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OS/2 Shareware BBS: 10 Tools
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yacl-012.zip
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base
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bytestrm.cxx
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C/C++ Source or Header
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1995-04-04
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3KB
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118 lines
/*
*
* Copyright (C) 1994, M. A. Sridhar
*
*
* This software is Copyright M. A. Sridhar, 1994. You are free
* to copy, modify or distribute this software as you see fit,
* and to use it for any purpose, provided this copyright
* notice and the following disclaimer are included with all
* copies.
*
* DISCLAIMER
*
* The author makes no warranties, either expressed or implied,
* with respect to this software, its quality, performance,
* merchantability, or fitness for any particular purpose. This
* software is distributed AS IS. The user of this software
* assumes all risks as to its quality and performance. In no
* event shall the author be liable for any direct, indirect or
* consequential damages, even if the author has been advised
* as to the possibility of such damages.
*
*/
#ifdef __GNUC__
#pragma implementation
#endif
#include "base/bytestrm.h"
CL_ByteStream::CL_ByteStream (CL_ByteArray& s)
: _buffer (s)
{
_position = 0;
}
// ----------------- Read operations -------------------------
// Read from current position. Returns # bytes read, 0 on eof, -1
// on error.
long CL_ByteStream::Read (uchar* output, long num_bytes) const
{
long ret = maxl (0, minl (_buffer.Size() - _position, num_bytes));
if (ret > 0) {
_buffer.CopyTo (output, ret, _position);
((CL_ByteStream*) this)->_position += ret; // const cast away
}
return ret;
}
// ----------------- Write operations ------------------------
// Write at current position.
bool CL_ByteStream::Write (uchar* buffer, long num_bytes)
{
long size = _buffer.Size();
if (size - _position < num_bytes) {
long new_size = _position + num_bytes;
if (!_buffer.ChangeSize (new_size))
return FALSE;
}
if (num_bytes > 0) {
_buffer.CopyFrom (buffer, num_bytes, _position);
_position += num_bytes;
}
return num_bytes >= 0;
}
// ----------------- Seek operations -------------------------
#define DEFAULT_EXPANSION 64
// Change the current position. Returns TRUE on success.
bool CL_ByteStream::SeekTo (CL_Offset position) const
{
if (position < 0)
return FALSE;
long size = _buffer.Size();
if (position > size && !_buffer.ChangeSize (size + DEFAULT_EXPANSION))
return FALSE;
((CL_ByteStream*) this)->_position = position; // const cast away
return TRUE;
}
bool CL_ByteStream::SeekToEnd () const
{
((CL_ByteStream*) this)->_position = _buffer.Size(); // Cast away const
return TRUE;
}
bool CL_ByteStream::SeekRelative (long change) const
{
CL_Offset new_pos = maxl (0, _position + change);
((CL_ByteStream*) this)->_position = new_pos; // Cast away const
return TRUE;
}