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