BSD 4_3_Net_2 release

[unix-history] / usr / src / lib / libc / stdio / fgets.c

diff --git a/usr/src/lib/libc/stdio/fgets.c b/usr/src/lib/libc/stdio/fgets.c
index e232c47..8a4c974 100644 (file)
--- a/usr/src/lib/libc/stdio/fgets.c
+++ b/usr/src/lib/libc/stdio/fgets.c
@@ -1,25 +1,103 @@
+/*-
+ * 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)
 #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 *
 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);

 }
 }