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strcoll: Remove incorrect STRDIFF-based optimization (Bug 18589).

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The optimization introduced in commit
f13c2a8dff, causes regressions in
sorting for languages that have digraphs that change sort order, like
cs_CZ which sorts ch between h and i.

My analysis shows the fast-forwarding optimization in STRCOLL advances
through a digraph while possibly stopping in the middle which results
in a subsequent skipping of the digraph and incorrect sorting. The
optimization is incorrect as implemented and because of that I'm
removing it for 2.23, and I will also commit this fix for 2.22 where
it was originally introduced.

This patch reverts the optimization, introduces a new bug-strcoll2.c
regression test that tests both cs_CZ.UTF-8 and da_DK.ISO-8859-1 and
ensures they sort one digraph each correctly. The optimization can't be
applied without regressing this test.

Checked on x86_64, bug-strcoll2.c fails without this patch and passes
after. This will also get a fix on 2.22 which has the same bug.
This commit is contained in:
Carlos O'Donell
2015-10-08 16:34:53 -04:00
parent fd91891a50
commit 87701a58e2
10 changed files with 116 additions and 67 deletions
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93
string/bug-strcoll2.c Normal file
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@ -0,0 +1,93 @@
/* Bug 18589: sort-test.sh fails at random.
Copyright (C) 1998-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <string.h>
#include <locale.h>
/* An incorrect strcoll optimization resulted in incorrect
results from strcoll for cs_CZ and da_DK. */
int
test_cs_CZ (void)
{
const char t1[] = "config";
const char t2[] = "choose";
if (setlocale (LC_ALL, "cs_CZ.UTF-8") == NULL)
{
perror ("setlocale");
return 1;
}
/* In Czech the digraph ch sorts after c, therefore we expect
config to sort before choose. */
int a = strcoll (t1, t2);
int b = strcoll (t2, t1);
printf ("strcoll (\"%s\", \"%s\") = %d\n", t1, t2, a);
printf ("strcoll (\"%s\", \"%s\") = %d\n", t2, t1, b);
if (a < 0 && b > 0)
{
puts ("PASS: config < choose");
return 0;
}
else
{
puts ("FAIL: Wrong sorting in cz_CZ.UTF-8.");
return 1;
}
}
int
test_da_DK (void)
{
const char t1[] = "AS";
const char t2[] = "AA";
if (setlocale (LC_ALL, "da_DK.ISO-8859-1") == NULL)
{
perror ("setlocale");
return 1;
}
/* AA should be treated as the last letter of the Danish alphabet,
hence sorting after AS. */
int a = strcoll (t1, t2);
int b = strcoll (t2, t1);
printf ("strcoll (\"%s\", \"%s\") = %d\n", t1, t2, a);
printf ("strcoll (\"%s\", \"%s\") = %d\n", t2, t1, b);
if (a < 0 && b > 0)
{
puts ("PASS: AS < AA");
return 0;
}
else
{
puts ("FAIL: Wrong sorting in da_DK.ISO-8859-1");
return 1;
}
}
static int
do_test (void)
{
int err = 0;
err |= test_cs_CZ ();
err |= test_da_DK ();
return err;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"