colorchord/chash.c

441 lines
9.7 KiB
C

#include "chash.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <malloc.h>
#define I_AM_LITTLE (((union { unsigned x; unsigned char c; }){1}).c)
static unsigned long GetStrHash( const char * c )
{
int place = 0;
unsigned int hashSoFar = 0;
if( !c ) return 0;
do
{
unsigned char cc = (*c);
unsigned long this = cc;
this <<= (((place++)&3)<<3);
hashSoFar += this;
} while( *(c++) );
return hashSoFar;
}
static unsigned long GeneralUsePrimes[] = { 7, 13, 37, 73, 131, 229, 337, 821,
2477, 4594, 8941, 14797, 24953, 39041, 60811, 104729, 151909,
259339, 435637, 699817, 988829, 1299827 };
struct chash * GenerateHashTable( int allowMultiple )
{
int bucketplace = 0;
int count = GeneralUsePrimes[bucketplace];
struct chash * ret = malloc( sizeof( struct chash ) );
ret->entryCount = 0;
ret->allowMultiple = allowMultiple;
ret->bucketCountPlace = bucketplace;
ret->buckets = malloc( sizeof( struct chashentry ) * count );
memset( ret->buckets, 0, sizeof( struct chashentry ) * count );
return ret;
}
void ** HashTableInsert( struct chash * hash, const char * key, int dontDupKey )
{
int buckets = GeneralUsePrimes[hash->bucketCountPlace];
int thisHash = GetStrHash( key ) % buckets;
int multi = hash->allowMultiple;
struct chashentry * thisEntry;
struct chashentry * overextndEntry = &hash->buckets[buckets];
int i;
//Cannot insert null!
if( !key )
{
return 0;
}
//Half full?
if( hash->entryCount > (buckets>>1) )
{
//Resize!
int newbucketcount = GeneralUsePrimes[hash->bucketCountPlace + 1];
struct chashentry * newbuckets = malloc( sizeof( struct chashentry ) * newbucketcount );
struct chashentry * oldbuckets = hash->buckets;
overextndEntry = &newbuckets[newbucketcount];
memset( newbuckets, 0, sizeof( struct chashentry ) * newbucketcount );
for( i = 0; i < buckets; i++ )
{
struct chashentry * oe = &oldbuckets[i];
int newhash;
struct chashentry * ne;
//Empty? Continue!
if( !oe->key ) continue;
newhash = GetStrHash( oe->key ) % newbucketcount;
ne = &newbuckets[newhash];
while( ne->key )
{
ne++;
if( ne == overextndEntry ) ne = &newbuckets[0];
}
ne->key = oe->key;
ne->value = oe->value;
}
//Replacing done, now update all.
hash->buckets = newbuckets;
free( oldbuckets );
hash->bucketCountPlace++;
buckets = newbucketcount;
thisHash = GetStrHash( key ) % buckets;
}
thisEntry = &hash->buckets[thisHash];
while( thisEntry->key )
{
//If we aren't allowing multiple entries, say so!
if( !multi && strcmp( thisEntry->key, key ) == 0 )
{
return &thisEntry->value;
}
thisEntry++;
if( thisEntry == overextndEntry ) thisEntry = &hash->buckets[0];
}
thisEntry->value = 0;
if( dontDupKey )
{
thisEntry->key = key;
}
else
{
thisEntry->key = strdup( key );
}
thisEntry->hash = thisHash;
hash->entryCount++;
return &thisEntry->value;
}
//Re-process a range; populated is the number of elements we expect to run into.
//If we removed some, it will be less length by that much.
//NOTE: This function doesn't range check diddily.
static void RedoHashRange( struct chash * hash, int start, int length, int populated )
{
int i;
int buckets = GeneralUsePrimes[hash->bucketCountPlace];
struct chashentry * thisEntry = &hash->buckets[start];
struct chashentry * overEntry = &hash->buckets[buckets];
struct chashentry * copyEntry;
struct chashlist * resort = alloca( sizeof( struct chashlist ) + sizeof( struct chashentry ) * (populated) );
resort->length = populated;
copyEntry = &resort->items[0];
for( i = 0; i < length; i++ )
{
if( thisEntry->key )
{
copyEntry->key = thisEntry->key;
copyEntry->value = thisEntry->value;
copyEntry->hash = thisEntry->hash;
copyEntry++;
thisEntry->key = 0;
}
thisEntry++;
if( thisEntry == overEntry ) thisEntry = &hash->buckets[0];
}
hash->entryCount -= populated;
copyEntry = &resort->items[0];
for( i = 0; i < populated; i++ )
{
*HashTableInsert( hash, copyEntry->key, 1 ) = copyEntry->value;
copyEntry++;
}
}
int HashTableRemove( struct chash * hash, const char * key )
{
int buckets = GeneralUsePrimes[hash->bucketCountPlace];
int thisHash = GetStrHash( key ) % buckets;
int multi = hash->allowMultiple;
struct chashentry * thisEntry = &hash->buckets[thisHash];
struct chashentry * overEntry = &hash->buckets[buckets];
int startentry = thisHash;
int entriesSearched = 0;
int removedEntries = 0;
//Search the list for matches, search until we have an empty spot.
while( thisEntry->key )
{
if( strcmp( thisEntry->key, key ) == 0 )
{
free( (char*)thisEntry->key );
thisEntry->key = 0;
removedEntries++;
if( !multi )
{
break;
}
}
thisEntry++;
if( thisEntry == overEntry ) thisEntry = &hash->buckets[0];
entriesSearched++;
}
if( removedEntries == 0 )
return 0;
hash->entryCount -= removedEntries;
RedoHashRange( hash, startentry, entriesSearched, entriesSearched-removedEntries );
return removedEntries;
}
int HashTableRemoveSpecific( struct chash * hash, const char * key, void * value )
{
int buckets = GeneralUsePrimes[hash->bucketCountPlace];
int thisHash = GetStrHash( key ) % buckets;
int multi = hash->allowMultiple;
struct chashentry * thisEntry = &hash->buckets[thisHash];
struct chashentry * overEntry = &hash->buckets[buckets];
int startentry = thisHash;
int entriesSearched = 0;
int removedEntries = 0;
//Search the list for matches, search until we have an empty spot.
while( thisEntry->key )
{
if( strcmp( thisEntry->key, key ) == 0 && thisEntry->value == value )
{
free( (char*)thisEntry->key );
thisEntry->key = 0;
removedEntries++;
if( !multi )
{
break;
}
}
thisEntry++;
if( thisEntry == overEntry ) thisEntry = &hash->buckets[0];
entriesSearched++;
}
if( removedEntries == 0 )
return 0;
hash->entryCount -= removedEntries;
RedoHashRange( hash, startentry, entriesSearched, entriesSearched-removedEntries );
return removedEntries;
}
void HashDestroy( struct chash * hash, int deleteKeys )
{
int buckets = GeneralUsePrimes[hash->bucketCountPlace];
int i;
if( deleteKeys )
{
struct chashentry * start = &hash->buckets[0];
for( i = 0; i < buckets; i++ )
{
free( (char*) (start++)->key );
}
}
free( hash->buckets );
free( hash );
}
void ** HashUpdateEntry( struct chash * hash, const char * key )
{
int buckets = GeneralUsePrimes[hash->bucketCountPlace];
int thisHash = GetStrHash( key ) % buckets;
struct chashentry * thisEntry = &hash->buckets[thisHash];
struct chashentry * overEntry = &hash->buckets[buckets];
while( thisEntry->key )
{
//We allow null keys.
if( !key && !thisEntry->key )
{
return &thisEntry->value;
}
if( key && thisEntry->key && strcmp( thisEntry->key, key ) == 0 )
{
return &thisEntry->value;
}
thisEntry++;
if( thisEntry == overEntry ) thisEntry = &hash->buckets[0];
}
return 0;
}
void * HashGetEntry( struct chash * hash, const char * key )
{
void ** v = HashUpdateEntry( hash, key );
if( v )
return *v;
return 0;
}
struct chashlist * HashGetAllEntries( struct chash * hash, const char * key )
{
int retreser = 3;
int buckets = GeneralUsePrimes[hash->bucketCountPlace];
int thisHash = GetStrHash( key ) % buckets;
int multi = hash->allowMultiple;
struct chashentry * thisEntry = &hash->buckets[thisHash];
struct chashentry * overEntry = &hash->buckets[buckets];
struct chashlist * ret = malloc( sizeof( struct chashlist ) + sizeof( struct chashentry ) * retreser );
ret->length = 0;
while( thisEntry->key )
{
if( strcmp( thisEntry->key, key ) == 0 )
{
ret->items[ret->length].key = thisEntry->key;
ret->items[ret->length].value = thisEntry->value;
ret->items[ret->length].hash = thisEntry->hash;
ret->length++;
if( !multi )
{
return ret;
}
if( ret->length == retreser )
{
retreser *= 2;
ret = realloc( ret, sizeof( struct chashlist ) + sizeof( struct chashentry ) * retreser );
}
}
thisEntry++;
if( thisEntry == overEntry ) thisEntry = &hash->buckets[0];
}
if( ret->length == 0 )
{
free( ret );
return 0;
}
return ret;
}
static void merge( struct chashentry ** tmpitems, int start, int middle, int end )
{
int aptr = start;
int bptr = middle;
int i = 0;
int count = end-start+1;
struct chashentry * ret[count];
if( count == 1 ) return;
while( i < count )
{
if( bptr == end+1 || ( aptr != middle && strcmp( tmpitems[aptr]->key, tmpitems[bptr]->key ) < 0 ) )
{
ret[i++] = tmpitems[aptr];
aptr++;
}
else
{
ret[i++] = tmpitems[bptr];
bptr++;
}
}
for( i = 0; i < count; i++ )
{
tmpitems[i+start] = ret[i];
}
}
static void merge_sort( struct chashentry ** tmpitems, int start, int end )
{
int middle = (end+start)/2;
if( end <= start )
return;
merge_sort( tmpitems, start, middle );
merge_sort( tmpitems, middle+1, end );
merge( tmpitems, start, middle+1, end );
}
struct chashlist * HashProduceSortedTable( struct chash * hash )
{
struct chashentry ** tmpitems = alloca( sizeof( struct chashlist * ) * hash->entryCount ); //temp list of pointers.
struct chashentry * thisEntry = &hash->buckets[0];
struct chashlist * ret = malloc( sizeof( struct chashlist ) + sizeof( struct chashentry ) * hash->entryCount );
int i;
int index = 0;
int buckets = GeneralUsePrimes[hash->bucketCountPlace];
ret->length = hash->entryCount;
if( hash->entryCount == 0 )
{
return ret;
}
//Move the table into tmp.
for( i = 0; i < buckets; i++, thisEntry++ )
{
if( !thisEntry->key ) continue;
tmpitems[index++] = thisEntry;
}
//Sort tmpitems
merge_sort( tmpitems, 0, index-1 );
for( i = 0; i < hash->entryCount; i++ )
{
ret->items[i].key = (tmpitems[i])->key;
ret->items[i].value = (tmpitems[i])->value;
ret->items[i].hash = (tmpitems[i])->hash;
}
return ret;
}