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File: [cvs.NetBSD.org] / src / lib / libc / stdlib / reallocarr.c (download)

Revision 1.5, Thu Aug 20 22:27:49 2015 UTC (8 years, 7 months ago) by kamil
Branch: MAIN
CVS Tags: prg-localcount2-base3, prg-localcount2-base2, prg-localcount2-base1, prg-localcount2-base, prg-localcount2, phil-wifi-base, phil-wifi-20200421, phil-wifi-20200411, phil-wifi-20200406, phil-wifi-20191119, phil-wifi-20190609, phil-wifi, pgoyette-localcount-base, pgoyette-localcount-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, pgoyette-localcount-20160806, pgoyette-localcount-20160726, pgoyette-localcount, pgoyette-compat-merge-20190127, pgoyette-compat-base, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, pgoyette-compat-0930, pgoyette-compat-0906, pgoyette-compat-0728, pgoyette-compat-0625, pgoyette-compat-0521, pgoyette-compat-0502, pgoyette-compat-0422, pgoyette-compat-0415, pgoyette-compat-0407, pgoyette-compat-0330, pgoyette-compat-0322, pgoyette-compat-0315, pgoyette-compat, perseant-stdc-iso10646-base, perseant-stdc-iso10646, netbsd-9-base, netbsd-9-3-RELEASE, netbsd-9-2-RELEASE, netbsd-9-1-RELEASE, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, netbsd-8-base, netbsd-8-2-RELEASE, netbsd-8-1-RELEASE, netbsd-8-1-RC1, netbsd-8-0-RELEASE, netbsd-8-0-RC2, netbsd-8-0-RC1, netbsd-8, netbsd-10-base, netbsd-10-0-RC6, netbsd-10-0-RC5, netbsd-10-0-RC4, netbsd-10-0-RC3, netbsd-10-0-RC2, netbsd-10-0-RC1, netbsd-10, matt-nb8-mediatek-base, matt-nb8-mediatek, localcount-20160914, is-mlppp-base, is-mlppp, cjep_sun2x-base1, cjep_sun2x-base, cjep_sun2x, cjep_staticlib_x-base1, cjep_staticlib_x-base, cjep_staticlib_x, bouyer-socketcan-base1, bouyer-socketcan-base, bouyer-socketcan, HEAD
Changes since 1.4: +11 -5 lines

Minor alterations to reallocarr(3)

Add comment about division.
Mark error branches with __predict_false().
Reduce one branch with the OR trick.

/* $NetBSD: reallocarr.c,v 1.5 2015/08/20 22:27:49 kamil Exp $ */

/*-
 * Copyright (c) 2015 Joerg Sonnenberger <joerg@NetBSD.org>.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
 * COPYRIGHT HOLDERS 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.
 */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
__RCSID("$NetBSD: reallocarr.c,v 1.5 2015/08/20 22:27:49 kamil Exp $");

#include "namespace.h"
#include <errno.h>
/* Old POSIX has SIZE_MAX in limits.h */
#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#ifdef _LIBC
#ifdef __weak_alias
__weak_alias(reallocarr, _reallocarr)
#endif
#endif

#define SQRT_SIZE_MAX (((size_t)1) << (sizeof(size_t) * CHAR_BIT / 2))

#if !HAVE_REALLOCARR
int
reallocarr(void *ptr, size_t number, size_t size)
{
	int saved_errno, result;
	void *optr;
	void *nptr;

	saved_errno = errno;
	memcpy(&optr, ptr, sizeof(ptr));
	if (number == 0 || size == 0) {
		free(optr);
		nptr = NULL;
		memcpy(ptr, &nptr, sizeof(ptr));
		errno = saved_errno;
		return 0;
	}

	/*
	 * Try to avoid division here.
	 *
	 * It isn't possible to overflow during multiplication if neither
	 * operand uses any of the most significant half of the bits.
	 */
	if (__predict_false((number|size) >= SQRT_SIZE_MAX &&
	                    number > SIZE_MAX / size)) {
		errno = saved_errno;
		return EOVERFLOW;
	}

	nptr = realloc(optr, number * size);
	if (__predict_false(nptr == NULL)) {
		result = errno;
	} else {
		result = 0;
		memcpy(ptr, &nptr, sizeof(ptr));
	}
	errno = saved_errno;
	return result;
}
#endif