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/***
*setvbuf.c - set buffer size for a stream** Copyright (c) 1985-2001, 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.* 04-06-93 SKS Replace _CRTAPI* with __cdecl* 04-27-93 CFW Change _IONBF size to 2 bytes to hold wide char.* 06-22-93 GJF Set _IOSETVBUF (new) to indicate user-specified* buffering (in addition to setting _IOYOURBUF or* _IOMYBUF).* 11-12-93 GJF Return failure if size == 1 (instead of putting* 0 into stream->_bufsiz, preventing any i/o)* 04-05-94 GJF #ifdef-ed out _cflush reference for msvcrt*.dll, it* is unnecessary.* 01-10-95 CFW Debug CRT allocs.* 02-06-94 CFW assert -> _ASSERTE.* 02-20-95 GJF Merged in Mac version.* 03-07-95 GJF _[un]lock_str macros now take FILE * arg.* 03-02-98 GJF Exception-safe locking.* 01-04-99 GJF Changes for 64-bit size_t.* 05-17-99 PML Remove all Macintosh support.********************************************************************************/
#include <cruntime.h>
#include <stdio.h>
#include <file2.h>
#include <malloc.h>
#include <internal.h>
#include <mtdll.h>
#include <limits.h>
#include <dbgint.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 __cdecl setvbuf ( FILE *str, char *buffer, int type, size_t size ){ REG1 FILE *stream; int retval=0; /* assume good return */
_ASSERTE(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 < 2) || (size > INT_MAX) || ((type != _IOFBF) && (type != _IOLBF))) ) return(-1);
/*
* force size to be even by masking down to the nearest multiple * of 2 */ size &= (size_t)~1;
/*
* Init stream pointers */ stream = str;
#ifdef _MT
/*
* Lock the file */ _lock_str(stream); __try {#endif
/*
* 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 | _IOSETVBUF | _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_crt(size)) == NULL ) {#ifndef CRTDLL
/*
* force library pre-termination procedure (placed here * because the code path should almost never be hit) */ _cflush++;#endif /* CRTDLL */
retval = -1; goto done; } stream->_flag |= _IOMYBUF | _IOSETVBUF; }
/*
* CASE 3: User Buffering -- Use the buffer supplied by the user. */ else { stream->_flag |= _IOYOURBUF | _IOSETVBUF; }
/*
* Common return for all cases. */ stream->_bufsiz = (int)size; stream->_ptr = stream->_base = buffer; stream->_cnt = 0;done:
#ifdef _MT
; } __finally { _unlock_str(stream); }#endif
return(retval);}
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