const wxMemoryOutputStream& stream)
  58 {
  59     const wxFileOffset lenFile = stream.GetLength();
  60     if ( lenFile == wxInvalidOffset )
  61     {
  62         m_i_streambuf = NULL;
  63         m_lasterror = wxSTREAM_EOF;
  64         return;
  65     }
  66
  67     const size_t len = wx_truncate_cast(size_t, lenFile);
  68     wxASSERT_MSG( len == lenFile + size_t(0), _T("huge files not supported") );
  69
  70     m_i_streambuf = new wxStreamBuffer(wxStreamBuffer::read);
  71     m_i_streambuf->SetBufferIO(len); // create buffer
  72     stream.CopyTo(m_i_streambuf->GetBufferStart(), len);
  73     m_i_streambuf->SetIntPosition(0); // seek to start pos
  74     m_i_streambuf->Fixed(true);
  75     m_length = len;
  76 }
  77
  78 void
  79 wxMemoryInputStream::InitFromStream(wxInputStream& stream, wxFileOffset lenFile)
  80 {
  81     if ( lenFile == wxInvalidOffset )
  82         lenFile = stream.GetLength();
  83
  84     if ( lenFile == wxInvalidOffset )
  85     {
  86         m_i_streambuf = NULL;
  87         m_lasterror = wxSTREAM_EOF;
  88         return;
  89     }
  90
  91     const size_t len = wx_truncate_cast(size_t, lenFile);
  92     wxASSERT_MSG( (wxFileOffset)len == lenFile, _T("huge files not supported") );
  93
  94     m_i_streambuf = new wxStreamBuffer(wxStreamBuffer::read);
  95     m_i_streambuf->SetBufferIO(len); // create buffer
  96     stream.Read(m_i_streambuf->GetBufferStart(), len);
  97     m_i_streambuf->SetIntPosition(0); // seek to start pos
  98     m_i_streambuf->Fixed(true);
  99     m_length = stream.LastRead();
 100 }
 101
 102 bool wxMemoryInputStream::CanRead() const
 103 {
 104     return m_i_streambuf->GetIntPosition() != m_length;
 105 }
 106
 107 wxMemoryInputStream::~wxMemoryInputStream()
 108 {
 109     delete m_i_streambuf;
 110 }
 111
 112 char wxMemoryInputStream::Peek()
 113 {
 114     char *buf = (char *)m_i_streambuf->GetBufferStart();
 115     size_t pos = m_i_streambuf->GetIntPosition();
 116     if ( pos == m_length )
 117     {
 118         m_lasterror = wxSTREAM_READ_ERROR;
 119
 120         return 0;
 121     }
 122
 123     return buf[pos];
 124 }
 125
 126 size_t wxMemoryInputStream::OnSysRead(void *buffer, size_t nbytes)
 127 {
 128     size_t pos = m_i_streambuf->GetIntPosition();
 129     if ( pos == m_length )
 130     {
 131         m_lasterror = wxSTREAM_EOF;
 132
 133         return 0;
 134     }
 135
 136     m_i_streambuf->Read(buffer, nbytes);
 137     m_lasterror = wxSTREAM_NO_ERROR;
 138
 139     return m_i_streambuf->GetIntPosition() - pos;
 140 }
 141
 142 wxFileOffset wxMemoryInputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 143 {
 144     return m_i_streambuf->Seek(pos, mode);
 145 }
 146
 147 wxFileOffset wxMemoryInputStream::OnSysTell() const
 148 {
 149     return m_i_streambuf->Tell();
 150 }
 151
 152 // ----------------------------------------------------------------------------
 153 // wxMemoryOutputStream
 154 // ----------------------------------------------------------------------------
 155
 156 IMPLEMENT_DYNAMIC_CLASS(wxMemoryOutputStream, wxOutputStream)
 157
 158 wxMemoryOutputStream::wxMemoryOutputStream(void *data, size_t len)
 159 {
 160     m_o_streambuf = new wxStreamBuffer(wxStreamBuffer::write);
 161     if ( data )
 162         m_o_streambuf->SetBufferIO(data, len);
 163     m_o_streambuf->Fixed(false);
 164     m_o_streambuf->Flushable(false);
 165 }
 166
 167 wxMemoryOutputStream::~wxMemoryOutputStream()
 168 {
 169     delete m_o_streambuf;
 170 }
 171
 172 size_t wxMemoryOutputStream::OnSysWrite(const void *buffer, size_t nbytes)
 173 {
 174     size_t oldpos = m_o_streambuf->GetIntPosition();
 175     m_o_streambuf->Write(buffer, nbytes);
 176     size_t newpos = m_o_streambuf->GetIntPosition();
 177
 178     // FIXME can someone please explain what this does? (VZ)
 179     if ( !newpos )
 180         newpos = m_o_streambuf->GetBufferSize();
 181
 182     return newpos - oldpos;
 183 }
 184
 185 wxFileOffset wxMemoryOutputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 186 {
 187     return m_o_streambuf->Seek(pos, mode);
 188 }
 189
 190 wxFileOffset wxMemoryOutputStream::OnSysTell() const
 191 {
 192     return m_o_streambuf->Tell();
 193 }
 194
 195 size_t wxMemoryOutputStream::CopyTo(void *buffer, size_t len) const
 196 {
 197     wxCHECK_MSG( buffer, 0, _T("must have buffer to CopyTo") );
 198
 199     if ( len > GetSize() )
 200         len = GetSize();
 201
 202     memcpy(buffer, m_o_streambuf->GetBufferStart(), len);
 203
 204     return len;
 205 }
 206
 207 #endif // wxUSE_STREAMS