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authorLudovic Courtès <ludo@gnu.org>2010-07-04 18:44:08 +0200
committerLudovic Courtès <ludo@gnu.org>2010-07-04 18:44:08 +0200
commit0cc92ac41bdfd083bc4ce051da757cb2b00c2c02 (patch)
treec670cea7d07a4f238edc0c3e5d76a3e5ee67aae9 /libguile/srfi-13.c
parent100e20c7fa1a3ae268152842a0781d9f867eda96 (diff)
downloadguile-0cc92ac41bdfd083bc4ce051da757cb2b00c2c02.tar.gz
Optimize `string=' for the common case.
* libguile/srfi-13.c (scm_string_eq): Add a fast path for the common case.
Diffstat (limited to 'libguile/srfi-13.c')
-rw-r--r--libguile/srfi-13.c24
1 files changed, 23 insertions, 1 deletions
diff --git a/libguile/srfi-13.c b/libguile/srfi-13.c
index c4e85712c..eec2961d4 100644
--- a/libguile/srfi-13.c
+++ b/libguile/srfi-13.c
@@ -1,6 +1,6 @@
/* srfi-13.c --- SRFI-13 procedures for Guile
*
- * Copyright (C) 2001, 2004, 2005, 2006, 2008, 2009 Free Software Foundation, Inc.
+ * Copyright (C) 2001, 2004, 2005, 2006, 2008, 2009, 2010 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
@@ -1168,6 +1168,28 @@ SCM_DEFINE (scm_string_eq, "string=", 2, 4, 0,
"value otherwise.")
#define FUNC_NAME s_scm_string_eq
{
+ if (SCM_LIKELY (scm_i_is_narrow_string (s1) == scm_i_is_narrow_string (s2)
+ && SCM_UNBNDP (start1) && SCM_UNBNDP (end1)
+ && SCM_UNBNDP (start2) && SCM_UNBNDP (end2)))
+ {
+ /* Fast path for this common case, which avoids the repeated calls to
+ `scm_i_string_ref'. */
+ size_t len1, len2;
+
+ len1 = scm_i_string_length (s1);
+ len2 = scm_i_string_length (s2);
+
+ if (SCM_LIKELY (len1 == len2))
+ {
+ if (!scm_i_is_narrow_string (s1))
+ len1 *= 4;
+
+ return scm_from_bool (memcmp (scm_i_string_data (s1),
+ scm_i_string_data (s2),
+ len1) == 0);
+ }
+ }
+
return compare_strings (FUNC_NAME, 0,
s1, s2, start1, end1, start2, end2,
SCM_BOOL_F, SCM_BOOL_F, SCM_BOOL_F, SCM_BOOL_F, SCM_BOOL_T);