Optimize successive calls SourceFile.getLine().

Optimize successive calls SourceFile.getLine().

R=nweiz@google.com

Committed: https://github.com/dart-lang/source_span/commit/02eff66dd575747d607b5d17fc7206835b7231a6

[Bob Nystrom, 2015-09-01 23:58:07]

rnystrom@google.com changed reviewers:
+ nweiz@google.com

[Bob Nystrom, 2015-09-01 23:58:07]

This makes the YAML benchmark somewhere around 25-35% faster.

[nweiz, 2015-09-02 00:06:31]

lgtm

https://codereview.chromium.org/1319303004/diff/1/lib/src/file.dart
File lib/src/file.dart (right):

https://codereview.chromium.org/1319303004/diff/1/lib/src/file.dart#newcode99
lib/src/file.dart:99: return _cachedLine = _binarySearch(offset) - 1;
This is cute, but I think it's clearer to assign separately.

https://codereview.chromium.org/1319303004/diff/1/lib/src/file.dart#newcode102
lib/src/file.dart:102: /// Returns `true` if [offset] is within [_cachedLine].
"within" -> "near"

https://codereview.chromium.org/1319303004/diff/1/lib/src/file.dart#newcode132
lib/src/file.dart:132: /// items, 0 when all items match, and list.length when
none does.
Since we can guarantee there will be at least one line start and that they'll
all be different, I think we can simplify some of this return documentation.

[Bob Nystrom, 2015-09-02 00:37:19]

Committed patchset #2 (id:20001) manually as
02eff66dd575747d607b5d17fc7206835b7231a6 (presubmit successful).

[Bob Nystrom, 2015-10-28 20:31:51]

Description was changed from

==========
Optimize successive calls SourceFile.getLine().

R=nweiz@google.com

Committed:
https://github.com/dart-lang/source_span/commit/02eff66dd575747d607b5d17fc720...
==========

to

==========
Optimize successive calls SourceFile.getLine().

R=nweiz@google.com

Committed:
https://github.com/dart-lang/source_span/commit/02eff66dd575747d607b5d17fc720...
==========