/
stream.cpp
1621 lines (1281 loc) · 39.8 KB
/
stream.cpp
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/////////////////////////////////////////////////////////////////////////////
// Name: src/common/stream.cpp
// Purpose: wxStream base classes
// Author: Guilhem Lavaux
// Modified by: VZ (23.11.00) to fix realloc()ing new[]ed memory,
// general code review
// Created: 11/07/98
// Copyright: (c) Guilhem Lavaux
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
// ============================================================================
// declarations
// ============================================================================
// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------
// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"
#if wxUSE_STREAMS
#include "wx/stream.h"
#ifndef WX_PRECOMP
#include "wx/log.h"
#endif
#include <ctype.h>
#include "wx/datstrm.h"
#include "wx/textfile.h"
#include "wx/scopeguard.h"
// ----------------------------------------------------------------------------
// constants
// ----------------------------------------------------------------------------
// the temporary buffer size used when copying from stream to stream
#define BUF_TEMP_SIZE 4096
// ============================================================================
// implementation
// ============================================================================
// ----------------------------------------------------------------------------
// wxStreamBuffer
// ----------------------------------------------------------------------------
void wxStreamBuffer::SetError(wxStreamError err)
{
if ( m_stream && m_stream->m_lasterror == wxSTREAM_NO_ERROR )
m_stream->m_lasterror = err;
}
void wxStreamBuffer::InitBuffer()
{
m_buffer_start =
m_buffer_end =
m_buffer_pos = nullptr;
// if we are going to allocate the buffer, we should free it later as well
m_destroybuf = true;
}
void wxStreamBuffer::Init()
{
InitBuffer();
m_fixed = true;
}
void wxStreamBuffer::InitWithStream(wxStreamBase& stream, BufMode mode)
{
Init();
m_stream = &stream;
m_mode = mode;
m_flushable = true;
}
wxStreamBuffer::wxStreamBuffer(BufMode mode)
{
Init();
m_stream = nullptr;
m_mode = mode;
m_flushable = false;
}
wxStreamBuffer::wxStreamBuffer(const wxStreamBuffer& buffer)
{
// doing this has big chances to lead to a crash when the source buffer is
// destroyed (otherwise assume the caller knows what he does)
wxASSERT_MSG( !buffer.m_destroybuf,
wxT("it's a bad idea to copy this buffer") );
m_buffer_start = buffer.m_buffer_start;
m_buffer_end = buffer.m_buffer_end;
m_buffer_pos = buffer.m_buffer_pos;
m_fixed = buffer.m_fixed;
m_flushable = buffer.m_flushable;
m_stream = buffer.m_stream;
m_mode = buffer.m_mode;
m_destroybuf = false;
}
void wxStreamBuffer::FreeBuffer()
{
if ( m_destroybuf )
{
free(m_buffer_start);
m_buffer_start = nullptr;
}
}
wxStreamBuffer::~wxStreamBuffer()
{
FreeBuffer();
}
wxInputStream *wxStreamBuffer::GetInputStream() const
{
return m_mode == write ? nullptr : (wxInputStream *)m_stream;
}
wxOutputStream *wxStreamBuffer::GetOutputStream() const
{
return m_mode == read ? nullptr : (wxOutputStream *)m_stream;
}
void wxStreamBuffer::SetBufferIO(void *buffer_start,
void *buffer_end,
bool takeOwnership)
{
SetBufferIO(buffer_start, (char *)buffer_end - (char *)buffer_start,
takeOwnership);
}
void wxStreamBuffer::SetBufferIO(void *start,
size_t len,
bool takeOwnership)
{
// start by freeing the old buffer
FreeBuffer();
m_buffer_start = (char *)start;
m_buffer_end = m_buffer_start + len;
// if we own it, we free it
m_destroybuf = takeOwnership;
ResetBuffer();
}
void wxStreamBuffer::SetBufferIO(size_t bufsize)
{
if ( bufsize )
{
// this will free the old buffer and allocate the new one
SetBufferIO(malloc(bufsize), bufsize, true /* take ownership */);
}
else // no buffer size => no buffer
{
// still free the old one
FreeBuffer();
InitBuffer();
}
}
void wxStreamBuffer::ResetBuffer()
{
if ( m_stream )
{
m_stream->Reset();
m_stream->m_lastcount = 0;
}
m_buffer_pos = m_mode == read && m_flushable
? m_buffer_end
: m_buffer_start;
}
void wxStreamBuffer::Truncate()
{
size_t new_size = m_buffer_pos - m_buffer_start;
if ( m_buffer_pos == m_buffer_end )
return;
if ( !new_size )
{
FreeBuffer();
InitBuffer();
return;
}
char *new_start = (char *)realloc(m_buffer_start, new_size);
wxCHECK_RET( new_size, wxT("shrinking buffer shouldn't fail") );
m_buffer_start = new_start;
m_buffer_end = m_buffer_start + new_size;
m_buffer_pos = m_buffer_end;
}
// fill the buffer with as much data as possible (only for read buffers)
bool wxStreamBuffer::FillBuffer()
{
wxInputStream *inStream = GetInputStream();
// It's legal to have no stream, so we don't complain about it just return false
if ( !inStream )
return false;
size_t count = inStream->OnSysRead(GetBufferStart(), GetBufferSize());
if ( !count )
return false;
m_buffer_end = m_buffer_start + count;
m_buffer_pos = m_buffer_start;
return true;
}
// write the buffer contents to the stream (only for write buffers)
bool wxStreamBuffer::FlushBuffer()
{
wxCHECK_MSG( m_flushable, false, wxT("can't flush this buffer") );
// FIXME: what is this check for? (VZ)
if ( m_buffer_pos == m_buffer_start )
return false;
wxOutputStream *outStream = GetOutputStream();
wxCHECK_MSG( outStream, false, wxT("should have a stream in wxStreamBuffer") );
size_t current = m_buffer_pos - m_buffer_start;
size_t count = outStream->OnSysWrite(m_buffer_start, current);
if ( count != current )
return false;
m_buffer_pos = m_buffer_start;
return true;
}
size_t wxStreamBuffer::GetDataLeft()
{
/* Why is this done? RR. */
if ( m_buffer_pos == m_buffer_end && m_flushable)
FillBuffer();
return GetBytesLeft();
}
// copy up to size bytes from our buffer into the provided one
void wxStreamBuffer::GetFromBuffer(void *buffer, size_t size)
{
// don't get more bytes than left in the buffer
size_t left = GetBytesLeft();
if ( size > left )
size = left;
memcpy(buffer, m_buffer_pos, size);
m_buffer_pos += size;
}
// copy the contents of the provided buffer into this one
void wxStreamBuffer::PutToBuffer(const void *buffer, size_t size)
{
size_t left = GetBytesLeft();
if ( size > left )
{
if ( m_fixed )
{
// we can't realloc the buffer, so just copy what we can
size = left;
}
else // !m_fixed
{
// realloc the buffer to have enough space for the data
if ( m_buffer_pos + size > m_buffer_end )
{
size_t delta = m_buffer_pos - m_buffer_start;
size_t new_size = delta + size;
char *startOld = m_buffer_start;
m_buffer_start = (char *)realloc(m_buffer_start, new_size);
if ( !m_buffer_start )
{
// don't leak memory if realloc() failed
m_buffer_start = startOld;
// what else can we do?
return;
}
// adjust the pointers invalidated by realloc()
m_buffer_pos = m_buffer_start + delta;
m_buffer_end = m_buffer_start + new_size;
} // else: the buffer is big enough
}
}
memcpy(m_buffer_pos, buffer, size);
m_buffer_pos += size;
}
void wxStreamBuffer::PutChar(char c)
{
wxOutputStream *outStream = GetOutputStream();
wxCHECK_RET( outStream, wxT("should have a stream in wxStreamBuffer") );
// if we don't have buffer at all, just forward this call to the stream,
if ( !HasBuffer() )
{
outStream->OnSysWrite(&c, sizeof(c));
}
else
{
// otherwise check we have enough space left
if ( !GetDataLeft() && !FlushBuffer() )
{
// we don't
SetError(wxSTREAM_WRITE_ERROR);
}
else
{
PutToBuffer(&c, sizeof(c));
m_stream->m_lastcount = 1;
}
}
}
char wxStreamBuffer::Peek()
{
wxCHECK_MSG( m_stream && HasBuffer(), 0,
wxT("should have the stream and the buffer in wxStreamBuffer") );
if ( !GetDataLeft() )
{
SetError(wxSTREAM_READ_ERROR);
return 0;
}
char c;
GetFromBuffer(&c, sizeof(c));
m_buffer_pos--;
return c;
}
char wxStreamBuffer::GetChar()
{
wxInputStream *inStream = GetInputStream();
wxCHECK_MSG( inStream, 0, wxT("should have a stream in wxStreamBuffer") );
char c;
if ( !HasBuffer() )
{
inStream->OnSysRead(&c, sizeof(c));
}
else
{
if ( !GetDataLeft() )
{
SetError(wxSTREAM_READ_ERROR);
c = 0;
}
else
{
GetFromBuffer(&c, sizeof(c));
m_stream->m_lastcount = 1;
}
}
return c;
}
size_t wxStreamBuffer::Read(void *buffer, size_t size)
{
wxCHECK_MSG( buffer, 0, wxT("null data pointer") );
/* Clear buffer first */
memset(buffer, 0x00, size);
// lasterror is reset before all new IO calls
if ( m_stream )
m_stream->Reset();
size_t readBytes;
if ( !HasBuffer() )
{
wxInputStream *inStream = GetInputStream();
wxCHECK_MSG( inStream, 0, wxT("should have a stream in wxStreamBuffer") );
readBytes = inStream->OnSysRead(buffer, size);
}
else // we have a buffer, use it
{
size_t orig_size = size;
while ( size > 0 )
{
size_t left = GetDataLeft();
// if the requested number of bytes if greater than the buffer
// size, read data in chunks
if ( size > left )
{
GetFromBuffer(buffer, left);
size -= left;
buffer = (char *)buffer + left;
if ( !FillBuffer() )
{
SetError(wxSTREAM_EOF);
break;
}
}
else // otherwise just do it in one gulp
{
GetFromBuffer(buffer, size);
size = 0;
}
}
readBytes = orig_size - size;
}
if ( m_stream )
m_stream->m_lastcount = readBytes;
return readBytes;
}
// this should really be called "Copy()"
size_t wxStreamBuffer::Read(wxStreamBuffer *dbuf)
{
wxCHECK_MSG( m_mode != write, 0, wxT("can't read from this buffer") );
char buf[BUF_TEMP_SIZE];
size_t nRead,
total = 0;
do
{
nRead = Read(buf, WXSIZEOF(buf));
if ( nRead )
{
nRead = dbuf->Write(buf, nRead);
total += nRead;
}
}
while ( nRead );
return total;
}
size_t wxStreamBuffer::Write(const void *buffer, size_t size)
{
wxCHECK_MSG( buffer, 0, wxT("null data pointer") );
if (m_stream)
{
// lasterror is reset before all new IO calls
m_stream->Reset();
}
size_t ret;
if ( !HasBuffer() && m_fixed )
{
wxOutputStream *outStream = GetOutputStream();
wxCHECK_MSG( outStream, 0, wxT("should have a stream in wxStreamBuffer") );
// no buffer, just forward the call to the stream
ret = outStream->OnSysWrite(buffer, size);
}
else // we [may] have a buffer, use it
{
size_t orig_size = size;
while ( size > 0 )
{
size_t left = GetBytesLeft();
// if the buffer is too large to fit in the stream buffer, split
// it in smaller parts
//
// NB: If stream buffer isn't fixed (as for wxMemoryOutputStream),
// we always go to the second case.
//
// FIXME: fine, but if it fails we should (re)try writing it by
// chunks as this will (hopefully) always work (VZ)
if ( size > left && m_fixed )
{
PutToBuffer(buffer, left);
size -= left;
buffer = static_cast<const char*>(buffer) + left;
if ( !FlushBuffer() )
{
SetError(wxSTREAM_WRITE_ERROR);
break;
}
m_buffer_pos = m_buffer_start;
}
else // we can do it in one gulp
{
PutToBuffer(buffer, size);
size = 0;
}
}
ret = orig_size - size;
}
if (m_stream)
{
// i am not entirely sure what we do this for
m_stream->m_lastcount = ret;
}
return ret;
}
size_t wxStreamBuffer::Write(wxStreamBuffer *sbuf)
{
wxCHECK_MSG( m_mode != read, 0, wxT("can't write to this buffer") );
wxCHECK_MSG( sbuf->m_mode != write, 0, wxT("can't read from that buffer") );
char buf[BUF_TEMP_SIZE];
size_t nWrite,
total = 0;
do
{
size_t nRead = sbuf->Read(buf, WXSIZEOF(buf));
if ( nRead )
{
nWrite = Write(buf, nRead);
if ( nWrite < nRead )
{
// put back data we couldn't copy
wxInputStream *in_stream = (wxInputStream *)sbuf->GetStream();
in_stream->Ungetch(buf + nWrite, nRead - nWrite);
}
total += nWrite;
}
else
{
nWrite = 0;
}
}
while ( nWrite == WXSIZEOF(buf) );
return total;
}
wxFileOffset wxStreamBuffer::Seek(wxFileOffset pos, wxSeekMode mode)
{
wxFileOffset ret_off, diff;
wxFileOffset 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:
wxFAIL_MSG( wxT("invalid seek mode") );
return wxInvalidOffset;
}
if (diff < 0 || diff > last_access)
return wxInvalidOffset;
size_t int_diff = wx_truncate_cast(size_t, diff);
wxCHECK_MSG( (wxFileOffset)int_diff == diff, wxInvalidOffset, wxT("huge file not supported") );
SetIntPosition(int_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
{
size_t int_diff = wx_truncate_cast(size_t, diff);
wxCHECK_MSG( (wxFileOffset)int_diff == diff, wxInvalidOffset, wxT("huge file not supported") );
SetIntPosition(int_diff);
return diff;
}
case wxFromEnd:
// Hard to compute: always seek to the requested position.
ret_off = m_stream->OnSysSeek(pos, wxFromEnd);
ResetBuffer();
return ret_off;
}
return wxInvalidOffset;
}
wxFileOffset wxStreamBuffer::Tell() const
{
wxFileOffset pos;
// ask the stream for position if we have a real one
if ( m_stream )
{
pos = m_stream->OnSysTell();
if ( pos == wxInvalidOffset )
return wxInvalidOffset;
}
else // no associated stream
{
pos = 0;
}
pos += GetIntPosition();
if ( m_mode == read && m_flushable )
pos -= GetLastAccess();
return pos;
}
// ----------------------------------------------------------------------------
// wxStreamBase
// ----------------------------------------------------------------------------
wxIMPLEMENT_ABSTRACT_CLASS(wxStreamBase, wxObject);
wxStreamBase::wxStreamBase()
{
m_lasterror = wxSTREAM_NO_ERROR;
m_lastcount = 0;
}
wxStreamBase::~wxStreamBase()
{
}
size_t wxStreamBase::GetSize() const
{
wxFileOffset length = GetLength();
if ( length == (wxFileOffset)wxInvalidOffset )
return 0;
const size_t len = wx_truncate_cast(size_t, length);
wxASSERT_MSG( len == length + size_t(0), wxT("large files not supported") );
return len;
}
wxFileOffset wxStreamBase::OnSysSeek(wxFileOffset WXUNUSED(seek), wxSeekMode WXUNUSED(mode))
{
return wxInvalidOffset;
}
wxFileOffset wxStreamBase::OnSysTell() const
{
return wxInvalidOffset;
}
// ----------------------------------------------------------------------------
// wxInputStream
// ----------------------------------------------------------------------------
wxIMPLEMENT_ABSTRACT_CLASS(wxInputStream, wxStreamBase);
wxInputStream::wxInputStream()
{
m_wback = nullptr;
m_wbacksize =
m_wbackcur = 0;
}
wxInputStream::~wxInputStream()
{
free(m_wback);
}
bool wxInputStream::CanRead() const
{
// we don't know if there is anything to read or not and by default we
// prefer to be optimistic and try to read data unless we know for sure
// there is no more of it
return m_lasterror != wxSTREAM_EOF;
}
bool wxInputStream::Eof() const
{
// the only way the base class can know we're at EOF is when we'd already
// tried to read beyond it in which case last error is set accordingly
return GetLastError() == wxSTREAM_EOF;
}
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 nullptr;
// 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 m_wback;
}
size_t wxInputStream::GetWBack(void *buf, size_t size)
{
wxCHECK_MSG( buf, 0, wxT("null data pointer") );
/* Clear buffer first */
memset(buf, 0x00, size);
if (!m_wback)
return 0;
// how many bytes do we have in the buffer?
size_t toget = m_wbacksize - m_wbackcur;
if ( size < toget )
{
// we won't read everything
toget = size;
}
// copy the data from the cache
memcpy(buf, m_wback + m_wbackcur, toget);
m_wbackcur += toget;
if ( m_wbackcur == m_wbacksize )
{
// TODO: should we really free it here all the time? maybe keep it?
free(m_wback);
m_wback = nullptr;
m_wbacksize = 0;
m_wbackcur = 0;
}
// return the number of bytes copied
return toget;
}
size_t wxInputStream::Ungetch(const void *buf, size_t bufsize)
{
wxCHECK_MSG( buf, 0, wxT("null data pointer") );
if ( m_lasterror != wxSTREAM_NO_ERROR && m_lasterror != wxSTREAM_EOF )
{
// can't operate on this stream until the error is cleared
return 0;
}
char *ptrback = AllocSpaceWBack(bufsize);
if (!ptrback)
return 0;
// Eof() shouldn't return true any longer
if ( m_lasterror == wxSTREAM_EOF )
m_lasterror = wxSTREAM_NO_ERROR;
memcpy(ptrback, buf, bufsize);
return bufsize;
}
bool wxInputStream::Ungetch(char c)
{
return Ungetch(&c, sizeof(c)) != 0;
}
int wxInputStream::GetC()
{
unsigned char c;
Read(&c, sizeof(c));
return LastRead() ? c : wxEOF;
}
wxInputStream& wxInputStream::Read(void *buf, size_t size)
{
wxCHECK_MSG( buf, *this, wxT("null data pointer") );
char *p = (char *)buf;
m_lastcount = 0;
size_t read = GetWBack(buf, size);
for ( ;; )
{
size -= read;
m_lastcount += read;
p += read;
if ( !size )
{
// we read the requested amount of data
break;
}
if ( p != buf && !CanRead() )
{
// we have already read something and we would block in OnSysRead()
// now: don't do it but return immediately
break;
}
read = OnSysRead(p, size);
if ( !read )
{
// no more data available
break;
}
}
return *this;
}
char wxInputStream::Peek()
{
char c;
Read(&c, sizeof(c));
if (m_lasterror == wxSTREAM_NO_ERROR)
{
Ungetch(c);
return c;
}
return 0;
}
wxInputStream& wxInputStream::Read(wxOutputStream& stream_out)
{
size_t lastcount = 0;
char buf[BUF_TEMP_SIZE];
for ( ;; )
{
size_t bytes_read = Read(buf, WXSIZEOF(buf)).LastRead();
if ( !bytes_read )
break;
if ( stream_out.Write(buf, bytes_read).LastWrite() != bytes_read )
break;
lastcount += bytes_read;
}
m_lastcount = lastcount;
return *this;
}
bool wxInputStream::ReadAll(void *buffer_, size_t size)
{
char* buffer = static_cast<char*>(buffer_);
size_t totalCount = 0;
for ( ;; )
{
const size_t lastCount = Read(buffer, size).LastRead();
// There is no point in continuing looping if we can't read anything at
// all.
if ( !lastCount )
break;
totalCount += lastCount;
// ... Or if an error occurred on the stream.
if ( !IsOk() )
break;
// Return successfully if we read exactly the requested number of
// bytes (normally the ">" case should never occur and so we could use
// "==" test, but be safe and avoid overflowing size even in case of
// bugs in LastRead()).
if ( lastCount >= size )
{
size = 0;
break;
}
// Advance the buffer before trying to read the rest of data.
size -= lastCount;
buffer += lastCount;
}
m_lastcount = totalCount;
return size == 0;
}
wxFileOffset wxInputStream::SeekI(wxFileOffset pos, wxSeekMode mode)
{
// RR: This code is duplicated in wxBufferedInputStream. This is
// not really a good design, but buffered stream are different
// from all others in that they handle two stream-related objects:
// the stream buffer and parent stream.
// I don't know whether it should be put as well in wxFileInputStream::OnSysSeek
if (m_lasterror==wxSTREAM_EOF)
m_lasterror=wxSTREAM_NO_ERROR;
// avoid unnecessary seek operations (optimization)
wxFileOffset currentPos = TellI(), size = GetLength();
if ((mode == wxFromStart && currentPos == pos) ||
(mode == wxFromCurrent && pos == 0) ||
(mode == wxFromEnd && size != wxInvalidOffset && currentPos == size-pos))
return currentPos;
if (!IsSeekable() && mode == wxFromCurrent && pos > 0)
{
// rather than seeking, we can just read data and discard it;
// this allows to forward-seek also non-seekable streams!
char buf[BUF_TEMP_SIZE];
size_t bytes_read;
// read chunks of BUF_TEMP_SIZE bytes until we reach the new position
for ( ; pos >= BUF_TEMP_SIZE; pos -= bytes_read)
{
bytes_read = Read(buf, WXSIZEOF(buf)).LastRead();
if ( m_lasterror != wxSTREAM_NO_ERROR )
return wxInvalidOffset;
wxASSERT(bytes_read == WXSIZEOF(buf));
}
// read the last 'pos' bytes
bytes_read = Read(buf, (size_t)pos).LastRead();
if ( m_lasterror != wxSTREAM_NO_ERROR )
return wxInvalidOffset;
wxASSERT(bytes_read == (size_t)pos);
// we should now have sought to the right position...
return TellI();
}
/* RR: A call to SeekI() will automatically invalidate any previous
call to Ungetch(), otherwise it would be possible to SeekI() to