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Replaced the implementation of %StringEquals, which was a poorly

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optimized duplicate of String::Equals, with a simple call to
String::Equals.


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@555 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
christian.plesner.hansen@gmail.com 2008-10-22 12:33:20 +00:00
parent 85251f756c
commit b338967098
1 changed files with 8 additions and 32 deletions
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40
src/runtime.cc
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@ -2790,38 +2790,14 @@ static Object* Runtime_StringEquals(Arguments args) {
CONVERT_CHECKED(String, x, args[0]);
CONVERT_CHECKED(String, y, args[1]);
// This is very similar to String::Equals(String*) but that version
// requires flattened strings as input, whereas we flatten the
// strings only if the fast cases fail. Note that this may fail,
// requiring a GC. String::Equals(String*) returns a bool and has
// no way to signal a failure.
if (y == x) return Smi::FromInt(EQUAL);
if (x->IsSymbol() && y->IsSymbol()) return Smi::FromInt(NOT_EQUAL);
// Compare contents
int len = x->length();
if (len != y->length()) return Smi::FromInt(NOT_EQUAL);
if (len == 0) return Smi::FromInt(EQUAL);
// Handle one elment strings.
if (x->Get(0) != y->Get(0)) return Smi::FromInt(NOT_EQUAL);
if (len == 1) return Smi::FromInt(EQUAL);
// Fast case: First, middle and last characters.
if (x->Get(len>>1) != y->Get(len>>1)) return Smi::FromInt(NOT_EQUAL);
if (x->Get(len - 1) != y->Get(len - 1)) return Smi::FromInt(NOT_EQUAL);
x->TryFlatten();
y->TryFlatten();
static StringInputBuffer buf1;
static StringInputBuffer buf2;
buf1.Reset(x);
buf2.Reset(y);
while (buf1.has_more()) {
if (buf1.GetNext() != buf2.GetNext())
return Smi::FromInt(NOT_EQUAL);
}
return Smi::FromInt(EQUAL);
bool not_equal = !x->Equals(y);
// This is slightly convoluted because the value that signifies
// equality is 0 and inequality is 1 so we have to negate the result
// from String::Equals.
ASSERT(not_equal == 0 || not_equal == 1);
STATIC_CHECK(EQUAL == 0);
STATIC_CHECK(NOT_EQUAL == 1);
return Smi::FromInt(not_equal);
}