stdgets.c

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

#include	"stdio_s.h"

/*	Read a line into a buffer.
**
**	Written by Kiem-Phong Vo.
*/

#if __STD_C
char* _stdgets(reg Sfio_t* f, char* us, reg int n, int isgets)
#else
char* _stdgets(f,us,n,isgets)
reg Sfio_t*	f;	/* stream to read from */
char*		us;	/* space to read into */
reg int		n;	/* max number of bytes to read */
int		isgets;	/* gets(), not fgets() */
#endif
{
	reg int		p;
	reg uchar	*is, *ps;

	SFMTXSTART(f, NIL(char*));

	if(n <= 0 || !us || (f->mode != SF_READ && _sfmode(f,SF_READ,0) < 0))
		SFMTXRETURN(f, NIL(char*));

	SFLOCK(f,0);

	n -= 1;
	is = (uchar*)us;
	
	while(n)
	{	/* peek the read buffer for data */
		if((p = f->endb - (ps = f->next)) <= 0 )
		{	f->getr = '\n';
			f->mode |= SF_RC;
			if(SFRPEEK(f,ps,p) <= 0)
				break;
		}

		if(p > n)
			p = n;

#if _lib_memccpy
		if((ps = (uchar*)memccpy((char*)is,(char*)ps,'\n',p)) != NIL(uchar*))
			p = ps-is;
		is += p;
		ps  = f->next+p;
#else
		if(!(f->flags&(SF_BOTH|SF_MALLOC)))
		{	while(p-- && (*is++ = *ps++) != '\n')
				;
			p = ps-f->next;
		}
		else
		{	reg int	c = ps[p-1];
			if(c != '\n')
				ps[p-1] = '\n';
			while((*is++ = *ps++) != '\n')
				;
			if(c != '\n')
			{	f->next[p-1] = c;
				if((ps-f->next) >= p)
					is[-1] = c;
			}
		}
#endif

		/* gobble up read data and continue */
		f->next = ps;
		if(is[-1] == '\n')
			break;
		else if(n > 0)
			n -= p;
	}

	if((_Sfi = f->val = is - ((uchar*)us)) <= 0)
		us = NIL(char*);
	else if(isgets && is[-1] == '\n')
		is[-1] = '\0';
	else	*is = '\0';

	SFOPEN(f,0);
	SFMTXRETURN(f, us);
}