Revision: 4343
http://skim-app.svn.sourceforge.net/skim-app/?rev=4343&view=rev
Author: hofman
Date: 2008-08-03 12:44:28 +0000 (Sun, 03 Aug 2008)
Log Message:
-----------
Use CFHash to get hash of case insensitive keys.
Modified Paths:
--------------
trunk/SKCFCallBacks.m
Modified: trunk/SKCFCallBacks.m
===================================================================
--- trunk/SKCFCallBacks.m 2008-08-03 11:07:51 UTC (rev 4342)
+++ trunk/SKCFCallBacks.m 2008-08-03 12:44:28 UTC (rev 4343)
@@ -60,6 +60,7 @@
{
if(value == NULL) return 0;
+ uint32_t hash = 0;
CFAllocatorRef allocator = CFGetAllocator(value);
CFIndex len = CFStringGetLength(value);
@@ -75,69 +76,7 @@
// If we create the string with external characters,
CFStringGetCharactersPtr is guaranteed to succeed; since we're going to call
CFStringGetCharacters anyway in fastHash if CFStringGetCharactsPtr fails, let's
do it now when we lowercase the string
CFMutableStringRef mutableString =
CFStringCreateMutableWithExternalCharactersNoCopy(allocator, buffer, len, len +
10, (buffer != stackBuffer ? allocator : kCFAllocatorNull));
CFStringLowercase(mutableString, NULL);
-
- // Golden ratio - arbitrary start value to avoid mapping all 0's to all 0's
- // or anything like that.
- static const uint32_t PHI = 0x9e3779b9U;
-
- // Paul Hsieh's SuperFastHash
- // http://www.azillionmonkeys.com/qed/hash.html
- // Implementation from Apple's WebCore/khtml/xml/dom_stringimpl.cpp,
designed
- // to hash UTF-16 characters.
-
- unsigned l = CFStringGetLength(mutableString);
- uint32_t hash = PHI;
- uint32_t tmp;
-
- const UniChar *s = CFStringGetCharactersPtr(mutableString);
- UniChar *buf = NULL, stackBuf[STACK_BUFFER_SIZE];
-
- if (s == NULL) {
-
- if (l > STACK_BUFFER_SIZE) {
- buf = (UniChar *)CFAllocatorAllocate(allocator, l *
sizeof(UniChar), 0);
- NSCAssert(buf != NULL, @"unable to allocate memory");
- } else {
- buf = stackBuf;
- }
- CFStringGetCharacters(mutableString, CFRangeMake(0, l), buf);
- s = buf;
- }
-
- int rem = l & 1;
- l >>= 1;
-
- // Main loop
- for (; l > 0; l--) {
- hash += s[0];
- tmp = (s[1] << 11) ^ hash;
- hash = (hash << 16) ^ tmp;
- s += 2;
- hash += hash >> 11;
- }
-
- // Handle end case
- if (rem) {
- hash += s[0];
- hash ^= hash << 11;
- hash += hash >> 17;
- }
-
- if (buf != stackBuf) CFAllocatorDeallocate(allocator, buf);
-
- // Force "avalanching" of final 127 bits
- hash ^= hash << 3;
- hash += hash >> 5;
- hash ^= hash << 2;
- hash += hash >> 15;
- hash ^= hash << 10;
-
- // this avoids ever returning a hash code of 0, since that is used to
- // signal "hash not computed yet", using a value that is likely to be
- // effectively the same as 0 when the low bits are masked
- if (hash == 0)
- hash = 0x80000000;
-
+ hash = CFHash(mutableString);
// if we used the allocator, this should free the buffer for us
CFRelease(mutableString);
return hash;
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