560 lines
No EOL
17 KiB
C#
560 lines
No EOL
17 KiB
C#
using System;
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using System.Diagnostics;
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using i16 = System.Int16;
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using u16 = System.UInt16;
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using u8 = System.Byte;
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namespace Community.CsharpSqlite
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{
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public partial class Sqlite3
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{
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/*
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** 2005 May 23
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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**
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** This file contains functions used to access the internal hash tables
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** of user defined functions and collation sequences.
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*************************************************************************
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** Included in SQLite3 port to C#-SQLite; 2008 Noah B Hart
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** C#-SQLite is an independent reimplementation of the SQLite software library
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**
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** SQLITE_SOURCE_ID: 2011-05-19 13:26:54 ed1da510a239ea767a01dc332b667119fa3c908e
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**
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*************************************************************************
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*/
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//#include "sqliteInt.h"
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/*
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** Invoke the 'collation needed' callback to request a collation sequence
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** in the encoding enc of name zName, length nName.
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*/
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private static void callCollNeeded(sqlite3 db, int enc, string zName)
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{
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Debug.Assert(db.xCollNeeded == null || db.xCollNeeded16 == null);
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if (db.xCollNeeded != null)
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{
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string zExternal = zName;// sqlite3DbStrDup(db, zName);
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if (zExternal == null)
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return;
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db.xCollNeeded(db.pCollNeededArg, db, enc, zExternal);
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sqlite3DbFree(db, ref zExternal);
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}
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#if !SQLITE_OMIT_UTF16
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if( db.xCollNeeded16!=null ){
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string zExternal;
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sqlite3_value pTmp = sqlite3ValueNew(db);
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sqlite3ValueSetStr(pTmp, -1, zName, SQLITE_UTF8, SQLITE_STATIC);
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zExternal = sqlite3ValueText(pTmp, SQLITE_UTF16NATIVE);
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if( zExternal!="" ){
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db.xCollNeeded16( db.pCollNeededArg, db, db.aDbStatic[0].pSchema.enc, zExternal );//(int)ENC(db), zExternal);
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}
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sqlite3ValueFree(ref pTmp);
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}
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#endif
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}
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/*
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** This routine is called if the collation factory fails to deliver a
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** collation function in the best encoding but there may be other versions
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** of this collation function (for other text encodings) available. Use one
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** of these instead if they exist. Avoid a UTF-8 <. UTF-16 conversion if
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** possible.
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*/
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private static int synthCollSeq(sqlite3 db, CollSeq pColl)
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{
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CollSeq pColl2;
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string z = pColl.zName;
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int i;
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byte[] aEnc = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 };
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for (i = 0; i < 3; i++)
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{
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pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, 0);
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if (pColl2.xCmp != null)
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{
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pColl = pColl2.Copy(); //memcpy(pColl, pColl2, sizeof(CollSeq));
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pColl.xDel = null; /* Do not copy the destructor */
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return SQLITE_OK;
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}
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}
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return SQLITE_ERROR;
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}
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/*
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** This function is responsible for invoking the collation factory callback
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** or substituting a collation sequence of a different encoding when the
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** requested collation sequence is not available in the desired encoding.
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**
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** If it is not NULL, then pColl must point to the database native encoding
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** collation sequence with name zName, length nName.
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**
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** The return value is either the collation sequence to be used in database
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** db for collation type name zName, length nName, or NULL, if no collation
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** sequence can be found.
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**
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** See also: sqlite3LocateCollSeq(), sqlite3FindCollSeq()
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*/
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private static CollSeq sqlite3GetCollSeq(
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sqlite3 db, /* The database connection */
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u8 enc, /* The desired encoding for the collating sequence */
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CollSeq pColl, /* Collating sequence with native encoding, or NULL */
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string zName /* Collating sequence name */
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)
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{
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CollSeq p;
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p = pColl;
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if (p == null)
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{
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p = sqlite3FindCollSeq(db, enc, zName, 0);
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}
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if (p == null || p.xCmp == null)
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{
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/* No collation sequence of this type for this encoding is registered.
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** Call the collation factory to see if it can supply us with one.
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*/
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callCollNeeded(db, enc, zName);
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p = sqlite3FindCollSeq(db, enc, zName, 0);
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}
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if (p != null && p.xCmp == null && synthCollSeq(db, p) != 0)
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{
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p = null;
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}
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Debug.Assert(p == null || p.xCmp != null);
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return p;
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}
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/*
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** This routine is called on a collation sequence before it is used to
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** check that it is defined. An undefined collation sequence exists when
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** a database is loaded that contains references to collation sequences
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** that have not been defined by sqlite3_create_collation() etc.
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**
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** If required, this routine calls the 'collation needed' callback to
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** request a definition of the collating sequence. If this doesn't work,
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** an equivalent collating sequence that uses a text encoding different
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** from the main database is substituted, if one is available.
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*/
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private static int sqlite3CheckCollSeq(Parse pParse, CollSeq pColl)
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{
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if (pColl != null)
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{
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string zName = pColl.zName;
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sqlite3 db = pParse.db;
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CollSeq p = sqlite3GetCollSeq(db, ENC(db), pColl, zName);
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if (null == p)
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{
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sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
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pParse.nErr++;
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return SQLITE_ERROR;
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}
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//
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//Debug.Assert(p == pColl);
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if (p != pColl) // Had to lookup appropriate sequence
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{
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pColl.enc = p.enc;
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pColl.pUser = p.pUser;
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pColl.type = p.type;
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pColl.xCmp = p.xCmp;
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pColl.xDel = p.xDel;
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}
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}
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return SQLITE_OK;
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}
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/*
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** Locate and return an entry from the db.aCollSeq hash table. If the entry
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** specified by zName and nName is not found and parameter 'create' is
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** true, then create a new entry. Otherwise return NULL.
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**
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** Each pointer stored in the sqlite3.aCollSeq hash table contains an
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** array of three CollSeq structures. The first is the collation sequence
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** prefferred for UTF-8, the second UTF-16le, and the third UTF-16be.
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**
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** Stored immediately after the three collation sequences is a copy of
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** the collation sequence name. A pointer to this string is stored in
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** each collation sequence structure.
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*/
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private static CollSeq[] findCollSeqEntry(
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sqlite3 db, /* Database connection */
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string zName, /* Name of the collating sequence */
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int create /* Create a new entry if true */
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)
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{
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CollSeq[] pColl;
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int nName = sqlite3Strlen30(zName);
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pColl = sqlite3HashFind(db.aCollSeq, zName, nName, (CollSeq[])null);
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if ((null == pColl) && create != 0)
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{
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pColl = new CollSeq[3]; //sqlite3DbMallocZero(db, 3*sizeof(*pColl) + nName + 1 );
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if (pColl != null)
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{
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CollSeq pDel = null;
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pColl[0] = new CollSeq();
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pColl[0].zName = zName;
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pColl[0].enc = SQLITE_UTF8;
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pColl[1] = new CollSeq();
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pColl[1].zName = zName;
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pColl[1].enc = SQLITE_UTF16LE;
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pColl[2] = new CollSeq();
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pColl[2].zName = zName;
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pColl[2].enc = SQLITE_UTF16BE;
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//memcpy(pColl[0].zName, zName, nName);
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//pColl[0].zName[nName] = 0;
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CollSeq[] pDelArray = sqlite3HashInsert(ref db.aCollSeq, pColl[0].zName, nName, pColl);
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if (pDelArray != null)
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pDel = pDelArray[0];
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/* If a malloc() failure occurred in sqlite3HashInsert(), it will
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** return the pColl pointer to be deleted (because it wasn't added
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** to the hash table).
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*/
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Debug.Assert(pDel == null || pDel == pColl[0]);
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if (pDel != null)
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{
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//// db.mallocFailed = 1;
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pDel = null; //was sqlite3DbFree(db,ref pDel);
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pColl = null;
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}
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}
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}
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return pColl;
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}
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/*
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** Parameter zName points to a UTF-8 encoded string nName bytes long.
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** Return the CollSeq* pointer for the collation sequence named zName
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** for the encoding 'enc' from the database 'db'.
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**
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** If the entry specified is not found and 'create' is true, then create a
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** new entry. Otherwise return NULL.
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**
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** A separate function sqlite3LocateCollSeq() is a wrapper around
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** this routine. sqlite3LocateCollSeq() invokes the collation factory
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** if necessary and generates an error message if the collating sequence
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** cannot be found.
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**
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** See also: sqlite3LocateCollSeq(), sqlite3GetCollSeq()
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*/
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private static CollSeq sqlite3FindCollSeq(
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sqlite3 db,
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u8 enc,
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string zName,
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u8 create
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)
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{
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CollSeq[] pColl;
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if (zName != null)
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{
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pColl = findCollSeqEntry(db, zName, create);
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}
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else
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{
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pColl = new CollSeq[enc];
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pColl[enc - 1] = db.pDfltColl;
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}
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Debug.Assert(SQLITE_UTF8 == 1 && SQLITE_UTF16LE == 2 && SQLITE_UTF16BE == 3);
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Debug.Assert(enc >= SQLITE_UTF8 && enc <= SQLITE_UTF16BE);
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if (pColl != null)
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{
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enc -= 1; // if (pColl != null) pColl += enc - 1;
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return pColl[enc];
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}
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else
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return null;
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}
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/* During the search for the best function definition, this procedure
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** is called to test how well the function passed as the first argument
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** matches the request for a function with nArg arguments in a system
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** that uses encoding enc. The value returned indicates how well the
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** request is matched. A higher value indicates a better match.
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**
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** The returned value is always between 0 and 6, as follows:
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**
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** 0: Not a match, or if nArg<0 and the function is has no implementation.
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** 1: A variable arguments function that prefers UTF-8 when a UTF-16
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** encoding is requested, or vice versa.
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** 2: A variable arguments function that uses UTF-16BE when UTF-16LE is
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** requested, or vice versa.
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** 3: A variable arguments function using the same text encoding.
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** 4: A function with the exact number of arguments requested that
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** prefers UTF-8 when a UTF-16 encoding is requested, or vice versa.
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** 5: A function with the exact number of arguments requested that
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** prefers UTF-16LE when UTF-16BE is requested, or vice versa.
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** 6: An exact match.
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**
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*/
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private static int matchQuality(FuncDef p, int nArg, int enc)
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{
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int match = 0;
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if (p.nArg == -1 || p.nArg == nArg
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|| (nArg == -1 && (p.xFunc != null || p.xStep != null))
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)
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{
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match = 1;
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if (p.nArg == nArg || nArg == -1)
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{
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match = 4;
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}
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if (enc == p.iPrefEnc)
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{
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match += 2;
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}
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else if ((enc == SQLITE_UTF16LE && p.iPrefEnc == SQLITE_UTF16BE) ||
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(enc == SQLITE_UTF16BE && p.iPrefEnc == SQLITE_UTF16LE))
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{
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match += 1;
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}
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}
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return match;
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}
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/*
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** Search a FuncDefHash for a function with the given name. Return
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** a pointer to the matching FuncDef if found, or 0 if there is no match.
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*/
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private static FuncDef functionSearch(
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FuncDefHash pHash, /* Hash table to search */
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int h, /* Hash of the name */
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string zFunc, /* Name of function */
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int nFunc /* Number of bytes in zFunc */
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)
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{
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FuncDef p;
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for (p = pHash.a[h]; p != null; p = p.pHash)
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{
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if (p.zName.Length == nFunc && p.zName.StartsWith(zFunc, StringComparison.OrdinalIgnoreCase))
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{
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return p;
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}
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}
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return null;
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}
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/*
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** Insert a new FuncDef into a FuncDefHash hash table.
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*/
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private static void sqlite3FuncDefInsert(
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FuncDefHash pHash, /* The hash table into which to insert */
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FuncDef pDef /* The function definition to insert */
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)
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{
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FuncDef pOther;
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int nName = sqlite3Strlen30(pDef.zName);
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u8 c1 = (u8)pDef.zName[0];
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int h = (sqlite3UpperToLower[c1] + nName) % ArraySize(pHash.a);
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pOther = functionSearch(pHash, h, pDef.zName, nName);
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if (pOther != null)
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{
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Debug.Assert(pOther != pDef && pOther.pNext != pDef);
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pDef.pNext = pOther.pNext;
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pOther.pNext = pDef;
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}
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else
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{
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pDef.pNext = null;
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pDef.pHash = pHash.a[h];
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pHash.a[h] = pDef;
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}
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}
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/*
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** Locate a user function given a name, a number of arguments and a flag
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** indicating whether the function prefers UTF-16 over UTF-8. Return a
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** pointer to the FuncDef structure that defines that function, or return
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** NULL if the function does not exist.
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**
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** If the createFlag argument is true, then a new (blank) FuncDef
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** structure is created and liked into the "db" structure if a
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** no matching function previously existed. When createFlag is true
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** and the nArg parameter is -1, then only a function that accepts
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** any number of arguments will be returned.
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**
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** If createFlag is false and nArg is -1, then the first valid
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** function found is returned. A function is valid if either xFunc
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** or xStep is non-zero.
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**
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** If createFlag is false, then a function with the required name and
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** number of arguments may be returned even if the eTextRep flag does not
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** match that requested.
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*/
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private static FuncDef sqlite3FindFunction(
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sqlite3 db, /* An open database */
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string zName, /* Name of the function. Not null-terminated */
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int nName, /* Number of characters in the name */
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int nArg, /* Number of arguments. -1 means any number */
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u8 enc, /* Preferred text encoding */
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u8 createFlag /* Create new entry if true and does not otherwise exist */
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)
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{
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FuncDef p; /* Iterator variable */
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FuncDef pBest = null; /* Best match found so far */
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int bestScore = 0;
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int h; /* Hash value */
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Debug.Assert(enc == SQLITE_UTF8 || enc == SQLITE_UTF16LE || enc == SQLITE_UTF16BE);
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h = (sqlite3UpperToLower[(u8)zName[0]] + nName) % ArraySize(db.aFunc.a);
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/* First search for a match amongst the application-defined functions.
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*/
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p = functionSearch(db.aFunc, h, zName, nName);
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while (p != null)
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{
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int score = matchQuality(p, nArg, enc);
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if (score > bestScore)
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{
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pBest = p;
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bestScore = score;
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}
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p = p.pNext;
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}
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/* If no match is found, search the built-in functions.
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**
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** If the SQLITE_PreferBuiltin flag is set, then search the built-in
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** functions even if a prior app-defined function was found. And give
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** priority to built-in functions.
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**
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** Except, if createFlag is true, that means that we are trying to
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** install a new function. Whatever FuncDef structure is returned it will
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** have fields overwritten with new information appropriate for the
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** new function. But the FuncDefs for built-in functions are read-only.
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** So we must not search for built-ins when creating a new function.
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*/
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if (0 == createFlag && (pBest == null || (db.flags & SQLITE_PreferBuiltin) != 0))
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{
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#if SQLITE_OMIT_WSD
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FuncDefHash pHash = GLOBAL( FuncDefHash, sqlite3GlobalFunctions );
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#else
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FuncDefHash pHash = sqlite3GlobalFunctions;
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#endif
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bestScore = 0;
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p = functionSearch(pHash, h, zName, nName);
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while (p != null)
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{
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int score = matchQuality(p, nArg, enc);
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if (score > bestScore)
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{
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pBest = p;
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bestScore = score;
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}
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p = p.pNext;
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}
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}
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|
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/* If the createFlag parameter is true and the search did not reveal an
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** exact match for the name, number of arguments and encoding, then add a
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** new entry to the hash table and return it.
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*/
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if (createFlag != 0 && (bestScore < 6 || pBest.nArg != nArg) &&
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(pBest = new FuncDef()) != null)
|
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{ //sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){
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//pBest.zName = (char *)&pBest[1];
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pBest.nArg = (i16)nArg;
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pBest.iPrefEnc = enc;
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pBest.zName = zName; //memcpy(pBest.zName, zName, nName);
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//pBest.zName[nName] = 0;
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sqlite3FuncDefInsert(db.aFunc, pBest);
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}
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if (pBest != null && (pBest.xStep != null || pBest.xFunc != null || createFlag != 0))
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{
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return pBest;
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}
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return null;
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}
|
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|
|
/*
|
|
** Free all resources held by the schema structure. The void* argument points
|
|
** at a Schema struct. This function does not call sqlite3DbFree(db, ) on the
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|
** pointer itself, it just cleans up subsidiary resources (i.e. the contents
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** of the schema hash tables).
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|
**
|
|
** The Schema.cache_size variable is not cleared.
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|
*/
|
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|
|
private static void sqlite3SchemaClear(Schema p)
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|
{
|
|
Hash temp1;
|
|
Hash temp2;
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|
HashElem pElem;
|
|
Schema pSchema = p;
|
|
|
|
temp1 = pSchema.tblHash;
|
|
temp2 = pSchema.trigHash;
|
|
sqlite3HashInit(pSchema.trigHash);
|
|
sqlite3HashClear(pSchema.idxHash);
|
|
for (pElem = sqliteHashFirst(temp2); pElem != null; pElem = sqliteHashNext(pElem))
|
|
{
|
|
Trigger pTrigger = (Trigger)sqliteHashData(pElem);
|
|
sqlite3DeleteTrigger(null, ref pTrigger);
|
|
}
|
|
sqlite3HashClear(temp2);
|
|
sqlite3HashInit(pSchema.trigHash);
|
|
for (pElem = temp1.first; pElem != null; pElem = pElem.next)//sqliteHashFirst(&temp1); pElem; pElem = sqliteHashNext(pElem))
|
|
{
|
|
Table pTab = (Table)pElem.data; //sqliteHashData(pElem);
|
|
sqlite3DeleteTable(null, ref pTab);
|
|
}
|
|
sqlite3HashClear(temp1);
|
|
sqlite3HashClear(pSchema.fkeyHash);
|
|
pSchema.pSeqTab = null;
|
|
if ((pSchema.flags & DB_SchemaLoaded) != 0)
|
|
{
|
|
pSchema.iGeneration++;
|
|
pSchema.flags = (u16)(pSchema.flags & (~DB_SchemaLoaded));
|
|
}
|
|
p.Clear();
|
|
}
|
|
|
|
/*
|
|
** Find and return the schema associated with a BTree. Create
|
|
** a new one if necessary.
|
|
*/
|
|
|
|
private static Schema sqlite3SchemaGet(sqlite3 db, Btree pBt)
|
|
{
|
|
Schema p;
|
|
if (pBt != null)
|
|
{
|
|
p = sqlite3BtreeSchema(pBt, -1, (dxFreeSchema)sqlite3SchemaClear);//Schema.Length, sqlite3SchemaFree);
|
|
}
|
|
else
|
|
{
|
|
p = new Schema(); // (Schema *)sqlite3DbMallocZero(0, sizeof(Schema));
|
|
}
|
|
if (p == null)
|
|
{
|
|
//// db.mallocFailed = 1;
|
|
}
|
|
else if (0 == p.file_format)
|
|
{
|
|
sqlite3HashInit(p.tblHash);
|
|
sqlite3HashInit(p.idxHash);
|
|
sqlite3HashInit(p.trigHash);
|
|
sqlite3HashInit(p.fkeyHash);
|
|
p.enc = SQLITE_UTF8;
|
|
}
|
|
return p;
|
|
}
|
|
}
|
|
} |