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