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/*
 *	SETBUF - change buffer for stream
 *
 *	Copyright (C) 1986 by Ian Macky, SRI International
 *
 *	Note that for name disambiguation reasons, "setbuffer" is changed
 *	to "_setbuf" in a stdio.h preprocessor declaration.
 */

#include "stdio.h"

#if 0
char _sobuf[BUFSIZ];			/* some people want this buffer */
#endif					/* Flushed 8/30/87 --KLH */

void
setbuf(f, buf)
FILE *f;
char *buf;
{
    setbuffer(f, buf, BUFSIZ);
}

void
setbuffer(f, buf, size)
FILE *f;
char *buf;
int size;
{
    if (buf) (void) setvbuf(f, buf, _IOFBF, size);	/* Full buffering */
    else (void) setvbuf(f, (char *)NULL, _IONBF, 0);	/* No buffering */
}

void
setlinebuf(f)
FILE *f;
{
    if (f->siocheck != _SIOF_OPEN)
	return;
    if (f->sioflgs & _SIOF_DYNAMBUF)		/* If auto buffer, */
	setvbuf(f, (char *)NULL, _IOLBF, 0);	/* just re-allocate. */
    else						/* otherwise, */
	setvbuf(f, f->siopbuf, _IOLBF, f->siolbuf);	/* preserve user buf */
}

/*
 *	setvbuf - from ANSI draft (which claims it's from SYS5)
 */

int
setvbuf(f, buf, type, size)
FILE *f;
char *buf;
int type;
int size;
{
    extern char *malloc();

    if (f->siocheck != _SIOF_OPEN)
	return -1;			/* Bad FILE pointer */
    fflush(f);				/* flush buffers so clean slate */
    if (f->siopbuf && (f->sioflgs & _SIOF_DYNAMBUF))	/* If old buf was */
	free(f->siopbuf);		/* dynamic, release it now. */

    f->sioflgs &= ~(_SIOF_BUF|_SIOF_AUTOBUF|_SIOF_LINEBUF|_SIOF_DYNAMBUF);
    f->siopbuf = NULL;
    f->sioocnt = f->siocnt = 0;		/* force calls to fgetc/fputc */
    switch (type) {
	case _IONBF:			/* No buffering */
	    return 0;			/* return successfully */
	case _IOLBF:			/* Line buffering */
	case _IOFBF:			/* Full buffering */
	    break;
	default:
	    return -1;			/* Bad _IOxxx type argument */
    }

    if (buf == NULL) {			/* Point to user buffer? */
	if ((f->siopbuf = malloc(BUFSIZ)) == NULL)	/* No, use own */
	    return -1;			/* Could not allocate, stay unbuffed */
	f->sioflgs |= _SIOF_DYNAMBUF;	/* Won, remember dynamic */
	f->siolbuf = BUFSIZ;		/* Set size of buffer */
    } else {
	if (size <= 0)			/* User specified buffer, check size */
	    return -1;			/* Bad size, fail. */
	f->siopbuf = buf;
	f->siolbuf = size;		/* Set size of buffer */
    }
#ifdef _SIOP_BITS
    if (f->sioflgs & _SIOF_CONVERTED) {
#ifdef _SIOP_MAXBITS			/* Enforce limit on converted buffer */
	if (f->siolbuf > (1<<_SIOP_MAXBITS))
	    f->siolbuf = (1<<_SIOP_MAXBITS);
#else
	register unsigned n, i;
	i = f->siopmask = (f->siolbuf & (-f->siolbuf)) - 1;
	for (n = 0; i; i >>= 1, n++);	/* Find # bits in mask */
	f->siopbits = n;
#endif
    }
#endif /* _SIOP_BITS */

    f->sioflgs |= _SIOF_BUF;		/* Remember we are buffered */
    if (type == _IOLBF)			/* Specify line-buffered if so */
	f->sioflgs |= _SIOF_LINEBUF;
    _prime(f);				/* prime stream for I/O */
    return 0;				/* Success! */
}