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 // Copyright:   (c) Guilhem Lavaux
   8 // Licence:     wxWindows licence
   9 /////////////////////////////////////////////////////////////////////////////
  10
  11 // ============================================================================
  12 // declarations
  13 // ============================================================================
  14
  15 // ----------------------------------------------------------------------------
  16 // headers
  17 // ----------------------------------------------------------------------------
  18
  19 // For compilers that support precompilation, includes "wx.h".
  20 #include "wx/wxprec.h"
  21
  22 #ifdef __BORLANDC__
  23     #pragma hdrstop
  24 #endif
  25
  26 #if wxUSE_STREAMS
  27
  28 #include "wx/mstream.h"
  29
  30 #ifndef   WX_PRECOMP
  31     #include  "wx/stream.h"
  32 #endif  //WX_PRECOMP
  33
  34 #include <stdlib.h>
  35
  36 // ============================================================================
  37 // implementation
  38 // ============================================================================
  39
  40 // ----------------------------------------------------------------------------
  41 // wxMemoryInputStream
  42 // ----------------------------------------------------------------------------
  43
  44 IMPLEMENT_ABSTRACT_CLASS(wxMemoryInputStream, wxInputStream)
  45
  46 wxMemoryInputStream::wxMemoryInputStream(const void *data, size_t len)
  47 {
  48     m_i_streambuf = new wxStreamBuffer(wxStreamBuffer::read);
  49     m_i_streambuf->SetBufferIO(const_cast<void *>(data), len);
  50     m_i_streambuf->SetIntPosition(0); // seek to start pos
  51     m_i_streambuf->Fixed(true);
  52
  53     m_length = len;
  54 }
  55
  56 wxMemoryInputStream::wxMemoryInputStream(const wxMemoryOutputStream& stream)
  57 {
  58     const wxFileOffset lenFile = stream.GetLength();
  59     if ( lenFile == wxInvalidOffset )
  60     {
  61         m_i_streambuf = NULL;
  62         m_lasterror = wxSTREAM_EOF;
  63         return;
  64     }
  65
  66     const size_t len = wx_truncate_cast(size_t, lenFile);
  67     wxASSERT_MSG( len == lenFile + size_t(0), wxT("huge files not supported") );
  68
  69     m_i_streambuf = new wxStreamBuffer(wxStreamBuffer::read);
  70     m_i_streambuf->SetBufferIO(len); // create buffer
  71     stream.CopyTo(m_i_streambuf->GetBufferStart(), len);
  72     m_i_streambuf->SetIntPosition(0); // seek to start pos
  73     m_i_streambuf->Fixed(true);
  74     m_length = len;
  75 }
  76
  77 void
  78 wxMemoryInputStream::InitFromStream(wxInputStream& stream, wxFileOffset lenFile)
  79 {
  80     if ( lenFile == wxInvalidOffset )
  81         lenFile = stream.GetLength();
  82
  83     if ( lenFile == wxInvalidOffset )
  84     {
  85         m_i_streambuf = NULL;
  86         m_lasterror = wxSTREAM_EOF;
  87         return;
  88     }
  89
  90     const size_t len = wx_truncate_cast(size_t, lenFile);
  91     wxASSERT_MSG( (wxFileOffset)len == lenFile, wxT("huge files not supported") );
  92
  93     m_i_streambuf = new wxStreamBuffer(wxStreamBuffer::read);
  94     m_i_streambuf->SetBufferIO(len); // create buffer
  95     stream.Read(m_i_streambuf->GetBufferStart(), len);
  96     m_i_streambuf->SetIntPosition(0); // seek to start pos
  97     m_i_streambuf->Fixed(true);
  98     m_length = stream.LastRead();
  99 }
 100
 101 bool wxMemoryInputStream::CanRead() const
 102 {
 103     return m_i_streambuf->GetIntPosition() != m_length;
 104 }
 105
 106 wxMemoryInputStream::~wxMemoryInputStream()
 107 {
 108     delete m_i_streambuf;
 109 }
 110
 111 char wxMemoryInputStream::Peek()
 112 {
 113     char *buf = (char *)m_i_streambuf->GetBufferStart();
 114     size_t pos = m_i_streambuf->GetIntPosition();
 115     if ( pos == m_length )
 116     {
 117         m_lasterror = wxSTREAM_READ_ERROR;
 118
 119         return 0;
 120     }
 121
 122     return buf[pos];
 123 }
 124
 125 size_t wxMemoryInputStream::OnSysRead(void *buffer, size_t nbytes)
 126 {
 127     size_t pos = m_i_streambuf->GetIntPosition();
 128     if ( pos == m_length )
 129     {
 130         m_lasterror = wxSTREAM_EOF;
 131
 132         return 0;
 133     }
 134
 135     m_i_streambuf->Read(buffer, nbytes);
 136     m_lasterror = wxSTREAM_NO_ERROR;
 137
 138     return m_i_streambuf->GetIntPosition() - pos;
 139 }
 140
 141 wxFileOffset wxMemoryInputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 142 {
 143     return m_i_streambuf->Seek(pos, mode);
 144 }
 145
 146 wxFileOffset wxMemoryInputStream::OnSysTell() const
 147 {
 148     return m_i_streambuf->Tell();
 149 }
 150
 151 // ----------------------------------------------------------------------------
 152 // wxMemoryOutputStream
 153 // ----------------------------------------------------------------------------
 154
 155 IMPLEMENT_DYNAMIC_CLASS(wxMemoryOutputStream, wxOutputStream)
 156
 157 wxMemoryOutputStream::wxMemoryOutputStream(void *data, size_t len)
 158 {
 159     m_o_streambuf = new wxStreamBuffer(wxStreamBuffer::write);
 160     if ( data )
 161         m_o_streambuf->SetBufferIO(data, len);
 162     m_o_streambuf->Fixed(false);
 163     m_o_streambuf->Flushable(false);
 164 }
 165
 166 wxMemoryOutputStream::~wxMemoryOutputStream()
 167 {
 168     delete m_o_streambuf;
 169 }
 170
 171 size_t wxMemoryOutputStream::OnSysWrite(const void *buffer, size_t nbytes)
 172 {
 173     size_t oldpos = m_o_streambuf->GetIntPosition();
 174     m_o_streambuf->Write(buffer, nbytes);
 175     size_t newpos = m_o_streambuf->GetIntPosition();
 176
 177     // FIXME can someone please explain what this does? (VZ)
 178     if ( !newpos )
 179         newpos = m_o_streambuf->GetBufferSize();
 180
 181     return newpos - oldpos;
 182 }
 183
 184 wxFileOffset wxMemoryOutputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode)
 185 {
 186     return m_o_streambuf->Seek(pos, mode);
 187 }
 188
 189 wxFileOffset wxMemoryOutputStream::OnSysTell() const
 190 {
 191     return m_o_streambuf->Tell();
 192 }
 193
 194 size_t wxMemoryOutputStream::CopyTo(void *buffer, size_t len) const
 195 {
 196     wxCHECK_MSG( buffer, 0, wxT("must have buffer to CopyTo") );
 197
 198     if ( len > GetSize() )
 199         len = GetSize();
 200
 201     memcpy(buffer, m_o_streambuf->GetBufferStart(), len);
 202
 203     return len;
 204 }
 205
 206 #endif // wxUSE_STREAMS