Improve performance of String::ToCString for OneByteString and parsing of doubles. Leads to signifi…

Improve performance of String::ToCString for OneByteStrings and parsing of doubles. Leads to significant speedups in json parsing.
Committed: https://code.google.com/p/dart/source/detail?r=18925

[siva, 2013-02-22 21:47:09]

lgtm

https://codereview.chromium.org/12317076/diff/5001/runtime/lib/double.cc
File runtime/lib/double.cc (right):

https://codereview.chromium.org/12317076/diff/5001/runtime/lib/double.cc#newc...
runtime/lib/double.cc:207: char* p_end = NULL;
Can this local declaration be moved down under
if (dot_ok) {
 ....
}

https://codereview.chromium.org/12317076/diff/5001/runtime/lib/double.cc#newc...
runtime/lib/double.cc:208: const char* cstr = value.ToCString();
ASSERT(cstr != NULL);

https://codereview.chromium.org/12317076/diff/5001/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/12317076/diff/5001/runtime/vm/object.cc#newco...
runtime/vm/object.cc:11119: // Quick conversion if OneByteString contains one
byte characters.
... contains only ASCII characters.

https://codereview.chromium.org/12317076/diff/5001/runtime/vm/object.cc#newco...
runtime/vm/object.cc:11126: const uint8_t* original_str =
OneByteString::CharAddr(*this, 0);
Since you are using the raw pointer here in a loop it would make sense to add a
NoGCScope around this scope.

[srdjan, 2013-02-22 22:27:37]

https://codereview.chromium.org/12317076/diff/5001/runtime/lib/double.cc
File runtime/lib/double.cc (right):

https://codereview.chromium.org/12317076/diff/5001/runtime/lib/double.cc#newc...
runtime/lib/double.cc:207: char* p_end = NULL;
On 2013/02/22 21:47:09, siva wrote:
> Can this local declaration be moved down under
> if (dot_ok) {
>  ....
> }

Done.

https://codereview.chromium.org/12317076/diff/5001/runtime/lib/double.cc#newc...
runtime/lib/double.cc:208: const char* cstr = value.ToCString();
On 2013/02/22 21:47:09, siva wrote:
> ASSERT(cstr != NULL);

Done.

https://codereview.chromium.org/12317076/diff/5001/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/12317076/diff/5001/runtime/vm/object.cc#newco...
runtime/vm/object.cc:11119: // Quick conversion if OneByteString contains one
byte characters.
On 2013/02/22 21:47:09, siva wrote:
> ... contains only ASCII characters.

Done.

https://codereview.chromium.org/12317076/diff/5001/runtime/vm/object.cc#newco...
runtime/vm/object.cc:11126: const uint8_t* original_str =
OneByteString::CharAddr(*this, 0);
On 2013/02/22 21:47:09, siva wrote:
> Since you are using the raw pointer here in a loop it would make sense to add
a
> NoGCScope around this scope.

Done.

[srdjan, 2013-02-22 22:43:42]

Committed patchset #3 manually as r18925 (presubmit successful).