The Tor Browser: intl/icu/source/common/uhash.h@6474c204b198 (annotated)

intl/icu/source/common/uhash.h@6474c204b198 (annotated)

intl/icu/source/common/uhash.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /*
 ******************************************************************************
 *   Copyright (C) 1997-2011, 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"
 #include "cmemory.h"
 #include "uelement.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 a UHashtable.
  * The hashing and comparison functions take a pointer to a
  * UHashTok, but the deleter receives the void* pointer within it.
  */
 typedef UElement 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 equality (boolean) comparison function.
  */
 typedef UElementsAreEqual UKeyComparator;
 /**
  * A value equality (boolean) comparison function.
  */
 typedef UElementsAreEqual UValueComparator;
 /* see cmemory.h for UObjectDeleter and uprv_deleteUObject() */
 /**
  * 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;
     /* Function pointers */
     UHashFunction *keyHasher;      /* Computes hash from key.
                                    * Never null. */
     UKeyComparator *keyComparator; /* Compares keys for equality.
                                    * Never null. */
     UValueComparator *valueComparator; /* Compares the values for equality */
     UObjectDeleter *keyDeleter;    /* Deletes keys when required.
                                    * If NULL won't do anything */
     UObjectDeleter *valueDeleter;  /* Deletes values when required.
                                    * If NULL won't do anything */
     /* 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. */
     /* 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 */
     int8_t      primeIndex;     /* Index into our prime table for length.
                                  * length == PRIMES[primeIndex] */
     UBool       allocated; /* Was this UHashtable allocated? */
 };
 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,
            UValueComparator *valueComp,
            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,
                UValueComparator *valueComp,
                int32_t size,
                UErrorCode *status);
 /**
  * Initialize an existing 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_init(UHashtable *hash,
            UHashFunction *keyHash,
            UKeyComparator *keyComp,
            UValueComparator *valueComp,
            UErrorCode *status);
 /**
  * Close a UHashtable, releasing the memory used.
  * @param hash The UHashtable to close. If hash is NULL no operation is performed.
  */
 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 compare values.  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 UValueComparator *U_EXPORT2
 uhash_setValueComparator(UHashtable *hash, UValueComparator *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);
 /**
  * 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 UElement 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 UElement key);
 /********************************************************************
  * 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);
 /* Use uprv_free() itself as a deleter for any key or value allocated using uprv_malloc. */
 /**
  * Checks if the given hash tables are equal or not.
  * @param hash1
  * @param hash2
  * @return true if the hashtables are equal and false if not.
  */
 U_CAPI UBool U_EXPORT2
 uhash_equals(const UHashtable* hash1, const UHashtable* hash2);
 #endif

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intl/icu/source/common/uhash.h