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#include <ft2build.h>
#include FT_TYPES_H
#include FT_INTERNAL_HASH_H
#include FT_INTERNAL_MEMORY_H
#include FT_INTERNAL_DEBUG_H
#define FT_HASH_MAX_LOAD 2
#define FT_HASH_MIN_LOAD 1
#define FT_HASH_SUB_LOAD (FT_HASH_MAX_LOAD-FT_HASH_MIN_LOAD)
/* this one _must_ be a power of 2 !! */
#define FT_HASH_INITIAL_SIZE 8
FT_BASE_DEF( void )
ft_hash_done( FT_Hash table,
FT_Hash_ForeachFunc node_func,
const FT_Pointer node_data )
{
if ( table )
{
FT_Memory memory = table->memory;
if ( node_func )
ft_hash_foreach( table, node_func, node_data );
FT_FREE( table->buckets );
table->p = 0;
table->mask = 0;
table->slack = 0;
table->node_equal = NULL;
}
}
FT_BASE_DEF( FT_UInt )
ft_hash_get_size( FT_Hash table )
{
FT_UInt result = 0;
if ( table )
result = (table->p + table->mask + 1)*FT_HASH_MAX_LOAD - table->slack;
return result;
}
FT_BASE_DEF( FT_Error )
ft_hash_init( FT_Hash table,
FT_Hash_EqualFunc equal,
FT_Memory memory )
{
FT_Error error;
table->memory = memory;
table->p = 0;
table->mask = FT_HASH_INITIAL_SIZE-1;
table->slack = FT_HASH_INITIAL_SIZE*FT_HASH_MAX_LOAD;
table->node_equal = equal;
(void)FT_NEW_ARRAY( table->buckets, FT_HASH_INITIAL_SIZE*2 );
return error;
}
FT_BASE_DEF( void )
ft_hash_foreach( FT_Hash table,
FT_Hash_ForeachFunc foreach_func,
const FT_Pointer foreach_data )
{
FT_UInt count = table->p + table->mask + 1;
FT_HashNode* pnode = table->buckets;
FT_HashNode node, next;
for ( ; count > 0; count--, pnode++ )
{
node = *pnode;
while ( node )
{
next = node->link;
foreach_func( node, foreach_data );
node = next;
}
}
}
FT_BASE_DEF( FT_HashLookup )
ft_hash_lookup( FT_Hash table,
FT_HashNode keynode )
{
FT_UInt index;
FT_UInt32 hash = keynode->hash;
FT_HashNode node, *pnode;
index = (FT_UInt)(hash & table->mask);
if ( index < table->p )
index = (FT_UInt)(hash & (2*table->mask+1));
pnode = &table->buckets[index];
for (;;)
{
node = *pnode;
if ( node == NULL )
break;
if ( node->hash == hash && table->node_equal( node, keynode ) )
break;
pnode = &node->link;
}
return pnode;
}
FT_BASE_DEF( FT_Error )
ft_hash_add( FT_Hash table,
FT_HashLookup lookup,
FT_HashNode new_node )
{
FT_Error error = 0;
/* add it to the hash table */
new_node->link = *lookup;
*lookup = new_node;
if ( --table->slack < 0 )
{
FT_UInt p = table->p;
FT_UInt mask = table->mask;
FT_HashNode new_list, node, *pnode;
/* split a single bucket */
new_list = NULL;
pnode = table->buckets + p;
for (;;)
{
node = *pnode;
if ( node == NULL )
break;
if ( node->hash & mask )
{
*pnode = node->link;
node->link = new_list;
new_list = node;
}
else
pnode = &node->link;
}
table->buckets[ p + mask + 1 ] = new_list;
table->slack += FT_HASH_MAX_LOAD;
if ( p >= mask )
{
FT_Memory memory = table->memory;
if (FT_RENEW_ARRAY( table->buckets, (mask+1)*2, (mask+1)*4 ))
goto Exit;
table->mask = 2*mask + 1;
table->p = 0;
}
else
table->p = p + 1;
}
Exit:
return error;
}
FT_BASE_DEF( FT_Error )
ft_hash_remove( FT_Hash table,
FT_HashLookup lookup )
{
FT_HashNode node;
FT_UInt num_buckets;
FT_Error error = 0;
FT_ASSERT( pnode != NULL && node != NULL );
node = *lookup;
*lookup = node->link;
node->link = NULL;
num_buckets = ( table->p + table->mask + 1) ;
if ( ++ table->slack > (FT_Long)num_buckets*FT_HASH_SUB_LOAD )
{
FT_UInt p = table->p;
FT_UInt mask = table->mask;
FT_UInt old_index = p + mask;
FT_HashNode* pnode;
FT_HashNode* pold;
if ( old_index < FT_HASH_INITIAL_SIZE )
goto Exit;
if ( p == 0 )
{
FT_Memory memory = table->memory;
table->mask >>= 1;
p = table->mask;
if ( FT_RENEW_ARRAY( table->buckets, (mask+1)*2, (mask+1) ) )
{
/* this should never happen normally, but who knows :-) */
/* we need to re-inject the node in the hash table before */
/* returning there, since it's safer */
pnode = table->buckets;
node->link = *pnode;
*pnode = node;
goto Exit;
}
}
else
p--;
pnode = table->buckets + p;
while ( *pnode )
pnode = &(*pnode)->link;
pold = table->buckets + old_index;
*pnode = *pold;
*pold = NULL;
table->slack -= FT_HASH_MAX_LOAD;
table->p = p;
}
Exit:
return error;
}
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