+/*-
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
#if defined(LIBC_SCCS) && !defined(lint)
-static char sccsid[] = "@(#)fgets.c 5.2 (Berkeley) 3/9/86";
-#endif LIBC_SCCS and not lint
+static char sccsid[] = "@(#)fgets.c 5.4 (Berkeley) 5/4/91";
+#endif /* LIBC_SCCS and not lint */
-#include <stdio.h>
+#include <stdio.h>
+#include <string.h>
+/*
+ * Read at most n-1 characters from the given file.
+ * Stop when a newline has been read, or the count runs out.
+ * Return first argument, or NULL if no characters were read.
+ */
char *
-fgets(s, n, iop)
-char *s;
-register FILE *iop;
+fgets(buf, n, fp)
+ char *buf;
+ register size_t n;
+ register FILE *fp;
{
- register c;
- register char *cs;
+ register size_t len;
+ register char *s;
+ register unsigned char *p, *t;
+
+ if (n < 2) /* sanity check */
+ return (NULL);
+
+ s = buf;
+ n--; /* leave space for NUL */
+ do {
+ /*
+ * If the buffer is empty, refill it.
+ */
+ if ((len = fp->_r) <= 0) {
+ if (__srefill(fp)) {
+ /* EOF/error: stop with partial or no line */
+ if (s == buf)
+ return (NULL);
+ break;
+ }
+ len = fp->_r;
+ }
+ p = fp->_p;
- cs = s;
- while (--n>0 && (c = getc(iop)) != EOF) {
- *cs++ = c;
- if (c=='\n')
- break;
- }
- if (c == EOF && cs==s)
- return(NULL);
- *cs++ = '\0';
- return(s);
+ /*
+ * Scan through at most n bytes of the current buffer,
+ * looking for '\n'. If found, copy up to and including
+ * newline, and stop. Otherwise, copy entire chunk
+ * and loop.
+ */
+ if (len > n)
+ len = n;
+ t = memchr((void *)p, '\n', len);
+ if (t != NULL) {
+ len = ++t - p;
+ fp->_r -= len;
+ fp->_p = t;
+ (void) bcopy((void *)p, (void *)s, len);
+ s[len] = 0;
+ return (buf);
+ }
+ fp->_r -= len;
+ fp->_p += len;
+ (void) bcopy((void *)p, (void *)s, len);
+ s += len;
+ } while ((n -= len) != 0);
+ *s = 0;
+ return (buf);
}