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Diffstat (limited to 'third_party/sqlite/ext/fts3/fts3_expr.h')
-rw-r--r-- | third_party/sqlite/ext/fts3/fts3_expr.h | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/third_party/sqlite/ext/fts3/fts3_expr.h b/third_party/sqlite/ext/fts3/fts3_expr.h new file mode 100644 index 0000000..a48dee6 --- /dev/null +++ b/third_party/sqlite/ext/fts3/fts3_expr.h @@ -0,0 +1,96 @@ +/* +** 2008 Nov 28 +** +** 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. +** +****************************************************************************** +** +*/ + +#include "fts3_tokenizer.h" +#include "sqlite3.h" + +/* +** The following describes the syntax supported by the fts3 MATCH +** operator in a similar format to that used by the lemon parser +** generator. This module does not use actually lemon, it uses a +** custom parser. +** +** query ::= andexpr (OR andexpr)*. +** +** andexpr ::= notexpr (AND? notexpr)*. +** +** notexpr ::= nearexpr (NOT nearexpr|-TOKEN)*. +** notexpr ::= LP query RP. +** +** nearexpr ::= phrase (NEAR distance_opt nearexpr)*. +** +** distance_opt ::= . +** distance_opt ::= / INTEGER. +** +** phrase ::= TOKEN. +** phrase ::= COLUMN:TOKEN. +** phrase ::= "TOKEN TOKEN TOKEN...". +*/ + +typedef struct Fts3Expr Fts3Expr; +typedef struct Fts3Phrase Fts3Phrase; + +/* +** A "phrase" is a sequence of one or more tokens that must match in +** sequence. A single token is the base case and the most common case. +** For a sequence of tokens contained in "...", nToken will be the number +** of tokens in the string. +*/ +struct Fts3Phrase { + int nToken; /* Number of tokens in the phrase */ + int iColumn; /* Index of column this phrase must match */ + int isNot; /* Phrase prefixed by unary not (-) operator */ + struct PhraseToken { + char *z; /* Text of the token */ + int n; /* Number of bytes in buffer pointed to by z */ + int isPrefix; /* True if token ends in with a "*" character */ + } aToken[1]; /* One entry for each token in the phrase */ +}; + +/* +** A tree of these objects forms the RHS of a MATCH operator. +*/ +struct Fts3Expr { + int eType; /* One of the FTSQUERY_XXX values defined below */ + int nNear; /* Valid if eType==FTSQUERY_NEAR */ + Fts3Expr *pParent; /* pParent->pLeft==this or pParent->pRight==this */ + Fts3Expr *pLeft; /* Left operand */ + Fts3Expr *pRight; /* Right operand */ + Fts3Phrase *pPhrase; /* Valid if eType==FTSQUERY_PHRASE */ +}; + +int sqlite3Fts3ExprParse(sqlite3_tokenizer *, char **, int, int, + const char *, int, Fts3Expr **); +void sqlite3Fts3ExprFree(Fts3Expr *); + +/* +** Candidate values for Fts3Query.eType. Note that the order of the first +** four values is in order of precedence when parsing expressions. For +** example, the following: +** +** "a OR b AND c NOT d NEAR e" +** +** is equivalent to: +** +** "a OR (b AND (c NOT (d NEAR e)))" +*/ +#define FTSQUERY_NEAR 1 +#define FTSQUERY_NOT 2 +#define FTSQUERY_AND 3 +#define FTSQUERY_OR 4 +#define FTSQUERY_PHRASE 5 + +#ifdef SQLITE_TEST +void sqlite3Fts3ExprInitTestInterface(sqlite3 *db); +#endif |