-# strstr.m4 serial 1
-dnl Copyright (C) 2008 Free Software Foundation, Inc.
+# strstr.m4 serial 16
+dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
-dnl Check that strstr is efficient.
-AC_DEFUN([gl_FUNC_STRSTR],
+dnl Check that strstr works.
+AC_DEFUN([gl_FUNC_STRSTR_SIMPLE],
[
AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
- AC_CACHE_CHECK([whether strstr works in linear time],
- [gl_cv_func_strstr_linear],
- [AC_RUN_IFELSE([AC_LANG_PROGRAM([
-#include <string.h> /* for memmem */
+ AC_REQUIRE([gl_FUNC_MEMCHR])
+ if test "$gl_cv_func_memchr_works" != yes; then
+ REPLACE_STRSTR=1
+ else
+ dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
+ AC_CACHE_CHECK([whether strstr works],
+ [gl_cv_func_strstr_works_always],
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <string.h> /* for strstr */
+#define P "_EF_BF_BD"
+#define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
+#define NEEDLE P P P P P
+]], [[return !!strstr (HAYSTACK, NEEDLE);
+ ]])],
+ [gl_cv_func_strstr_works_always=yes],
+ [gl_cv_func_strstr_works_always=no],
+ [dnl glibc 2.12 and cygwin 1.7.7 have a known bug. uClibc is not
+ dnl affected, since it uses different source code for strstr than
+ dnl glibc.
+ dnl Assume that it works on all other platforms, even if it is not
+ dnl linear.
+ AC_EGREP_CPP([Lucky user],
+ [
+#ifdef __GNU_LIBRARY__
+ #include <features.h>
+ #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
+ || defined __UCLIBC__
+ Lucky user
+ #endif
+#elif defined __CYGWIN__
+ #include <cygwin/version.h>
+ #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
+ Lucky user
+ #endif
+#else
+ Lucky user
+#endif
+ ],
+ [gl_cv_func_strstr_works_always="guessing yes"],
+ [gl_cv_func_strstr_works_always="guessing no"])
+ ])
+ ])
+ case "$gl_cv_func_strstr_works_always" in
+ *yes) ;;
+ *)
+ REPLACE_STRSTR=1
+ ;;
+ esac
+ fi
+]) # gl_FUNC_STRSTR_SIMPLE
+
+dnl Additionally, check that strstr is efficient.
+AC_DEFUN([gl_FUNC_STRSTR],
+[
+ AC_REQUIRE([gl_FUNC_STRSTR_SIMPLE])
+ if test $REPLACE_STRSTR = 0; then
+ AC_CACHE_CHECK([whether strstr works in linear time],
+ [gl_cv_func_strstr_linear],
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <signal.h> /* for signal */
+#include <string.h> /* for strstr */
#include <stdlib.h> /* for malloc */
#include <unistd.h> /* for alarm */
-], [[size_t m = 1000000;
+static void quit (int sig) { exit (sig + 128); }
+]], [[
+ int result = 0;
+ size_t m = 1000000;
char *haystack = (char *) malloc (2 * m + 2);
char *needle = (char *) malloc (m + 2);
- void *result = 0;
/* Failure to compile this test due to missing alarm is okay,
since all such platforms (mingw) also have quadratic strstr. */
+ signal (SIGALRM, quit);
alarm (5);
/* Check for quadratic performance. */
if (haystack && needle)
{
- memset (haystack, 'A', 2 * m);
- haystack[2 * m] = 'B';
- haystack[2 * m + 1] = 0;
- memset (needle, 'A', m);
- needle[m] = 'B';
- needle[m + 1] = 0;
- result = strstr (haystack, needle);
+ memset (haystack, 'A', 2 * m);
+ haystack[2 * m] = 'B';
+ haystack[2 * m + 1] = 0;
+ memset (needle, 'A', m);
+ needle[m] = 'B';
+ needle[m + 1] = 0;
+ if (!strstr (haystack, needle))
+ result |= 1;
}
- return !result;]])],
- [gl_cv_func_strstr_linear=yes], [gl_cv_func_strstr_linear=no],
- [dnl pessimistically assume the worst, since even glibc 2.6.1
- dnl has quadratic complexity in its strstr
- gl_cv_func_strstr_linear="guessing no"])])
- if test "$gl_cv_func_strstr_linear" != yes; then
- REPLACE_STRSTR=1
- AC_LIBOBJ([strstr])
+ return result;
+ ]])],
+ [gl_cv_func_strstr_linear=yes], [gl_cv_func_strstr_linear=no],
+ [dnl Only glibc > 2.12 on processors without SSE 4.2 instructions and
+ dnl cygwin > 1.7.7 are known to have a bug-free strstr that works in
+ dnl linear time.
+ AC_EGREP_CPP([Lucky user],
+ [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
+ && !(defined __i386__ || defined __x86_64__) \
+ && !defined __UCLIBC__
+ Lucky user
+ #endif
+#endif
+#ifdef __CYGWIN__
+ #include <cygwin/version.h>
+ #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
+ Lucky user
+ #endif
+#endif
+ ],
+ [gl_cv_func_strstr_linear="guessing yes"],
+ [gl_cv_func_strstr_linear="guessing no"])
+ ])
+ ])
+ case "$gl_cv_func_strstr_linear" in
+ *yes) ;;
+ *)
+ REPLACE_STRSTR=1
+ ;;
+ esac
fi
-]) # gl_FUNC_MEMMEM
-
-# Prerequisites of lib/memmem.c.
-AC_DEFUN([gl_PREREQ_MEMMEM], [:])
-])
+]) # gl_FUNC_STRSTR
projects / gnulib.git / blobdiff