From 1ac9ce60b27157e014ed5b3c70548e6552608e48 Mon Sep 17 00:00:00 2001
From: Arne Goedeke <el@laramies.com>
Date: Mon, 10 Jun 2013 00:18:21 +0200
Subject: [PATCH] use string range information to optimize
utf8_to_string/string_to_utf8
---
src/builtin_functions.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/src/builtin_functions.c b/src/builtin_functions.c
index 28451e5e5e..b24aed6030 100644
--- a/src/builtin_functions.c
+++ b/src/builtin_functions.c
@@ -1969,11 +1969,20 @@ PMOD_EXPORT void f_string_to_utf8(INT32 args)
ptrdiff_t i,j;
INT_TYPE extended = 0;
PCHARP src;
+ INT32 min, max;
get_all_args("string_to_utf8", args, "%W.%i", &in, &extended);
len = in->len;
+ check_string_range(in, 1, &min, &max);
+
+ if (min >= 0 && max <= 0x7f) {
+ /* 7bit string -- already valid utf8. */
+ pop_n_elems(args - 1);
+ return;
+ }
+
for(i=0,src=MKPCHARP_STR(in); i < in->len; INC_PCHARP(src,1),i++) {
unsigned INT32 c = EXTRACT_PCHARP(src);
if (c & ~0x7f) {
@@ -2115,9 +2124,18 @@ PMOD_EXPORT void f_utf8_to_string(INT32 args)
int shift = 0;
ptrdiff_t i,j=0;
INT_TYPE extended = 0;
+ INT32 min, max;
get_all_args("utf8_to_string", args, "%S.%i", &in, &extended);
+ check_string_range(in, 1, &min, &max);
+
+ if (min >= 0 && max <= 0x7f) {
+ /* 7bit string -- already valid utf8. */
+ pop_n_elems(args - 1);
+ return;
+ }
+
for(i=0; i < in->len; i++) {
unsigned int c = STR0(in)[i];
len++;
--
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