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91 lines
1.8 KiB
C
91 lines
1.8 KiB
C
/* @(#)zerobytes.c 1.2 11/07/30 Copyright Copyright 1987, 1995-2011 J. Schilling */
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/*
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* fill memory with null bytes
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*
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* Copyright (c) 1987, 1995-2011 J. Schilling
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*/
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/*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* See the file CDDL.Schily.txt in this distribution for details.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file CDDL.Schily.txt from this distribution.
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*/
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#include <schily/standard.h>
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#include <schily/align.h>
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#include <schily/types.h>
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#include <schily/schily.h>
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#define DO8(a) a; a; a; a; a; a; a; a;
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/*
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* zero(to, cnt)
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*/
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EXPORT char *
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zerobytes(tov, cnt)
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void *tov;
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ssize_t cnt;
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{
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register char *to = (char *)tov;
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register ssize_t n;
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register long lval = 0L;
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/*
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* If we change cnt to be unsigned, check for == instead of <=
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*/
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if ((n = cnt) <= 0)
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return (to);
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if (n < 8 * sizeof (long)) { /* Simple may be faster... */
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do { /* n is always > 0 */
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*to++ = '\0';
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} while (--n > 0);
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return (to);
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}
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/*
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* Assign byte-wise until properly aligned for a long pointer.
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*/
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while (--n >= 0 && !laligned(to)) {
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*to++ = '\0';
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}
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n++;
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if (n >= (ssize_t)(8 * sizeof (long))) {
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register ssize_t rem = n % (8 * sizeof (long));
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n /= (8 * sizeof (long));
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{
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register long *tol = (long *)to;
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do {
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DO8 (*tol++ = lval);
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} while (--n > 0);
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to = (char *)tol;
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}
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n = rem;
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if (n >= 8) {
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n -= 8;
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do {
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DO8 (*to++ = '\0');
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} while ((n -= 8) >= 0);
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n += 8;
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}
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if (n > 0) do {
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*to++ = '\0';
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} while (--n > 0);
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return (to);
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}
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if (n > 0) do {
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*to++ = '\0';
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} while (--n > 0);
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return (to);
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}
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