/*

 ******************************************************************************

 *   Copyright (C) 1997-2004, 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.

 ******************************************************************************

 */

 #ifndef UHASH_H

 #define UHASH_H

 #include "unicode/utypes.h"

 /**

  * UHashtable stores key-value pairs and does moderately fast lookup

  * based on keys.  It provides a good tradeoff between access time and

  * storage space.  As elements are added to it, it grows to accomodate

  * them.  By default, the table never shrinks, even if all elements

  * are removed from it.

  *

  * Keys and values are stored as void* pointers.  These void* pointers

  * may be actual pointers to strings, objects, or any other structure

  * in memory, or they may simply be integral values cast to void*.

  * UHashtable doesn't care and manipulates them via user-supplied

  * functions.  These functions hash keys, compare keys, delete keys,

  * and delete values.  Some function pointers are optional (may be

  * NULL); others must be supplied.  Several prebuilt functions exist

  * to handle common key types.

  *

  * UHashtable ownership of keys and values is flexible, and controlled

  * by whether or not the key deleter and value deleter functions are

  * set.  If a void* key is actually a pointer to a deletable object,

  * then UHashtable can be made to delete that object by setting the

  * key deleter function pointer to a non-NULL value.  If this is done,

  * then keys passed to uhash_put() are owned by the hashtable and will

  * be deleted by it at some point, either as keys are replaced, or

  * when uhash_close() is finally called.  The same is true of values

  * and the value deleter function pointer.  Keys passed to methods

  * other than uhash_put() are never owned by the hashtable.

  *

  * NULL values are not allowed.  uhash_get() returns NULL to indicate

  * a key that is not in the table, and having a NULL value in the

  * table would generate an ambiguous result.  If a key and a NULL

  * value is passed to uhash_put(), this has the effect of doing a

  * uhash_remove() on that key.  This keeps uhash_get(), uhash_count(),

  * and uhash_nextElement() consistent with one another.

  *

  * To see everything in a hashtable, use uhash_nextElement() to

  * iterate through its contents.  Each call to this function returns a

  * UHashElement pointer.  A hash element contains a key, value, and

  * hashcode.  During iteration an element may be deleted by calling

  * uhash_removeElement(); iteration may safely continue thereafter.

  * The uhash_remove() function may also be safely called in

  * mid-iteration.  However, if uhash_put() is called during iteration

  * then the iteration will be out of sync.  Under no circumstances

  * should the UHashElement returned by uhash_nextElement be modified

  * directly.

  *

  * By default, the hashtable grows when necessary, but never shrinks,

  * even if all items are removed.  For most applications this is

  * optimal.  However, in a highly dynamic usage where memory is at a

  * premium, the table can be set to both grow and shrink by calling

  * uhash_setResizePolicy() with the policy U_GROW_AND_SHRINK.  In a

  * situation where memory is critical and the client wants a table

  * that does not grow at all, the constant U_FIXED can be used.

  */

 /********************************************************************

  * Data Structures

  ********************************************************************/

 U_CDECL_BEGIN

 /**

  * A key or value within the hashtable.  It may be either a 32-bit

  * integral value or an opaque void* pointer.  The void* pointer may

  * be smaller than 32 bits (e.g. 24 bits) or may be larger (e.g. 64

  * bits).  The hashing and comparison functions take a pointer to a

  * UHashTok, but the deleter receives the void* pointer within it.

  *

  * Because a UHashTok is the size of a native pointer or a 32-bit

  * integer, we pass it around by value.

  */

 union UHashTok {

     void*   pointer;

     int32_t integer;

 };

 typedef union UHashTok UHashTok;

 /**

  * This is a single hash element.

  */

 struct UHashElement {

     /* Reorder these elements to pack nicely if necessary */

     int32_t  hashcode;

     UHashTok value;

     UHashTok key;

 };

 typedef struct UHashElement UHashElement;

 /**

  * A hashing function.

  * @param key A key stored in a hashtable

  * @return A NON-NEGATIVE hash code for parm.

  */

 typedef int32_t U_CALLCONV UHashFunction(const UHashTok key);

 /**

  * A key comparison function.

  * @param key1 A key stored in a hashtable

  * @param key2 A key stored in a hashtable

  * @return TRUE if the two keys are equal.

  */

 typedef UBool U_CALLCONV UKeyComparator(const UHashTok key1,

                                         const UHashTok key2);

 /**

  * A function called by <TT>uhash_remove</TT>,

  * <TT>uhash_close</TT>, or <TT>uhash_put</TT> to delete

  * an existing key or value.

  * @param obj A key or value stored in a hashtable

  */

 typedef void U_CALLCONV UObjectDeleter(void* obj);

 /**

  * This specifies whether or not, and how, the hastable resizes itself.

  * See uhash_setResizePolicy().

  */

 enum UHashResizePolicy {

     U_GROW,            /* Grow on demand, do not shrink */

     U_GROW_AND_SHRINK, /* Grow and shrink on demand */

     U_FIXED            /* Never change size */

 };

 /**

  * The UHashtable struct.  Clients should treat this as an opaque data

  * type and manipulate it only through the uhash_... API.

  */

 struct UHashtable {

     /* Main key-value pair storage array */

     UHashElement *elements;

     /* Size parameters */

     int32_t     count;      /* The number of key-value pairs in this table.

                              * 0 <= count <= length.  In practice we

                              * never let count == length (see code). */

     int32_t     length;     /* The physical size of the arrays hashes, keys

                              * and values.  Must be prime. */

     int32_t     primeIndex;     /* Index into our prime table for length.

                                  * length == PRIMES[primeIndex] */

     /* Rehashing thresholds */

     int32_t     highWaterMark;  /* If count > highWaterMark, rehash */

     int32_t     lowWaterMark;   /* If count < lowWaterMark, rehash */

     float       highWaterRatio; /* 0..1; high water as a fraction of length */

     float       lowWaterRatio;  /* 0..1; low water as a fraction of length */

     /* Function pointers */

     UHashFunction *keyHasher;      /* Computes hash from key.

                                    * Never null. */

     UKeyComparator *keyComparator; /* Compares keys for equality.

                                    * Never null. */

     UObjectDeleter *keyDeleter;    /* Deletes keys when required.

                                    * If NULL won't do anything */

     UObjectDeleter *valueDeleter;  /* Deletes values when required.

                                    * If NULL won't do anything */

 };

 typedef struct UHashtable UHashtable;

 U_CDECL_END

 /********************************************************************

  * API

  ********************************************************************/

 /**

  * Initialize a new UHashtable.

  * @param keyHash A pointer to the key hashing function.  Must not be

  * NULL.

  * @param keyComp A pointer to the function that compares keys.  Must

  * not be NULL.

  * @param status A pointer to an UErrorCode to receive any errors.

  * @return A pointer to a UHashtable, or 0 if an error occurred.

  * @see uhash_openSize

  */

 U_CAPI UHashtable* U_EXPORT2 

 uhash_open(UHashFunction *keyHash,

            UKeyComparator *keyComp,

            UErrorCode *status);

 /**

  * Initialize a new UHashtable with a given initial size.

  * @param keyHash A pointer to the key hashing function.  Must not be

  * NULL.

  * @param keyComp A pointer to the function that compares keys.  Must

  * not be NULL.

  * @param size The initial capacity of this hash table.

  * @param status A pointer to an UErrorCode to receive any errors.

  * @return A pointer to a UHashtable, or 0 if an error occurred.

  * @see uhash_open

  */

 U_CAPI UHashtable* U_EXPORT2 

 uhash_openSize(UHashFunction *keyHash,

                UKeyComparator *keyComp,

                int32_t size,

                UErrorCode *status);

 /**

  * Close a UHashtable, releasing the memory used.

  * @param hash The UHashtable to close.

  */

 U_CAPI void U_EXPORT2 

 uhash_close(UHashtable *hash);

 /**

  * Set the function used to hash keys.

  * @param hash The UHashtable to set

  * @param fn the function to be used hash keys; must not be NULL

  * @return the previous key hasher; non-NULL

  */

 U_CAPI UHashFunction *U_EXPORT2 

 uhash_setKeyHasher(UHashtable *hash, UHashFunction *fn);

 /**

  * Set the function used to compare keys.  The default comparison is a

  * void* pointer comparison.

  * @param hash The UHashtable to set

  * @param fn the function to be used compare keys; must not be NULL

  * @return the previous key comparator; non-NULL

  */

 U_CAPI UKeyComparator *U_EXPORT2 

 uhash_setKeyComparator(UHashtable *hash, UKeyComparator *fn);

 /**

  * Set the function used to delete keys.  If this function pointer is

  * NULL, this hashtable does not delete keys.  If it is non-NULL, this

  * hashtable does delete keys.  This function should be set once

  * before any elements are added to the hashtable and should not be

  * changed thereafter.

  * @param hash The UHashtable to set

  * @param fn the function to be used delete keys, or NULL

  * @return the previous key deleter; may be NULL

  */

 U_CAPI UObjectDeleter *U_EXPORT2 

 uhash_setKeyDeleter(UHashtable *hash, UObjectDeleter *fn);

 /**

  * Set the function used to delete values.  If this function pointer

  * is NULL, this hashtable does not delete values.  If it is non-NULL,

  * this hashtable does delete values.  This function should be set

  * once before any elements are added to the hashtable and should not

  * be changed thereafter.

  * @param hash The UHashtable to set

  * @param fn the function to be used delete values, or NULL

  * @return the previous value deleter; may be NULL

  */

 U_CAPI UObjectDeleter *U_EXPORT2 

 uhash_setValueDeleter(UHashtable *hash, UObjectDeleter *fn);

 /**

  * Specify whether or not, and how, the hastable resizes itself.

  * By default, tables grow but do not shrink (policy U_GROW).

  * See enum UHashResizePolicy.

  * @param hash The UHashtable to set

  * @param policy The way the hashtable resizes itself, {U_GROW, U_GROW_AND_SHRINK, U_FIXED}

  */

 U_CAPI void U_EXPORT2 

 uhash_setResizePolicy(UHashtable *hash, enum UHashResizePolicy policy);

 /**

  * Get the number of key-value pairs stored in a UHashtable.

  * @param hash The UHashtable to query.

  * @return The number of key-value pairs stored in hash.

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_count(const UHashtable *hash);

 /**

  * Put a (key=pointer, value=pointer) item in a UHashtable.  If the

  * keyDeleter is non-NULL, then the hashtable owns 'key' after this

  * call.  If the valueDeleter is non-NULL, then the hashtable owns

  * 'value' after this call.  Storing a NULL value is the same as

  * calling uhash_remove().

  * @param hash The target UHashtable.

  * @param key The key to store.

  * @param value The value to store, may be NULL (see above).

  * @param status A pointer to an UErrorCode to receive any errors.

  * @return The previous value, or NULL if none.

  * @see uhash_get

  */

 U_CAPI void* U_EXPORT2 

 uhash_put(UHashtable *hash,

           void *key,

           void *value,

           UErrorCode *status);

 /**

  * Put a (key=integer, value=pointer) item in a UHashtable.

  * keyDeleter must be NULL.  If the valueDeleter is non-NULL, then the

  * hashtable owns 'value' after this call.  Storing a NULL value is

  * the same as calling uhash_remove().

  * @param hash The target UHashtable.

  * @param key The integer key to store.

  * @param value The value to store, may be NULL (see above).

  * @param status A pointer to an UErrorCode to receive any errors.

  * @return The previous value, or NULL if none.

  * @see uhash_get

  */

 U_CAPI void* U_EXPORT2 

 uhash_iput(UHashtable *hash,

            int32_t key,

            void* value,

            UErrorCode *status);

 /**

  * Put a (key=pointer, value=integer) item in a UHashtable.  If the

  * keyDeleter is non-NULL, then the hashtable owns 'key' after this

  * call.  valueDeleter must be NULL.  Storing a 0 value is the same as

  * calling uhash_remove().

  * @param hash The target UHashtable.

  * @param key The key to store.

  * @param value The integer value to store.

  * @param status A pointer to an UErrorCode to receive any errors.

  * @return The previous value, or 0 if none.

  * @see uhash_get

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_puti(UHashtable *hash,

            void* key,

            int32_t value,

            UErrorCode *status);

 /**

  * Put a (key=integer, value=integer) item in a UHashtable.  If the

  * keyDeleter is non-NULL, then the hashtable owns 'key' after this

  * call.  valueDeleter must be NULL.  Storing a 0 value is the same as

  * calling uhash_remove().

  * @param hash The target UHashtable.

  * @param key The key to store.

  * @param value The integer value to store.

  * @param status A pointer to an UErrorCode to receive any errors.

  * @return The previous value, or 0 if none.

  * @see uhash_get

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_iputi(UHashtable *hash,

            int32_t key,

            int32_t value,

            UErrorCode *status);

 /**

  * Retrieve a pointer value from a UHashtable using a pointer key,

  * as previously stored by uhash_put().

  * @param hash The target UHashtable.

  * @param key A pointer key stored in a hashtable

  * @return The requested item, or NULL if not found.

  */

 U_CAPI void* U_EXPORT2 

 uhash_get(const UHashtable *hash, 

           const void *key);

 /**

  * Retrieve a pointer value from a UHashtable using a integer key,

  * as previously stored by uhash_iput().

  * @param hash The target UHashtable.

  * @param key An integer key stored in a hashtable

  * @return The requested item, or NULL if not found.

  */

 U_CAPI void* U_EXPORT2 

 uhash_iget(const UHashtable *hash,

            int32_t key);

 /**

  * Retrieve an integer value from a UHashtable using a pointer key,

  * as previously stored by uhash_puti().

  * @param hash The target UHashtable.

  * @param key A pointer key stored in a hashtable

  * @return The requested item, or 0 if not found.

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_geti(const UHashtable *hash,

            const void* key);

 /**

  * Retrieve an integer value from a UHashtable using an integer key,

  * as previously stored by uhash_iputi().

  * @param hash The target UHashtable.

  * @param key An integer key stored in a hashtable

  * @return The requested item, or 0 if not found.

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_igeti(const UHashtable *hash,

            int32_t key);

 /**

  * Remove an item from a UHashtable stored by uhash_put().

  * @param hash The target UHashtable.

  * @param key A key stored in a hashtable

  * @return The item removed, or NULL if not found.

  */

 U_CAPI void* U_EXPORT2 

 uhash_remove(UHashtable *hash,

              const void *key);

 /**

  * Remove an item from a UHashtable stored by uhash_iput().

  * @param hash The target UHashtable.

  * @param key An integer key stored in a hashtable

  * @return The item removed, or NULL if not found.

  */

 U_CAPI void* U_EXPORT2 

 uhash_iremove(UHashtable *hash,

               int32_t key);

 /**

  * Remove an item from a UHashtable stored by uhash_puti().

  * @param hash The target UHashtable.

  * @param key An key stored in a hashtable

  * @return The item removed, or 0 if not found.

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_removei(UHashtable *hash,

               const void* key);

 /**

  * Remove an item from a UHashtable stored by uhash_iputi().

  * @param hash The target UHashtable.

  * @param key An integer key stored in a hashtable

  * @return The item removed, or 0 if not found.

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_iremovei(UHashtable *hash,

                int32_t key);

 /**

  * Remove all items from a UHashtable.

  * @param hash The target UHashtable.

  */

 U_CAPI void U_EXPORT2 

 uhash_removeAll(UHashtable *hash);

 /**

  * Locate an element of a UHashtable.  The caller must not modify the

  * returned object.  The primary use of this function is to obtain the

  * stored key when it may not be identical to the search key.  For

  * example, if the compare function is a case-insensitive string

  * compare, then the hash key may be desired in order to obtain the

  * canonical case corresponding to a search key.

  * @param hash The target UHashtable.

  * @param key A key stored in a hashtable

  * @return a hash element, or NULL if the key is not found.

  */

 U_CAPI const UHashElement* U_EXPORT2 

 uhash_find(const UHashtable *hash, const void* key);

 /**

  * Iterate through the elements of a UHashtable.  The caller must not

  * modify the returned object.  However, uhash_removeElement() may be

  * called during iteration to remove an element from the table.

  * Iteration may safely be resumed afterwards.  If uhash_put() is

  * called during iteration the iteration will then be out of sync and

  * should be restarted.

  * @param hash The target UHashtable.

  * @param pos This should be set to -1 initially, and left untouched

  * thereafter.

  * @return a hash element, or NULL if no further key-value pairs

  * exist in the table.

  */

 U_CAPI const UHashElement* U_EXPORT2 

 uhash_nextElement(const UHashtable *hash,

                   int32_t *pos);

 /**

  * Remove an element, returned by uhash_nextElement(), from the table.

  * Iteration may be safely continued afterwards.

  * @param hash The hashtable

  * @param e The element, returned by uhash_nextElement(), to remove.

  * Must not be NULL.  Must not be an empty or deleted element (as long

  * as this was returned by uhash_nextElement() it will not be empty or

  * deleted).  Note: Although this parameter is const, it will be

  * modified.

  * @return the value that was removed.

  */

 U_CAPI void* U_EXPORT2 

 uhash_removeElement(UHashtable *hash, const UHashElement* e);

 /********************************************************************

  * UHashTok convenience

  ********************************************************************/

 /**

  * Return a UHashTok for an integer.

  * @param i The given integer

  * @return a UHashTok for an integer.

  */

 /*U_CAPI UHashTok U_EXPORT2 

 uhash_toki(int32_t i);*/

 /**

  * Return a UHashTok for a pointer.

  * @param p The given pointer

  * @return a UHashTok for a pointer.

  */

 /*U_CAPI UHashTok U_EXPORT2 

 uhash_tokp(void* p);*/

 /********************************************************************

  * UChar* and char* Support Functions

  ********************************************************************/

 /**

  * Generate a hash code for a null-terminated UChar* string.  If the

  * string is not null-terminated do not use this function.  Use

  * together with uhash_compareUChars.

  * @param key The string (const UChar*) to hash.

  * @return A hash code for the key.

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_hashUChars(const UHashTok key);

 /**

  * Generate a hash code for a null-terminated char* string.  If the

  * string is not null-terminated do not use this function.  Use

  * together with uhash_compareChars.

  * @param key The string (const char*) to hash.

  * @return A hash code for the key.

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_hashChars(const UHashTok key);

 /* Used by UnicodeString to compute its hashcode - Not public API. */

 U_CAPI int32_t U_EXPORT2 

 uhash_hashUCharsN(const UChar *key, int32_t length);

 /**

  * Generate a case-insensitive hash code for a null-terminated char*

  * string.  If the string is not null-terminated do not use this

  * function.  Use together with uhash_compareIChars.

  * @param key The string (const char*) to hash.

  * @return A hash code for the key.

  */

 U_CAPI int32_t U_EXPORT2

 uhash_hashIChars(const UHashTok key);

 /**

  * Comparator for null-terminated UChar* strings.  Use together with

  * uhash_hashUChars.

  * @param key1 The string for comparison

  * @param key2 The string for comparison

  * @return true if key1 and key2 are equal, return false otherwise.

  */

 U_CAPI UBool U_EXPORT2 

 uhash_compareUChars(const UHashTok key1, const UHashTok key2);

 /**

  * Comparator for null-terminated char* strings.  Use together with

  * uhash_hashChars.

  * @param key1 The string for comparison

  * @param key2 The string for comparison

  * @return true if key1 and key2 are equal, return false otherwise.

  */

 U_CAPI UBool U_EXPORT2 

 uhash_compareChars(const UHashTok key1, const UHashTok key2);

 /**

  * Case-insensitive comparator for null-terminated char* strings.  Use

  * together with uhash_hashIChars.

  * @param key1 The string for comparison

  * @param key2 The string for comparison

  * @return true if key1 and key2 are equal, return false otherwise.

  */

 U_CAPI UBool U_EXPORT2 

 uhash_compareIChars(const UHashTok key1, const UHashTok key2);

 /********************************************************************

  * UnicodeString Support Functions

  ********************************************************************/

 /**

  * Hash function for UnicodeString* keys.

  * @param key The string (const char*) to hash.

  * @return A hash code for the key.

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_hashUnicodeString(const UHashTok key);

 /**

  * Hash function for UnicodeString* keys (case insensitive).

  * Make sure to use together with uhash_compareCaselessUnicodeString.

  * @param key The string (const char*) to hash.

  * @return A hash code for the key.

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_hashCaselessUnicodeString(const UHashTok key);

 /**

  * Comparator function for UnicodeString* keys.

  * @param key1 The string for comparison

  * @param key2 The string for comparison

  * @return true if key1 and key2 are equal, return false otherwise.

  */

 U_CAPI UBool U_EXPORT2 

 uhash_compareUnicodeString(const UHashTok key1, const UHashTok key2);

 /**

  * Comparator function for UnicodeString* keys (case insensitive).

  * Make sure to use together with uhash_hashCaselessUnicodeString.

  * @param key1 The string for comparison

  * @param key2 The string for comparison

  * @return true if key1 and key2 are equal, return false otherwise.

  */

 U_CAPI UBool U_EXPORT2 

 uhash_compareCaselessUnicodeString(const UHashTok key1, const UHashTok key2);

 /**

  * Deleter function for UnicodeString* keys or values.

  * @param obj The object to be deleted

  */

 U_CAPI void U_EXPORT2 

 uhash_deleteUnicodeString(void *obj);

 /********************************************************************

  * int32_t Support Functions

  ********************************************************************/

 /**

  * Hash function for 32-bit integer keys.

  * @param key The string (const char*) to hash.

  * @return A hash code for the key.

  */

 U_CAPI int32_t U_EXPORT2 

 uhash_hashLong(const UHashTok key);

 /**

  * Comparator function for 32-bit integer keys.

  * @param key1 The integer for comparison

  * @param Key2 The integer for comparison

  * @return true if key1 and key2 are equal, return false otherwise

  */

 U_CAPI UBool U_EXPORT2 

 uhash_compareLong(const UHashTok key1, const UHashTok key2);

 /********************************************************************

  * Other Support Functions

  ********************************************************************/

 /**

  * Deleter for Hashtable objects.

  * @param obj The object to be deleted

  */

 U_CAPI void U_EXPORT2 

 uhash_deleteHashtable(void *obj);

 /**

  * Deleter for UVector objects.

  * @param obj The object to be deleted

  */

 U_CAPI void U_EXPORT2 

 uhash_deleteUVector(void *obj);

 /**

  * Deleter for any key or value allocated using uprv_malloc.  Calls

  * uprv_free.

  * @param obj The object to be deleted

  */

 U_CAPI void U_EXPORT2 

 uhash_freeBlock(void *obj);

 #endif