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Diffstat (limited to 'ext/fts1/fts1_tokenizer.h')
-rw-r--r-- | ext/fts1/fts1_tokenizer.h | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/ext/fts1/fts1_tokenizer.h b/ext/fts1/fts1_tokenizer.h new file mode 100644 index 0000000..a48cb74 --- /dev/null +++ b/ext/fts1/fts1_tokenizer.h @@ -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_ */ |