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experiment with slower but better hashes

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git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@36344 72102866-910b-0410-8b05-ffd578937521
This commit is contained in:
rfm 2013-03-12 16:11:10 +00:00
parent 4de78bda70
commit cc87536fda
7 changed files with 429 additions and 79 deletions
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82
Source/GSString.m
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@ -3363,50 +3363,48 @@ transmute(GSStr self, NSString *aString)
{
if (self->_flags.hash == 0)
{
unsigned ret = 0;
unsigned len = self->_count;
uint32_t ret = 0;
int len = (int)self->_count;
if (len > 0)
{
register unsigned index = 0;
if (self->_flags.wide)
{
register const unichar *p = self->_contents.u;
const unichar *p = self->_contents.u;
while (index < len)
{
ret = (ret << 5) + ret + p[index++];
}
ret = GSPrivateHash(0, p, len * sizeof(unichar));
}
else
else if (len > 64)
{
return (self->_flags.hash = [super hash]);
}
else
{
register const unsigned char *p = self->_contents.c;
unichar buf[64];
unsigned index;
const unsigned char *p = self->_contents.c;
if (internalEncoding == NSISOLatin1StringEncoding)
{
while (index < len)
{
ret = (ret << 5) + ret + p[index++];
}
}
for (index = 0; index < len; index++)
{
buf[index] = p[index];
}
}
else
{
while (index < len)
{
unichar u = p[index++];
for (index = 0; index < len; index++)
{
unichar u = p[index];
if (u > 127)
{
unsigned char c = (unsigned char)u;
unsigned int s = 1;
unichar *d = &u;
GSToUnicode(&d, &s, &c, 1, internalEncoding, 0, 0);
}
ret = (ret << 5) + ret + u;
}
if (u > 127)
{
return (self->_flags.hash = [super hash]);
}
buf[index] = u;
}
}
ret = GSPrivateHash(0, buf, len * sizeof(unichar));
}
/*
@ -5530,25 +5528,41 @@ literalIsEqual(NXConstantString *self, id anObject)
}
/* Must match the implementation in NSString
* To avoid allocating memory, we build the hash incrementally.
*/
- (NSUInteger) hash
{
if (nxcslen > 0)
{
unsigned ret = 0;
uint32_t s0 = 0;
uint32_t s1 = 0;
unichar chunk[64];
uint32_t ret;
unichar n = 0;
unsigned i = 0;
unichar c;
int l = 0;
uint32_t t = 0;
while (i < nxcslen)
{
c = nextUTF8((const uint8_t *)nxcsptr, nxcslen, &i, &n);
ret = (ret << 5) + ret + c;
chunk[l++] = nextUTF8((const uint8_t *)nxcsptr, nxcslen, &i, &n);
if (64 == l)
{
GSPrivateIncrementalHash(&s0, &s1, chunk, l * sizeof(unichar));
t += l;
l = 0;
}
}
if (0 != n)
{
ret = (ret << 5) + ret + n; // Add final character
chunk[l++] = n; // Add final character
}
if (l > 0)
{
GSPrivateIncrementalHash(&s0, &s1, chunk, l * sizeof(unichar));
t += l;
}
ret = GSPrivateFinishHash(s0, s1, t * sizeof(unichar));
ret &= 0x0fffffff;
if (ret == 0)
{