sfflsbuf.c

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/* Copyright (c) Colorado School of Mines, 2006.*/
/* All rights reserved.                       */

#include	"sfhdr.h"

/*	Write a buffer out to a file descriptor or
**	extending a buffer for a SF_STRING stream.
**
**	Written by Kiem-Phong Vo
*/

#if __STD_C
int _sfflsbuf(reg Sfio_t* f, reg int c)
#else
int _sfflsbuf(f,c)
reg Sfio_t*	f;	/* write out the buffered content of this stream */
reg int		c;	/* if c>=0, c is also written out */ 
#endif
{
	reg ssize_t	n, w;
	reg uchar*	data;
	uchar		outc;
	reg int		local, isall;
	int		inpc = c;

	SFMTXSTART(f,-1);

	GETLOCAL(f,local);

	for(;; f->mode &= ~SF_LOCK)
	{	/* check stream mode */
		if(SFMODE(f,local) != SF_WRITE && _sfmode(f,SF_WRITE,local) < 0)
			SFMTXRETURN(f, -1);
		SFLOCK(f,local);

		/* current data extent */
		n = f->next - (data = f->data);

		if(n == (f->endb-data) && (f->flags&SF_STRING))
		{	/* extend string stream buffer */
			(void)SFWR(f,data,1,f->disc);

			/* !(f->flags&SF_STRING) is required because exception
			   handlers may turn a string stream to a file stream */
			if(f->next < f->endb || !(f->flags&SF_STRING) )
				n = f->next - (data = f->data);
			else
			{	SFOPEN(f,local);
				SFMTXRETURN(f, -1);
			}
		}

		if(c >= 0)
		{	/* write into buffer */
			if(n < (f->endb - (data = f->data)))
			{	*f->next++ = c;
				if(c == '\n' &&
				   (f->flags&SF_LINE) && !(f->flags&SF_STRING))
				{	c = -1;
					n += 1;
				}
				else	break;
			}
			else if(n == 0)
			{	/* unbuffered io */
				outc = (uchar)c;
				data = &outc;
				c = -1;
				n = 1;
			}
		}

		if(n == 0 || (f->flags&SF_STRING))
			break;

		isall = SFISALL(f,isall);
		if((w = SFWR(f,data,n,f->disc)) > 0)
		{	if((n -= w) > 0) /* save unwritten data, then resume */
				memcpy((char*)f->data,(char*)data+w,n);
			f->next = f->data+n;
			if(c < 0 && (!isall || n == 0))
				break;
		}
		else if(w == 0)
		{	SFOPEN(f,local);
			SFMTXRETURN(f, -1);
		}
		else if(c < 0)
			break;
	}

	SFOPEN(f,local);

	if(inpc < 0)
		inpc = f->endb-f->next;

	SFMTXRETURN(f,inpc);
}