[RFA] lmemmem.patch

[dje at google dot com (Doug Evans)]

Hi.  This patch adds a wrapper around memmem().
It's used in a forthcoming patch to gdb.

2008-03-24  Doug Evans  <dje@google.com>

	* include/libiberty.h: (lmemmem): Declare.

	* libiberty/Makefile.in (CFILES): Add lmemmem.c.
	(REQUIRED_OFILES): Add lmemmem.o.
	(lmemmem.o): New rule.
	* libiberty/configure.ac (funcs): Add memmem.
	(AC_CHECK_FUNCS): Add memmem.
	* libiberty/config.in: Regenerate.
	* libiberty/configure: Regenerate.
	* libiberty/lmemmem.c: New file.

Index: include/libiberty.h
===================================================================
RCS file: /cvs/src/src/include/libiberty.h,v
retrieving revision 1.57
diff -u -p -u -p -r1.57 libiberty.h
--- ./include/libiberty.h	6 Sep 2007 17:22:36 -0000	1.57
+++ ./include/libiberty.h	24 Mar 2008 16:34:12 -0000
@@ -1,6 +1,6 @@
 /* Function declarations for libiberty.
 
-   Copyright 2001, 2002, 2005, 2007 Free Software Foundation, Inc.
+   Copyright 2001, 2002, 2005, 2007, 2008 Free Software Foundation, Inc.
    
    Note - certain prototypes declared in this header file are for
    functions whoes implementation copyright does not belong to the
@@ -166,6 +166,10 @@ extern char *libiberty_concat_ptr;
   (libiberty_concat_ptr = (char *) alloca (concat_length ACONCAT_PARAMS + 1), \
    concat_copy2 ACONCAT_PARAMS)
 
+/* A well-defined memmem () that is always compiled in.  */
+
+extern void * lmemmem (const void *, size_t, const void *, size_t);
+
 /* Check whether two file descriptors refer to the same file.  */
 
 extern int fdmatch (int fd1, int fd2);
Index: libiberty/Makefile.in
===================================================================
RCS file: /cvs/src/src/libiberty/Makefile.in,v
retrieving revision 1.89
diff -u -p -u -p -r1.89 Makefile.in
--- ./libiberty/Makefile.in	25 Jul 2007 06:36:27 -0000	1.89
+++ ./libiberty/Makefile.in	24 Mar 2008 16:34:13 -0000
@@ -2,7 +2,7 @@
 # Originally written by K. Richard Pixley <rich@cygnus.com>.
 #
 # Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-# 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software
+# 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software
 # Foundation
 #
 # This file is part of the libiberty library.
@@ -133,6 +133,7 @@ CFILES = alloca.c argv.c asprintf.c atex
 	hashtab.c hex.c							\
 	index.c insque.c						\
 	lbasename.c							\
+	lmemmem.c							\
 	lrealpath.c							\
 	make-relative-prefix.c						\
 	make-temp-file.c md5.c memchr.c memcmp.c memcpy.c memmove.c	\
@@ -164,7 +165,7 @@ REQUIRED_OFILES = ./regex.o ./cplus-dem.
 	./fnmatch.o ./fopen_unlocked.o					\
 	./getopt.o ./getopt1.o ./getpwd.o ./getruntime.o		\
 	./hashtab.o ./hex.o						\
-	./lbasename.o ./lrealpath.o					\
+	./lbasename.o ./lmemmem.o ./lrealpath.o				\
 	./make-relative-prefix.o ./make-temp-file.o			\
 	./objalloc.o ./obstack.o					\
 	./partition.o ./pexecute.o ./physmem.o				\
@@ -748,6 +749,12 @@ $(CONFIGURED_OFILES): stamp-picdir
 	else true; fi
 	$(COMPILE.c) $(srcdir)/lbasename.c $(OUTPUT_OPTION)
 
+./lmemmem.o: $(srcdir)/lmemmem.c stamp-h
+	if [ x"$(PICFLAG)" != x ]; then \
+	  $(COMPILE.c) $(PICFLAG) $(srcdir)/lmemmem.c -o pic/$@; \
+	else true; fi
+	$(COMPILE.c) $(srcdir)/lmemmem.c $(OUTPUT_OPTION)
+
 ./lrealpath.o: $(srcdir)/lrealpath.c stamp-h $(INCDIR)/ansidecl.h \
 	$(INCDIR)/libiberty.h
 	if [ x"$(PICFLAG)" != x ]; then \
Index: libiberty/config.in
===================================================================
RCS file: /cvs/src/src/libiberty/config.in,v
retrieving revision 1.38
diff -u -p -u -p -r1.38 config.in
--- ./libiberty/config.in	22 Jul 2005 03:16:32 -0000	1.38
+++ ./libiberty/config.in	24 Mar 2008 16:34:13 -0000
@@ -139,6 +139,9 @@
 /* Define to 1 if you have the `memcpy' function. */
 #undef HAVE_MEMCPY
 
+/* Define to 1 if you have the `memmem' function. */
+#undef HAVE_MEMMEM
+
 /* Define to 1 if you have the `memmove' function. */
 #undef HAVE_MEMMOVE
 
Index: libiberty/configure
===================================================================
RCS file: /cvs/src/src/libiberty/configure,v
retrieving revision 1.89
diff -u -p -u -p -r1.89 configure
--- ./libiberty/configure	17 Jul 2007 18:05:02 -0000	1.89
+++ ./libiberty/configure	24 Mar 2008 16:34:13 -0000
@@ -5062,6 +5062,7 @@ vars="sys_errlist sys_nerr sys_siglist"
 checkfuncs="getrusage on_exit psignal strerror strsignal sysconf times sbrk gettimeofday"
 checkfuncs="$checkfuncs realpath canonicalize_file_name pstat_getstatic pstat_getdynamic sysmp"
 checkfuncs="$checkfuncs getsysinfo table sysctl wait3 wait4 __fsetlocking"
+checkfuncs="$checkfuncs memmem"
 
 # These are neither executed nor required, but they help keep
 # autoheader happy without adding a bunch of text to acconfig.h.
Index: libiberty/configure.ac
===================================================================
RCS file: /cvs/src/src/libiberty/configure.ac,v
retrieving revision 1.37
diff -u -p -u -p -r1.37 configure.ac
--- ./libiberty/configure.ac	17 Jul 2007 18:05:02 -0000	1.37
+++ ./libiberty/configure.ac	24 Mar 2008 16:34:13 -0000
@@ -356,6 +356,7 @@ vars="sys_errlist sys_nerr sys_siglist"
 checkfuncs="getrusage on_exit psignal strerror strsignal sysconf times sbrk gettimeofday"
 checkfuncs="$checkfuncs realpath canonicalize_file_name pstat_getstatic pstat_getdynamic sysmp"
 checkfuncs="$checkfuncs getsysinfo table sysctl wait3 wait4 __fsetlocking"
+checkfuncs="$checkfuncs memmem"
 
 # These are neither executed nor required, but they help keep
 # autoheader happy without adding a bunch of text to acconfig.h.
Index: libiberty/lmemmem.c
===================================================================
RCS file: libiberty/lmemmem.c
diff -N libiberty/lmemmem.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ ./libiberty/lmemmem.c	24 Mar 2008 16:34:13 -0000
@@ -0,0 +1,58 @@
+/* lmemmem -- search for a sequence of bytes
+   This function is in the public domain.  */
+
+/*
+
+@deftypefn Supplemental void *lmemmem (const void *@var{haystack}, size_t @var{haystacklen},
+                                       const void *@var{needle}, size_t @var{needlelen})
+
+Search the area of memory at @var{haystack} for the bytes at @var{needle},
+and return the first occurrence.
+Returns a pointer to the beginning of the string or NULL if not found.
+
+@end deftypefn
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#ifdef HAVE_STRING_H
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE /* memmem */
+#endif
+#include <string.h>
+#endif
+#include <sys/types.h> /* size_t */
+#include "libiberty.h"
+
+void*
+lmemmem (const void *haystack, size_t haystacklen,
+	 const void *needle, size_t needlelen)
+{
+#ifdef HAVE_MEMMEM
+  return memmem (haystack, haystacklen, needle, needlelen);
+#else
+  size_t i,j;
+  const char *h = (const char *) haystack;
+  const char *n = (const char *) needle;
+
+  if (needlelen > haystacklen)
+    return NULL;
+  if (needlelen == 0)
+    return (void *) haystack; /* this is what glibc memmem does */
+
+  for (i = 0; i <= haystacklen - needlelen; ++i)
+    {
+      for (j = 0; j < needlelen; ++j)
+	{
+	  if (h[i + j] != n[j])
+	    break;
+	}
+      if (j == needlelen)
+	return (void*) (h + i);
+    }
+
+  return NULL;
+#endif
+}