Provide a code point iterator to the String class to simplify iteration.

Provide a code point iterator to the String class to simplify iteration.

Committed: https://code.google.com/p/dart/source/detail?r=15109

[siva, 2012-11-19 18:25:29]

http://codereview.chromium.org/11416054/diff/7/runtime/vm/object.cc
File runtime/vm/object.cc (right):

http://codereview.chromium.org/11416054/diff/7/runtime/vm/object.cc#newcode10553
runtime/vm/object.cc:10553: if (Utf16::IsLeadSurrogate(ch) && (index_ !=
(str_.Length() - 1))) {
Shouldn't this be (index_ < (str_.Length() - 1))

http://codereview.chromium.org/11416054/diff/7/runtime/vm/object.cc#newcode10567
runtime/vm/object.cc:10567: if (index_ == (str_.Length() - 1)) {
Why not just make this
if (index_ >= (str_.Length() - 1)) {
  return false;
}
and remove ASSERT(index_ < str.Length());

http://codereview.chromium.org/11416054/diff/7/runtime/vm/object.cc#newcode10582
runtime/vm/object.cc:10582: }
If you structure the code as discussed offline it would
be more readable.

http://codereview.chromium.org/11416054/diff/7/runtime/vm/unicode.cc
File runtime/vm/unicode.cc (right):

http://codereview.chromium.org/11416054/diff/7/runtime/vm/unicode.cc#newcode197
runtime/vm/unicode.cc:197: intptr_t ch = it.Current();
int32_t ch = it.Current() ?

[cshapiro, 2012-11-19 18:55:10]

http://codereview.chromium.org/11416054/diff/7/runtime/vm/object.cc
File runtime/vm/object.cc (right):

http://codereview.chromium.org/11416054/diff/7/runtime/vm/object.cc#newcode10553
runtime/vm/object.cc:10553: if (Utf16::IsLeadSurrogate(ch) && (index_ !=
(str_.Length() - 1))) {
Removed in the re-upload.

http://codereview.chromium.org/11416054/diff/7/runtime/vm/object.cc#newcode10567
runtime/vm/object.cc:10567: if (index_ == (str_.Length() - 1)) {
I am not sure what this simplifies.  Having the index value range from [-1,
(Length-1)] makes it easier to check the invariants.

http://codereview.chromium.org/11416054/diff/7/runtime/vm/unicode.cc
File runtime/vm/unicode.cc (right):

http://codereview.chromium.org/11416054/diff/7/runtime/vm/unicode.cc#newcode197
runtime/vm/unicode.cc:197: intptr_t ch = it.Current();
Yes.  I will fix this before submitting.

[siva, 2012-11-19 19:29:54]

lgtm

http://codereview.chromium.org/11416054/diff/3006/runtime/vm/object.cc
File runtime/vm/object.cc (right):

http://codereview.chromium.org/11416054/diff/3006/runtime/vm/object.cc#newcod...
runtime/vm/object.cc:10552: int d = (ch_ <= 0xFFFF) ? 1 : 2;
(ch_ <= Utf16::kMaxBmpCodePoint)

[cshapiro, 2012-11-19 19:47:59]

http://codereview.chromium.org/11416054/diff/3006/runtime/vm/object.cc
File runtime/vm/object.cc (right):

http://codereview.chromium.org/11416054/diff/3006/runtime/vm/object.cc#newcod...
runtime/vm/object.cc:10552: int d = (ch_ <= 0xFFFF) ? 1 : 2;
I'll fix that before submitting.

I think we should add predicates for these things... IsBmpCodePoint,
IsSupplementaryCodePoint, etc.