Tcl_HashKeyType - tcl/tkコードリーディング

概要

ハッシュテーブルキータイプの構造体定義

定義

/*
* Flags used in Tcl_HashKeyType.
*
* TCL_HASH_KEY_RANDOMIZE_HASH -
*				There are some things, pointers for example
*				which don't hash well because they do not use
*				the lower bits. If this flag is set then the
*				hash table will attempt to rectify this by
*				randomising the bits and then using the upper
*				N bits as the index into the table.
* TCL_HASH_KEY_SYSTEM_HASH -	If this flag is set then all memory internally
*                              allocated for the hash table that is not for an
*                              entry will use the system heap.
*/

#define TCL_HASH_KEY_RANDOMIZE_HASH 0x1
#define TCL_HASH_KEY_SYSTEM_HASH    0x2

typedef unsigned int (Tcl_HashKeyProc) _ANSI_ARGS_(([[Tcl_HashTable]] *tablePtr,VOID *keyPtr));
typedef int (Tcl_CompareHashKeysProc) _ANSI_ARGS_((VOID *keyPtr, [[Tcl_HashEntry]] *hPtr));
typedef Tcl_HashEntry *(Tcl_AllocHashEntryProc) _ANSI_ARGS_(( Tcl_HashTable *tablePtr, VOID *keyPtr));
typedef void (Tcl_FreeHashEntryProc) _ANSI_ARGS_((Tcl_HashEntry *hPtr));

tcl/generic/tcl.h

メンバー

• int version; バージョン
• int flags;　フラグ、TCL_HASH_KEY_RANDOMIZE_HASH と TCL_HASH_KEY_SYSTEM_HASH が指定できる。
• Tcl_HashKeyProc *hashKeyProc;ハッシュ値を計算する関数。NULLの時は、ポインター自体がハッシュ値として使用される。
• Tcl_CompareHashKeysProc *compareKeysProc; 2つのキーを比較する。マッチするなら0、そうでないなら0以外の値を返す。この値がNULLの場合はポインターが比較される。
• Tcl_AllocHashEntryProc *allocEntryProc; 新しいエントリーの為にメモリをアロケートするために呼ばれる関数。NULLの場合はTcl_Allocが使われる。
• Tcl_FreeHashEntryProc *freeEntryProc; エントリーのメモリを解放する時に呼ばれる関数。NULLならTcl_Freeが使用される。

ソース

 /*
  * Structure definition for the methods associated with a hash table key type.
  */
 
 #define TCL_HASH_KEY_TYPE_VERSION 1
 struct Tcl_HashKeyType {
     int version;		/* Version of the table. If this structure is
 				 * extended in future then the version can be
 				 * used to distinguish between different
 				 * structures. */
     int flags;			/* Flags, see above for details. */
     Tcl_HashKeyProc *hashKeyProc;
 				/* Calculates a hash value for the key. If
 				 * this is NULL then the pointer itself is
 				 * used as a hash value. */
     Tcl_CompareHashKeysProc *compareKeysProc;
 				/* Compares two keys and returns zero if they
 				 * do not match, and non-zero if they do. If
 				 * this is NULL then the pointers are
 				 * compared. */
     Tcl_AllocHashEntryProc *allocEntryProc;
 				/* Called to allocate memory for a new entry,
 				 * i.e. if the key is a string then this could
 				 * allocate a single block which contains
 				 * enough space for both the entry and the
 				 * string. Only the key field of the allocated
 				 * Tcl_HashEntry structure needs to be filled
 				 * in. If something else needs to be done to
 				 * the key, i.e. incrementing a reference
 				 * count then that should be done by this
 				 * function. If this is NULL then Tcl_Alloc is
 				 * used to allocate enough space for a
 				 * Tcl_HashEntry and the key pointer is
 				 * assigned to key.oneWordValue. */
     Tcl_FreeHashEntryProc *freeEntryProc;
 				/* Called to free memory associated with an
 				 * entry. If something else needs to be done
 				 * to the key, i.e. decrementing a reference
 				 * count then that should be done by this
 				 * function. If this is NULL then Tcl_Free is
 				 * used to free the Tcl_HashEntry. */
 };