Check in the pristine copy of ICU 4.6...

icu46/source/common/uhash.c

+/*
+******************************************************************************
+*   Copyright (C) 1997-2009, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+******************************************************************************
+*   Date        Name        Description
+*   03/22/00    aliu        Adapted from original C++ ICU Hashtable.
+*   07/06/01    aliu        Modified to support int32_t keys on
+*                           platforms with sizeof(void*) < 32.
+******************************************************************************
+*/
+
+#include "uhash.h"
+#include "unicode/ustring.h"
+#include "cstring.h"
+#include "cmemory.h"
+#include "uassert.h"
+
+/* This hashtable is implemented as a double hash.  All elements are
+ * stored in a single array with no secondary storage for collision
+ * resolution (no linked list, etc.).  When there is a hash collision
+ * (when two unequal keys have the same hashcode) we resolve this by
+ * using a secondary hash.  The secondary hash is an increment
+ * computed as a hash function (a different one) of the primary
+ * hashcode.  This increment is added to the initial hash value to
+ * obtain further slots assigned to the same hash code.  For this to
+ * work, the length of the array and the increment must be relatively
+ * prime.  The easiest way to achieve this is to have the length of
+ * the array be prime, and the increment be any value from
+ * 1..length-1.
+ *
+ * Hashcodes are 32-bit integers.  We make sure all hashcodes are
+ * non-negative by masking off the top bit.  This has two effects: (1)
+ * modulo arithmetic is simplified.  If we allowed negative hashcodes,
+ * then when we computed hashcode % length, we could get a negative
+ * result, which we would then have to adjust back into range.  It's
+ * simpler to just make hashcodes non-negative. (2) It makes it easy
+ * to check for empty vs. occupied slots in the table.  We just mark
+ * empty or deleted slots with a negative hashcode.
+ *
+ * The central function is _uhash_find().  This function looks for a
+ * slot matching the given key and hashcode.  If one is found, it
+ * returns a pointer to that slot.  If the table is full, and no match
+ * is found, it returns NULL -- in theory.  This would make the code
+ * more complicated, since all callers of _uhash_find() would then
+ * have to check for a NULL result.  To keep this from happening, we
+ * don't allow the table to fill.  When there is only one
+ * empty/deleted slot left, uhash_put() will refuse to increase the
+ * count, and fail.  This simplifies the code.  In practice, one will
+ * seldom encounter this using default UHashtables.  However, if a
+ * hashtable is set to a U_FIXED resize policy, or if memory is
+ * exhausted, then the table may fill.
+ *
+ * High and low water ratios control rehashing.  They establish levels
+ * of fullness (from 0 to 1) outside of which the data array is
+ * reallocated and repopulated.  Setting the low water ratio to zero
+ * means the table will never shrink.  Setting the high water ratio to
+ * one means the table will never grow.  The ratios should be
+ * coordinated with the ratio between successive elements of the
+ * PRIMES table, so that when the primeIndex is incremented or
+ * decremented during rehashing, it brings the ratio of count / length
+ * back into the desired range (between low and high water ratios).
+ */
+
+/********************************************************************
+ * PRIVATE Constants, Macros
+ ********************************************************************/
+
+/* This is a list of non-consecutive primes chosen such that
+ * PRIMES[i+1] ~ 2*PRIMES[i].  (Currently, the ratio ranges from 1.81
+ * to 2.18; the inverse ratio ranges from 0.459 to 0.552.)  If this
+ * ratio is changed, the low and high water ratios should also be
+ * adjusted to suit.
+ *
+ * These prime numbers were also chosen so that they are the largest
+ * prime number while being less than a power of two.
+ */
+static const int32_t PRIMES[] = {
+    13, 31, 61, 127, 251, 509, 1021, 2039, 4093, 8191, 16381, 32749,
+    65521, 131071, 262139, 524287, 1048573, 2097143, 4194301, 8388593,
+    16777213, 33554393, 67108859, 134217689, 268435399, 536870909,
+    1073741789, 2147483647 /*, 4294967291 */
+};
+
+#define PRIMES_LENGTH (sizeof(PRIMES) / sizeof(PRIMES[0]))
+#define DEFAULT_PRIME_INDEX 3
+
+/* These ratios are tuned to the PRIMES array such that a resize
+ * places the table back into the zone of non-resizing.  That is,
+ * after a call to _uhash_rehash(), a subsequent call to
+ * _uhash_rehash() should do nothing (should not churn).  This is only
+ * a potential problem with U_GROW_AND_SHRINK.
+ */
+static const float RESIZE_POLICY_RATIO_TABLE[6] = {
+    /* low, high water ratio */
+    0.0F, 0.5F, /* U_GROW: Grow on demand, do not shrink */
+    0.1F, 0.5F, /* U_GROW_AND_SHRINK: Grow and shrink on demand */
+    0.0F, 1.0F  /* U_FIXED: Never change size */
+};
+
+/*
+  Invariants for hashcode values:
+
+  * DELETED < 0
+  * EMPTY < 0
+  * Real hashes >= 0
+
+  Hashcodes may not start out this way, but internally they are
+  adjusted so that they are always positive.  We assume 32-bit
+  hashcodes; adjust these constants for other hashcode sizes.
+*/
+#define HASH_DELETED    ((int32_t) 0x80000000)
+#define HASH_EMPTY      ((int32_t) HASH_DELETED + 1)
+
+#define IS_EMPTY_OR_DELETED(x) ((x) < 0)
+
+/* This macro expects a UHashTok.pointer as its keypointer and
+   valuepointer parameters */
+#define HASH_DELETE_KEY_VALUE(hash, keypointer, valuepointer) \
+            if (hash->keyDeleter != NULL && keypointer != NULL) { \
+                (*hash->keyDeleter)(keypointer); \
+            } \
+            if (hash->valueDeleter != NULL && valuepointer != NULL) { \
+                (*hash->valueDeleter)(valuepointer); \
+            }
+
+/*
+ * Constants for hinting whether a key or value is an integer
+ * or a pointer.  If a hint bit is zero, then the associated
+ * token is assumed to be an integer.
+ */
+#define HINT_KEY_POINTER   (1)
+#define HINT_VALUE_POINTER (2)
+
+/********************************************************************
+ * PRIVATE Implementation
+ ********************************************************************/
+
+static UHashTok
+_uhash_setElement(UHashtable *hash, UHashElement* e,
+                  int32_t hashcode,
+                  UHashTok key, UHashTok value, int8_t hint) {
+
+    UHashTok oldValue = e->value;
+    if (hash->keyDeleter != NULL && e->key.pointer != NULL &&
+        e->key.pointer != key.pointer) { /* Avoid double deletion */
+        (*hash->keyDeleter)(e->key.pointer);
+    }
+    if (hash->valueDeleter != NULL) {
+        if (oldValue.pointer != NULL &&
+            oldValue.pointer != value.pointer) { /* Avoid double deletion */
+            (*hash->valueDeleter)(oldValue.pointer);
+        }
+        oldValue.pointer = NULL;
+    }
+    /* Compilers should copy the UHashTok union correctly, but even if
+     * they do, memory heap tools (e.g. BoundsChecker) can get
+     * confused when a pointer is cloaked in a union and then copied.
+     * TO ALLEVIATE THIS, we use hints (based on what API the user is
+     * calling) to copy pointers when we know the user thinks
+     * something is a pointer. */
+    if (hint & HINT_KEY_POINTER) {
+        e->key.pointer = key.pointer;
+    } else {
+        e->key = key;
+    }
+    if (hint & HINT_VALUE_POINTER) {
+        e->value.pointer = value.pointer;
+    } else {
+        e->value = value;
+    }
+    e->hashcode = hashcode;
+    return oldValue;
+}
+
+/**
+ * Assumes that the given element is not empty or deleted.
+ */
+static UHashTok
+_uhash_internalRemoveElement(UHashtable *hash, UHashElement* e) {
+    UHashTok empty;
+    U_ASSERT(!IS_EMPTY_OR_DELETED(e->hashcode));
+    --hash->count;
+    empty.pointer = NULL; empty.integer = 0;
+    return _uhash_setElement(hash, e, HASH_DELETED, empty, empty, 0);
+}
+
+static void
+_uhash_internalSetResizePolicy(UHashtable *hash, enum UHashResizePolicy policy) {
+    U_ASSERT(hash != NULL);
+    U_ASSERT(((int32_t)policy) >= 0);
+    U_ASSERT(((int32_t)policy) < 3);
+    hash->lowWaterRatio  = RESIZE_POLICY_RATIO_TABLE[policy * 2];
+    hash->highWaterRatio = RESIZE_POLICY_RATIO_TABLE[policy * 2 + 1];
+}
+
+/**
+ * Allocate internal data array of a size determined by the given
+ * prime index.  If the index is out of range it is pinned into range.
+ * If the allocation fails the status is set to
+ * U_MEMORY_ALLOCATION_ERROR and all array storage is freed.  In
+ * either case the previous array pointer is overwritten.
+ *
+ * Caller must ensure primeIndex is in range 0..PRIME_LENGTH-1.
+ */
+static void
+_uhash_allocate(UHashtable *hash,
+                int32_t primeIndex,
+                UErrorCode *status) {
+
+    UHashElement *p, *limit;
+    UHashTok emptytok;
+
+    if (U_FAILURE(*status)) return;
+
+    U_ASSERT(primeIndex >= 0 && primeIndex < PRIMES_LENGTH);
+
+    hash->primeIndex = primeIndex;
+    hash->length = PRIMES[primeIndex];
+
+    p = hash->elements = (UHashElement*)
+        uprv_malloc(sizeof(UHashElement) * hash->length);
+
+    if (hash->elements == NULL) {
+        *status = U_MEMORY_ALLOCATION_ERROR;
+        return;
+    }
+
+    emptytok.pointer = NULL; /* Only one of these two is needed */
+    emptytok.integer = 0;    /* but we don't know which one. */
+    
+    limit = p + hash->length;
+    while (p < limit) {
+        p->key = emptytok;
+        p->value = emptytok;
+        p->hashcode = HASH_EMPTY;
+        ++p;
+    }
+
+    hash->count = 0;
+    hash->lowWaterMark = (int32_t)(hash->length * hash->lowWaterRatio);
+    hash->highWaterMark = (int32_t)(hash->length * hash->highWaterRatio);
+}
+
+static UHashtable*
+_uhash_init(UHashtable *result,
+              UHashFunction *keyHash, 
+              UKeyComparator *keyComp,
+              UValueComparator *valueComp,
+              int32_t primeIndex,
+              UErrorCode *status)
+{
+    if (U_FAILURE(*status)) return NULL;
+    U_ASSERT(keyHash != NULL);
+    U_ASSERT(keyComp != NULL);
+
+    result->keyHasher       = keyHash;
+    result->keyComparator   = keyComp;
+    result->valueComparator = valueComp;
+    result->keyDeleter      = NULL;
+    result->valueDeleter    = NULL;
+    result->allocated       = FALSE;
+    _uhash_internalSetResizePolicy(result, U_GROW);
+
+    _uhash_allocate(result, primeIndex, status);
+
+    if (U_FAILURE(*status)) {
+        return NULL;
+    }
+
+    return result;
+}
+
+static UHashtable*
+_uhash_create(UHashFunction *keyHash, 
+              UKeyComparator *keyComp,
+              UValueComparator *valueComp,
+              int32_t primeIndex,
+              UErrorCode *status) {
+    UHashtable *result;
+
+    if (U_FAILURE(*status)) return NULL;
+
+    result = (UHashtable*) uprv_malloc(sizeof(UHashtable));
+    if (result == NULL) {
+        *status = U_MEMORY_ALLOCATION_ERROR;
+        return NULL;
+    }
+
+    _uhash_init(result, keyHash, keyComp, valueComp, primeIndex, status);
+    result->allocated       = TRUE;
+
+    if (U_FAILURE(*status)) {
+        uprv_free(result);
+        return NULL;
+    }
+
+    return result;
+}
+
+/**
+ * Look for a key in the table, or if no such key exists, the first
+ * empty slot matching the given hashcode.  Keys are compared using
+ * the keyComparator function.
+ *
+ * First find the start position, which is the hashcode modulo
+ * the length.  Test it to see if it is:
+ *
+ * a. identical:  First check the hash values for a quick check,
+ *    then compare keys for equality using keyComparator.
+ * b. deleted
+ * c. empty
+ *
+ * Stop if it is identical or empty, otherwise continue by adding a
+ * "jump" value (moduloing by the length again to keep it within
+ * range) and retesting.  For efficiency, there need enough empty
+ * values so that the searchs stop within a reasonable amount of time.
+ * This can be changed by changing the high/low water marks.
+ *
+ * In theory, this function can return NULL, if it is full (no empty
+ * or deleted slots) and if no matching key is found.  In practice, we
+ * prevent this elsewhere (in uhash_put) by making sure the last slot
+ * in the table is never filled.
+ *
+ * The size of the table should be prime for this algorithm to work;
+ * otherwise we are not guaranteed that the jump value (the secondary
+ * hash) is relatively prime to the table length.
+ */
+static UHashElement*
+_uhash_find(const UHashtable *hash, UHashTok key,
+            int32_t hashcode) {
+
+    int32_t firstDeleted = -1;  /* assume invalid index */
+    int32_t theIndex, startIndex;
+    int32_t jump = 0; /* lazy evaluate */
+    int32_t tableHash;
+    UHashElement *elements = hash->elements;
+
+    hashcode &= 0x7FFFFFFF; /* must be positive */
+    startIndex = theIndex = (hashcode ^ 0x4000000) % hash->length;
+
+    do {
+        tableHash = elements[theIndex].hashcode;
+        if (tableHash == hashcode) {          /* quick check */
+            if ((*hash->keyComparator)(key, elements[theIndex].key)) {
+                return &(elements[theIndex]);
+            }
+        } else if (!IS_EMPTY_OR_DELETED(tableHash)) {
+            /* We have hit a slot which contains a key-value pair,
+             * but for which the hash code does not match.  Keep
+             * looking.
+             */
+        } else if (tableHash == HASH_EMPTY) { /* empty, end o' the line */
+            break;
+        } else if (firstDeleted < 0) { /* remember first deleted */
+            firstDeleted = theIndex;
+        }
+        if (jump == 0) { /* lazy compute jump */
+            /* The jump value must be relatively prime to the table
+             * length.  As long as the length is prime, then any value
+             * 1..length-1 will be relatively prime to it.
+             */
+            jump = (hashcode % (hash->length - 1)) + 1;
+        }
+        theIndex = (theIndex + jump) % hash->length;
+    } while (theIndex != startIndex);
+
+    if (firstDeleted >= 0) {
+        theIndex = firstDeleted; /* reset if had deleted slot */
+    } else if (tableHash != HASH_EMPTY) {
+        /* We get to this point if the hashtable is full (no empty or
+         * deleted slots), and we've failed to find a match.  THIS
+         * WILL NEVER HAPPEN as long as uhash_put() makes sure that
+         * count is always < length.
+         */
+        U_ASSERT(FALSE);
+        return NULL; /* Never happens if uhash_put() behaves */
+    }
+    return &(elements[theIndex]);
+}
+
+/**
+ * Attempt to grow or shrink the data arrays in order to make the
+ * count fit between the high and low water marks.  hash_put() and
+ * hash_remove() call this method when the count exceeds the high or
+ * low water marks.  This method may do nothing, if memory allocation
+ * fails, or if the count is already in range, or if the length is
+ * already at the low or high limit.  In any case, upon return the
+ * arrays will be valid.
+ */
+static void
+_uhash_rehash(UHashtable *hash, UErrorCode *status) {
+
+    UHashElement *old = hash->elements;
+    int32_t oldLength = hash->length;
+    int32_t newPrimeIndex = hash->primeIndex;
+    int32_t i;
+
+    if (hash->count > hash->highWaterMark) {
+        if (++newPrimeIndex >= PRIMES_LENGTH) {
+            return;
+        }
+    } else if (hash->count < hash->lowWaterMark) {
+        if (--newPrimeIndex < 0) {
+            return;
+        }
+    } else {
+        return;
+    }
+
+    _uhash_allocate(hash, newPrimeIndex, status);
+
+    if (U_FAILURE(*status)) {
+        hash->elements = old;
+        hash->length = oldLength;       
+        return;
+    }
+
+    for (i = oldLength - 1; i >= 0; --i) {
+        if (!IS_EMPTY_OR_DELETED(old[i].hashcode)) {
+            UHashElement *e = _uhash_find(hash, old[i].key, old[i].hashcode);
+            U_ASSERT(e != NULL);
+            U_ASSERT(e->hashcode == HASH_EMPTY);
+            e->key = old[i].key;
+            e->value = old[i].value;
+            e->hashcode = old[i].hashcode;
+            ++hash->count;
+        }
+    }
+
+    uprv_free(old);
+}
+
+static UHashTok
+_uhash_remove(UHashtable *hash,
+              UHashTok key) {
+    /* First find the position of the key in the table.  If the object
+     * has not been removed already, remove it.  If the user wanted
+     * keys deleted, then delete it also.  We have to put a special
+     * hashcode in that position that means that something has been
+     * deleted, since when we do a find, we have to continue PAST any
+     * deleted values.
+     */
+    UHashTok result;
+    UHashElement* e = _uhash_find(hash, key, hash->keyHasher(key));
+    U_ASSERT(e != NULL);
+    result.pointer = NULL;
+    result.integer = 0;
+    if (!IS_EMPTY_OR_DELETED(e->hashcode)) {
+        result = _uhash_internalRemoveElement(hash, e);
+        if (hash->count < hash->lowWaterMark) {
+            UErrorCode status = U_ZERO_ERROR;
+            _uhash_rehash(hash, &status);
+        }
+    }
+    return result;
+}
+
+static UHashTok
+_uhash_put(UHashtable *hash,
+           UHashTok key,
+           UHashTok value,
+           int8_t hint,
+           UErrorCode *status) {
+
+    /* Put finds the position in the table for the new value.  If the
+     * key is already in the table, it is deleted, if there is a
+     * non-NULL keyDeleter.  Then the key, the hash and the value are
+     * all put at the position in their respective arrays.
+     */
+    int32_t hashcode;
+    UHashElement* e;
+    UHashTok emptytok;
+
+    if (U_FAILURE(*status)) {
+        goto err;
+    }
+    U_ASSERT(hash != NULL);
+    /* Cannot always check pointer here or iSeries sees NULL every time. */
+    if ((hint & HINT_VALUE_POINTER) && value.pointer == NULL) {
+        /* Disallow storage of NULL values, since NULL is returned by
+         * get() to indicate an absent key.  Storing NULL == removing.
+         */
+        return _uhash_remove(hash, key);
+    }
+    if (hash->count > hash->highWaterMark) {
+        _uhash_rehash(hash, status);
+        if (U_FAILURE(*status)) {
+            goto err;
+        }
+    }
+
+    hashcode = (*hash->keyHasher)(key);
+    e = _uhash_find(hash, key, hashcode);
+    U_ASSERT(e != NULL);
+
+    if (IS_EMPTY_OR_DELETED(e->hashcode)) {
+        /* Important: We must never actually fill the table up.  If we
+         * do so, then _uhash_find() will return NULL, and we'll have
+         * to check for NULL after every call to _uhash_find().  To
+         * avoid this we make sure there is always at least one empty
+         * or deleted slot in the table.  This only is a problem if we
+         * are out of memory and rehash isn't working.
+         */
+        ++hash->count;
+        if (hash->count == hash->length) {
+            /* Don't allow count to reach length */
+            --hash->count;
+            *status = U_MEMORY_ALLOCATION_ERROR;
+            goto err;
+        }
+    }
+
+    /* We must in all cases handle storage properly.  If there was an
+     * old key, then it must be deleted (if the deleter != NULL).
+     * Make hashcodes stored in table positive.
+     */
+    return _uhash_setElement(hash, e, hashcode & 0x7FFFFFFF, key, value, hint);
+
+ err:
+    /* If the deleters are non-NULL, this method adopts its key and/or
+     * value arguments, and we must be sure to delete the key and/or
+     * value in all cases, even upon failure.
+     */
+    HASH_DELETE_KEY_VALUE(hash, key.pointer, value.pointer);
+    emptytok.pointer = NULL; emptytok.integer = 0;
+    return emptytok;
+}
+
+
+/********************************************************************
+ * PUBLIC API
+ ********************************************************************/
+
+U_CAPI UHashtable* U_EXPORT2
+uhash_open(UHashFunction *keyHash, 
+           UKeyComparator *keyComp,
+           UValueComparator *valueComp,
+           UErrorCode *status) {
+
+    return _uhash_create(keyHash, keyComp, valueComp, DEFAULT_PRIME_INDEX, status);
+}
+
+U_CAPI UHashtable* U_EXPORT2
+uhash_openSize(UHashFunction *keyHash, 
+               UKeyComparator *keyComp,
+               UValueComparator *valueComp,
+               int32_t size,
+               UErrorCode *status) {
+
+    /* Find the smallest index i for which PRIMES[i] >= size. */
+    int32_t i = 0;
+    while (i<(PRIMES_LENGTH-1) && PRIMES[i]<size) {
+        ++i;
+    }
+
+    return _uhash_create(keyHash, keyComp, valueComp, i, status);
+}
+
+U_CAPI UHashtable* U_EXPORT2
+uhash_init(UHashtable *fillinResult,
+           UHashFunction *keyHash, 
+           UKeyComparator *keyComp,
+           UValueComparator *valueComp,
+           UErrorCode *status) {
+
+    return _uhash_init(fillinResult, keyHash, keyComp, valueComp, DEFAULT_PRIME_INDEX, status);
+}
+
+U_CAPI void U_EXPORT2
+uhash_close(UHashtable *hash) {
+    if (hash == NULL) {
+        return;
+    }
+    if (hash->elements != NULL) {
+        if (hash->keyDeleter != NULL || hash->valueDeleter != NULL) {
+            int32_t pos=-1;
+            UHashElement *e;
+            while ((e = (UHashElement*) uhash_nextElement(hash, &pos)) != NULL) {
+                HASH_DELETE_KEY_VALUE(hash, e->key.pointer, e->value.pointer);
+            }
+        }
+        uprv_free(hash->elements);
+        hash->elements = NULL;
+    }
+    if (hash->allocated) {
+        uprv_free(hash);
+    }
+}
+
+U_CAPI UHashFunction *U_EXPORT2
+uhash_setKeyHasher(UHashtable *hash, UHashFunction *fn) {
+    UHashFunction *result = hash->keyHasher;
+    hash->keyHasher = fn;
+    return result;
+}
+
+U_CAPI UKeyComparator *U_EXPORT2
+uhash_setKeyComparator(UHashtable *hash, UKeyComparator *fn) {
+    UKeyComparator *result = hash->keyComparator;
+    hash->keyComparator = fn;
+    return result;
+}
+U_CAPI UValueComparator *U_EXPORT2 
+uhash_setValueComparator(UHashtable *hash, UValueComparator *fn){
+    UValueComparator *result = hash->valueComparator;
+    hash->valueComparator = fn;
+    return result;
+}
+
+U_CAPI UObjectDeleter *U_EXPORT2
+uhash_setKeyDeleter(UHashtable *hash, UObjectDeleter *fn) {
+    UObjectDeleter *result = hash->keyDeleter;
+    hash->keyDeleter = fn;
+    return result;
+}
+
+U_CAPI UObjectDeleter *U_EXPORT2
+uhash_setValueDeleter(UHashtable *hash, UObjectDeleter *fn) {
+    UObjectDeleter *result = hash->valueDeleter;
+    hash->valueDeleter = fn;
+    return result;
+}
+
+U_CAPI void U_EXPORT2
+uhash_setResizePolicy(UHashtable *hash, enum UHashResizePolicy policy) {
+    UErrorCode status = U_ZERO_ERROR;
+    _uhash_internalSetResizePolicy(hash, policy);
+    hash->lowWaterMark  = (int32_t)(hash->length * hash->lowWaterRatio);
+    hash->highWaterMark = (int32_t)(hash->length * hash->highWaterRatio);    
+    _uhash_rehash(hash, &status);
+}
+
+U_CAPI int32_t U_EXPORT2
+uhash_count(const UHashtable *hash) {
+    return hash->count;
+}
+
+U_CAPI void* U_EXPORT2
+uhash_get(const UHashtable *hash,
+          const void* key) {
+    UHashTok keyholder;
+    keyholder.pointer = (void*) key;
+    return _uhash_find(hash, keyholder, hash->keyHasher(keyholder))->value.pointer;
+}
+
+U_CAPI void* U_EXPORT2
+uhash_iget(const UHashtable *hash,
+           int32_t key) {
+    UHashTok keyholder;
+    keyholder.integer = key;
+    return _uhash_find(hash, keyholder, hash->keyHasher(keyholder))->value.pointer;
+}
+
+U_CAPI int32_t U_EXPORT2
+uhash_geti(const UHashtable *hash,
+           const void* key) {
+    UHashTok keyholder;
+    keyholder.pointer = (void*) key;
+    return _uhash_find(hash, keyholder, hash->keyHasher(keyholder))->value.integer;
+}
+
+U_CAPI int32_t U_EXPORT2
+uhash_igeti(const UHashtable *hash,
+           int32_t key) {
+    UHashTok keyholder;
+    keyholder.integer = key;
+    return _uhash_find(hash, keyholder, hash->keyHasher(keyholder))->value.integer;
+}
+
+U_CAPI void* U_EXPORT2
+uhash_put(UHashtable *hash,
+          void* key,
+          void* value,
+          UErrorCode *status) {
+    UHashTok keyholder, valueholder;
+    keyholder.pointer = key;
+    valueholder.pointer = value;
+    return _uhash_put(hash, keyholder, valueholder,
+                      HINT_KEY_POINTER | HINT_VALUE_POINTER,
+                      status).pointer;
+}
+
+U_CAPI void* U_EXPORT2
+uhash_iput(UHashtable *hash,
+           int32_t key,
+           void* value,
+           UErrorCode *status) {
+    UHashTok keyholder, valueholder;
+    keyholder.integer = key;
+    valueholder.pointer = value;
+    return _uhash_put(hash, keyholder, valueholder,
+                      HINT_VALUE_POINTER,
+                      status).pointer;
+}
+
+U_CAPI int32_t U_EXPORT2
+uhash_puti(UHashtable *hash,
+           void* key,
+           int32_t value,
+           UErrorCode *status) {
+    UHashTok keyholder, valueholder;
+    keyholder.pointer = key;
+    valueholder.integer = value;
+    return _uhash_put(hash, keyholder, valueholder,
+                      HINT_KEY_POINTER,
+                      status).integer;
+}
+
+
+U_CAPI int32_t U_EXPORT2
+uhash_iputi(UHashtable *hash,
+           int32_t key,
+           int32_t value,
+           UErrorCode *status) {
+    UHashTok keyholder, valueholder;
+    keyholder.integer = key;
+    valueholder.integer = value;
+    return _uhash_put(hash, keyholder, valueholder,
+                      0, /* neither is a ptr */
+                      status).integer;
+}
+
+U_CAPI void* U_EXPORT2
+uhash_remove(UHashtable *hash,
+             const void* key) {
+    UHashTok keyholder;
+    keyholder.pointer = (void*) key;
+    return _uhash_remove(hash, keyholder).pointer;
+}
+
+U_CAPI void* U_EXPORT2
+uhash_iremove(UHashtable *hash,
+              int32_t key) {
+    UHashTok keyholder;
+    keyholder.integer = key;
+    return _uhash_remove(hash, keyholder).pointer;
+}
+
+U_CAPI int32_t U_EXPORT2
+uhash_removei(UHashtable *hash,
+              const void* key) {
+    UHashTok keyholder;
+    keyholder.pointer = (void*) key;
+    return _uhash_remove(hash, keyholder).integer;
+}
+
+U_CAPI int32_t U_EXPORT2
+uhash_iremovei(UHashtable *hash,
+               int32_t key) {
+    UHashTok keyholder;
+    keyholder.integer = key;
+    return _uhash_remove(hash, keyholder).integer;
+}
+
+U_CAPI void U_EXPORT2
+uhash_removeAll(UHashtable *hash) {
+    int32_t pos = -1;
+    const UHashElement *e;
+    U_ASSERT(hash != NULL);
+    if (hash->count != 0) {
+        while ((e = uhash_nextElement(hash, &pos)) != NULL) {
+            uhash_removeElement(hash, e);
+        }
+    }
+    U_ASSERT(hash->count == 0);
+}
+
+U_CAPI const UHashElement* U_EXPORT2
+uhash_find(const UHashtable *hash, const void* key) {
+    UHashTok keyholder;
+    const UHashElement *e;
+    keyholder.pointer = (void*) key;
+    e = _uhash_find(hash, keyholder, hash->keyHasher(keyholder));
+    return IS_EMPTY_OR_DELETED(e->hashcode) ? NULL : e;
+}
+
+U_CAPI const UHashElement* U_EXPORT2
+uhash_nextElement(const UHashtable *hash, int32_t *pos) {
+    /* Walk through the array until we find an element that is not
+     * EMPTY and not DELETED.
+     */
+    int32_t i;
+    U_ASSERT(hash != NULL);
+    for (i = *pos + 1; i < hash->length; ++i) {
+        if (!IS_EMPTY_OR_DELETED(hash->elements[i].hashcode)) {
+            *pos = i;
+            return &(hash->elements[i]);
+        }
+    }
+
+    /* No more elements */
+    return NULL;
+}
+
+U_CAPI void* U_EXPORT2
+uhash_removeElement(UHashtable *hash, const UHashElement* e) {
+    U_ASSERT(hash != NULL);
+    U_ASSERT(e != NULL);
+    if (!IS_EMPTY_OR_DELETED(e->hashcode)) {
+        UHashElement *nce = (UHashElement *)e;
+        return _uhash_internalRemoveElement(hash, nce).pointer;
+    }
+    return NULL;
+}
+
+/********************************************************************
+ * UHashTok convenience
+ ********************************************************************/
+
+/**
+ * Return a UHashTok for an integer.
+ */
+/*U_CAPI UHashTok U_EXPORT2
+uhash_toki(int32_t i) {
+    UHashTok tok;
+    tok.integer = i;
+    return tok;
+}*/
+
+/**
+ * Return a UHashTok for a pointer.
+ */
+/*U_CAPI UHashTok U_EXPORT2
+uhash_tokp(void* p) {
+    UHashTok tok;
+    tok.pointer = p;
+    return tok;
+}*/
+
+/********************************************************************
+ * PUBLIC Key Hash Functions
+ ********************************************************************/
+
+/*
+  Compute the hash by iterating sparsely over about 32 (up to 63)
+  characters spaced evenly through the string.  For each character,
+  multiply the previous hash value by a prime number and add the new
+  character in, like a linear congruential random number generator,
+  producing a pseudorandom deterministic value well distributed over
+  the output range. [LIU]
+*/
+
+#define STRING_HASH(TYPE, STR, STRLEN, DEREF) \
+    int32_t hash = 0;                         \
+    const TYPE *p = (const TYPE*) STR;        \
+    if (p != NULL) {                          \
+        int32_t len = (int32_t)(STRLEN);      \
+        int32_t inc = ((len - 32) / 32) + 1;  \
+        const TYPE *limit = p + len;          \
+        while (p<limit) {                     \
+            hash = (hash * 37) + DEREF;       \
+            p += inc;                         \
+        }                                     \
+    }                                         \
+    return hash
+
+U_CAPI int32_t U_EXPORT2
+uhash_hashUChars(const UHashTok key) {
+    STRING_HASH(UChar, key.pointer, u_strlen(p), *p);
+}
+
+/* Used by UnicodeString to compute its hashcode - Not public API. */
+U_CAPI int32_t U_EXPORT2
+uhash_hashUCharsN(const UChar *str, int32_t length) {
+    STRING_HASH(UChar, str, length, *p);
+}
+
+U_CAPI int32_t U_EXPORT2
+uhash_hashChars(const UHashTok key) {
+    STRING_HASH(uint8_t, key.pointer, uprv_strlen((char*)p), *p);
+}
+
+U_CAPI int32_t U_EXPORT2
+uhash_hashIChars(const UHashTok key) {
+    STRING_HASH(uint8_t, key.pointer, uprv_strlen((char*)p), uprv_tolower(*p));
+}
+
+U_CAPI UBool U_EXPORT2 
+uhash_equals(const UHashtable* hash1, const UHashtable* hash2){
+    
+    int32_t count1, count2, pos, i;
+
+    if(hash1==hash2){
+        return TRUE;
+    }
+
+    /*
+     * Make sure that we are comparing 2 valid hashes of the same type
+     * with valid comparison functions.
+     * Without valid comparison functions, a binary comparison
+     * of the hash values will yield random results on machines
+     * with 64-bit pointers and 32-bit integer hashes.
+     * A valueComparator is normally optional.
+     */
+    if (hash1==NULL || hash2==NULL ||
+        hash1->keyComparator != hash2->keyComparator ||
+        hash1->valueComparator != hash2->valueComparator ||
+        hash1->valueComparator == NULL)
+    {
+        /*
+        Normally we would return an error here about incompatible hash tables,
+        but we return FALSE instead.
+        */
+        return FALSE;
+    }
+
+    count1 = uhash_count(hash1);
+    count2 = uhash_count(hash2);
+    if(count1!=count2){
+        return FALSE;
+    }
+    
+    pos=-1;
+    for(i=0; i<count1; i++){
+        const UHashElement* elem1 = uhash_nextElement(hash1, &pos);
+        const UHashTok key1 = elem1->key;
+        const UHashTok val1 = elem1->value;
+        /* here the keys are not compared, instead the key form hash1 is used to fetch
+         * value from hash2. If the hashes are equal then then both hashes should 
+         * contain equal values for the same key!
+         */
+        const UHashElement* elem2 = _uhash_find(hash2, key1, hash2->keyHasher(key1));
+        const UHashTok val2 = elem2->value;
+        if(hash1->valueComparator(val1, val2)==FALSE){
+            return FALSE;
+        }
+    }
+    return TRUE;
+}
+
+/********************************************************************
+ * PUBLIC Comparator Functions
+ ********************************************************************/
+
+U_CAPI UBool U_EXPORT2
+uhash_compareUChars(const UHashTok key1, const UHashTok key2) {
+    const UChar *p1 = (const UChar*) key1.pointer;
+    const UChar *p2 = (const UChar*) key2.pointer;
+    if (p1 == p2) {
+        return TRUE;
+    }
+    if (p1 == NULL || p2 == NULL) {
+        return FALSE;
+    }
+    while (*p1 != 0 && *p1 == *p2) {
+        ++p1;
+        ++p2;
+    }
+    return (UBool)(*p1 == *p2);
+}
+
+U_CAPI UBool U_EXPORT2
+uhash_compareChars(const UHashTok key1, const UHashTok key2) {
+    const char *p1 = (const char*) key1.pointer;
+    const char *p2 = (const char*) key2.pointer;
+    if (p1 == p2) {
+        return TRUE;
+    }
+    if (p1 == NULL || p2 == NULL) {
+        return FALSE;
+    }
+    while (*p1 != 0 && *p1 == *p2) {
+        ++p1;
+        ++p2;
+    }
+    return (UBool)(*p1 == *p2);
+}
+
+U_CAPI UBool U_EXPORT2
+uhash_compareIChars(const UHashTok key1, const UHashTok key2) {
+    const char *p1 = (const char*) key1.pointer;
+    const char *p2 = (const char*) key2.pointer;
+    if (p1 == p2) {
+        return TRUE;
+    }
+    if (p1 == NULL || p2 == NULL) {
+        return FALSE;
+    }
+    while (*p1 != 0 && uprv_tolower(*p1) == uprv_tolower(*p2)) {
+        ++p1;
+        ++p2;
+    }
+    return (UBool)(*p1 == *p2);
+}
+
+/********************************************************************
+ * PUBLIC int32_t Support Functions
+ ********************************************************************/
+
+U_CAPI int32_t U_EXPORT2
+uhash_hashLong(const UHashTok key) {
+    return key.integer;
+}
+
+U_CAPI UBool U_EXPORT2
+uhash_compareLong(const UHashTok key1, const UHashTok key2) {
+    return (UBool)(key1.integer == key2.integer);
+}
+
+/********************************************************************
+ * PUBLIC Deleter Functions
+ ********************************************************************/
+
+U_CAPI void U_EXPORT2
+uhash_freeBlock(void *obj) {
+    uprv_free(obj);
+}
+