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f265160c26
* bootstrap.conf (gnulib_modules): Add stdckdint. * lib/cmpbuf.c: Use ckd_mul rather than INT_MULTIPLY_WRAPV. Include stdckdint.h, not "intprops.h". * src/diff.c: Similar, but for both ckd_add and ckd_mul. * src/io.c: Likewise for ckd_add.
109 lines
3.1 KiB
C
109 lines
3.1 KiB
C
/* Buffer primitives for comparison operations.
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Copyright (C) 1993, 1995, 1998, 2001-2002, 2006, 2009-2013, 2015-2023 Free
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Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include <config.h>
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#include <errno.h>
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#include <limits.h>
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#include <signal.h>
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#include <stdckdint.h>
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#include <unistd.h>
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#include <stdint.h>
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#include <inttypes.h>
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#include <sys/types.h>
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#include "cmpbuf.h"
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#ifndef SSIZE_MAX
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# define SSIZE_MAX TYPE_MAXIMUM (ssize_t)
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#endif
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#undef MIN
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#define MIN(a, b) ((a) <= (b) ? (a) : (b))
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/* Read NBYTES bytes from descriptor FD into BUF.
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NBYTES must not be SIZE_MAX.
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Return the number of characters successfully read.
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On error, return SIZE_MAX, setting errno.
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The number returned is always NBYTES unless end-of-file or error. */
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size_t
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block_read (int fd, char *buf, size_t nbytes)
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{
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char *bp = buf;
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char const *buflim = buf + nbytes;
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size_t readlim = MIN (SSIZE_MAX, SIZE_MAX);
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do
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{
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size_t bytes_remaining = buflim - bp;
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size_t bytes_to_read = MIN (bytes_remaining, readlim);
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ssize_t nread = read (fd, bp, bytes_to_read);
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if (nread <= 0)
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{
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if (nread == 0)
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break;
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/* Accommodate Tru64 5.1, which can't read more than INT_MAX
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bytes at a time. They call that a 64-bit OS? */
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if (errno == EINVAL && INT_MAX < bytes_to_read)
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{
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readlim = INT_MAX;
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continue;
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}
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/* This is needed for programs that have signal handlers on
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older hosts without SA_RESTART. It also accommodates
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ancient AIX hosts that set errno to EINTR after uncaught
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SIGCONT. See <news:1r77ojINN85n@ftp.UU.NET>
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(1993-04-22). */
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if (! SA_RESTART && errno == EINTR)
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continue;
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return SIZE_MAX;
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}
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bp += nread;
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}
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while (bp < buflim);
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return bp - buf;
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}
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/* Least common multiple of two buffer sizes A and B. However, if
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either A or B is zero, or if the multiple is greater than LCM_MAX,
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return a reasonable buffer size. */
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size_t
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buffer_lcm (size_t a, size_t b, size_t lcm_max)
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{
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size_t lcm, m, n, q, r;
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/* Yield reasonable values if buffer sizes are zero. */
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if (!a)
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return b ? b : 8 * 1024;
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if (!b)
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return a;
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/* n = gcd (a, b) */
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for (m = a, n = b; (r = m % n) != 0; m = n, n = r)
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continue;
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/* Yield a if there is an overflow. */
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q = a / n;
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return !ckd_mul (&lcm, b, q) && lcm <= lcm_max ? lcm : a;
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}
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