diff options
Diffstat (limited to 'gnulib/m4/memmem.m4')
| -rw-r--r-- | gnulib/m4/memmem.m4 | 134 |
1 files changed, 101 insertions, 33 deletions
diff --git a/gnulib/m4/memmem.m4 b/gnulib/m4/memmem.m4 index 87ab663..9102e77 100644 --- a/gnulib/m4/memmem.m4 +++ b/gnulib/m4/memmem.m4 @@ -1,81 +1,149 @@ -# memmem.m4 serial 13 -dnl Copyright (C) 2002, 2003, 2004, 2007, 2008 Free Software Foundation, Inc. +# memmem.m4 serial 24 +dnl Copyright (C) 2002-2004, 2007-2013 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 memmem is present. +dnl Check that memmem is present and functional. AC_DEFUN([gl_FUNC_MEMMEM_SIMPLE], [ dnl Persuade glibc <string.h> to declare memmem(). AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS]) - AC_REPLACE_FUNCS(memmem) - AC_CHECK_DECLS_ONCE(memmem) + AC_CHECK_FUNCS([memmem]) + if test $ac_cv_func_memmem = yes; then + HAVE_MEMMEM=1 + else + HAVE_MEMMEM=0 + fi + AC_CHECK_DECLS_ONCE([memmem]) if test $ac_cv_have_decl_memmem = no; then HAVE_DECL_MEMMEM=0 + else + dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092. + dnl Also check that we handle empty needles correctly. + AC_CACHE_CHECK([whether memmem works], + [gl_cv_func_memmem_works_always], + [AC_RUN_IFELSE([AC_LANG_PROGRAM([[ +#include <string.h> /* for memmem */ +#define P "_EF_BF_BD" +#define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P +#define NEEDLE P P P P P +]], [[ + int result = 0; + if (memmem (HAYSTACK, strlen (HAYSTACK), NEEDLE, strlen (NEEDLE))) + result |= 1; + /* Check for empty needle behavior. */ + { + const char *haystack = "AAA"; + if (memmem (haystack, 3, NULL, 0) != haystack) + result |= 2; + } + return result; + ]])], + [gl_cv_func_memmem_works_always=yes], + [gl_cv_func_memmem_works_always=no], + [dnl glibc 2.9..2.12 and cygwin 1.7.7 have issue #12092 above. + dnl Also empty needles work on glibc >= 2.1 and cygwin >= 1.7.0. + dnl uClibc is not affected, since it uses different source code. + dnl Assume that it works on all other platforms (even if not linear). + AC_EGREP_CPP([Lucky user], + [ +#ifdef __GNU_LIBRARY__ + #include <features.h> + #if ((__GLIBC__ == 2 && ((__GLIBC_MINOR > 0 && __GLIBC_MINOR__ < 9) \ + || __GLIBC_MINOR__ > 12)) \ + || (__GLIBC__ > 2)) \ + || defined __UCLIBC__ + Lucky user + #endif +#elif defined __CYGWIN__ + #include <cygwin/version.h> + #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7) + Lucky user + #endif +#else + Lucky user +#endif + ], + [gl_cv_func_memmem_works_always="guessing yes"], + [gl_cv_func_memmem_works_always="guessing no"]) + ]) + ]) + case "$gl_cv_func_memmem_works_always" in + *yes) ;; + *) + REPLACE_MEMMEM=1 + ;; + esac fi gl_PREREQ_MEMMEM ]) # gl_FUNC_MEMMEM_SIMPLE -dnl Additionally, check that memmem is efficient and handles empty needles. +dnl Additionally, check that memmem has linear performance characteristics AC_DEFUN([gl_FUNC_MEMMEM], [ AC_REQUIRE([gl_FUNC_MEMMEM_SIMPLE]) - if test $ac_cv_have_decl_memmem = yes; then + if test $HAVE_DECL_MEMMEM = 1 && test $REPLACE_MEMMEM = 0; then AC_CACHE_CHECK([whether memmem works in linear time], - [gl_cv_func_memmem_works], + [gl_cv_func_memmem_works_fast], [AC_RUN_IFELSE([AC_LANG_PROGRAM([[ #include <signal.h> /* for signal */ #include <string.h> /* for memmem */ #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 + 1); char *needle = (char *) malloc (m + 1); - void *result = 0; /* Failure to compile this test due to missing alarm is okay, since all such platforms (mingw) also lack memmem. */ - signal (SIGALRM, SIG_DFL); + signal (SIGALRM, quit); alarm (5); /* Check for quadratic performance. */ if (haystack && needle) { - memset (haystack, 'A', 2 * m); - haystack[2 * m] = 'B'; - memset (needle, 'A', m); - needle[m] = 'B'; - result = memmem (haystack, 2 * m + 1, needle, m + 1); + memset (haystack, 'A', 2 * m); + haystack[2 * m] = 'B'; + memset (needle, 'A', m); + needle[m] = 'B'; + if (!memmem (haystack, 2 * m + 1, needle, m + 1)) + result |= 1; } - /* Check for empty needle behavior. */ - return !result || !memmem ("a", 1, 0, 0);]])], - [gl_cv_func_memmem_works=yes], [gl_cv_func_memmem_works=no], - [dnl Only glibc >= 2.9 and cygwin >= 1.7.0 are known to have a - dnl memmem that works in linear time. - AC_EGREP_CPP([Lucky user], - [ + return result; + ]])], + [gl_cv_func_memmem_works_fast=yes], [gl_cv_func_memmem_works_fast=no], + [dnl Only glibc >= 2.9 and cygwin > 1.7.0 are known to have a + dnl memmem that works in linear time. + AC_EGREP_CPP([Lucky user], + [ #include <features.h> #ifdef __GNU_LIBRARY__ - #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 9) || (__GLIBC__ > 2) + #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 9) || (__GLIBC__ > 2)) \ + && !defined __UCLIBC__ Lucky user #endif #endif #ifdef __CYGWIN__ #include <cygwin/version.h> - #if CYGWIN_VERSION_DLL_MAJOR >= 1007 + #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 0) Lucky user #endif #endif - ], - [gl_cv_func_memmem_works=yes], - [gl_cv_func_memmem_works="guessing no"]) - ]) + ], + [gl_cv_func_memmem_works_fast="guessing yes"], + [gl_cv_func_memmem_works_fast="guessing no"]) + ]) ]) - if test "$gl_cv_func_memmem_works" != yes; then - REPLACE_MEMMEM=1 - AC_LIBOBJ([memmem]) - fi + case "$gl_cv_func_memmem_works_fast" in + *yes) ;; + *) + REPLACE_MEMMEM=1 + ;; + esac fi ]) # gl_FUNC_MEMMEM |