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/***
*setvbuf.c - set buffer size for a stream
*
* Copyright (c) 1985-1993, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines setvbuf() - set the buffering mode and size for a stream.
*
*Revision History:
* 09-19-83 RN initial version
* 06-26-85 TC modified to allow user defined buffers of various sizes
* 06-24-86 DFW kludged to fix incompatability with Xenix values of
* _IOFBF, _IOLBF
* 02-09-87 JCR added "buffer=&(_iob2[fileno(stream)]._charbuf);"
* to handle _IONBF case
* 02-25-87 JCR added support for default buffer and IBMC20-condition
* code
* 04-13-87 JCR changed type of szie from int to size_t (unsigned int)
* and changed a related comparison
* 06-29-87 JCR Took out the _OLD_IOFBF/_OLD_IOLBF kludge for MSC.
* Should be taken out for IBM too...
* 09-28-87 JCR Corrected _iob2 indexing (now uses _iob_index() macro).
* 11-02-87 JCR Multi-thread support
* 12-11-87 JCR Added "_LOAD_DS" to declaration
* 05-27-88 PHG Merged DLL and normal versions
* 06-06-88 JCR Optimized _iob2 references
* 06-14-88 JCR Use near pointer to reference _iob[] entries
* 08-09-88 JCR Buffer size can't be greater than INT_MAX
* 08-25-88 GJF Don't use FP_OFF() macro for the 386
* 08-18-89 GJF Clean up, now specific to OS/2 2.0 (i.e., 386 flat
* model). Also fixed copyright and indents.
* 02-15-90 GJF _iob[], _iob2[] merge. Also, cleanup, a little tuning
* and fixed copyright.
* 03-19-90 GJF Made calling type _CALLTYPE1, added #include
* <cruntime.h> and removed #include <register.h>.
* 05-29-90 SBM Use _flush, not [_]fflush[_lk]
* 07-23-90 SBM Replaced <assertm.h> by <assert.h>
* 10-03-90 GJF New-style function declarator.
* 04-27-93 CFW Change _IONBF size to 2 bytes to hold wide char.
*
*******************************************************************************/
#include <cruntime.h>
#include <stdio.h>
#include <file2.h>
#include <assert.h>
#include <malloc.h>
#include <internal.h>
#include <os2dll.h>
#include <limits.h>
/***
*int setvbuf(stream, buffer, type, size) - set buffering for a file
*
*Purpose:
* Controls buffering and buffer size for the specified stream. The
* array pointed to by buf is used as a buffer, unless NULL, in which
* case we'll allocate a buffer automatically. type specifies the type
* of buffering: _IONBF = no buffer, _IOFBF = buffered, _IOLBF = same
* as _IOFBF.
*
*Entry:
* FILE *stream - stream to control buffer on
* char *buffer - pointer to buffer to use (NULL means auto allocate)
* int type - type of buffering (_IONBF, _IOFBF or _IOLBF)
* size_t size - size of buffer
*
*Exit:
* return 0 if successful
* returns non-zero if fails
*
*Exceptions:
*
*******************************************************************************/
int _CRTAPI1 setvbuf (
FILE *str,
char *buffer,
int type,
size_t size
)
{
REG1 FILE *stream;
#ifdef MTHREAD
int index;
#endif
int retval=0; /* assume good return */
assert(str != NULL);
/*
* (1) Make sure type is one of the three legal values.
* (2) If we are buffering, make sure size is greater than 0.
*/
if ( (type != _IONBF) && ((size == 0) || (size > INT_MAX) ||
((type != _IOFBF) && (type != _IOLBF))) )
return(-1);
/* force size to be even */
size &= (size_t)~1;
/*
* Init stream pointers
*/
stream = str;
#ifdef MTHREAD
index = _iob_index(stream);
#endif
/*
* Lock the file
*/
_lock_str(index);
/*
* Flush the current buffer and free it, if it is ours.
*/
_flush(stream);
_freebuf(stream);
/*
* Clear a bunch of bits in stream->_flag (all bits related to
* buffering and those which used to be in stream2->_flag2). Most
* of these should never be set when setvbuf() is called, but it
* doesn't cost anything to be safe.
*/
stream->_flag &= ~(_IOMYBUF | _IOYOURBUF | _IONBF | _IOFEOF |
_IOFLRTN | _IOCTRLZ);
/*
* CASE 1: No Buffering.
*/
if (type & _IONBF) {
stream->_flag |= _IONBF;
buffer = (char *)&(stream->_charbuf);
size = 2;
}
/*
* NOTE: Cases 2 and 3 (below) cover type == _IOFBF or type == _IOLBF
* Line buffering is treated as the same as full buffering, so the
* _IOLBF bit in stream->_flag is never set. Finally, since _IOFBF is
* defined to be 0, full buffering is simply assumed whenever _IONBF
* is not set.
*/
/*
* CASE 2: Default Buffering -- Allocate a buffer for the user.
*/
else if ( buffer == NULL ) {
if ( (buffer = malloc(size)) == NULL ) {
/*
* force library pre-termination procedure (placed here
* because the code path should almost never be hit)
*/
_cflush++;
retval = -1;
goto done;
}
stream->_flag |= _IOMYBUF;
}
/*
* CASE 3: User Buffering -- Use the buffer supplied by the user.
*/
else {
stream->_flag |= _IOYOURBUF;
}
/*
* Common return for all cases.
*/
stream->_bufsiz = size;
stream->_ptr = stream->_base = buffer;
stream->_cnt = 0;
done:
_unlock_str(index);
return(retval);
}
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