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authorHans-Christoph Steiner <hans@eds.org>2012-03-30 20:42:12 -0400
committerHans-Christoph Steiner <hans@eds.org>2012-03-30 20:42:12 -0400
commit7bb481fda9ecb134804b49c2ce77ca28f7eea583 (patch)
tree31b520b9914d3e2453968abe375f2c102772c3dc /ext/fts1/fts1_hash.h
Imported Upstream version 2.0.3
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+/*
+** 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 _FTS1_HASH_H_
+#define _FTS1_HASH_H_
+
+/* Forward declarations of structures. */
+typedef struct fts1Hash fts1Hash;
+typedef struct fts1HashElem fts1HashElem;
+
+/* 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 fts1Hash {
+ 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 */
+ fts1HashElem *first; /* The first element of the array */
+ void *(*xMalloc)(int); /* malloc() function to use */
+ void (*xFree)(void *); /* free() function to use */
+ int htsize; /* Number of buckets in the hash table */
+ struct _fts1ht { /* the hash table */
+ int count; /* Number of entries with this hash */
+ fts1HashElem *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 fts1HashElem {
+ fts1HashElem *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:
+**
+** FTS1_HASH_STRING pKey points to a string that is nKey bytes long
+** (including the null-terminator, if any). Case
+** is respected in comparisons.
+**
+** FTS1_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 fts1HashInit is 1.
+*/
+#define FTS1_HASH_STRING 1
+#define FTS1_HASH_BINARY 2
+
+/*
+** Access routines. To delete, insert a NULL pointer.
+*/
+void sqlite3Fts1HashInit(fts1Hash*, int keytype, int copyKey);
+void *sqlite3Fts1HashInsert(fts1Hash*, const void *pKey, int nKey, void *pData);
+void *sqlite3Fts1HashFind(const fts1Hash*, const void *pKey, int nKey);
+void sqlite3Fts1HashClear(fts1Hash*);
+
+/*
+** Shorthand for the functions above
+*/
+#define fts1HashInit sqlite3Fts1HashInit
+#define fts1HashInsert sqlite3Fts1HashInsert
+#define fts1HashFind sqlite3Fts1HashFind
+#define fts1HashClear sqlite3Fts1HashClear
+
+/*
+** Macros for looping over all elements of a hash table. The idiom is
+** like this:
+**
+** fts1Hash h;
+** fts1HashElem *p;
+** ...
+** for(p=fts1HashFirst(&h); p; p=fts1HashNext(p)){
+** SomeStructure *pData = fts1HashData(p);
+** // do something with pData
+** }
+*/
+#define fts1HashFirst(H) ((H)->first)
+#define fts1HashNext(E) ((E)->next)
+#define fts1HashData(E) ((E)->data)
+#define fts1HashKey(E) ((E)->pKey)
+#define fts1HashKeysize(E) ((E)->nKey)
+
+/*
+** Number of entries in a hash table
+*/
+#define fts1HashCount(H) ((H)->count)
+
+#endif /* _FTS1_HASH_H_ */