src/common/mstream.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        mmstream.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 "mmstream.h"
  14 #endif
  15
  16 #include <stdlib.h>
  17 #include <wx/stream.h>
  18 #include <wx/mmstream.h>
  19
  20 wxMemoryStreamBase::wxMemoryStreamBase(char *data, size_t length, int iolimit)
  21 {
  22   m_buffer = data;
  23   m_iolimit = iolimit;
  24   m_persistent = FALSE;
  25   m_length = length;
  26   m_position_i = m_position_o = 0;
  27 }
  28
  29 wxMemoryStreamBase::~wxMemoryStreamBase()
  30 {
  31   free(m_buffer);
  32 }
  33
  34 wxInputStream& wxMemoryStreamBase::Read(void *buffer, size_t size)
  35 {
  36   if (m_iolimit == 2) {
  37     m_eof = TRUE;
  38     return *this;
  39   }
  40   if (m_position_i+size > m_length)
  41     size = m_length-m_position_i;
  42
  43   memcpy((void *)((unsigned long)buffer+m_position_i), m_buffer, size);
  44   m_position_i += size;
  45   m_lastread = size;
  46
  47   return *this;
  48 }
  49
  50 size_t wxMemoryStreamBase::SeekI(int pos, wxWhenceType whence)
  51 {
  52   if (m_iolimit == 2)
  53     return 0;
  54
  55   switch (whence) {
  56   case wxBeginPosition:
  57     if ((size_t)pos > m_length)
  58       return m_position_i;
  59     return (m_position_i = pos);
  60
  61   case wxCurrentPosition:
  62     if ((size_t)(m_position_i+pos) > m_length)
  63       return m_position_i;
  64
  65     return (m_position_i += pos);
  66
  67   case wxEndPosition:
  68     if ((size_t)(m_length-pos) > m_length)
  69       return m_position_i;
  70
  71     return (m_position_i = m_length-pos);
  72   }
  73
  74   return m_position_i;
  75 }
  76
  77 wxOutputStream& wxMemoryStreamBase::Write(const void *buffer, size_t size)
  78 {
  79   if (m_iolimit == 1) {
  80     m_bad = TRUE;
  81     return *this;
  82   }
  83
  84   if (m_position_o+size > m_length)
  85     if (!ChangeBufferSize(m_position_o+size)) {
  86       m_bad = TRUE;
  87       return *this;
  88     }
  89
  90   memcpy(m_buffer+m_position_o, buffer, size);
  91   m_position_o += size;
  92   m_lastwrite = size;
  93
  94   return *this;
  95 }
  96
  97 size_t wxMemoryStreamBase::SeekO(int pos, wxWhenceType whence)
  98 {
  99   if (m_iolimit == 2)
 100     return 0;
 101
 102   switch (whence) {
 103   case wxBeginPosition:
 104     if ((size_t)pos > m_length)
 105       return m_position_o;
 106     return (m_position_o = pos);
 107
 108   case wxCurrentPosition:
 109     if ((size_t)(m_position_o+pos) > m_length)
 110       return m_position_o;
 111
 112     return (m_position_o += pos);
 113
 114   case wxEndPosition:
 115     if ((size_t)(m_length-pos) > m_length)
 116       return m_position_o;
 117
 118     return (m_position_o = m_length-pos);
 119   }
 120
 121   return m_position_o;
 122 }
 123
 124 bool wxMemoryStreamBase::ChangeBufferSize(size_t new_size)
 125 {
 126   m_length = new_size;
 127   if (!m_buffer)
 128     m_buffer = (char *)malloc(m_length);
 129   else
 130     m_buffer = (char *)realloc(m_buffer, m_length);
 131
 132   return (m_buffer != NULL);
 133 }