src/common/mstream.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        mstream.cpp
   3 // Purpose:     "Memory stream" classes
   4 // Author:      Guilhem Lavaux
   5 // Modified by:
   6 // Created:     04/01/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Guilhem Lavaux
   9 // Licence:     wxWindows license
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #ifdef __GNUG__
  13 #pragma implementation "mstream.h"
  14 #endif
  15
  16 #include <stdlib.h>
  17 #include <wx/stream.h>
  18 #include <wx/mstream.h>
  19
  20 #if !USE_SHARED_LIBRARY
  21 IMPLEMENT_CLASS(wxMemoryStreamBase, wxStream)
  22 IMPLEMENT_CLASS(wxMemoryInputStream, wxMemoryStreamBase)
  23 IMPLEMENT_DYNAMIC_CLASS(wxMemoryOutputStream, wxMemoryStreamBase)
  24 IMPLEMENT_DYNAMIC_CLASS(wxMemoryStream, wxMemoryStreamBase)
  25 #endif
  26
  27 wxMemoryStreamBase::wxMemoryStreamBase(char *data, size_t length, int iolimit)
  28 {
  29   m_buffer = data;
  30   m_iolimit = iolimit;
  31   m_persistent = FALSE;
  32   m_length = length;
  33   m_position_i = m_position_o = 0;
  34 }
  35
  36 wxMemoryStreamBase::~wxMemoryStreamBase()
  37 {
  38   free(m_buffer);
  39 }
  40
  41 wxInputStream& wxMemoryStreamBase::Read(void *buffer, size_t size)
  42 {
  43   if (m_iolimit == 2) {
  44     m_eof = TRUE;
  45     return *this;
  46   }
  47   if (m_position_i+size > m_length)
  48     size = m_length-m_position_i;
  49
  50   memcpy((void *)((unsigned long)buffer+m_position_i), m_buffer, size);
  51   m_position_i += size;
  52   m_lastread = size;
  53
  54   return *this;
  55 }
  56
  57 size_t wxMemoryStreamBase::SeekI(int pos, wxWhenceType whence)
  58 {
  59   if (m_iolimit == 2)
  60     return 0;
  61
  62   switch (whence) {
  63   case wxBeginPosition:
  64     if ((size_t)pos > m_length)
  65       return m_position_i;
  66     return (m_position_i = pos);
  67
  68   case wxCurrentPosition:
  69     if ((size_t)(m_position_i+pos) > m_length)
  70       return m_position_i;
  71
  72     return (m_position_i += pos);
  73
  74   case wxEndPosition:
  75     if ((size_t)(m_length-pos) > m_length)
  76       return m_position_i;
  77
  78     return (m_position_i = m_length-pos);
  79   }
  80
  81   return m_position_i;
  82 }
  83
  84 wxOutputStream& wxMemoryStreamBase::Write(const void *buffer, size_t size)
  85 {
  86   if (m_iolimit == 1) {
  87     m_bad = TRUE;
  88     return *this;
  89   }
  90
  91   if (m_position_o+size > m_length)
  92     if (!ChangeBufferSize(m_position_o+size)) {
  93       m_bad = TRUE;
  94       return *this;
  95     }
  96
  97   memcpy(m_buffer+m_position_o, buffer, size);
  98   m_position_o += size;
  99   m_lastwrite = size;
 100
 101   return *this;
 102 }
 103
 104 size_t wxMemoryStreamBase::SeekO(int pos, wxWhenceType whence)
 105 {
 106   if (m_iolimit == 2)
 107     return 0;
 108
 109   switch (whence) {
 110   case wxBeginPosition:
 111     if ((size_t)pos > m_length)
 112       return m_position_o;
 113     return (m_position_o = pos);
 114
 115   case wxCurrentPosition:
 116     if ((size_t)(m_position_o+pos) > m_length)
 117       return m_position_o;
 118
 119     return (m_position_o += pos);
 120
 121   case wxEndPosition:
 122     if ((size_t)(m_length-pos) > m_length)
 123       return m_position_o;
 124
 125     return (m_position_o = m_length-pos);
 126   }
 127
 128   return m_position_o;
 129 }
 130
 131 bool wxMemoryStreamBase::ChangeBufferSize(size_t new_size)
 132 {
 133   m_length = new_size;
 134   if (!m_buffer)
 135     m_buffer = (char *)malloc(m_length);
 136   else
 137     m_buffer = (char *)realloc(m_buffer, m_length);
 138
 139   return (m_buffer != NULL);
 140 }