2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1991, 1993
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8 * modification, are permitted provided that the following conditions
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34 static char sccsid[] = "@(#)sum2.c 8.1 (Berkeley) 6/6/93";
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
40 #include <sys/types.h>
48 csum2(int fd, uint32_t *cval, off_t *clen)
57 * Draft 8 POSIX 1003.2:
59 * s = sum of all bytes
60 * r = s % 2^16 + (s % 2^32) / 2^16
61 * lcrc = (r % 2^16) + r / 2^16
64 while ((nr = read(fd, buf, sizeof(buf))) > 0)
65 for (total += nr, p = buf; nr--; ++p)
70 lcrc = (lcrc & 0xffff) + (lcrc >> 16);
71 lcrc = (lcrc & 0xffff) + (lcrc >> 16);