Title: [197255] trunk/Source/WebCore
- Revision
- 197255
- Author
- [email protected]
- Date
- 2016-02-27 10:30:58 -0800 (Sat, 27 Feb 2016)
Log Message
Optimize parseHTMLInteger()
https://bugs.webkit.org/show_bug.cgi?id=154772
Reviewed by Ryosuke Niwa.
Optimize parseHTMLInteger() a bit now that it is used a lot more and
that it has decent API test coverage. In particular, we now:
- Avoid using a StringBuilder for the digits.
- Get rid of a is8Bit() branch.
- Only traverse the input string once.
* html/parser/HTMLParserIdioms.cpp:
(WebCore::parseHTMLIntegerInternal):
(WebCore::parseHTMLInteger):
(WebCore::parseHTMLNonNegativeInteger): Deleted.
Modified Paths
Diff
Modified: trunk/Source/WebCore/ChangeLog (197254 => 197255)
--- trunk/Source/WebCore/ChangeLog 2016-02-27 17:49:29 UTC (rev 197254)
+++ trunk/Source/WebCore/ChangeLog 2016-02-27 18:30:58 UTC (rev 197255)
@@ -1,3 +1,21 @@
+2016-02-27 Chris Dumez <[email protected]>
+
+ Optimize parseHTMLInteger()
+ https://bugs.webkit.org/show_bug.cgi?id=154772
+
+ Reviewed by Ryosuke Niwa.
+
+ Optimize parseHTMLInteger() a bit now that it is used a lot more and
+ that it has decent API test coverage. In particular, we now:
+ - Avoid using a StringBuilder for the digits.
+ - Get rid of a is8Bit() branch.
+ - Only traverse the input string once.
+
+ * html/parser/HTMLParserIdioms.cpp:
+ (WebCore::parseHTMLIntegerInternal):
+ (WebCore::parseHTMLInteger):
+ (WebCore::parseHTMLNonNegativeInteger): Deleted.
+
2016-02-27 Andreas Kling <[email protected]>
[iOS] Discard decoded image data on top-level navigation.
Modified: trunk/Source/WebCore/html/parser/HTMLParserIdioms.cpp (197254 => 197255)
--- trunk/Source/WebCore/html/parser/HTMLParserIdioms.cpp 2016-02-27 17:49:29 UTC (rev 197254)
+++ trunk/Source/WebCore/html/parser/HTMLParserIdioms.cpp 2016-02-27 18:30:58 UTC (rev 197255)
@@ -155,66 +155,54 @@
template <typename CharacterType>
static bool parseHTMLIntegerInternal(const CharacterType* position, const CharacterType* end, int& value)
{
- // Step 3
- bool isPositive = true;
-
- // Step 4
- while (position < end) {
- if (!isHTMLSpace(*position))
- break;
+ while (position < end && isHTMLSpace(*position))
++position;
- }
- // Step 5
if (position == end)
return false;
- ASSERT_WITH_SECURITY_IMPLICATION(position < end);
- // Step 6
+ bool isNegative = false;
if (*position == '-') {
- isPositive = false;
+ isNegative = true;
++position;
} else if (*position == '+')
++position;
- if (position == end)
- return false;
- ASSERT_WITH_SECURITY_IMPLICATION(position < end);
- // Step 7
- if (!isASCIIDigit(*position))
+ if (position == end || !isASCIIDigit(*position))
return false;
- // Step 8
- StringBuilder cleanCharacters;
- if (!isPositive)
- cleanCharacters.append('-');
- while (position < end) {
- if (!isASCIIDigit(*position))
- break;
- cleanCharacters.append(*position++);
- }
+ constexpr int intMax = std::numeric_limits<int>::max();
+ constexpr int base = 10;
+ constexpr int maxMultiplier = intMax / base;
- // Step 9
- bool ok;
- if (cleanCharacters.is8Bit())
- value = charactersToIntStrict(cleanCharacters.characters8(), cleanCharacters.length(), &ok);
- else
- value = charactersToIntStrict(cleanCharacters.characters16(), cleanCharacters.length(), &ok);
- return ok;
+ unsigned result = 0;
+ do {
+ int digitValue = *position - '0';
+
+ if (result > maxMultiplier || (result == maxMultiplier && digitValue > (intMax % base) + isNegative))
+ return false;
+
+ result = base * result + digitValue;
+ ++position;
+ } while (position < end && isASCIIDigit(*position));
+
+ value = isNegative ? -result : result;
+ return true;
}
// https://html.spec.whatwg.org/multipage/infrastructure.html#rules-for-parsing-integers
bool parseHTMLInteger(const String& input, int& value)
{
- // Step 1
- // Step 2
unsigned length = input.length();
- if (!length || input.is8Bit()) {
- const LChar* start = input.characters8();
+ if (!length)
+ return false;
+
+ if (LIKELY(input.is8Bit())) {
+ auto* start = input.characters8();
return parseHTMLIntegerInternal(start, start + length, value);
}
- const UChar* start = input.characters16();
+ auto* start = input.characters16();
return parseHTMLIntegerInternal(start, start + length, value);
}
_______________________________________________
webkit-changes mailing list
[email protected]
https://lists.webkit.org/mailman/listinfo/webkit-changes
