Reviewers: Lasse Reichstein,
Description:
Special case handling of one char split on an ASCII string.
Please review this at http://codereview.chromium.org/7285030/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/runtime.cc
Index: src/runtime.cc
===================================================================
--- src/runtime.cc (revision 8501)
+++ src/runtime.cc (working copy)
@@ -5754,19 +5754,35 @@
ASSERT(limit > 0);
// Collect indices of pattern in subject, and the end-of-string index.
// Stop after finding at most limit values.
- StringSearch<PatternChar, SubjectChar> search(isolate, pattern);
int pattern_length = pattern.length();
int index = 0;
- while (limit > 0) {
- index = search.Search(subject, index);
- if (index < 0) return;
- indices->Add(index);
- index += pattern_length;
- limit--;
+ if (sizeof(SubjectChar) == kCharSize &&
+ sizeof(PatternChar) == kCharSize &&
+ pattern_length == 1) {
+ // ASCII subject with one char ASCII pattern allows direct use of
memchr.
+ char pattern_first_char = pattern[0];
+ const char* subject_start = reinterpret_cast<const
char*>(subject.start());
+ const char* subject_end = subject_start + subject.length();
+ const char* pos = subject_start;
+ while (limit > 0) {
+ pos = reinterpret_cast<const char*>(
+ memchr(pos, pattern_first_char, subject_end - pos));
+ if (pos == NULL) return;
+ indices->Add(pos++ - subject_start);
+ limit--;
+ }
+ } else {
+ StringSearch<PatternChar, SubjectChar> search(isolate, pattern);
+ while (limit > 0) {
+ index = search.Search(subject, index);
+ if (index < 0) return;
+ indices->Add(index);
+ index += pattern_length;
+ limit--;
+ }
}
}
-
RUNTIME_FUNCTION(MaybeObject*, Runtime_StringSplit) {
ASSERT(args.length() == 3);
HandleScope handle_scope(isolate);
--
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