add memmem compat

This commit is contained in:
Omar Polo 2022-10-31 22:53:16 +00:00
parent 4b93be289b
commit 19a8d9fe74
5 changed files with 217 additions and 0 deletions

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@ -8,6 +8,7 @@ DISTFILES = Makefile \
imsg-buffer.c \
imsg.c \
imsg.h \
memmem.c \
queue.h \
reallocarray.c \
recallocarray.c \

183
compat/memmem.c Normal file
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@ -0,0 +1,183 @@
/* $OpenBSD: memmem.c,v 1.5 2020/04/16 12:39:28 claudio Exp $ */
/*
* Copyright (c) 2005-2020 Rich Felker, et al.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <string.h>
#include <stdint.h>
static char *
twobyte_memmem(const unsigned char *h, size_t k, const unsigned char *n)
{
uint16_t nw = n[0]<<8 | n[1], hw = h[0]<<8 | h[1];
for (h+=2, k-=2; k; k--, hw = hw<<8 | *h++)
if (hw == nw) return (char *)h-2;
return hw == nw ? (char *)h-2 : 0;
}
static char *
threebyte_memmem(const unsigned char *h, size_t k, const unsigned char *n)
{
uint32_t nw = n[0]<<24 | n[1]<<16 | n[2]<<8;
uint32_t hw = h[0]<<24 | h[1]<<16 | h[2]<<8;
for (h+=3, k-=3; k; k--, hw = (hw|*h++)<<8)
if (hw == nw) return (char *)h-3;
return hw == nw ? (char *)h-3 : 0;
}
static char *
fourbyte_memmem(const unsigned char *h, size_t k, const unsigned char *n)
{
uint32_t nw = n[0]<<24 | n[1]<<16 | n[2]<<8 | n[3];
uint32_t hw = h[0]<<24 | h[1]<<16 | h[2]<<8 | h[3];
for (h+=4, k-=4; k; k--, hw = hw<<8 | *h++)
if (hw == nw) return (char *)h-4;
return hw == nw ? (char *)h-4 : 0;
}
#define MAX(a,b) ((a)>(b)?(a):(b))
#define MIN(a,b) ((a)<(b)?(a):(b))
#define BITOP(a,b,op) \
((a)[(size_t)(b)/(8*sizeof *(a))] op (size_t)1<<((size_t)(b)%(8*sizeof *(a))))
/*
* Maxime Crochemore and Dominique Perrin, Two-way string-matching,
* Journal of the ACM, 38(3):651-675, July 1991.
*/
static char *
twoway_memmem(const unsigned char *h, const unsigned char *z,
const unsigned char *n, size_t l)
{
size_t i, ip, jp, k, p, ms, p0, mem, mem0;
size_t byteset[32 / sizeof(size_t)] = { 0 };
size_t shift[256];
/* Computing length of needle and fill shift table */
for (i=0; i<l; i++)
BITOP(byteset, n[i], |=), shift[n[i]] = i+1;
/* Compute maximal suffix */
ip = -1; jp = 0; k = p = 1;
while (jp+k<l) {
if (n[ip+k] == n[jp+k]) {
if (k == p) {
jp += p;
k = 1;
} else k++;
} else if (n[ip+k] > n[jp+k]) {
jp += k;
k = 1;
p = jp - ip;
} else {
ip = jp++;
k = p = 1;
}
}
ms = ip;
p0 = p;
/* And with the opposite comparison */
ip = -1; jp = 0; k = p = 1;
while (jp+k<l) {
if (n[ip+k] == n[jp+k]) {
if (k == p) {
jp += p;
k = 1;
} else k++;
} else if (n[ip+k] < n[jp+k]) {
jp += k;
k = 1;
p = jp - ip;
} else {
ip = jp++;
k = p = 1;
}
}
if (ip+1 > ms+1) ms = ip;
else p = p0;
/* Periodic needle? */
if (memcmp(n, n+p, ms+1)) {
mem0 = 0;
p = MAX(ms, l-ms-1) + 1;
} else mem0 = l-p;
mem = 0;
/* Search loop */
for (;;) {
/* If remainder of haystack is shorter than needle, done */
if (z-h < l) return 0;
/* Check last byte first; advance by shift on mismatch */
if (BITOP(byteset, h[l-1], &)) {
k = l-shift[h[l-1]];
if (k) {
if (k < mem) k = mem;
h += k;
mem = 0;
continue;
}
} else {
h += l;
mem = 0;
continue;
}
/* Compare right half */
for (k=MAX(ms+1,mem); k<l && n[k] == h[k]; k++);
if (k < l) {
h += k-ms;
mem = 0;
continue;
}
/* Compare left half */
for (k=ms+1; k>mem && n[k-1] == h[k-1]; k--);
if (k <= mem) return (char *)h;
h += p;
mem = mem0;
}
}
void *
memmem(const void *h0, size_t k, const void *n0, size_t l)
{
const unsigned char *h = h0, *n = n0;
/* Return immediately on empty needle */
if (!l) return (void *)h;
/* Return immediately when needle is longer than haystack */
if (k<l) return 0;
/* Use faster algorithms for short needles */
h = memchr(h0, *n, k);
if (!h || l==1) return (void *)h;
k -= h - (const unsigned char *)h0;
if (k<l) return 0;
if (l==2) return twobyte_memmem(h, k, n);
if (l==3) return threebyte_memmem(h, k, n);
if (l==4) return fourbyte_memmem(h, k, n);
return twoway_memmem(h, h+k, n, l);
}

5
configure vendored
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@ -250,6 +250,7 @@ runtest landlock LANDLOCK || true
runtest libevent LIBEVENT || true
runtest libevent2 LIBEVENT2 || true
runtest libtls LIBTLS || true
runtest memmem MEMMEM "" -D_GNU_SOURCE || true
runtest openssl OPENSSL || true
runtest pr_set_name PR_SET_NAME || true
runtest program_invocation_short_name PROGRAM_INVOCATION_SHORT_NAME "" -D_GNU_SOURCE || true
@ -390,6 +391,10 @@ fi
if [ ${HAVE_IMSG} -eq 0 ]; then
COBJS="${COBJS} compat/imsg.o compat/imsg-buffer.o"
fi
if [ ${HAVE_MEMMEM} -eq 0 ]; then
echo "extern void *memmem(const void *, size_t, const void *, size_t);"
COBJS="${COBJS} compat/memmem.o"
fi
if [ ${HAVE_REALLOCARRAY} -eq 0 ]; then
echo "extern void *reallocarray(void*, size_t, size_t);"
COBJS="${COBJS} compat/reallocarray.o"

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@ -10,6 +10,7 @@ DISTFILES = Makefile \
libevent.c \
libevent2.c \
libtls.c \
memmem.c \
noop.c \
openssl.c \
pr_set_name.c \

27
have/memmem.c Normal file
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@ -0,0 +1,27 @@
/*
* Copyright (c) 2022 Omar Polo <op@omarpolo.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <string.h>
int
main(void)
{
char big[33], little[2];
memset(big, 0, sizeof(big));
memset(little, 0, sizeof(little));
return (memmem(big, sizeof(big), little, sizeof(little)) == NULL);
}