142 lines
4.7 KiB
C
142 lines
4.7 KiB
C
/***************************************************************************
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* Copyright 1995 Michael Veksler. mveksler@vnet.ibm.com
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***************************************************************************
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* File: generic_hash.h
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* Purpose : dynamically growing hash, may use shared or local memory.
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***************************************************************************
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*/
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#ifndef _GENERIC_HASH_H_
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#define _GENERIC_HASH_H_
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#include "wintypes.h"
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#include "shm_block.h"
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/* default hash values */
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#define HASH_LOAD 70
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#define HASH_MEM_ALLOC (HASH_PTR (*)(int size)) malloc
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#define HASH_MEM_FREE (void (*)(HASH_PTR)) free
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#define HASH_MEM_ACCESS access_local_hash
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#define HASH_REALLOC_JUMPS 1.5 /* Relative size of the new memory */
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#define MIN_HASH 13
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typedef union {
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char string[1];
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WORD words[1];
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DWORD dwords[1];
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char *ptr;
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SEGPTR segptr;
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} HASH_VAL;
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typedef struct hash_item_struct {
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DWORD key;
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HASH_VAL data;
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} HASH_ITEM;
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/* point to the hash structure */
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typedef union {
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HASH_ITEM* ptr; /* Local pointer */
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REL_PTR rel; /* IPC relative address */
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SEGPTR segptr; /* Universal (can be IPC or local) */
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} HASH_PTR;
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typedef struct hash_share_struct {
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int total_items; /* total number of items (array size) */
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int free_items; /* number of free items (excluding deleted) */
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int deleted_items; /* number of deleted items */
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int ptr_updates; /* Number of updates to `items' pointer */
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/* (of items) - used for intecepting */
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/* changes to the pointer. */
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HASH_PTR items; /* pointer to the items */
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} HASH_SHARED;
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typedef BOOL HASH_ITEM_TEST(HASH_VAL *value, HASH_VAL *seeked_data);
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/* NOTE:
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* 1. Keys 0 and -1 are reserved.
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* 2. none of these items should be accessed directly, use existing
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* functions. If they are not enough, add a new function.
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*/
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typedef struct hash_container_struct {
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int bytes_per_item;
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int maximum_load; /* in percents (0..100) default is 70 */
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int min_free_items; /* minimum free items before reallocating
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(Function of maximum_load) */
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int last_ptr_update; /* to be compared with shared.ptr_updates */
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BOOL shared_was_malloced; /* Need that to know how to destroy hash */
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/* This is an optional handler.
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* If not NULL, this function is used for distinguishing between
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* different data with the same key (key field holds integer and
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* is too short for long keys like strings).
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*/
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HASH_ITEM_TEST *is_correct_item;
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/* Handlers used for reallocating memory
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* [by allocating new data and then freeing old data]
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*/
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HASH_PTR (*allocate_mem)(int size);
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void (*free_mem)(HASH_PTR);
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/* Translator from HASH_PTR construct to a regular pointer.
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use HASH_MEM_ACCESS, if no translation is needed */
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HASH_ITEM *(*access_mem)(HASH_PTR);
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HASH_ITEM *items;
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HASH_SHARED *shared; /* Things to be on shared memory. */
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} HASH_CONTAINER;
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/********** Hash maintenance functions ***********/
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/* Attach existing & running remote (i.e. shared) hash.
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* Attach the items using the data stored in "shared"
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*/
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HASH_CONTAINER *attach_remote_hash(HASH_SHARED *shared, int bytes_per_datum,
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HASH_ITEM *(*access_mem)(HASH_PTR));
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HASH_CONTAINER *create_remote_hash(HASH_SHARED *shared,
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int bytes_per_datum,
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int total_items,
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HASH_PTR (*allocate_mem)(int size),
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HASH_ITEM *(*access_mem)(HASH_PTR));
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/* hash constructor: create brand new hash (not on shared memory) */
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HASH_CONTAINER *create_hash(int bytes_per_datum, int total_items);
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/* set the extra handlers to non default values */
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void set_hash_handlers(HASH_CONTAINER *hash,
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HASH_ITEM_TEST *is_correct_item,
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HASH_PTR (*allocate_mem)(int size),
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void (*free_mem)(HASH_PTR),
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HASH_ITEM *(*access_mem)(HASH_PTR));
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/* set extra parameters */
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void set_hash_parameters(HASH_CONTAINER *hash, int load);
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/* hash destructors */
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void destroy_hash(HASH_CONTAINER *hash);
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void detach_hash(HASH_CONTAINER *hash);
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/********** Hash usage *************/
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/* All following functions have the same format:
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* hash- the hash structure to use
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* key- used as primary means to get to the entry.
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* data- 1. a secondary key (used only if `is_correct_item' is set).
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* 2. data to store. (for hash_add_item).
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*/
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HASH_VAL *hash_locate_item(HASH_CONTAINER* hash,int key, HASH_VAL* seeked_data);
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BOOL hash_add_item(HASH_CONTAINER* hash, int key, HASH_VAL* data);
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BOOL hash_delete_item(HASH_CONTAINER* hash, int key, HASH_VAL* seeked_data);
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void *ret_null(); /* function returning null (used for */
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/* disabling memory reallocation) */
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/* access function used by local (non IPC) memory */
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HASH_ITEM *access_local_hash(HASH_PTR ptr);
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#endif /* _GENERIC_HASH_H_ */
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