Changeset 37048 in webkit

Timestamp:

Sep 28, 2008, 7:00:42 PM (17 years ago)

Author:

mrowe@apple.com

Message:

Speed up parseInt and parseFloat.

Repeatedly indexing into a UString is slow, so retrieve a pointer into the underlying buffer once up front
and use that instead. This is a 7% win on a parseInt/parseFloat micro-benchmark.

Reviewed by Cameron Zwarich.

Location:

trunk/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• kjs/JSGlobalObjectFunctions.cpp (modified) (4 diffs)

trunk/JavaScriptCore/ChangeLog

@@ +1 @@
+2008-09-28  Mark Rowe  <mrowe@apple.com>
+
+        Reviewed by Cameron Zwarich.
+
+        Speed up parseInt and parseFloat.
+
+        Repeatedly indexing into a UString is slow, so retrieve a pointer into the underlying buffer once up front
+        and use that instead.  This is a 7% win on a parseInt/parseFloat micro-benchmark.
+
+        * kjs/JSGlobalObjectFunctions.cpp:
+        (JSC::parseInt):
+        (JSC::parseFloat):
+
 2008-09-28  Simon Hausmann  <hausmann@webkit.org>
 

trunk/JavaScriptCore/kjs/JSGlobalObjectFunctions.cpp

@@ -196 +196 @@
 {
     int length = s.size();
+    const UChar* data = s.data();
     int p = 0;
 
-    while (p < length && isStrWhiteSpace(s[p]))
+    while (p < length && isStrWhiteSpace(data[p]))
         ++p;
 
     double sign = 1;
     if (p < length) {
-        if (s[p] == '+')
+        if (data[p] == '+')
             ++p;
-        else if (s[p] == '-') {
+        else if (data[p] == '-') {
             sign = -1;
             ++p;
@@ -211 +212 @@
     }
 
-    if ((radix == 0 || radix == 16) && length - p >= 2 && s[p] == '0' && (s[p + 1] == 'x' || s[p + 1] == 'X')) {
+    if ((radix == 0 || radix == 16) && length - p >= 2 && data[p] == '0' && (data[p + 1] == 'x' || data[p + 1] == 'X')) {
         radix = 16;
         p += 2;
     } else if (radix == 0) {
-        if (p < length && s[p] == '0')
+        if (p < length && data[p] == '0')
             radix = 8;
         else
@@ -228 +229 @@
     double number = 0;
     while (p < length) {
-        int digit = parseDigit(s[p], radix);
+        int digit = parseDigit(data[p], radix);
         if (digit == -1)
             break;
@@ -255 +256 @@
     // Need to skip any whitespace and then one + or - sign.
     int length = s.size();
+    const UChar* data = s.data();
     int p = 0;
-    while (p < length && isStrWhiteSpace(s[p]))
+    while (p < length && isStrWhiteSpace(data[p]))
         ++p;
 
-    if (p < length && (s[p] == '+' || s[p] == '-'))
+    if (p < length && (data[p] == '+' || data[p] == '-'))
         ++p;
 
-    if (length - p >= 2 && s[p] == '0' && (s[p + 1] == 'x' || s[p + 1] == 'X'))
+    if (length - p >= 2 && data[p] == '0' && (data[p + 1] == 'x' || data[p + 1] == 'X'))
         return 0;