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+# strcasestr.m4 serial 21
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+dnl Copyright (C) 2005, 2007-2013 Free Software Foundation, Inc.
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+dnl This file is free software; the Free Software Foundation
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+dnl gives unlimited permission to copy and/or distribute it,
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+dnl with or without modifications, as long as this notice is preserved.
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+
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+dnl Check that strcasestr is present and works.
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+AC_DEFUN([gl_FUNC_STRCASESTR_SIMPLE],
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+[
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+ AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
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+
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+ dnl Persuade glibc <string.h> to declare strcasestr().
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+ AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
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+
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+ AC_REQUIRE([gl_FUNC_MEMCHR])
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+ AC_CHECK_FUNCS([strcasestr])
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+ if test $ac_cv_func_strcasestr = no; then
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+ HAVE_STRCASESTR=0
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+ else
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+ if test "$gl_cv_func_memchr_works" != yes; then
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+ REPLACE_STRCASESTR=1
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+ else
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+ dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
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+ AC_CACHE_CHECK([whether strcasestr works],
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+ [gl_cv_func_strcasestr_works_always],
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+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
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+#include <string.h> /* for strcasestr */
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+#define P "_EF_BF_BD"
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+#define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
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+#define NEEDLE P P P P P
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+]], [[return !!strcasestr (HAYSTACK, NEEDLE);
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+ ]])],
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+ [gl_cv_func_strcasestr_works_always=yes],
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+ [gl_cv_func_strcasestr_works_always=no],
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+ [dnl glibc 2.12 and cygwin 1.7.7 have a known bug. uClibc is not
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+ dnl affected, since it uses different source code for strcasestr
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+ dnl than glibc.
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+ dnl Assume that it works on all other platforms, even if it is not
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+ dnl linear.
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+ AC_EGREP_CPP([Lucky user],
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+ [
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+#ifdef __GNU_LIBRARY__
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+ #include <features.h>
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+ #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
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+ || defined __UCLIBC__
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+ Lucky user
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+ #endif
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+#elif defined __CYGWIN__
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+ #include <cygwin/version.h>
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+ #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
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+ Lucky user
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+ #endif
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+#else
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+ Lucky user
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+#endif
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+ ],
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+ [gl_cv_func_strcasestr_works_always="guessing yes"],
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+ [gl_cv_func_strcasestr_works_always="guessing no"])
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+ ])
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+ ])
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+ case "$gl_cv_func_strcasestr_works_always" in
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+ *yes) ;;
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+ *)
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+ REPLACE_STRCASESTR=1
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+ ;;
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+ esac
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+ fi
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+ fi
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+]) # gl_FUNC_STRCASESTR_SIMPLE
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+
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+dnl Additionally, check that strcasestr is efficient.
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+AC_DEFUN([gl_FUNC_STRCASESTR],
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+[
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+ AC_REQUIRE([gl_FUNC_STRCASESTR_SIMPLE])
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+ if test $HAVE_STRCASESTR = 1 && test $REPLACE_STRCASESTR = 0; then
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+ AC_CACHE_CHECK([whether strcasestr works in linear time],
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+ [gl_cv_func_strcasestr_linear],
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+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
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+#include <signal.h> /* for signal */
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+#include <string.h> /* for strcasestr */
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+#include <stdlib.h> /* for malloc */
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+#include <unistd.h> /* for alarm */
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+static void quit (int sig) { exit (sig + 128); }
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+]], [[
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+ int result = 0;
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+ size_t m = 1000000;
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+ char *haystack = (char *) malloc (2 * m + 2);
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+ char *needle = (char *) malloc (m + 2);
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+ /* Failure to compile this test due to missing alarm is okay,
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+ since all such platforms (mingw) also lack strcasestr. */
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+ signal (SIGALRM, quit);
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+ alarm (5);
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+ /* Check for quadratic performance. */
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+ if (haystack && needle)
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+ {
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+ memset (haystack, 'A', 2 * m);
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+ haystack[2 * m] = 'B';
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+ haystack[2 * m + 1] = 0;
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+ memset (needle, 'A', m);
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+ needle[m] = 'B';
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+ needle[m + 1] = 0;
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+ if (!strcasestr (haystack, needle))
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+ result |= 1;
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+ }
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+ return result;
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+ ]])],
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+ [gl_cv_func_strcasestr_linear=yes], [gl_cv_func_strcasestr_linear=no],
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+ [dnl Only glibc > 2.12 and cygwin > 1.7.7 are known to have a
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+ dnl strcasestr that works in linear time.
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+ AC_EGREP_CPP([Lucky user],
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+ [
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+#include <features.h>
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+#ifdef __GNU_LIBRARY__
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+ #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
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+ && !defined __UCLIBC__
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+ Lucky user
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+ #endif
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+#endif
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+#ifdef __CYGWIN__
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+ #include <cygwin/version.h>
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+ #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
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+ Lucky user
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+ #endif
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+#endif
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+ ],
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+ [gl_cv_func_strcasestr_linear="guessing yes"],
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+ [gl_cv_func_strcasestr_linear="guessing no"])
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+ ])
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+ ])
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+ case "$gl_cv_func_strcasestr_linear" in
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+ *yes) ;;
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+ *)
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+ REPLACE_STRCASESTR=1
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+ ;;
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+ esac
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+ fi
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+]) # gl_FUNC_STRCASESTR
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+
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+# Prerequisites of lib/strcasestr.c.
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+AC_DEFUN([gl_PREREQ_STRCASESTR], [
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+ :
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+])
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