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/*
**	FPUTC - put a character to stream
**
**	(c) Copyright Ken Harrenstien 1989
**		for all changes after v.38, 12-Apr-1988
**	(c) Copyright Ian Macky, SRI International 1986
*/

#include <stdio.h>
#include <errno.h>

extern int write();	/* Syscall */

int fputc(c, f)
register int c;
register FILE *f;
{
    char tinybuf[1];			/* grossness!  ick! */

    if (!_writeable(f))			/* Verify FILE pointer is OK */
	return EOF;
    if (--f->siocnt >= 0)		/* If have room in buffer, */
	return *++f->siocp = c;		/* just deposit char there. */

    /* No room left in buffer.  Empty it if we have one. */
    if (f->sioflgs & _SIOF_BUF) {
	if (f->sioflgs & _SIOF_LINEBUF && --f->siolcnt >= 0) {
	    if ((*++f->siocp = c) == '\n' && fflush(f))
		return EOF;			/* couldn't flush old data */
	    return c;
	}
#ifdef NEWSTREXP
	if (f->sioflgs & _SIOF_GROWBUF) {	/* if an expanding string, */
	    if (!_expand(f, f->siosinc))
		return EOF;
	    return putc(c, f);
	}
#endif
	/* Normal buffering */
	if (fflush(f)) return EOF;		/* couldn't flush old data */
	return fputc(c, f);
    }

    /* Don't have a buffer to empty.  Should we create one? */
    if (f->sioflgs & _SIOF_AUTOBUF) {
	if (setvbuf(f, (char *)NULL,
			((f->sioflgs&_SIOF_LINEBUF) ? _IOLBF : _IOFBF), 0)) {
	    f->sioerr = ENOMEM;		/* Non-zero return means failed. */
	    return EOF;
	}
	return putc(c, f);
    }

    /* We're not using any buffering at all.  Write char directly. */
    tinybuf[0] = c;
    if (write(f->siofd, tinybuf, 1) == -1) {
	f->sioerr = errno;
	return EOF;
    }
    f->siofdoff++;
    return c;
}

int _writeable(f)
FILE *f;
{
    if (f->siocheck != _SIOF_OPEN)	/* make sure real FILE block */
	return 0;			/* and open, too. */
    if (f->sioflgs & _SIOF_WRITE)
	return 1;
    if (f->sioflgs & _SIOF_UPDATE &&
	(!(f->sioflgs & _SIOF_READ) || (f->sioflgs & _SIOF_EOF))) {
	f->sioflgs = f->sioflgs & ~_SIOF_READ | _SIOF_WRITE;
	_prime(f);			/* prime i/o */
	return 1;
    }
    return 0;
}

#ifdef NEWSTREXP
/*
 *	expand the given string file <by> chars.
 */

int _expand(f, by)
FILE *f;
int by;
{
    int new_size;
    char *new_buf, *realloc();

    if (!(f->sioflgs & _SIOF_GROWBUF))	/* if not an auto-expand string */
	return 0;			/* then don't do it!! */
    new_size = f->siolbuf + by;		/* new size of string buf */
    if (!(new_buf = realloc(f->siopbuf, new_size)))
	return 0;			/* couldn't get bigger buffer */
    if (new_buf != f->siopbuf) {	/* if our buffer moved */
	f->siopbuf = new_buf;		/* move to same pos in new buffer */
	f->siocp = new_buf + (f->siolbuf - f->siocnt) - 1;
    }
    f->siolbuf = new_size;		/* it's this big */
    f->siocnt = by;			/* this much gap now */
    return 1;
}
#endif /* NEWSTREXP */