138 lines
5.5 KiB
C
138 lines
5.5 KiB
C
#ifndef HASHTABLE_H
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#define HASHTABLE_H 1
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#include <dix-config.h>
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#include <X11/Xfuncproto.h>
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#include <X11/Xdefs.h>
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#include "list.h"
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/** @brief A hashing function.
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@param[in/out] cdata Opaque data that can be passed to HtInit that will
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eventually end up here
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@param[in] ptr The data to be hashed. The size of the data, if
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needed, can be configured via a record that can be
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passed via cdata.
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@param[in] numBits The number of bits this hash needs to have in the
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resulting hash
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@return A numBits-bit hash of the data
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*/
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typedef unsigned (*HashFunc)(void * cdata, const void * ptr, int numBits);
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/** @brief A comparison function for hashed keys.
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@param[in/out] cdata Opaque data that ca be passed to Htinit that will
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eventually end up here
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@param[in] l The left side data to be compared
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@param[in] r The right side data to be compared
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@return -1 if l < r, 0 if l == r, 1 if l > r
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*/
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typedef int (*HashCompareFunc)(void * cdata, const void * l, const void * r);
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struct HashTableRec;
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typedef struct HashTableRec *HashTable;
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/** @brief A configuration for HtGenericHash */
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typedef struct {
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int keySize;
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} HtGenericHashSetupRec, *HtGenericHashSetupPtr;
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/** @brief ht_create initializes a hash table for a certain hash table
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configuration
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@param[out] ht The hash table structure to initialize
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@param[in] keySize The key size in bytes
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@param[in] dataSize The data size in bytes
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@param[in] hash The hash function to use for hashing keys
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@param[in] compare The comparison function for hashing keys
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@param[in] cdata Opaque data that will be passed to hash and
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comparison functions
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*/
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extern _X_EXPORT HashTable ht_create(int keySize,
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int dataSize,
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HashFunc hash,
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HashCompareFunc compare,
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void *cdata);
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/** @brief HtDestruct deinitializes the structure. It does not free the
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memory allocated to HashTableRec
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*/
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extern _X_EXPORT void ht_destroy(HashTable ht);
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/** @brief Adds a new key to the hash table. The key will be copied
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and a pointer to the value will be returned. The data will
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be initialized with zeroes.
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@param[in/out] ht The hash table
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@param[key] key The key. The contents of the key will be copied.
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@return On error NULL is returned, otherwise a pointer to the data
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associated with the newly inserted key.
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@note If dataSize is 0, a pointer to the end of the key may be returned
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to avoid returning NULL. Obviously the data pointed cannot be
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modified, as implied by dataSize being 0.
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*/
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extern _X_EXPORT void *ht_add(HashTable ht, const void *key);
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/** @brief Removes a key from the hash table along with its
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associated data, which will be free'd.
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*/
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extern _X_EXPORT void ht_remove(HashTable ht, const void *key);
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/** @brief Finds the associated data of a key from the hash table.
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@return If the key cannot be found, the function returns NULL.
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Otherwise it returns a pointer to the data associated
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with the key.
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@note If dataSize == 0, this function may return NULL
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even if the key has been inserted! If dataSize == NULL,
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use HtMember instead to determine if a key has been
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inserted.
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*/
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extern _X_EXPORT void *ht_find(HashTable ht, const void *key);
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/** @brief A generic hash function */
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extern _X_EXPORT unsigned ht_generic_hash(void *cdata,
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const void *ptr,
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int numBits);
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/** @brief A generic comparison function. It compares data byte-wise. */
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extern _X_EXPORT int ht_generic_compare(void *cdata,
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const void *l,
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const void *r);
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/** @brief A debugging function that dumps the distribution of the
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hash table: for each bucket, list the number of elements
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contained within. */
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extern _X_EXPORT void ht_dump_distribution(HashTable ht);
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/** @brief A debugging function that dumps the contents of the hash
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table: for each bucket, list the elements contained
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within. */
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extern _X_EXPORT void ht_dump_contents(HashTable ht,
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void (*print_key)(void *opaque, void *key),
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void (*print_value)(void *opaque, void *value),
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void* opaque);
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/** @brief A hashing function to be used for hashing resource IDs when
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used with HashTables. It makes no use of cdata, so that can
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be NULL. It uses HashXID underneath, and should HashXID be
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unable to hash the value, it switches into using the generic
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hash function. */
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extern _X_EXPORT unsigned ht_resourceid_hash(void *cdata,
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const void * data,
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int numBits);
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/** @brief A comparison function to be used for comparing resource
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IDs when used with HashTables. It makes no use of cdata,
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so that can be NULL. */
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extern _X_EXPORT int ht_resourceid_compare(void *cdata,
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const void *a,
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const void *b);
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#endif // HASHTABLE_H
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