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hash.c
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hash.c
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/*
* Part of Very Secure FTPd
* Licence: GPL v2
* Author: Chris Evans
* hash.c
*
* Routines to handle simple hash table lookups and modifications.
*/
#include "hash.h"
#include "sysutil.h"
#include "utility.h"
#pragma CHECKED_SCOPE on
struct hash_node
{
_Array_ptr<void> p_key : byte_count(key_size);
_Array_ptr<void> p_value : byte_count(value_size);
_Ptr<struct hash_node> p_prev;
_Ptr<struct hash_node> p_next;
unsigned int key_size;
unsigned int value_size;
};
/* Internal functions */
struct hash_node **hash_get_bucket(struct hash *p_hash : itype(_Ptr<struct hash>), void* p_key : byte_count(p_hash->key_size)) : itype(_Ptr<_Ptr<struct hash_node>>);
struct hash_node *hash_get_node_by_key(struct hash *p_hash : itype(_Ptr<struct hash>), void* p_key : byte_count(p_hash->key_size)) : itype(_Ptr<struct hash_node>);
struct hash *hash_alloc(unsigned int buckets, unsigned int key_size, unsigned int value_size, hashfunc_t hash_func : itype(_Ptr<unsigned int (unsigned int, _Array_ptr<void> : byte_count(0))>)) : itype(_Ptr<struct hash>)
{
_Ptr<struct hash> p_hash = vsf_sysutil_malloc<struct hash>(sizeof(*p_hash));
p_hash->key_size = key_size;
p_hash->value_size = value_size;
p_hash->hash_func = hash_func;
_Array_ptr<_Ptr<struct hash_node>> tmp : count(buckets) = vsf_sysutil_malloc<_Ptr<struct hash_node>>(((unsigned int )sizeof(_Ptr<struct hash_node>)) * buckets);
p_hash->buckets = buckets, p_hash->p_nodes = _Dynamic_bounds_cast<_Array_ptr<_Ptr<struct hash_node>>>(tmp, count(p_hash->buckets));
vsf_sysutil_memclr<_Ptr<struct hash_node>>(p_hash->p_nodes, ((unsigned int)sizeof(_Ptr<struct hash_node>)) * p_hash->buckets);
return p_hash;
}
void*
hash_lookup_entry(struct hash *p_hash : itype(_Ptr<struct hash>), void* p_key : itype(_Array_ptr<void>) byte_count(p_hash->key_size)) : itype(_Array_ptr<void>) byte_count(p_hash->value_size)
{
_Ptr<struct hash_node> p_node = hash_get_node_by_key(p_hash, p_key);
if (!p_node)
{
return 0;
}
return _Dynamic_bounds_cast<_Array_ptr<void>>(p_node->p_value, byte_count(p_hash->value_size));
}
void
hash_add_entry(struct hash *p_hash : itype(_Ptr<struct hash>), void* p_key : itype(_Array_ptr<void>) byte_count(p_hash->key_size), void* p_value : itype(_Array_ptr<void>) byte_count(p_hash->value_size))
{
_Ptr<_Ptr<struct hash_node>> p_bucket = ((void *)0);
_Ptr<struct hash_node> p_new_node = 0;
if (hash_lookup_entry(p_hash, p_key))
{
bug("duplicate hash key");
}
p_bucket = hash_get_bucket(p_hash, p_key);
p_new_node = vsf_sysutil_malloc<struct hash_node>(sizeof(*p_new_node));
p_new_node->p_prev = 0;
p_new_node->p_next = 0;
_Array_ptr<void> new_key : byte_count(p_hash->key_size) = vsf_sysutil_malloc<void>(p_hash->key_size);
vsf_sysutil_memcpy<void>(new_key, p_key, p_hash->key_size);
p_new_node->key_size = p_hash->key_size, p_new_node->p_key = new_key;
_Array_ptr<void> new_value : byte_count(p_hash->value_size) = vsf_sysutil_malloc<void>(p_hash->value_size);
vsf_sysutil_memcpy<void>(new_value, p_value, p_hash->value_size);
p_new_node->value_size = p_hash->value_size, p_new_node->p_value = new_value;
if (!*p_bucket)
{
*p_bucket = p_new_node;
}
else
{
p_new_node->p_next = *p_bucket;
(*p_bucket)->p_prev = p_new_node;
*p_bucket = p_new_node;
}
}
void
hash_free_entry(struct hash *p_hash : itype(_Ptr<struct hash>), void* p_key : itype(_Array_ptr<void>) byte_count(p_hash->key_size))
{
_Ptr<struct hash_node> p_node = hash_get_node_by_key(p_hash, p_key);
if (!p_node)
{
bug("hash node not found");
}
vsf_sysutil_free<void>(p_node->p_key);
vsf_sysutil_free<void>(p_node->p_value);
if (p_node->p_prev)
{
p_node->p_prev->p_next = p_node->p_next;
}
else
{
_Ptr<_Ptr<struct hash_node>> p_bucket = hash_get_bucket(p_hash, p_key);
*p_bucket = p_node->p_next;
}
if (p_node->p_next)
{
p_node->p_next->p_prev = p_node->p_prev;
}
vsf_sysutil_free<struct hash_node>(p_node);
}
struct hash_node **hash_get_bucket(struct hash *p_hash : itype(_Ptr<struct hash>), void* p_key : byte_count(p_hash->key_size)) : itype(_Ptr<_Ptr<struct hash_node>>)
{
_Ptr<void> unsafe_key = 0;
_Unchecked {
unsafe_key = _Assume_bounds_cast<_Ptr<void>>(p_key);
}
unsigned int bucket = (*p_hash->hash_func)(p_hash->buckets, unsafe_key);
if (bucket >= p_hash->buckets)
{
bug("bad bucket lookup");
}
return &(p_hash->p_nodes[bucket]);
}
struct hash_node *hash_get_node_by_key(struct hash *p_hash : itype(_Ptr<struct hash>), void* p_key : byte_count(p_hash->key_size)) : itype(_Ptr<struct hash_node>)
{
_Ptr<_Ptr<struct hash_node>> p_bucket = hash_get_bucket(p_hash, p_key);
_Ptr<struct hash_node> p_node = *p_bucket;
if (!p_node)
{
return p_node;
}
while (p_node != 0 &&
({ _Array_ptr<void> tmp : byte_count(p_hash->key_size) = _Dynamic_bounds_cast<_Array_ptr<void>>(p_node->p_key, byte_count(p_hash->key_size)); vsf_sysutil_memcmp<void>(p_key, tmp , p_hash->key_size); }) != 0)
{
p_node = p_node->p_next;
}
return p_node;
}