persistentstorage/sqlite3api/SQLite/fts2_hash.h
changeset 0 08ec8eefde2f
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/persistentstorage/sqlite3api/SQLite/fts2_hash.h	Fri Jan 22 11:06:30 2010 +0200
@@ -0,0 +1,110 @@
+/*
+** 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.  We've modified it slightly to serve as a standalone
+** hash table implementation for the full-text indexing module.
+**
+*/
+#ifndef _FTS2_HASH_H_
+#define _FTS2_HASH_H_
+
+/* Forward declarations of structures. */
+typedef struct fts2Hash fts2Hash;
+typedef struct fts2HashElem fts2HashElem;
+
+/* 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 fts2Hash {
+  char keyClass;          /* HASH_INT, _POINTER, _STRING, _BINARY */
+  char copyKey;           /* True if copy of key made on insert */
+  int count;              /* Number of entries in this table */
+  fts2HashElem *first;    /* The first element of the array */
+  int htsize;             /* Number of buckets in the hash table */
+  struct _fts2ht {        /* the hash table */
+    int count;               /* Number of entries with this hash */
+    fts2HashElem *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 fts2HashElem {
+  fts2HashElem *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 2 different modes of operation for a hash table:
+**
+**   FTS2_HASH_STRING        pKey points to a string that is nKey bytes long
+**                           (including the null-terminator, if any).  Case
+**                           is respected in comparisons.
+**
+**   FTS2_HASH_BINARY        pKey points to binary data nKey bytes long. 
+**                           memcmp() is used to compare keys.
+**
+** A copy of the key is made if the copyKey parameter to fts2HashInit is 1.  
+*/
+#define FTS2_HASH_STRING    1
+#define FTS2_HASH_BINARY    2
+
+/*
+** Access routines.  To delete, insert a NULL pointer.
+*/
+void sqlite3Fts2HashInit(fts2Hash*, int keytype, int copyKey);
+void *sqlite3Fts2HashInsert(fts2Hash*, const void *pKey, int nKey, void *pData);
+void *sqlite3Fts2HashFind(const fts2Hash*, const void *pKey, int nKey);
+void sqlite3Fts2HashClear(fts2Hash*);
+
+/*
+** Shorthand for the functions above
+*/
+#define fts2HashInit   sqlite3Fts2HashInit
+#define fts2HashInsert sqlite3Fts2HashInsert
+#define fts2HashFind   sqlite3Fts2HashFind
+#define fts2HashClear  sqlite3Fts2HashClear
+
+/*
+** Macros for looping over all elements of a hash table.  The idiom is
+** like this:
+**
+**   fts2Hash h;
+**   fts2HashElem *p;
+**   ...
+**   for(p=fts2HashFirst(&h); p; p=fts2HashNext(p)){
+**     SomeStructure *pData = fts2HashData(p);
+**     // do something with pData
+**   }
+*/
+#define fts2HashFirst(H)  ((H)->first)
+#define fts2HashNext(E)   ((E)->next)
+#define fts2HashData(E)   ((E)->data)
+#define fts2HashKey(E)    ((E)->pKey)
+#define fts2HashKeysize(E) ((E)->nKey)
+
+/*
+** Number of entries in a hash table
+*/
+#define fts2HashCount(H)  ((H)->count)
+
+#endif /* _FTS2_HASH_H_ */