--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/persistentstorage/sqlite3api/SQLite/fts3_tokenizer.h Fri Jan 22 11:06:30 2010 +0200
@@ -0,0 +1,145 @@
+/*
+** 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 _FTS3_TOKENIZER_H_
+#define _FTS3_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. When a new tokenizer
+** implementation is registered, the caller provides a pointer to
+** an sqlite3_tokenizer_module containing pointers to the callback
+** functions that make up an implementation.
+**
+** When an fts3 table is created, it passes any arguments passed to
+** the tokenizer clause of the CREATE VIRTUAL TABLE statement to the
+** sqlite3_tokenizer_module.xCreate() function of the requested tokenizer
+** implementation. The xCreate() function in turn returns an
+** sqlite3_tokenizer structure representing the specific tokenizer to
+** be used for the fts3 table (customized by the tokenizer clause arguments).
+**
+** To tokenize an input buffer, the sqlite3_tokenizer_module.xOpen()
+** method is called. It returns an sqlite3_tokenizer_cursor object
+** that may be used to tokenize a specific input buffer based on
+** the tokenization rules supplied by a specific sqlite3_tokenizer
+** object.
+*/
+typedef struct sqlite3_tokenizer_module sqlite3_tokenizer_module;
+typedef struct sqlite3_tokenizer sqlite3_tokenizer;
+typedef struct sqlite3_tokenizer_cursor sqlite3_tokenizer_cursor;
+
+struct sqlite3_tokenizer_module {
+
+ /*
+ ** Structure version. Should always be set to 0.
+ */
+ int iVersion;
+
+ /*
+ ** Create a new tokenizer. The values in the argv[] array are the
+ ** arguments passed to the "tokenizer" clause of the CREATE VIRTUAL
+ ** TABLE statement that created the fts3 table. For example, if
+ ** the following SQL is executed:
+ **
+ ** CREATE .. USING fts3( ... , tokenizer <tokenizer-name> arg1 arg2)
+ **
+ ** then argc is set to 2, and the argv[] array contains pointers
+ ** to the strings "arg1" and "arg2".
+ **
+ ** This method should return either SQLITE_OK (0), or an SQLite error
+ ** code. If SQLITE_OK is returned, then *ppTokenizer should be set
+ ** to point at the newly created tokenizer structure. The generic
+ ** sqlite3_tokenizer.pModule variable should not be initialised by
+ ** this callback. The caller will do so.
+ */
+ int (*xCreate)(
+ int argc, /* Size of argv array */
+ const char *const*argv, /* Tokenizer argument strings */
+ sqlite3_tokenizer **ppTokenizer /* OUT: Created tokenizer */
+ );
+
+ /*
+ ** Destroy an existing tokenizer. The fts3 module calls this method
+ ** exactly once for each successful call to xCreate().
+ */
+ int (*xDestroy)(sqlite3_tokenizer *pTokenizer);
+
+ /*
+ ** Create a tokenizer cursor to tokenize an input buffer. The caller
+ ** is responsible for ensuring that the input buffer remains valid
+ ** until the cursor is closed (using the xClose() method).
+ */
+ int (*xOpen)(
+ sqlite3_tokenizer *pTokenizer, /* Tokenizer object */
+ const char *pInput, int nBytes, /* Input buffer */
+ sqlite3_tokenizer_cursor **ppCursor /* OUT: Created tokenizer cursor */
+ );
+
+ /*
+ ** Destroy an existing tokenizer cursor. The fts3 module calls this
+ ** method exactly once for each successful call to xOpen().
+ */
+ int (*xClose)(sqlite3_tokenizer_cursor *pCursor);
+
+ /*
+ ** Retrieve the next token from the tokenizer cursor pCursor. This
+ ** method should either return SQLITE_OK and set the values of the
+ ** "OUT" variables identified below, or SQLITE_DONE to indicate that
+ ** the end of the buffer has been reached, or an SQLite error code.
+ **
+ ** *ppToken should be set to point at a buffer containing the
+ ** normalized version of the token (i.e. after any case-folding and/or
+ ** stemming has been performed). *pnBytes should be set to the length
+ ** of this buffer in bytes. The input text that generated the token is
+ ** identified by the byte offsets returned in *piStartOffset and
+ ** *piEndOffset.
+ **
+ ** The buffer *ppToken is set to point at is managed by the tokenizer
+ ** implementation. It is only required to be valid until the next call
+ ** to xNext() or xClose().
+ */
+ /* TODO(shess) current implementation requires pInput to be
+ ** nul-terminated. This should either be fixed, or pInput/nBytes
+ ** should be converted to zInput.
+ */
+ int (*xNext)(
+ sqlite3_tokenizer_cursor *pCursor, /* Tokenizer cursor */
+ const char **ppToken, int *pnBytes, /* OUT: Normalized text for token */
+ int *piStartOffset, /* OUT: Byte offset of token in input buffer */
+ int *piEndOffset, /* OUT: Byte offset of end of token in input buffer */
+ int *piPosition /* OUT: Number of tokens returned before this one */
+ );
+};
+
+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 */
+};
+
+#endif /* _FTS3_TOKENIZER_H_ */