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authorCameron Katri <me@cameronkatri.com>2021-05-09 14:20:58 -0400
committerCameron Katri <me@cameronkatri.com>2021-05-09 14:20:58 -0400
commit5fd83771641d15c418f747bd343ba6738d3875f7 (patch)
tree5abf0f78f680d9837dbd93d4d4c3933bb7509599 /file_cmds/cksum/sum1.c
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Diffstat (limited to 'file_cmds/cksum/sum1.c')
-rw-r--r--file_cmds/cksum/sum1.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/file_cmds/cksum/sum1.c b/file_cmds/cksum/sum1.c
new file mode 100644
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+++ b/file_cmds/cksum/sum1.c
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+/*-
+ * Copyright (c) 1991, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * 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.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)sum1.c 8.1 (Berkeley) 6/6/93";
+#endif
+#endif /* not lint */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: src/usr.bin/cksum/sum1.c,v 1.8 2003/03/13 23:32:28 robert Exp $");
+
+#include <sys/types.h>
+
+#include <unistd.h>
+#include <stdint.h>
+
+#include "extern.h"
+
+int
+csum1(int fd, uint32_t *cval, off_t *clen)
+{
+ ssize_t nr;
+ u_int lcrc;
+ off_t total;
+ u_char *p;
+ u_char buf[8192];
+
+ /*
+ * 16-bit checksum, rotating right before each addition;
+ * overflow is discarded.
+ */
+ lcrc = 0;
+ total = 0;
+ while ((nr = read(fd, buf, sizeof(buf))) > 0)
+ for (total += nr, p = buf; nr--; ++p) {
+ if (lcrc & 1)
+ lcrc |= 0x10000;
+ lcrc = ((lcrc >> 1) + *p) & 0xffff;
+ }
+ if (nr < 0)
+ return (1);
+
+ *cval = lcrc;
+ *clen = total;
+ return (0);
+}