persistentstorage/sqlite3api/SQLite/fts1_tokenizer.h
changeset 0 08ec8eefde2f
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/persistentstorage/sqlite3api/SQLite/fts1_tokenizer.h	Fri Jan 22 11:06:30 2010 +0200
@@ -0,0 +1,90 @@
+/*
+** 2006 July 10
+**
+** The author disclaims copyright to this source code.
+**
+*************************************************************************
+** Defines the interface to tokenizers used by fulltext-search.  There
+** are three basic components:
+**
+** sqlite3_tokenizer_module is a singleton defining the tokenizer
+** interface functions.  This is essentially the class structure for
+** tokenizers.
+**
+** sqlite3_tokenizer is used to define a particular tokenizer, perhaps
+** including customization information defined at creation time.
+**
+** sqlite3_tokenizer_cursor is generated by a tokenizer to generate
+** tokens from a particular input.
+*/
+#ifndef _FTS1_TOKENIZER_H_
+#define _FTS1_TOKENIZER_H_
+
+/* TODO(shess) Only used for SQLITE_OK and SQLITE_DONE at this time.
+** If tokenizers are to be allowed to call sqlite3_*() functions, then
+** we will need a way to register the API consistently.
+*/
+#include "sqlite3.h"
+
+/*
+** Structures used by the tokenizer interface.
+*/
+typedef struct sqlite3_tokenizer sqlite3_tokenizer;
+typedef struct sqlite3_tokenizer_cursor sqlite3_tokenizer_cursor;
+typedef struct sqlite3_tokenizer_module sqlite3_tokenizer_module;
+
+struct sqlite3_tokenizer_module {
+  int iVersion;                  /* currently 0 */
+
+  /*
+  ** Create and destroy a tokenizer.  argc/argv are passed down from
+  ** the fulltext virtual table creation to allow customization.
+  */
+  int (*xCreate)(int argc, const char *const*argv,
+                 sqlite3_tokenizer **ppTokenizer);
+  int (*xDestroy)(sqlite3_tokenizer *pTokenizer);
+
+  /*
+  ** Tokenize a particular input.  Call xOpen() to prepare to
+  ** tokenize, xNext() repeatedly until it returns SQLITE_DONE, then
+  ** xClose() to free any internal state.  The pInput passed to
+  ** xOpen() must exist until the cursor is closed.  The ppToken
+  ** result from xNext() is only valid until the next call to xNext()
+  ** or until xClose() is called.
+  */
+  /* TODO(shess) current implementation requires pInput to be
+  ** nul-terminated.  This should either be fixed, or pInput/nBytes
+  ** should be converted to zInput.
+  */
+  int (*xOpen)(sqlite3_tokenizer *pTokenizer,
+               const char *pInput, int nBytes,
+               sqlite3_tokenizer_cursor **ppCursor);
+  int (*xClose)(sqlite3_tokenizer_cursor *pCursor);
+  int (*xNext)(sqlite3_tokenizer_cursor *pCursor,
+               const char **ppToken, int *pnBytes,
+               int *piStartOffset, int *piEndOffset, int *piPosition);
+};
+
+struct sqlite3_tokenizer {
+  const sqlite3_tokenizer_module *pModule;  /* The module for this tokenizer */
+  /* Tokenizer implementations will typically add additional fields */
+};
+
+struct sqlite3_tokenizer_cursor {
+  sqlite3_tokenizer *pTokenizer;       /* Tokenizer for this cursor. */
+  /* Tokenizer implementations will typically add additional fields */
+};
+
+/*
+** Get the module for a tokenizer which generates tokens based on a
+** set of non-token characters.  The default is to break tokens at any
+** non-alnum character, though the set of delimiters can also be
+** specified by the first argv argument to xCreate().
+*/
+/* TODO(shess) This doesn't belong here.  Need some sort of
+** registration process.
+*/
+void sqlite3Fts1SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+void sqlite3Fts1PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule);
+
+#endif /* _FTS1_TOKENIZER_H_ */