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Diffstat (limited to 'minzip/Hash.h')
-rw-r--r-- | minzip/Hash.h | 186 |
1 files changed, 0 insertions, 186 deletions
diff --git a/minzip/Hash.h b/minzip/Hash.h deleted file mode 100644 index 8194537f3..000000000 --- a/minzip/Hash.h +++ /dev/null @@ -1,186 +0,0 @@ -/* - * Copyright 2007 The Android Open Source Project - * - * General purpose hash table, used for finding classes, methods, etc. - * - * When the number of elements reaches 3/4 of the table's capacity, the - * table will be resized. - */ -#ifndef _MINZIP_HASH -#define _MINZIP_HASH - -#include "inline_magic.h" - -#include <stdlib.h> -#include <stdbool.h> -#include <assert.h> - -/* compute the hash of an item with a specific type */ -typedef unsigned int (*HashCompute)(const void* item); - -/* - * Compare a hash entry with a "loose" item after their hash values match. - * Returns { <0, 0, >0 } depending on ordering of items (same semantics - * as strcmp()). - */ -typedef int (*HashCompareFunc)(const void* tableItem, const void* looseItem); - -/* - * This function will be used to free entries in the table. This can be - * NULL if no free is required, free(), or a custom function. - */ -typedef void (*HashFreeFunc)(void* ptr); - -/* - * Used by mzHashForeach(). - */ -typedef int (*HashForeachFunc)(void* data, void* arg); - -/* - * One entry in the hash table. "data" values are expected to be (or have - * the same characteristics as) valid pointers. In particular, a NULL - * value for "data" indicates an empty slot, and HASH_TOMBSTONE indicates - * a no-longer-used slot that must be stepped over during probing. - * - * Attempting to add a NULL or tombstone value is an error. - * - * When an entry is released, we will call (HashFreeFunc)(entry->data). - */ -typedef struct HashEntry { - unsigned int hashValue; - void* data; -} HashEntry; - -#define HASH_TOMBSTONE ((void*) 0xcbcacccd) // invalid ptr value - -/* - * Expandable hash table. - * - * This structure should be considered opaque. - */ -typedef struct HashTable { - int tableSize; /* must be power of 2 */ - int numEntries; /* current #of "live" entries */ - int numDeadEntries; /* current #of tombstone entries */ - HashEntry* pEntries; /* array on heap */ - HashFreeFunc freeFunc; -} HashTable; - -/* - * Create and initialize a HashTable structure, using "initialSize" as - * a basis for the initial capacity of the table. (The actual initial - * table size may be adjusted upward.) If you know exactly how many - * elements the table will hold, pass the result from mzHashSize() in.) - * - * Returns "false" if unable to allocate the table. - */ -HashTable* mzHashTableCreate(size_t initialSize, HashFreeFunc freeFunc); - -/* - * Compute the capacity needed for a table to hold "size" elements. Use - * this when you know ahead of time how many elements the table will hold. - * Pass this value into mzHashTableCreate() to ensure that you can add - * all elements without needing to reallocate the table. - */ -size_t mzHashSize(size_t size); - -/* - * Clear out a hash table, freeing the contents of any used entries. - */ -void mzHashTableClear(HashTable* pHashTable); - -/* - * Free a hash table. - */ -void mzHashTableFree(HashTable* pHashTable); - -/* - * Get #of entries in hash table. - */ -INLINE int mzHashTableNumEntries(HashTable* pHashTable) { - return pHashTable->numEntries; -} - -/* - * Get total size of hash table (for memory usage calculations). - */ -INLINE int mzHashTableMemUsage(HashTable* pHashTable) { - return sizeof(HashTable) + pHashTable->tableSize * sizeof(HashEntry); -} - -/* - * Look up an entry in the table, possibly adding it if it's not there. - * - * If "item" is not found, and "doAdd" is false, NULL is returned. - * Otherwise, a pointer to the found or added item is returned. (You can - * tell the difference by seeing if return value == item.) - * - * An "add" operation may cause the entire table to be reallocated. - */ -void* mzHashTableLookup(HashTable* pHashTable, unsigned int itemHash, void* item, - HashCompareFunc cmpFunc, bool doAdd); - -/* - * Remove an item from the hash table, given its "data" pointer. Does not - * invoke the "free" function; just detaches it from the table. - */ -bool mzHashTableRemove(HashTable* pHashTable, unsigned int hash, void* item); - -/* - * Execute "func" on every entry in the hash table. - * - * If "func" returns a nonzero value, terminate early and return the value. - */ -int mzHashForeach(HashTable* pHashTable, HashForeachFunc func, void* arg); - -/* - * An alternative to mzHashForeach(), using an iterator. - * - * Use like this: - * HashIter iter; - * for (mzHashIterBegin(hashTable, &iter); !mzHashIterDone(&iter); - * mzHashIterNext(&iter)) - * { - * MyData* data = (MyData*)mzHashIterData(&iter); - * } - */ -typedef struct HashIter { - void* data; - HashTable* pHashTable; - int idx; -} HashIter; -INLINE void mzHashIterNext(HashIter* pIter) { - int i = pIter->idx +1; - int lim = pIter->pHashTable->tableSize; - for ( ; i < lim; i++) { - void* data = pIter->pHashTable->pEntries[i].data; - if (data != NULL && data != HASH_TOMBSTONE) - break; - } - pIter->idx = i; -} -INLINE void mzHashIterBegin(HashTable* pHashTable, HashIter* pIter) { - pIter->pHashTable = pHashTable; - pIter->idx = -1; - mzHashIterNext(pIter); -} -INLINE bool mzHashIterDone(HashIter* pIter) { - return (pIter->idx >= pIter->pHashTable->tableSize); -} -INLINE void* mzHashIterData(HashIter* pIter) { - assert(pIter->idx >= 0 && pIter->idx < pIter->pHashTable->tableSize); - return pIter->pHashTable->pEntries[pIter->idx].data; -} - - -/* - * Evaluate hash table performance by examining the number of times we - * have to probe for an entry. - * - * The caller should lock the table beforehand. - */ -typedef unsigned int (*HashCalcFunc)(const void* item); -void mzHashTableProbeCount(HashTable* pHashTable, HashCalcFunc calcFunc, - HashCompareFunc cmpFunc); - -#endif /*_MINZIP_HASH*/ |