sl@0: /* FGETS.C
sl@0:  * 
sl@0:  * Portions Copyright (c) 1990-1999 Nokia Corporation and/or its subsidiary(-ies).
sl@0:  * All rights reserved.
sl@0:  */
sl@0: 
sl@0: /*
sl@0:  * Copyright (c) 1990 The Regents of the University of California.
sl@0:  * All rights reserved.
sl@0:  *
sl@0:  * Redistribution and use in source and binary forms are permitted
sl@0:  * provided that the above copyright notice and this paragraph are
sl@0:  * duplicated in all such forms and that any documentation,
sl@0:  * advertising materials, and other materials related to such
sl@0:  * distribution and use acknowledge that the software was developed
sl@0:  * by the University of California, Berkeley.  The name of the
sl@0:  * University may not be used to endorse or promote products derived
sl@0:  * from this software without specific prior written permission.
sl@0:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
sl@0:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
sl@0:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
sl@0:  */
sl@0: 
sl@0: /*
sl@0: 
sl@0: FUNCTION
sl@0:         <<fgets>>---get character string from a file or stream
sl@0: INDEX
sl@0: 	fgets
sl@0: 
sl@0: ANSI_SYNOPSIS
sl@0:         #include <stdio.h>
sl@0: 	char *fgets(char *<[buf]>, int <[n]>, FILE *<[fp]>);
sl@0: 
sl@0: TRAD_SYNOPSIS
sl@0: 	#include <stdio.h>
sl@0: 	char *fgets(<[buf]>,<[n]>,<[fp]>)
sl@0:         char *<[buf]>;
sl@0: 	int <[n]>;
sl@0: 	FILE *<[fp]>;
sl@0: 
sl@0: DESCRIPTION
sl@0: 	Reads at most <[n-1]> characters from <[fp]> until a newline
sl@0: 	is found. The characters including to the newline are stored
sl@0: 	in <[buf]>. The buffer is terminated with a 0.
sl@0: 
sl@0: 
sl@0: RETURNS
sl@0: 	<<fgets>> returns the buffer passed to it, with the data
sl@0: 	filled in. If end of file occurs with some data already
sl@0: 	accumulated, the data is returned with no other indication. If
sl@0: 	no data are read, NULL is returned instead.
sl@0: 
sl@0: PORTABILITY
sl@0: 	<<fgets>> should replace all uses of <<gets>>. Note however
sl@0: 	that <<fgets>> returns all of the data, while <<gets>> removes
sl@0: 	the trailing newline (with no indication that it has done so.)
sl@0: 
sl@0: Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
sl@0: <<lseek>>, <<read>>, <<sbrk>>, <<write>>.
sl@0: */
sl@0: 
sl@0: #include <stdio.h>
sl@0: #include <string.h>
sl@0: #include "LOCAL.H"
sl@0: 
sl@0: /**
sl@0: Get a string from a stream.
sl@0: @return   On success, the string read is returned.
sl@0: On end-of-file or error, null pointer is returned.
sl@0: @param buf pointer to a buffer where to store data read. 
sl@0: @param n max number of bytes to be read. 
sl@0: @param fp pointer to an open file.
sl@0: */
sl@0: EXPORT_C char *
sl@0: fgets (char *buf, int n, FILE * fp)
sl@0: {
sl@0:   size_t len;
sl@0:   char *s;
sl@0:   unsigned char *p, *t;
sl@0: 
sl@0:   if (n < 2)			/* sanity check */
sl@0:     return 0;
sl@0: 
sl@0:   s = buf;
sl@0:   n--;				/* leave space for NUL */
sl@0:   do
sl@0:     {
sl@0:       /*
sl@0:        * If the buffer is empty, refill it.
sl@0:        */
sl@0:       if ((len = fp->_r) <= 0)
sl@0: 	{
sl@0: 	  if (__srefill (fp))
sl@0: 	    {
sl@0: 	      /* EOF: stop with partial or no line */
sl@0: 	      if (s == buf)
sl@0: 		return 0;
sl@0: 	      break;
sl@0: 	    }
sl@0: 	  len = fp->_r;
sl@0: 	}
sl@0:       p = fp->_p;
sl@0: 
sl@0:       /*
sl@0:        * Scan through at most n bytes of the current buffer,
sl@0:        * looking for '\n'.  If found, copy up to and including
sl@0:        * newline, and stop.  Otherwise, copy entire chunk
sl@0:        * and loop.
sl@0:        */
sl@0:       if ((int)len > n)
sl@0: 	len = n;
sl@0:       t = (unsigned char *) memchr ((void*) p, '\n', len);
sl@0:       if (t != 0)
sl@0: 	{
sl@0: 	  len = ++t - p;
sl@0: 	  fp->_r -= len;
sl@0: 	  fp->_p = t;
sl@0: 	  (void) memcpy ((void*) s, (void*) p, len);
sl@0: 	  s[len] = 0;
sl@0: 	  return (buf);
sl@0: 	}
sl@0:       fp->_r -= len;
sl@0:       fp->_p += len;
sl@0:       (void) memcpy ((void*) s, (void*) p, len);
sl@0:       s += len;
sl@0:     }
sl@0:   while ((n -= len) != 0);
sl@0:   *s = 0;
sl@0:   return buf;
sl@0: }