wxWidgets/src/common/stream.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        stream.cpp
// Purpose:     wxStream base classes
// Author:      Guilhem Lavaux
// Modified by:
// Created:     11/07/98
// RCS-ID:      $Id$
// Copyright:   (c) Guilhem Lavaux
// Licence:     wxWindows license
/////////////////////////////////////////////////////////////////////////////

#ifdef __GNUG__
#pragma implementation "stream.h"
#endif

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
  #pragma hdrstop
#endif

#ifndef WX_PRECOMP
  #include "wx/defs.h"
#endif

#if wxUSE_STREAMS

#include <ctype.h>
#include "wx/stream.h"
#include "wx/datstrm.h"
#include "wx/objstrm.h"

#define BUF_TEMP_SIZE 10000

// ----------------------------------------------------------------------------
// wxStreamBuffer
// ----------------------------------------------------------------------------

#define CHECK_ERROR(err) \
   if (m_stream->m_lasterror == wxStream_NOERROR) \
     m_stream->m_lasterror = err

wxStreamBuffer::wxStreamBuffer(wxStreamBase& stream, BufMode mode)
  : m_buffer_start(NULL), m_buffer_end(NULL), m_buffer_pos(NULL),
    m_buffer_size(0), m_fixed(TRUE), m_flushable(TRUE), m_stream(&stream),
    m_mode(mode), m_destroybuf(FALSE), m_destroystream(FALSE)
{
}

wxStreamBuffer::wxStreamBuffer(BufMode mode)
  : m_buffer_start(NULL), m_buffer_end(NULL), m_buffer_pos(NULL),
    m_buffer_size(0), m_fixed(TRUE), m_flushable(FALSE), m_stream(NULL),
    m_mode(mode), m_destroybuf(FALSE), m_destroystream(TRUE)
{
  m_stream = new wxStreamBase();
}

wxStreamBuffer::wxStreamBuffer(const wxStreamBuffer& buffer)
{
  m_buffer_start = buffer.m_buffer_start;
  m_buffer_end = buffer.m_buffer_end;
  m_buffer_pos = buffer.m_buffer_pos;
  m_buffer_size = buffer.m_buffer_size;
  m_fixed = buffer.m_fixed;
  m_flushable = buffer.m_flushable;
  m_stream = buffer.m_stream;
  m_mode = buffer.m_mode;
  m_destroybuf = FALSE;
  m_destroystream = FALSE;
}

wxStreamBuffer::~wxStreamBuffer()
{
  if (m_destroybuf)
    wxDELETEA(m_buffer_start);
  if (m_destroystream)
    delete m_stream;
}

void wxStreamBuffer::SetBufferIO(char *buffer_start, char *buffer_end)
{
  if (m_destroybuf)
    wxDELETEA(m_buffer_start);
  m_buffer_start = buffer_start;
  m_buffer_end   = buffer_end;

  m_buffer_size = m_buffer_end-m_buffer_start;
  m_destroybuf = FALSE;
  ResetBuffer();
}

void wxStreamBuffer::SetBufferIO(size_t bufsize)
{
  char *b_start;

  if (m_destroybuf)
    wxDELETEA(m_buffer_start);

  if (!bufsize) {
    m_buffer_start = (char*)NULL;
    m_buffer_end = (char*)NULL;
    m_buffer_pos = (char*)NULL;
    m_buffer_size = 0;
    return;
  }

  b_start = new char[bufsize];
  SetBufferIO(b_start, b_start + bufsize);
  m_destroybuf = TRUE;
}

void wxStreamBuffer::ResetBuffer()
{
  m_stream->m_lasterror = wxStream_NOERROR;
  m_stream->m_lastcount = 0;
  if (m_mode == read && m_flushable)
    m_buffer_pos = m_buffer_end;
  else
    m_buffer_pos = m_buffer_start;
}

bool wxStreamBuffer::FillBuffer()
{
  size_t count;

  count = m_stream->OnSysRead(m_buffer_start, m_buffer_size);
  m_buffer_end = m_buffer_start+count;
  m_buffer_pos = m_buffer_start;

  if (count == 0)
    return FALSE;
  return TRUE;
}

bool wxStreamBuffer::FlushBuffer()
{
  size_t count, current;

  if (m_buffer_pos == m_buffer_start || !m_flushable)
    return FALSE;

  current = m_buffer_pos-m_buffer_start;
  count = m_stream->OnSysWrite(m_buffer_start, current);
  if (count != current)
    return FALSE;
  m_buffer_pos = m_buffer_start;

  return TRUE;
}

void wxStreamBuffer::GetFromBuffer(void *buffer, size_t size)
{
  size_t s_toget = m_buffer_end-m_buffer_pos;

  if (size < s_toget)
    s_toget = size;

  memcpy(buffer, m_buffer_pos, s_toget);
  m_buffer_pos += s_toget;
}

void wxStreamBuffer::PutToBuffer(const void *buffer, size_t size)
{
  size_t s_toput = m_buffer_end-m_buffer_pos;

  if (s_toput < size && !m_fixed) {
    if (!m_buffer_start)
      SetBufferIO(size);
    else {
      size_t delta = m_buffer_pos-m_buffer_start;

      m_buffer_start = (char *)realloc(m_buffer_start, m_buffer_size+size);
      m_buffer_pos   = m_buffer_start + delta;
      // I round a bit
      m_buffer_size += size;
      m_buffer_end   = m_buffer_start+m_buffer_size;
    }
    s_toput = size;
  }
  if (s_toput > size)
    s_toput = size;
  memcpy(m_buffer_pos, buffer, s_toput);
  m_buffer_pos += s_toput;
}

void wxStreamBuffer::PutChar(char c)
{
  wxASSERT(m_stream != NULL);

  if (!m_buffer_size) {
    m_stream->OnSysWrite(&c, 1);
    return;
  }

  if (GetDataLeft() == 0 && !FlushBuffer()) {
    CHECK_ERROR(wxStream_WRITE_ERR);
    return;
  }

  PutToBuffer(&c, 1);
  m_stream->m_lastcount = 1;
}

char wxStreamBuffer::Peek()
{
  char c;

  wxASSERT(m_stream != NULL && m_buffer_size != 0);

  if (!GetDataLeft()) {
    CHECK_ERROR(wxStream_READ_ERR);
    return 0;
  }

  GetFromBuffer(&c, 1);
  m_buffer_pos--;

  return c;
}

char wxStreamBuffer::GetChar()
{
  char c;

  wxASSERT(m_stream != NULL);

  if (!m_buffer_size) {
    m_stream->OnSysRead(&c, 1);
    return c;
  }

  if (!GetDataLeft()) {
    CHECK_ERROR(wxStream_READ_ERR);
    return 0;
  }

  GetFromBuffer(&c, 1);
  
  m_stream->m_lastcount = 1;
  return c;
}

size_t wxStreamBuffer::Read(void *buffer, size_t size)
{
  wxASSERT(m_stream != NULL);

  if (m_mode == write)
    return 0;

  // ------------------
  // Buffering disabled
  // ------------------

  m_stream->m_lasterror = wxStream_NOERROR;
  if (!m_buffer_size)
    return (m_stream->m_lastcount += m_stream->OnSysRead(buffer, size));

  // -----------------
  // Buffering enabled
  // -----------------
  size_t buf_left, orig_size = size;

  while (size > 0) {
    buf_left = GetDataLeft(); 

    // First case: the requested buffer is larger than the stream buffer,
    //             we split it.
    if (size > buf_left) {
      GetFromBuffer(buffer, buf_left);
      size  -= buf_left;
      buffer = (char *)buffer + buf_left; // ANSI C++ violation.

      if (!FillBuffer()) {
        CHECK_ERROR(wxStream_EOF);
        return (m_stream->m_lastcount = orig_size-size);
      }
    } else {

      // Second case: we just copy from the stream buffer.
      GetFromBuffer(buffer, size);
      break;
    }
  }
  return (m_stream->m_lastcount += orig_size);
}

size_t wxStreamBuffer::Read(wxStreamBuffer *s_buf)
{
  char buf[BUF_TEMP_SIZE];
  size_t s = 0, bytes_read = BUF_TEMP_SIZE;

  if (m_mode == write)
    return 0;

  while (bytes_read != 0) {
    bytes_read = Read(buf, bytes_read);
    bytes_read = s_buf->Write(buf, bytes_read);
    s += bytes_read;
  }
  return s;
}

size_t wxStreamBuffer::Write(const void *buffer, size_t size)
{
  wxASSERT(m_stream != NULL);

  if (m_mode == read)
    return 0;

  // ------------------
  // Buffering disabled
  // ------------------

  m_stream->m_lasterror = wxStream_NOERROR;
  if (!m_buffer_size && m_fixed)
    return (m_stream->m_lastcount = m_stream->OnSysWrite(buffer, size));

  // ------------------
  // Buffering enabled
  // ------------------

  size_t buf_left, orig_size = size;

  while (size > 0) {
    buf_left = m_buffer_end - m_buffer_pos;

    // First case: the buffer to write is larger than the stream buffer,
    //             we split it
    // NB: If stream buffer isn't fixed (as for wxMemoryOutputStream),
    // we always go to the second case.
    if (size > buf_left && m_fixed) {
      PutToBuffer(buffer, buf_left);
      size -= buf_left;
      buffer = (char *)buffer + buf_left; // ANSI C++ violation.

      if (!FlushBuffer()) {
	CHECK_ERROR(wxStream_WRITE_ERR);
        return (m_stream->m_lastcount = orig_size-size);
      }

      m_buffer_pos = m_buffer_start;

    } else {

      // Second case: just copy it in the stream buffer.
      PutToBuffer(buffer, size);
      break;
    }
  }
  return (m_stream->m_lastcount = orig_size);
}

size_t wxStreamBuffer::Write(wxStreamBuffer *sbuf)
{
  char buf[BUF_TEMP_SIZE];
  size_t s = 0, bytes_count = BUF_TEMP_SIZE, b_count2;
  wxInputStream *in_stream;

  if (m_mode == read)
    return 0;

  in_stream = (wxInputStream *)sbuf->Stream();

  while (bytes_count == BUF_TEMP_SIZE) {
    b_count2 = sbuf->Read(buf, bytes_count);
    bytes_count = Write(buf, b_count2);
    if (b_count2 > bytes_count)
      in_stream->Ungetch(buf+bytes_count, b_count2-bytes_count);
    s += bytes_count;
  }
  return s;
}

off_t wxStreamBuffer::Seek(off_t pos, wxSeekMode mode)
{
  off_t ret_off, diff, last_access;

  last_access = GetLastAccess();

  if (!m_flushable) {
    switch (mode) {
      case wxFromStart:   diff = pos;                     break;
      case wxFromCurrent: diff = pos + GetIntPosition();  break;
      case wxFromEnd:     diff = pos + last_access;       break;
      default: return wxInvalidOffset;
    }
    if (diff < 0 || diff > last_access)
      return wxInvalidOffset;
    SetIntPosition(diff);
    return diff;
  }

  switch (mode) {
  case wxFromStart: {
    // We'll try to compute an internal position later ...
    ret_off = m_stream->OnSysSeek(pos, wxFromStart);
    ResetBuffer();
    return ret_off;
  }
  case wxFromCurrent: {
    diff = pos + GetIntPosition();

    if ( (diff > last_access) || (diff < 0) ) {
      // We must take into account the fact that we have read something
      // previously.
      ret_off = m_stream->OnSysSeek(diff-last_access, wxFromCurrent);
      ResetBuffer();
      return ret_off;
    } else {
      SetIntPosition(diff);
      return pos;
    }
  }
  case wxFromEnd:
    // Hard to compute: always seek to the requested position.
    ret_off = m_stream->OnSysSeek(pos, wxFromEnd);
    ResetBuffer();
    return ret_off;
  }
  return wxInvalidOffset;
}

off_t wxStreamBuffer::Tell() const
{
    off_t pos = m_stream->OnSysTell();
    if (pos == wxInvalidOffset)
        return wxInvalidOffset;

    pos += GetIntPosition();
	
    if (m_mode == read && m_flushable)
        pos -= GetLastAccess();
    
    return pos;
}

size_t wxStreamBuffer::GetDataLeft()
{
    /* Why is this done? RR. */
    if (m_buffer_end == m_buffer_pos && m_flushable)
        FillBuffer();
	
    return m_buffer_end-m_buffer_pos;
}

// ----------------------------------------------------------------------------
// wxStreamBase
// ----------------------------------------------------------------------------

wxStreamBase::wxStreamBase()
{
    m_lasterror = wxStream_NOERROR;
    m_lastcount = 0;
}

wxStreamBase::~wxStreamBase()
{
}

size_t wxStreamBase::OnSysRead(void *WXUNUSED(buffer), size_t WXUNUSED(size))
{
    return 0;
}

size_t wxStreamBase::OnSysWrite(const void *WXUNUSED(buffer), size_t WXUNUSED(bufsize))
{
    return 0;
}

off_t wxStreamBase::OnSysSeek(off_t WXUNUSED(seek), wxSeekMode WXUNUSED(mode))
{
    return wxInvalidOffset;
}

off_t wxStreamBase::OnSysTell() const
{
    return wxInvalidOffset;
}

// ----------------------------------------------------------------------------
// wxInputStream
// ----------------------------------------------------------------------------

wxInputStream::wxInputStream()
  : wxStreamBase(),
    m_wback(NULL), m_wbacksize(0), m_wbackcur(0)
{
}

wxInputStream::~wxInputStream()
{
  if (m_wback)
    free(m_wback);
}

char *wxInputStream::AllocSpaceWBack(size_t needed_size)
{
    /* get number of bytes left from previous wback buffer */
    size_t toget = m_wbacksize - m_wbackcur;

    /* allocate a buffer large enough to hold prev + new data */
    char *temp_b = (char *) malloc(needed_size + toget);

    if (!temp_b)
        return NULL;

    /* copy previous data (and free old buffer) if needed */
    if (m_wback)
    {
        memmove(temp_b + needed_size, m_wback + m_wbackcur, toget);
        free(m_wback);
    }

    /* done */
    m_wback = temp_b;
    m_wbackcur = 0;
    m_wbacksize = needed_size + toget;

    return (char *) m_wback;
}

size_t wxInputStream::GetWBack(char *buf, size_t bsize)
{
    size_t s_toget = m_wbacksize-m_wbackcur;

    if (!m_wback)
        return 0;

    if (bsize < s_toget)
       s_toget = bsize;

    memcpy(buf, (m_wback+m_wbackcur), s_toget);

    m_wbackcur += s_toget;
    if (m_wbackcur == m_wbacksize) 
    {
        free(m_wback);
        m_wback = (char *)NULL;
        m_wbacksize = 0;
        m_wbackcur = 0;
    }
    
    return s_toget;
}

size_t wxInputStream::Ungetch(const void *buf, size_t bufsize)
{
    char *ptrback = AllocSpaceWBack(bufsize);
    if (!ptrback)
        return 0;
 
    memcpy(ptrback, buf, bufsize);
    return bufsize;
}

bool wxInputStream::Ungetch(char c)
{
    char * ptrback = AllocSpaceWBack(1);
    if (!ptrback)
        return FALSE;

    *ptrback = c;
    return TRUE;
}

char wxInputStream::GetC()
{
    char c;
    Read(&c, 1);
    return c;
}

wxInputStream& wxInputStream::Read(void *buffer, size_t size)
{
    char *buf = (char *)buffer;

    size_t retsize = GetWBack(buf, size);
    if (retsize == size) 
    {
        m_lastcount = size;
        m_lasterror = wxStream_NOERROR;
        return *this;
    }
    size -= retsize;
    buf  += retsize;

    m_lastcount = OnSysRead(buf, size) + retsize;
    return *this;
}

char wxInputStream::Peek()
{
    char c;
    Read(&c, 1);
    if (m_lasterror == wxStream_NOERROR) 
    {
        Ungetch(c);
        return c;
    }
    
    return 0;
}

wxInputStream& wxInputStream::Read(wxOutputStream& stream_out)
{
    char buf[BUF_TEMP_SIZE]; 
    size_t bytes_read = BUF_TEMP_SIZE;

    while (bytes_read == BUF_TEMP_SIZE) 
    {
        bytes_read = Read(buf, bytes_read).LastRead();
        bytes_read = stream_out.Write(buf, bytes_read).LastWrite();
    }
    return *this;
}

off_t wxInputStream::SeekI(off_t pos, wxSeekMode mode)
{
    /* Should be check and improve, just to remove a slight bug !
       I don't know whether it should be put as well in wxFileInputStream::OnSysSeek ? */
    if (m_lasterror==wxSTREAM_EOF) 
        m_lasterror=wxSTREAM_NOERROR;

    /* A call to SeekI() will automatically invalidate any previous call
       to Ungetch(), otherwise it would be possible to SeekI() to one
       one position, unread some bytes there, SeekI() to another position
       and the data would be corrupted. */
    if (m_wback) 
    {
        free(m_wback);
        m_wback = (char*) NULL;
        m_wbacksize = 0;
        m_wbackcur = 0;
    }

    return OnSysSeek(pos, mode);
}

off_t wxInputStream::TellI() const
{
    return OnSysTell();
}

// --------------------
// Overloaded operators
// --------------------

#if wxUSE_SERIAL
wxInputStream& wxInputStream::operator>>(wxObject *& obj)
{
    wxObjectInputStream obj_s(*this);
    obj = obj_s.LoadObject();
    return *this;
}
#endif


// ----------------------------------------------------------------------------
// wxOutputStream
// ----------------------------------------------------------------------------
wxOutputStream::wxOutputStream()
  : wxStreamBase()
{
}

wxOutputStream::~wxOutputStream()
{
}

void wxOutputStream::PutC(char c)
{
    Write((void *) &c, 1);
}

wxOutputStream& wxOutputStream::Write(const void *buffer, size_t size)
{
    m_lastcount = OnSysWrite(buffer, size);
    return *this;
}

wxOutputStream& wxOutputStream::Write(wxInputStream& stream_in)
{
    stream_in.Read(*this);
    return *this;
}

off_t wxOutputStream::TellO() const
{
    return OnSysTell();
}

off_t wxOutputStream::SeekO(off_t pos, wxSeekMode mode)
{
    return OnSysSeek(pos, mode);
}

void wxOutputStream::Sync()
{
}

#if wxUSE_SERIAL
wxOutputStream& wxOutputStream::operator<<(wxObject& obj)
{
    wxObjectOutputStream obj_s(*this);
    obj_s.SaveObject(obj);
    return *this;
}
#endif

// ----------------------------------------------------------------------------
// wxCountingOutputStream
// ----------------------------------------------------------------------------

wxCountingOutputStream::wxCountingOutputStream ()
  : wxOutputStream()
{
     m_currentPos = 0;
}

size_t wxCountingOutputStream::GetSize() const
{
    return m_lastcount;
}

size_t wxCountingOutputStream::OnSysWrite(const void *WXUNUSED(buffer), size_t size)
{
    m_currentPos += size;
    if (m_currentPos > m_lastcount) m_lastcount = m_currentPos;
    return m_currentPos;
}

off_t wxCountingOutputStream::OnSysSeek(off_t pos, wxSeekMode mode)
{
    if (mode == wxFromStart)
        m_currentPos = pos;
    if (mode == wxFromEnd)
        m_currentPos = m_lastcount + pos;
    else
        m_currentPos += pos;
    
    if (m_currentPos > m_lastcount) m_lastcount = m_currentPos;
  
    return m_currentPos;
}

off_t wxCountingOutputStream::OnSysTell() const
{
    return m_currentPos;
}
  
// ----------------------------------------------------------------------------
// wxFilterInputStream
// ----------------------------------------------------------------------------

wxFilterInputStream::wxFilterInputStream()
  : wxInputStream()
{
}

wxFilterInputStream::wxFilterInputStream(wxInputStream& stream)
  : wxInputStream()
{
    m_parent_i_stream = &stream;
}

wxFilterInputStream::~wxFilterInputStream()
{
}

// ----------------------------------------------------------------------------
// wxFilterOutputStream
// ----------------------------------------------------------------------------
wxFilterOutputStream::wxFilterOutputStream()
  : wxOutputStream()
{
}

wxFilterOutputStream::wxFilterOutputStream(wxOutputStream& stream)
  : wxOutputStream()
{
    m_parent_o_stream = &stream;
}

wxFilterOutputStream::~wxFilterOutputStream()
{
}

// ----------------------------------------------------------------------------
// wxBufferedInputStream
// ----------------------------------------------------------------------------
wxBufferedInputStream::wxBufferedInputStream(wxInputStream& s)
  : wxFilterInputStream(s)
{
    m_i_streambuf = new wxStreamBuffer(*this, wxStreamBuffer::read);
    m_i_streambuf->SetBufferIO(1024);
}

wxBufferedInputStream::~wxBufferedInputStream()
{
    off_t unused_bytes=m_i_streambuf->GetBufferPos()-m_i_streambuf->GetBufferEnd();
    m_parent_i_stream->SeekI(unused_bytes,wxFromCurrent);

    delete m_i_streambuf;
}

char wxBufferedInputStream::Peek()
{
    return m_i_streambuf->Peek();
}

wxInputStream& wxBufferedInputStream::Read(void *buffer, size_t size)
{
    size_t retsize;
    char *buf = (char *)buffer;

    retsize = GetWBack(buf, size);
    m_lastcount = retsize;
    if (retsize == size) 
    {
        m_lasterror = wxStream_NOERROR;
        return *this;
    }
    size -= retsize;
    buf  += retsize;

    m_i_streambuf->Read(buf, size);

    return *this;
}

off_t wxBufferedInputStream::SeekI(off_t pos, wxSeekMode mode)
{
    return m_i_streambuf->Seek(pos, mode);
}

off_t wxBufferedInputStream::TellI() const
{
    return m_i_streambuf->Tell();
}

size_t wxBufferedInputStream::OnSysRead(void *buffer, size_t bufsize)
{
    return m_parent_i_stream->Read(buffer, bufsize).LastRead();
}

off_t wxBufferedInputStream::OnSysSeek(off_t seek, wxSeekMode mode)
{
    return m_parent_i_stream->SeekI(seek, mode);
}

off_t wxBufferedInputStream::OnSysTell() const
{
    return m_parent_i_stream->TellI();
}


// ----------------------------------------------------------------------------
// wxBufferedOutputStream
// ----------------------------------------------------------------------------

wxBufferedOutputStream::wxBufferedOutputStream(wxOutputStream& s)
  : wxFilterOutputStream(s)
{
    m_o_streambuf = new wxStreamBuffer(*this, wxStreamBuffer::write);
    m_o_streambuf->SetBufferIO(1024);
}

wxBufferedOutputStream::~wxBufferedOutputStream()
{
    Sync();
    delete m_o_streambuf;
}

wxOutputStream& wxBufferedOutputStream::Write(const void *buffer, size_t size)
{
    m_lastcount = 0;
    m_o_streambuf->Write(buffer, size);
    return *this;
}

off_t wxBufferedOutputStream::SeekO(off_t pos, wxSeekMode mode)
{
    Sync();
    return m_o_streambuf->Seek(pos, mode);
}

off_t wxBufferedOutputStream::TellO() const
{
    return m_o_streambuf->Tell();
}

void wxBufferedOutputStream::Sync()
{
    m_o_streambuf->FlushBuffer();
    m_parent_o_stream->Sync();
}

size_t wxBufferedOutputStream::OnSysWrite(const void *buffer, size_t bufsize)
{
    return m_parent_o_stream->Write(buffer, bufsize).LastWrite();
}

off_t wxBufferedOutputStream::OnSysSeek(off_t seek, wxSeekMode mode)
{
    return m_parent_o_stream->SeekO(seek, mode);
}

off_t wxBufferedOutputStream::OnSysTell() const
{
    return m_parent_o_stream->TellO();
}

size_t wxBufferedOutputStream::GetSize() const
{
   return m_parent_o_stream->GetSize() + m_o_streambuf->GetIntPosition();
}

// ----------------------------------------------------------------------------
// Some IOManip function
// ----------------------------------------------------------------------------

wxOutputStream& wxEndL(wxOutputStream& stream)
{
#ifdef __MSW__
  return stream.Write("\r\n", 2);
#else
#ifdef __WXMAC__
  return stream.Write("\r", 1);
#else
  return stream.Write("\n", 1);
#endif
#endif
}

#endif
  // wxUSE_STREAMS