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/*
* multihash.c
* Copyright 2013-2014 John Lindgren
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions, and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions, and the following disclaimer in the documentation
* provided with the distribution.
*
* This software is provided "as is" and without any warranty, express or
* implied. In no event shall the authors be liable for any damages arising from
* the use of this software.
*/
#include "multihash.h"
EXPORT void HashBase::add (Node * node, unsigned hash)
{
if (! buckets)
{
buckets = new Node *[InitialSize]();
size = InitialSize;
}
unsigned b = hash & (size - 1);
node->next = buckets[b];
node->hash = hash;
buckets[b] = node;
used ++;
if (used > size)
resize (size << 1);
}
EXPORT HashBase::Node * HashBase::lookup (MatchFunc match, const void * data,
unsigned hash, NodeLoc * loc) const
{
if (! buckets)
return nullptr;
unsigned b = hash & (size - 1);
Node * * node_ptr = & buckets[b];
Node * node = * node_ptr;
while (1)
{
if (! node)
return nullptr;
if (node->hash == hash && match (node, data))
break;
node_ptr = & node->next;
node = * node_ptr;
}
if (loc)
{
loc->ptr = node_ptr;
loc->next = node->next;
}
return node;
}
EXPORT void HashBase::remove (const NodeLoc & loc)
{
* loc.ptr = loc.next;
used --;
if (used < size >> 2 && size > InitialSize)
resize (size >> 1);
}
EXPORT void HashBase::iterate (FoundFunc func, void * state)
{
for (unsigned b = 0; b < size; b ++)
{
Node * * ptr = & buckets[b];
Node * node = * ptr;
while (node)
{
Node * next = node->next;
if (func (node, state))
{
* ptr = next;
used --;
}
else
ptr = & node->next;
node = next;
}
}
if (used < size >> 2 && size > InitialSize)
resize (size >> 1);
}
void HashBase::resize (unsigned new_size)
{
Node * * new_buckets = new Node *[new_size]();
for (unsigned b1 = 0; b1 < size; b1 ++)
{
Node * node = buckets[b1];
while (node)
{
Node * next = node->next;
unsigned b2 = node->hash & (new_size - 1);
node->next = new_buckets[b2];
new_buckets[b2] = node;
node = next;
}
}
delete[] buckets;
buckets = new_buckets;
size = new_size;
}
EXPORT int MultiHash::lookup (const void * data, unsigned hash, AddFunc add,
FoundFunc found, void * state)
{
const unsigned c = (hash >> Shift) & (Channels - 1);
HashBase & channel = channels[c];
int status = 0;
tiny_lock (& locks[c]);
HashBase::NodeLoc loc;
Node * node = channel.lookup (match, data, hash, & loc);
if (node)
{
status |= Found;
if (found && found (node, state))
{
status |= Removed;
channel.remove (loc);
}
}
else if (add && (node = add (data, state)))
{
status |= Added;
channel.add (node, hash);
}
tiny_unlock (& locks[c]);
return status;
}
EXPORT void MultiHash::iterate (FoundFunc func, void * state)
{
for (TinyLock & lock : locks)
tiny_lock (& lock);
for (HashBase & channel : channels)
channel.iterate (func, state);
for (TinyLock & lock : locks)
tiny_unlock (& lock);
}
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