Update the Android-specific fix in StringHash::equal to match the fix recently made in webkit.org.

StringHash::equal includes an Android-specific fix for platforms which don't
provide 4-byte alignment ...

https://android-git.corp.google.com/w/?p=platform/external/webkit.git;a=commitdiff;h=05d23612a67d710479fb2359e98d7ac49a982025

This was recently fixed in webkit.org ...

http://trac.webkit.org/changeset/51006

This patch updates Android to use the fix from webkit.org to avoid future merge conflicts.

Background ...

The fix in webkit.org uses a loop, whereas the Android fix uses memcmp.
Tests by WebKit have apparently shown a loop to be faster than memcmp for small
strings. This is consistent with an equivalent fix in AtomicString ...

http://trac.webkit.org/changeset/19930

Change-Id: Ic9c0f729117e31bfdcb1bc1c28e85c048a464173

1 files changed, 8 insertions, 1 deletions

diff --git a/WebCore/platform/text/StringHash.h b/WebCore/platform/text/StringHash.h
index 885dd8b..fc6cb3c 100644
--- a/WebCore/platform/text/StringHash.h
+++ b/WebCore/platform/text/StringHash.h
@@ -48,8 +48,15 @@ namespace WebCore {
                 return false;
 
 #if PLATFORM(ARM) || PLATFORM(SH4)
-            return memcmp(a->characters(), b->characters(), sizeof(UChar) * aLength) == 0;
+            const UChar* aChars = a->characters();
+            const UChar* bChars = b->characters();
+            for (unsigned i = 0; i != aLength; ++i) {
+                if (*aChars++ != *bChars++)
+                    return false;
+            }
+            return true;
 #else
+            /* Do it 4-bytes-at-a-time on architectures where it's safe */
             const uint32_t* aChars = reinterpret_cast<const uint32_t*>(a->characters());
             const uint32_t* bChars = reinterpret_cast<const uint32_t*>(b->characters());