From 8bd92558019cbbe307f3340f33e3ebb6bd27fae6 Mon Sep 17 00:00:00 2001
From: Bruno Haible <bruno@clisp.org>
Date: Wed, 24 Jan 2007 02:45:50 +0000
Subject: [PATCH] New module 'streq'.

---
 lib/streq.h   | 173 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 modules/streq |  21 +++++++
 2 files changed, 194 insertions(+)
 create mode 100644 lib/streq.h
 create mode 100644 modules/streq

diff --git a/lib/streq.h b/lib/streq.h
new file mode 100644
index 000000000..133a5d351
--- /dev/null
+++ b/lib/streq.h
@@ -0,0 +1,173 @@
+/* Optimized string comparison.
+   Copyright (C) 2001-2002, 2007 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU Library General Public License as published
+   by the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+   USA.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>.  */
+
+#include <string.h>
+
+/* STREQ allows to optimize string comparison with a small literal string.
+     STREQ (s, "EUC-KR", 'E', 'U', 'C', '-', 'K', 'R', 0, 0, 0)
+   is semantically equivalent to
+     strcmp (s, "EUC-KR") == 0
+   just faster.  */
+
+/* Help GCC to generate good code for string comparisons with
+   immediate strings. */
+#if defined (__GNUC__) && defined (__OPTIMIZE__)
+
+static inline int
+streq9 (const char *s1, const char *s2)
+{
+  return strcmp (s1 + 9, s2 + 9) == 0;
+}
+
+static inline int
+streq8 (const char *s1, const char *s2, char s28)
+{
+  if (s1[8] == s28)
+    {
+      if (s28 == 0)
+        return 1;
+      else
+        return streq9 (s1, s2);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq7 (const char *s1, const char *s2, char s27, char s28)
+{
+  if (s1[7] == s27)
+    {
+      if (s27 == 0)
+        return 1;
+      else
+        return streq8 (s1, s2, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq6 (const char *s1, const char *s2, char s26, char s27, char s28)
+{
+  if (s1[6] == s26)
+    {
+      if (s26 == 0)
+        return 1;
+      else
+        return streq7 (s1, s2, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq5 (const char *s1, const char *s2, char s25, char s26, char s27, char s28)
+{
+  if (s1[5] == s25)
+    {
+      if (s25 == 0)
+        return 1;
+      else
+        return streq6 (s1, s2, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq4 (const char *s1, const char *s2, char s24, char s25, char s26, char s27, char s28)
+{
+  if (s1[4] == s24)
+    {
+      if (s24 == 0)
+        return 1;
+      else
+        return streq5 (s1, s2, s25, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq3 (const char *s1, const char *s2, char s23, char s24, char s25, char s26, char s27, char s28)
+{
+  if (s1[3] == s23)
+    {
+      if (s23 == 0)
+        return 1;
+      else
+        return streq4 (s1, s2, s24, s25, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq2 (const char *s1, const char *s2, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
+{
+  if (s1[2] == s22)
+    {
+      if (s22 == 0)
+        return 1;
+      else
+        return streq3 (s1, s2, s23, s24, s25, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq1 (const char *s1, const char *s2, char s21, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
+{
+  if (s1[1] == s21)
+    {
+      if (s21 == 0)
+        return 1;
+      else
+        return streq2 (s1, s2, s22, s23, s24, s25, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq0 (const char *s1, const char *s2, char s20, char s21, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
+{
+  if (s1[0] == s20)
+    {
+      if (s20 == 0)
+        return 1;
+      else
+        return streq1 (s1, s2, s21, s22, s23, s24, s25, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+#define STREQ(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \
+  streq0 (s1, s2, s20, s21, s22, s23, s24, s25, s26, s27, s28)
+
+#else
+
+#define STREQ(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \
+  (strcmp (s1, s2) == 0)
+
+#endif
diff --git a/modules/streq b/modules/streq
new file mode 100644
index 000000000..97d0a72c4
--- /dev/null
+++ b/modules/streq
@@ -0,0 +1,21 @@
+Description:
+Optimized string comparison.
+
+Files:
+lib/streq.h
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+
+Include:
+"streq.h"
+
+License:
+LGPL
+
+Maintainer:
+Bruno Haible
+
-- 
2.11.0