/*+
−
** 2001 September 22+
−
**+
−
** The author disclaims copyright to this source code.  In place of+
−
** a legal notice, here is a blessing:+
−
**+
−
**    May you do good and not evil.+
−
**    May you find forgiveness for yourself and forgive others.+
−
**    May you share freely, never taking more than you give.+
−
**+
−
*************************************************************************+
−
** This is the header file for the generic hash-table implemenation+
−
** used in SQLite.+
−
**+
−
** $Id: hash.h 1282 2008-11-13 09:31:33Z LarsPson $+
−
*/+
−
#ifndef _SQLITE_HASH_H_+
−
#define _SQLITE_HASH_H_+
−
+
−
/* Forward declarations of structures. */+
−
typedef struct Hash Hash;+
−
typedef struct HashElem HashElem;+
−
+
−
/* A complete hash table is an instance of the following structure.+
−
** The internals of this structure are intended to be opaque -- client+
−
** code should not attempt to access or modify the fields of this structure+
−
** directly.  Change this structure only by using the routines below.+
−
** However, many of the "procedures" and "functions" for modifying and+
−
** accessing this structure are really macros, so we can't really make+
−
** this structure opaque.+
−
*/+
−
struct Hash {+
−
  char keyClass;          /* SQLITE_HASH_INT, _POINTER, _STRING, _BINARY */+
−
  char copyKey;           /* True if copy of key made on insert */+
−
  int count;              /* Number of entries in this table */+
−
  int htsize;             /* Number of buckets in the hash table */+
−
  HashElem *first;        /* The first element of the array */+
−
  struct _ht {            /* the hash table */+
−
    int count;               /* Number of entries with this hash */+
−
    HashElem *chain;         /* Pointer to first entry with this hash */+
−
  } *ht;+
−
};+
−
+
−
/* Each element in the hash table is an instance of the following +
−
** structure.  All elements are stored on a single doubly-linked list.+
−
**+
−
** Again, this structure is intended to be opaque, but it can't really+
−
** be opaque because it is used by macros.+
−
*/+
−
struct HashElem {+
−
  HashElem *next, *prev;   /* Next and previous elements in the table */+
−
  void *data;              /* Data associated with this element */+
−
  void *pKey; int nKey;    /* Key associated with this element */+
−
};+
−
+
−
/*+
−
** There are 4 different modes of operation for a hash table:+
−
**+
−
**   SQLITE_HASH_INT         nKey is used as the key and pKey is ignored.+
−
**+
−
**   SQLITE_HASH_POINTER     pKey is used as the key and nKey is ignored.+
−
**+
−
**   SQLITE_HASH_STRING      pKey points to a string that is nKey bytes long+
−
**                           (including the null-terminator, if any).  Case+
−
**                           is ignored in comparisons.+
−
**+
−
**   SQLITE_HASH_BINARY      pKey points to binary data nKey bytes long. +
−
**                           memcmp() is used to compare keys.+
−
**+
−
** A copy of the key is made for SQLITE_HASH_STRING and SQLITE_HASH_BINARY+
−
** if the copyKey parameter to HashInit is 1.  +
−
*/+
−
/* #define SQLITE_HASH_INT       1 // NOT USED */+
−
/* #define SQLITE_HASH_POINTER   2 // NOT USED */+
−
#define SQLITE_HASH_STRING    3+
−
#define SQLITE_HASH_BINARY    4+
−
+
−
/*+
−
** Access routines.  To delete, insert a NULL pointer.+
−
*/+
−
void sqlite3HashInit(Hash*, int keytype, int copyKey);+
−
void *sqlite3HashInsert(Hash*, const void *pKey, int nKey, void *pData);+
−
void *sqlite3HashFind(const Hash*, const void *pKey, int nKey);+
−
HashElem *sqlite3HashFindElem(const Hash*, const void *pKey, int nKey);+
−
void sqlite3HashClear(Hash*);+
−
+
−
/*+
−
** Macros for looping over all elements of a hash table.  The idiom is+
−
** like this:+
−
**+
−
**   Hash h;+
−
**   HashElem *p;+
−
**   ...+
−
**   for(p=sqliteHashFirst(&h); p; p=sqliteHashNext(p)){+
−
**     SomeStructure *pData = sqliteHashData(p);+
−
**     // do something with pData+
−
**   }+
−
*/+
−
#define sqliteHashFirst(H)  ((H)->first)+
−
#define sqliteHashNext(E)   ((E)->next)+
−
#define sqliteHashData(E)   ((E)->data)+
−
#define sqliteHashKey(E)    ((E)->pKey)+
−
#define sqliteHashKeysize(E) ((E)->nKey)+
−
+
−
/*+
−
** Number of entries in a hash table+
−
*/+
−
#define sqliteHashCount(H)  ((H)->count)+
−
+
−
#endif /* _SQLITE_HASH_H_ */+
−