From 7153f9809d640cf4649fda9d2d51bd406e43e617 Mon Sep 17 00:00:00 2001
From: Per Hedbor <ph@opera.com>
Date: Mon, 20 May 2013 21:03:20 +0200
Subject: [PATCH] The operation "empty_string += string" is now significantly
faster.
This is rather common in code that works with buffers. Previously it
was, somewhat surpisingly, significantly faster to write code like:
if( strlen( x ) )
x += str;
else
x = str;
than it was to simply add the str to x regardless of whether or not x
already had contents.
Now the check is done in `+() instead. However, it still does not
handle things like "" + str + "", which might perhaps be useful, but
is significantly less common in real code.
str + "" was already handled.
---
src/operators.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/src/operators.c b/src/operators.c
index 9e40ffb91f..5f0c741df1 100644
--- a/src/operators.c
+++ b/src/operators.c
@@ -1571,7 +1571,13 @@ PMOD_EXPORT void f_add(INT32 args)
pop_n_elems(args-1);
return;
}
-
+ else if(args == 2 && (size == sp[-1].u.string->len))
+ {
+ stack_swap();
+ pop_stack();
+ return;
+ }
+
tmp=sp[-args].u.string->len;
r=new_realloc_shared_string(sp[-args].u.string,size,max_shift);
mark_free_svalue (sp - args);
--
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