Revision: 10412
Author: [email protected]
Date: Mon Jan 16 07:21:38 2012
Log: Fast path for string.replace that replaces a single character by
a string.
BUG=
TEST=
Review URL: http://codereview.chromium.org/9213002
http://code.google.com/p/v8/source/detail?r=10412
Modified:
/branches/bleeding_edge/src/heap.cc
/branches/bleeding_edge/src/runtime.cc
/branches/bleeding_edge/src/runtime.h
/branches/bleeding_edge/src/string.js
=======================================
--- /branches/bleeding_edge/src/heap.cc Mon Jan 16 04:38:59 2012
+++ /branches/bleeding_edge/src/heap.cc Mon Jan 16 07:21:38 2012
@@ -3011,7 +3011,7 @@
int end,
PretenureFlag pretenure) {
int length = end - start;
- if (length == 0) {
+ if (length <= 0) {
return empty_string();
} else if (length == 1) {
return LookupSingleCharacterStringFromCode(buffer->Get(start));
=======================================
--- /branches/bleeding_edge/src/runtime.cc Mon Jan 16 04:38:59 2012
+++ /branches/bleeding_edge/src/runtime.cc Mon Jan 16 07:21:38 2012
@@ -3231,6 +3231,59 @@
replacement,
last_match_info);
}
+
+
+Handle<String> Runtime::StringReplaceOneCharWithString(Isolate* isolate,
+ Handle<String>
subject,
+ Handle<String>
search,
+ Handle<String>
replace,
+ bool* found) {
+ if (subject->IsConsString()) {
+ ConsString* cons = ConsString::cast(*subject);
+ Handle<String> first = Handle<String>(cons->first());
+ Handle<String> second = Handle<String>(cons->second());
+ Handle<String> new_first = StringReplaceOneCharWithString(isolate,
+ first,
+ search,
+ replace,
+ found);
+ if (*found) {
+ return isolate->factory()->NewConsString(new_first, second);
+ } else {
+ Handle<String> new_second = StringReplaceOneCharWithString(isolate,
+ second,
+ search,
+ replace,
+ found);
+ return isolate->factory()->NewConsString(first, new_second);
+ }
+ } else {
+ int index = StringMatch(isolate, subject, search, 0);
+ if (index == -1) return subject;
+ *found = true;
+ Handle<String> first = isolate->factory()->NewSubString(subject, 0,
index);
+ Handle<String> cons1 = isolate->factory()->NewConsString(first,
replace);
+ Handle<String> second =
+ isolate->factory()->NewSubString(subject, index + 1,
subject->length());
+ return isolate->factory()->NewConsString(cons1, second);
+ }
+}
+
+
+RUNTIME_FUNCTION(MaybeObject*, Runtime_StringReplaceOneCharWithString) {
+ ASSERT(args.length() == 3);
+ HandleScope scope(isolate);
+ CONVERT_ARG_CHECKED(String, subject, 0);
+ CONVERT_ARG_CHECKED(String, search, 1);
+ CONVERT_ARG_CHECKED(String, replace, 2);
+ bool found = false;
+
+ return *(Runtime::StringReplaceOneCharWithString(isolate,
+ subject,
+ search,
+ replace,
+ &found));
+}
// Perform string match of pattern on subject, starting at start index.
=======================================
--- /branches/bleeding_edge/src/runtime.h Wed Dec 28 07:14:33 2011
+++ /branches/bleeding_edge/src/runtime.h Mon Jan 16 07:21:38 2012
@@ -197,6 +197,7 @@
F(StringLocaleCompare, 2, 1) \
F(SubString, 3, 1) \
F(StringReplaceRegExpWithString, 4, 1) \
+ F(StringReplaceOneCharWithString, 3, 1) \
F(StringMatch, 3, 1) \
F(StringTrim, 3, 1) \
F(StringToArray, 2, 1) \
@@ -629,6 +630,12 @@
// Get the intrinsic function with the given FunctionId.
static const Function* FunctionForId(FunctionId id);
+ static Handle<String> StringReplaceOneCharWithString(Isolate* isolate,
+ Handle<String>
subject,
+ Handle<String>
search,
+ Handle<String>
replace,
+ bool* found);
+
// General-purpose helper functions for runtime system.
static int StringMatch(Isolate* isolate,
Handle<String> sub,
=======================================
--- /branches/bleeding_edge/src/string.js Mon Nov 28 04:11:00 2011
+++ /branches/bleeding_edge/src/string.js Mon Jan 16 07:21:38 2012
@@ -244,6 +244,11 @@
// Convert the search argument to a string and search for it.
search = TO_STRING_INLINE(search);
+ if (search.length == 1 &&
+ IS_STRING(replace) &&
+ %StringIndexOf(replace, '$', 0) < 0) {
+ return %StringReplaceOneCharWithString(subject, search, replace);
+ }
var start = %StringIndexOf(subject, search, 0);
if (start < 0) return subject;
var end = start + search.length;
--
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