114 lines
2.3 KiB
C
114 lines
2.3 KiB
C
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/* @(#)cmpnullbytes.c 1.10 10/08/21 Copyright 1988,2002-2010 J. Schilling */
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#include <schily/mconfig.h>
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#ifndef lint
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static UConst char sccsid[] =
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"@(#)cmpnullbytes.c 1.10 10/08/21 Copyright 1988,2002-2010 J. Schilling";
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#endif /* lint */
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/*
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* compare data against null
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* Return the index of the first non-null character
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*
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* Copyright (c) 1988,2002-2010 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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* Return the index of the first non-null character
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*/
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EXPORT ssize_t
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cmpnullbytes(fromp, cnt)
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const void *fromp;
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ssize_t cnt;
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{
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register const char *from = (char *)fromp;
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register ssize_t n;
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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 (cnt);
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/*
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* Compare byte-wise until properly aligned for a long pointer.
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*/
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while (--n >= 0 && !laligned(from)) {
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if (*from++ != 0)
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goto cdiff;
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}
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n++;
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if (n >= (ssize_t)(8 * sizeof (long))) {
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if (laligned(from)) {
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register const long *froml = (const long *)from;
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register ssize_t rem = n % (8 * sizeof (long));
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n /= (8 * sizeof (long));
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do {
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/* BEGIN CSTYLED */
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DO8(
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if (*froml++ != 0)
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break;
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);
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/* END CSTYLED */
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} while (--n > 0);
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if (n > 0) {
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--froml;
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from = (const char *)froml;
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goto ldiff;
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}
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from = (const char *)froml;
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n = rem;
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}
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if (n >= 8) {
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n -= 8;
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do {
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/* BEGIN CSTYLED */
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DO8(
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if (*from++ != 0)
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goto cdiff;
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);
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/* END CSTYLED */
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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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if (*from++ != 0)
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goto cdiff;
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} while (--n > 0);
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return (cnt);
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}
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if (n > 0) do {
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if (*from++ != 0)
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goto cdiff;
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} while (--n > 0);
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return (cnt);
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ldiff:
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n = sizeof (long);
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do {
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if (*from++ != 0)
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goto cdiff;
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} while (--n > 0);
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cdiff:
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return ((ssize_t)(--from - (char *)fromp));
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}
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