initial import

stdio/fgets.c

@@ -0,0 +1,121 @@
+/* Copyright (C) 1991, 1992, 1995 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+/* Reads characters from STREAM into S, until either a newline character
+   is read, N - 1 characters have been read, or EOF is seen.  Returns
+   the newline, unlike gets.  Finishes by appending a null character and
+   returning S.  If EOF is seen before any characters have been written
+   to S, the function returns NULL without appending the null character.
+   If there is a file error, always return NULL.  */
+char *
+DEFUN(fgets, (s, n, stream), char *s AND int n AND register FILE *stream)
+{
+  register char *p = s;
+
+  if (!__validfp(stream) || s == NULL || n <= 0)
+    {
+      errno = EINVAL;
+      return NULL;
+    }
+
+  if (ferror (stream))
+    return NULL;
+
+  if (stream->__buffer == NULL && stream->__userbuf)
+    {
+      /* Unbuffered stream.  Not much optimization to do.  */
+      register int c = 0;
+      while (--n > 0 && (c = getc (stream)) != EOF) 
+	if ((*p++ = c) == '\n')
+	  break;
+      if (c == EOF && (p == s || ferror (stream)))
+	return NULL;
+      *p = '\0';
+      return s;
+    }
+
+  /* Leave space for the null.  */
+  --n;
+
+  if (n > 0 &&
+      (!stream->__seen || stream->__buffer == NULL || stream->__pushed_back))
+    {
+      /* Do one with getc to allocate a buffer.  */
+      int c = getc (stream);
+      if (c == EOF)
+	return NULL;
+      *p++ = c;
+      if (c == '\n')
+	{
+	  *p = '\0';
+	  return s;
+	}
+      else
+	--n;
+    }
+
+  while (n > 0)
+    {
+      size_t i;
+      char *found;
+
+      i = stream->__get_limit - stream->__bufp;	
+      if (i == 0)
+	{
+	  /* Refill the buffer.  */
+	  int c = __fillbf (stream);
+	  if (c == EOF)
+	    break;
+	  *p++ = c;
+	  --n;
+	  if (c == '\n')
+	    {
+	      *p = '\0';
+	      return s;
+	    }
+	  i = stream->__get_limit - stream->__bufp;	
+	}
+
+      if (i > n)
+	i = n;
+
+      found = (char *) __memccpy ((PTR) p, stream->__bufp, '\n', i);
+
+      if (found != NULL)
+	{
+	  stream->__bufp += found - p;
+	  p = found;
+	  break;
+	}
+
+      stream->__bufp += i;
+      n -= i;
+      p += i;
+    }
+
+  if (p == s)
+    return NULL;
+
+  *p = '\0';
+  return ferror (stream) ? NULL : s;
+}