using System;
using System.Diagnostics;

namespace Community.CsharpSqlite
{
	using sqlite3_value = Sqlite3.Mem;

	public partial class Sqlite3
	{
		/*
		** 2005 February 15
		**
		** 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 C code routines that used to generate VDBE code
		** that implements the ALTER TABLE command.
		*************************************************************************
		**  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: 2011-06-23 19:49:22 4374b7e83ea0a3fbc3691f9c0c936272862f32f2
		**
		*************************************************************************
		*/
		//#include "sqliteInt.h"

		/*
		** The code in this file only exists if we are not omitting the
		** ALTER TABLE logic from the build.
		*/
#if !SQLITE_OMIT_ALTERTABLE

		/*
** This function is used by SQL generated to implement the
** ALTER TABLE command. The first argument is the text of a CREATE TABLE or
** CREATE INDEX command. The second is a table name. The table name in
** the CREATE TABLE or CREATE INDEX statement is replaced with the third
** argument and the result returned. Examples:
**
** sqlite_rename_table('CREATE TABLE abc(a, b, c)', 'def')
**     . 'CREATE TABLE def(a, b, c)'
**
** sqlite_rename_table('CREATE INDEX i ON abc(a)', 'def')
**     . 'CREATE INDEX i ON def(a, b, c)'
*/

		private static void renameTableFunc(
		sqlite3_context context,
		int NotUsed,
		sqlite3_value[] argv
		)
		{
			string bResult = sqlite3_value_text(argv[0]);
			string zSql = bResult == null ? "" : bResult;
			string zTableName = sqlite3_value_text(argv[1]);

			int token = 0;
			Token tname = new Token();
			int zCsr = 0;
			int zLoc = 0;
			int len = 0;
			string zRet;

			sqlite3 db = sqlite3_context_db_handle(context);

			UNUSED_PARAMETER(NotUsed);

			/* The principle used to locate the table name in the CREATE TABLE
			** statement is that the table name is the first non-space token that
			** is immediately followed by a TK_LP or TK_USING token.
			*/
			if (zSql != "")
			{
				do
				{
					if (zCsr == zSql.Length)
					{
						/* Ran out of input before finding an opening bracket. Return NULL. */
						return;
					}

					/* Store the token that zCsr points to in tname. */
					zLoc = zCsr;
					tname.z = zSql.Substring(zCsr);//(char*)zCsr;
					tname.n = len;

					/* Advance zCsr to the next token. Store that token type in 'token',
					** and its length in 'len' (to be used next iteration of this loop).
					*/
					do
					{
						zCsr += len;
						len = (zCsr == zSql.Length) ? 1 : sqlite3GetToken(zSql, zCsr, ref token);
					} while (token == TK_SPACE);
					Debug.Assert(len > 0);
				} while (token != TK_LP && token != TK_USING);

				zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", zLoc, zSql.Substring(0, zLoc),
				zTableName, zSql.Substring(zLoc + tname.n));

				sqlite3_result_text(context, zRet, -1, SQLITE_DYNAMIC);
			}
		}

		/*
		** This C function implements an SQL user function that is used by SQL code
		** generated by the ALTER TABLE ... RENAME command to modify the definition
		** of any foreign key constraints that use the table being renamed as the
		** parent table. It is passed three arguments:
		**
		**   1) The complete text of the CREATE TABLE statement being modified,
		**   2) The old name of the table being renamed, and
		**   3) The new name of the table being renamed.
		**
		** It returns the new CREATE TABLE statement. For example:
		**
		**   sqlite_rename_parent('CREATE TABLE t1(a REFERENCES t2)', 't2', 't3')
		**       -> 'CREATE TABLE t1(a REFERENCES t3)'
		*/
#if !SQLITE_OMIT_FOREIGN_KEY

		private static void renameParentFunc(
		  sqlite3_context context,
		  int NotUsed,
		  sqlite3_value[] argv
		)
		{
			sqlite3 db = sqlite3_context_db_handle(context);
			string zOutput = "";
			string zResult;
			string zInput = sqlite3_value_text(argv[0]);
			string zOld = sqlite3_value_text(argv[1]);
			string zNew = sqlite3_value_text(argv[2]);

			int zIdx;         /* Pointer to token */
			int zLeft = 0;    /* Pointer to remainder of String */
			int n = 0;        /* Length of token z */
			int token = 0;    /* Type of token */

			UNUSED_PARAMETER(NotUsed);
			for (zIdx = 0; zIdx < zInput.Length; zIdx += n)//z=zInput; *z; z=z+n)
			{
				n = sqlite3GetToken(zInput, zIdx, ref token);
				if (token == TK_REFERENCES)
				{
					string zParent;
					do
					{
						zIdx += n;
						n = sqlite3GetToken(zInput, zIdx, ref token);
					} while (token == TK_SPACE);

					zParent = zIdx + n < zInput.Length ? zInput.Substring(zIdx, n) : "";//sqlite3DbStrNDup(db, zIdx, n);
					if (String.IsNullOrEmpty(zParent))
						break;
					sqlite3Dequote(ref zParent);
					if (zOld.Equals(zParent, StringComparison.OrdinalIgnoreCase))
					{
						string zOut = sqlite3MPrintf(db, "%s%.*s\"%w\"",
							zOutput, zIdx - zLeft, zInput.Substring(zLeft), zNew
						);
						sqlite3DbFree(db, ref zOutput);
						zOutput = zOut;
						zIdx += n;// zInput = &z[n];
						zLeft = zIdx;
					}
					sqlite3DbFree(db, ref zParent);
				}
			}

			zResult = sqlite3MPrintf(db, "%s%s", zOutput, zInput.Substring(zLeft));
			sqlite3_result_text(context, zResult, -1, SQLITE_DYNAMIC);
			sqlite3DbFree(db, ref zOutput);
		}

#endif

#if !SQLITE_OMIT_TRIGGER
		/* This function is used by SQL generated to implement the
** ALTER TABLE command. The first argument is the text of a CREATE TRIGGER
** statement. The second is a table name. The table name in the CREATE
** TRIGGER statement is replaced with the third argument and the result
** returned. This is analagous to renameTableFunc() above, except for CREATE
** TRIGGER, not CREATE INDEX and CREATE TABLE.
*/

		private static void renameTriggerFunc(
		sqlite3_context context,
		int NotUsed,
		sqlite3_value[] argv
		)
		{
			string zSql = sqlite3_value_text(argv[0]);
			string zTableName = sqlite3_value_text(argv[1]);

			int token = 0;
			Token tname = new Token();
			int dist = 3;
			int zCsr = 0;
			int zLoc = 0;
			int len = 1;
			string zRet;

			sqlite3 db = sqlite3_context_db_handle(context);

			UNUSED_PARAMETER(NotUsed);

			/* The principle used to locate the table name in the CREATE TRIGGER
			** statement is that the table name is the first token that is immediatedly
			** preceded by either TK_ON or TK_DOT and immediatedly followed by one
			** of TK_WHEN, TK_BEGIN or TK_FOR.
			*/
			if (zSql != null)
			{
				do
				{
					if (zCsr == zSql.Length)
					{
						/* Ran out of input before finding the table name. Return NULL. */
						return;
					}

					/* Store the token that zCsr points to in tname. */
					zLoc = zCsr;
					tname.z = zSql.Substring(zCsr, len);//(char*)zCsr;
					tname.n = len;

					/* Advance zCsr to the next token. Store that token type in 'token',
					** and its length in 'len' (to be used next iteration of this loop).
					*/
					do
					{
						zCsr += len;
						len = (zCsr == zSql.Length) ? 1 : sqlite3GetToken(zSql, zCsr, ref token);
					} while (token == TK_SPACE);
					Debug.Assert(len > 0);

					/* Variable 'dist' stores the number of tokens read since the most
					** recent TK_DOT or TK_ON. This means that when a WHEN, FOR or BEGIN
					** token is read and 'dist' equals 2, the condition stated above
					** to be met.
					**
					** Note that ON cannot be a database, table or column name, so
					** there is no need to worry about syntax like
					** "CREATE TRIGGER ... ON ON.ON BEGIN ..." etc.
					*/
					dist++;
					if (token == TK_DOT || token == TK_ON)
					{
						dist = 0;
					}
				} while (dist != 2 || (token != TK_WHEN && token != TK_FOR && token != TK_BEGIN));

				/* Variable tname now contains the token that is the old table-name
				** in the CREATE TRIGGER statement.
				*/
				zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", zLoc, zSql.Substring(0, zLoc),
				zTableName, zSql.Substring(zLoc + tname.n));
				sqlite3_result_text(context, zRet, -1, SQLITE_DYNAMIC);
			}
		}

#endif // * !SQLITE_OMIT_TRIGGER */

		/*
** Register built-in functions used to help implement ALTER TABLE
*/
		private static FuncDef[] aAlterTableFuncs;

		private static void sqlite3AlterFunctions()
		{
			aAlterTableFuncs = new FuncDef[] {
FUNCTION("sqlite_rename_table",   2, 0, 0, renameTableFunc),
#if !SQLITE_OMIT_TRIGGER
FUNCTION("sqlite_rename_trigger", 2, 0, 0, renameTriggerFunc),
#endif
#if !SQLITE_OMIT_FOREIGN_KEY
FUNCTION("sqlite_rename_parent",  3, 0, 0, renameParentFunc),
#endif
  };
			int i;
#if SQLITE_OMIT_WSD
  FuncDefHash pHash = GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
  FuncDef[] aFunc = GLOBAL(FuncDef, aAlterTableFuncs);
#else
			FuncDefHash pHash = sqlite3GlobalFunctions;
			FuncDef[] aFunc = aAlterTableFuncs;
#endif

			for (i = 0; i < ArraySize(aAlterTableFuncs); i++)
			{
				sqlite3FuncDefInsert(pHash, aFunc[i]);
			}
		}

		/*
		** This function is used to create the text of expressions of the form:
		**
		**   name=<constant1> OR name=<constant2> OR ...
		**
		** If argument zWhere is NULL, then a pointer string containing the text
		** "name=<constant>" is returned, where <constant> is the quoted version
		** of the string passed as argument zConstant. The returned buffer is
		** allocated using sqlite3DbMalloc(). It is the responsibility of the
		** caller to ensure that it is eventually freed.
		**
		** If argument zWhere is not NULL, then the string returned is
		** "<where> OR name=<constant>", where <where> is the contents of zWhere.
		** In this case zWhere is passed to sqlite3DbFree() before returning.
		**
		*/

		private static string whereOrName(sqlite3 db, string zWhere, string zConstant)
		{
			string zNew;
			if (String.IsNullOrEmpty(zWhere))
			{
				zNew = sqlite3MPrintf(db, "name=%Q", zConstant);
			}
			else
			{
				zNew = sqlite3MPrintf(db, "%s OR name=%Q", zWhere, zConstant);
				sqlite3DbFree(db, ref zWhere);
			}
			return zNew;
		}

#if !(SQLITE_OMIT_FOREIGN_KEY) && !(SQLITE_OMIT_TRIGGER)
		/*
** Generate the text of a WHERE expression which can be used to select all
** tables that have foreign key constraints that refer to table pTab (i.e.
** constraints for which pTab is the parent table) from the sqlite_master
** table.
*/

		private static string whereForeignKeys(Parse pParse, Table pTab)
		{
			FKey p;
			string zWhere = "";
			for (p = sqlite3FkReferences(pTab); p != null; p = p.pNextTo)
			{
				zWhere = whereOrName(pParse.db, zWhere, p.pFrom.zName);
			}
			return zWhere;
		}

#endif

		/*
** Generate the text of a WHERE expression which can be used to select all
** temporary triggers on table pTab from the sqlite_temp_master table. If
** table pTab has no temporary triggers, or is itself stored in the
** temporary database, NULL is returned.
*/

		private static string whereTempTriggers(Parse pParse, Table pTab)
		{
			Trigger pTrig;
			string zWhere = "";
			Schema pTempSchema = pParse.db.aDb[1].pSchema; /* Temp db schema */

			/* If the table is not located in the temp.db (in which case NULL is
			** returned, loop through the tables list of triggers. For each trigger
			** that is not part of the temp.db schema, add a clause to the WHERE
			** expression being built up in zWhere.
			*/
			if (pTab.pSchema != pTempSchema)
			{
				sqlite3 db = pParse.db;
				for (pTrig = sqlite3TriggerList(pParse, pTab); pTrig != null; pTrig = pTrig.pNext)
				{
					if (pTrig.pSchema == pTempSchema)
					{
						zWhere = whereOrName(db, zWhere, pTrig.zName);
					}
				}
			}
			if (!String.IsNullOrEmpty(zWhere))
			{
				zWhere = sqlite3MPrintf(pParse.db, "type='trigger' AND (%s)", zWhere);
				//sqlite3DbFree( pParse.db, ref zWhere );
				//zWhere = zNew;
			}
			return zWhere;
		}

		/*
		** Generate code to drop and reload the internal representation of table
		** pTab from the database, including triggers and temporary triggers.
		** Argument zName is the name of the table in the database schema at
		** the time the generated code is executed. This can be different from
		** pTab.zName if this function is being called to code part of an
		** "ALTER TABLE RENAME TO" statement.
		*/

		private static void reloadTableSchema(Parse pParse, Table pTab, string zName)
		{
			Vdbe v;
			string zWhere;
			int iDb;                   /* Index of database containing pTab */
#if !SQLITE_OMIT_TRIGGER
			Trigger pTrig;
#endif

			v = sqlite3GetVdbe(pParse);
			if (NEVER(v == null))
				return;
			Debug.Assert(sqlite3BtreeHoldsAllMutexes(pParse.db));
			iDb = sqlite3SchemaToIndex(pParse.db, pTab.pSchema);
			Debug.Assert(iDb >= 0);

#if !SQLITE_OMIT_TRIGGER
			/* Drop any table triggers from the internal schema. */
			for (pTrig = sqlite3TriggerList(pParse, pTab); pTrig != null; pTrig = pTrig.pNext)
			{
				int iTrigDb = sqlite3SchemaToIndex(pParse.db, pTrig.pSchema);
				Debug.Assert(iTrigDb == iDb || iTrigDb == 1);
				sqlite3VdbeAddOp4(v, OP_DropTrigger, iTrigDb, 0, 0, pTrig.zName, 0);
			}
#endif

			/* Drop the table and index from the internal schema. */
			sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab.zName, 0);

			/* Reload the table, index and permanent trigger schemas. */
			zWhere = sqlite3MPrintf(pParse.db, "tbl_name=%Q", zName);
			if (zWhere == null)
				return;
			sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere);

#if !SQLITE_OMIT_TRIGGER
			/* Now, if the table is not stored in the temp database, reload any temp
** triggers. Don't use IN(...) in case SQLITE_OMIT_SUBQUERY is defined.
*/
			if ((zWhere = whereTempTriggers(pParse, pTab)) != "")
			{
				sqlite3VdbeAddParseSchemaOp(v, 1, zWhere);
			}
#endif
		}

		/*
		** Parameter zName is the name of a table that is about to be altered
		** (either with ALTER TABLE ... RENAME TO or ALTER TABLE ... ADD COLUMN).
		** If the table is a system table, this function leaves an error message
		** in pParse->zErr (system tables may not be altered) and returns non-zero.
		**
		** Or, if zName is not a system table, zero is returned.
		*/

		private static int isSystemTable(Parse pParse, string zName)
		{
			if (zName.StartsWith("sqlite_", System.StringComparison.OrdinalIgnoreCase))
			{
				sqlite3ErrorMsg(pParse, "table %s may not be altered", zName);
				return 1;
			}
			return 0;
		}

		/*
		** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy"
		** command.
		*/

		private static void sqlite3AlterRenameTable(
		Parse pParse,             /* Parser context. */
		SrcList pSrc,             /* The table to rename. */
		Token pName               /* The new table name. */
		)
		{
			int iDb;                  /* Database that contains the table */
			string zDb;               /* Name of database iDb */
			Table pTab;               /* Table being renamed */
			string zName = null;      /* NULL-terminated version of pName */
			sqlite3 db = pParse.db;   /* Database connection */
			int nTabName;             /* Number of UTF-8 characters in zTabName */
			string zTabName;          /* Original name of the table */
			Vdbe v;
#if !SQLITE_OMIT_TRIGGER
			string zWhere = "";       /* Where clause to locate temp triggers */
#endif
			VTable pVTab = null;      /* Non-zero if this is a v-tab with an xRename() */
			int savedDbFlags;         /* Saved value of db->flags */

			savedDbFlags = db.flags;

			//if ( NEVER( db.mallocFailed != 0 ) ) goto exit_rename_table;
			Debug.Assert(pSrc.nSrc == 1);
			Debug.Assert(sqlite3BtreeHoldsAllMutexes(pParse.db));
			pTab = sqlite3LocateTable(pParse, 0, pSrc.a[0].zName, pSrc.a[0].zDatabase);
			if (pTab == null)
				goto exit_rename_table;
			iDb = sqlite3SchemaToIndex(pParse.db, pTab.pSchema);
			zDb = db.aDb[iDb].zName;
			db.flags |= SQLITE_PreferBuiltin;

			/* Get a NULL terminated version of the new table name. */
			zName = sqlite3NameFromToken(db, pName);
			if (zName == null)
				goto exit_rename_table;

			/* Check that a table or index named 'zName' does not already exist
			** in database iDb. If so, this is an error.
			*/
			if (sqlite3FindTable(db, zName, zDb) != null || sqlite3FindIndex(db, zName, zDb) != null)
			{
				sqlite3ErrorMsg(pParse,
				"there is already another table or index with this name: %s", zName);
				goto exit_rename_table;
			}

			/* Make sure it is not a system table being altered, or a reserved name
			** that the table is being renamed to.
			*/
			if (SQLITE_OK != isSystemTable(pParse, pTab.zName))
			{
				goto exit_rename_table;
			}
			if (SQLITE_OK != sqlite3CheckObjectName(pParse, zName))
			{
				goto exit_rename_table;
			}

#if !SQLITE_OMIT_VIEW
			if (pTab.pSelect != null)
			{
				sqlite3ErrorMsg(pParse, "view %s may not be altered", pTab.zName);
				goto exit_rename_table;
			}
#endif

#if !SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. */
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab.zName, 0) ){
goto exit_rename_table;
}
#endif

			if (sqlite3ViewGetColumnNames(pParse, pTab) != 0)
			{
				goto exit_rename_table;
			}
#if !SQLITE_OMIT_VIRTUALTABLE
			if (IsVirtual(pTab))
			{
				pVTab = sqlite3GetVTable(db, pTab);
				if (pVTab.pVtab.pModule.xRename == null)
				{
					pVTab = null;
				}
			}
#endif
			/* Begin a transaction and code the VerifyCookie for database iDb.
** Then modify the schema cookie (since the ALTER TABLE modifies the
** schema). Open a statement transaction if the table is a virtual
** table.
*/
			v = sqlite3GetVdbe(pParse);
			if (v == null)
			{
				goto exit_rename_table;
			}
			sqlite3BeginWriteOperation(pParse, pVTab != null ? 1 : 0, iDb);
			sqlite3ChangeCookie(pParse, iDb);

			/* If this is a virtual table, invoke the xRename() function if
			** one is defined. The xRename() callback will modify the names
			** of any resources used by the v-table implementation (including other
			** SQLite tables) that are identified by the name of the virtual table.
			*/
#if  !SQLITE_OMIT_VIRTUALTABLE
			if (pVTab != null)
			{
				int i = ++pParse.nMem;
				sqlite3VdbeAddOp4(v, OP_String8, 0, i, 0, zName, 0);
				sqlite3VdbeAddOp4(v, OP_VRename, i, 0, 0, pVTab, P4_VTAB);
				sqlite3MayAbort(pParse);
			}
#endif

			/* figure out how many UTF-8 characters are in zName */
			zTabName = pTab.zName;
			nTabName = sqlite3Utf8CharLen(zTabName, -1);

#if !(SQLITE_OMIT_FOREIGN_KEY) && !(SQLITE_OMIT_TRIGGER)
			if ((db.flags & SQLITE_ForeignKeys) != 0)
			{
				/* If foreign-key support is enabled, rewrite the CREATE TABLE
				** statements corresponding to all child tables of foreign key constraints
				** for which the renamed table is the parent table.  */
				if ((zWhere = whereForeignKeys(pParse, pTab)) != null)
				{
					sqlite3NestedParse(pParse,
						"UPDATE \"%w\".%s SET " +
							"sql = sqlite_rename_parent(sql, %Q, %Q) " +
							"WHERE %s;", zDb, SCHEMA_TABLE(iDb), zTabName, zName, zWhere);
					sqlite3DbFree(db, ref zWhere);
				}
			}
#endif

			/* Modify the sqlite_master table to use the new table name. */
			sqlite3NestedParse(pParse,
			"UPDATE %Q.%s SET " +
#if SQLITE_OMIT_TRIGGER
 "sql = sqlite_rename_table(sql, %Q), " +
#else
 "sql = CASE " +
			"WHEN type = 'trigger' THEN sqlite_rename_trigger(sql, %Q)" +
			"ELSE sqlite_rename_table(sql, %Q) END, " +
#endif
 "tbl_name = %Q, " +
			"name = CASE " +
			"WHEN type='table' THEN %Q " +
			"WHEN name LIKE 'sqlite_autoindex%%' AND type='index' THEN " +
			"'sqlite_autoindex_' || %Q || substr(name,%d+18) " +
			"ELSE name END " +
			"WHERE tbl_name=%Q AND " +
			"(type='table' OR type='index' OR type='trigger');",
			zDb, SCHEMA_TABLE(iDb), zName, zName, zName,
#if !SQLITE_OMIT_TRIGGER
 zName,
#endif
 zName, nTabName, zTabName
			);

#if !SQLITE_OMIT_AUTOINCREMENT
			/* If the sqlite_sequence table exists in this database, then update
** it with the new table name.
*/
			if (sqlite3FindTable(db, "sqlite_sequence", zDb) != null)
			{
				sqlite3NestedParse(pParse,
				"UPDATE \"%w\".sqlite_sequence set name = %Q WHERE name = %Q",
				zDb, zName, pTab.zName
				);
			}
#endif

#if !SQLITE_OMIT_TRIGGER
			/* If there are TEMP triggers on this table, modify the sqlite_temp_master
** table. Don't do this if the table being ALTERed is itself located in
** the temp database.
*/
			if ((zWhere = whereTempTriggers(pParse, pTab)) != "")
			{
				sqlite3NestedParse(pParse,
				"UPDATE sqlite_temp_master SET " +
				"sql = sqlite_rename_trigger(sql, %Q), " +
				"tbl_name = %Q " +
				"WHERE %s;", zName, zName, zWhere);
				sqlite3DbFree(db, ref zWhere);
			}
#endif

#if !(SQLITE_OMIT_FOREIGN_KEY) && !(SQLITE_OMIT_TRIGGER)
			if ((db.flags & SQLITE_ForeignKeys) != 0)
			{
				FKey p;
				for (p = sqlite3FkReferences(pTab); p != null; p = p.pNextTo)
				{
					Table pFrom = p.pFrom;
					if (pFrom != pTab)
					{
						reloadTableSchema(pParse, p.pFrom, pFrom.zName);
					}
				}
			}
#endif

			/* Drop and reload the internal table schema. */
			reloadTableSchema(pParse, pTab, zName);

		exit_rename_table:
			sqlite3SrcListDelete(db, ref pSrc);
			sqlite3DbFree(db, ref zName);
			db.flags = savedDbFlags;
		}

		/*
		** Generate code to make sure the file format number is at least minFormat.
		** The generated code will increase the file format number if necessary.
		*/

		private static void sqlite3MinimumFileFormat(Parse pParse, int iDb, int minFormat)
		{
			Vdbe v;
			v = sqlite3GetVdbe(pParse);
			/* The VDBE should have been allocated before this routine is called.
			** If that allocation failed, we would have quit before reaching this
			** point */
			if (ALWAYS(v))
			{
				int r1 = sqlite3GetTempReg(pParse);
				int r2 = sqlite3GetTempReg(pParse);
				int j1;
				sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, r1, BTREE_FILE_FORMAT);
				sqlite3VdbeUsesBtree(v, iDb);
				sqlite3VdbeAddOp2(v, OP_Integer, minFormat, r2);
				j1 = sqlite3VdbeAddOp3(v, OP_Ge, r2, 0, r1);
				sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT, r2);
				sqlite3VdbeJumpHere(v, j1);
				sqlite3ReleaseTempReg(pParse, r1);
				sqlite3ReleaseTempReg(pParse, r2);
			}
		}

		/*
		** This function is called after an "ALTER TABLE ... ADD" statement
		** has been parsed. Argument pColDef contains the text of the new
		** column definition.
		**
		** The Table structure pParse.pNewTable was extended to include
		** the new column during parsing.
		*/

		private static void sqlite3AlterFinishAddColumn(Parse pParse, Token pColDef)
		{
			Table pNew;              /* Copy of pParse.pNewTable */
			Table pTab;              /* Table being altered */
			int iDb;                 /* Database number */
			string zDb;              /* Database name */
			string zTab;             /* Table name */
			string zCol;             /* Null-terminated column definition */
			Column pCol;             /* The new column */
			Expr pDflt;              /* Default value for the new column */
			sqlite3 db;              /* The database connection; */

			db = pParse.db;
			if (pParse.nErr != 0 /*|| db.mallocFailed != 0 */ )
				return;
			pNew = pParse.pNewTable;
			Debug.Assert(pNew != null);
			Debug.Assert(sqlite3BtreeHoldsAllMutexes(db));
			iDb = sqlite3SchemaToIndex(db, pNew.pSchema);
			zDb = db.aDb[iDb].zName;
			zTab = pNew.zName.Substring(16);// zTab = &pNew->zName[16]; /* Skip the "sqlite_altertab_" prefix on the name */
			pCol = pNew.aCol[pNew.nCol - 1];
			pDflt = pCol.pDflt;
			pTab = sqlite3FindTable(db, zTab, zDb);
			Debug.Assert(pTab != null);

#if !SQLITE_OMIT_AUTHORIZATION
/* Invoke the authorization callback. */
if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab.zName, 0) ){
return;
}
#endif

			/* If the default value for the new column was specified with a
** literal NULL, then set pDflt to 0. This simplifies checking
** for an SQL NULL default below.
*/
			if (pDflt != null && pDflt.op == TK_NULL)
			{
				pDflt = null;
			}

			/* Check that the new column is not specified as PRIMARY KEY or UNIQUE.
			** If there is a NOT NULL constraint, then the default value for the
			** column must not be NULL.
			*/
			if (pCol.isPrimKey != 0)
			{
				sqlite3ErrorMsg(pParse, "Cannot add a PRIMARY KEY column");
				return;
			}
			if (pNew.pIndex != null)
			{
				sqlite3ErrorMsg(pParse, "Cannot add a UNIQUE column");
				return;
			}
			if ((db.flags & SQLITE_ForeignKeys) != 0 && pNew.pFKey != null && pDflt != null)
			{
				sqlite3ErrorMsg(pParse,
					"Cannot add a REFERENCES column with non-NULL default value");
				return;
			}
			if (pCol.notNull != 0 && pDflt == null)
			{
				sqlite3ErrorMsg(pParse,
				"Cannot add a NOT NULL column with default value NULL");
				return;
			}

			/* Ensure the default expression is something that sqlite3ValueFromExpr()
			** can handle (i.e. not CURRENT_TIME etc.)
			*/
			if (pDflt != null)
			{
				sqlite3_value pVal = null;
				if (sqlite3ValueFromExpr(db, pDflt, SQLITE_UTF8, SQLITE_AFF_NONE, ref pVal) != 0)
				{
					//        db.mallocFailed = 1;
					return;
				}
				if (pVal == null)
				{
					sqlite3ErrorMsg(pParse, "Cannot add a column with non-constant default");
					return;
				}
				sqlite3ValueFree(ref pVal);
			}

			/* Modify the CREATE TABLE statement. */
			zCol = pColDef.z.Substring(0, pColDef.n).Replace(";", " ").Trim();//sqlite3DbStrNDup(db, (char*)pColDef.z, pColDef.n);
			if (zCol != null)
			{
				//  char zEnd = zCol[pColDef.n-1];
				int savedDbFlags = db.flags;
				//      while( zEnd>zCol && (*zEnd==';' || sqlite3Isspace(*zEnd)) ){
				//    zEnd-- = '\0';
				//  }
				db.flags |= SQLITE_PreferBuiltin;
				sqlite3NestedParse(pParse,
				"UPDATE \"%w\".%s SET " +
				"sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d) " +
				"WHERE type = 'table' AND name = %Q",
				zDb, SCHEMA_TABLE(iDb), pNew.addColOffset, zCol, pNew.addColOffset + 1,
				zTab
				);
				sqlite3DbFree(db, ref zCol);
				db.flags = savedDbFlags;
			}

			/* If the default value of the new column is NULL, then set the file
			** format to 2. If the default value of the new column is not NULL,
			** the file format becomes 3.
			*/
			sqlite3MinimumFileFormat(pParse, iDb, pDflt != null ? 3 : 2);

			/* Reload the schema of the modified table. */
			reloadTableSchema(pParse, pTab, pTab.zName);
		}

		/*
		** This function is called by the parser after the table-name in
		** an "ALTER TABLE <table-name> ADD" statement is parsed. Argument
		** pSrc is the full-name of the table being altered.
		**
		** This routine makes a (partial) copy of the Table structure
		** for the table being altered and sets Parse.pNewTable to point
		** to it. Routines called by the parser as the column definition
		** is parsed (i.e. sqlite3AddColumn()) add the new Column data to
		** the copy. The copy of the Table structure is deleted by tokenize.c
		** after parsing is finished.
		**
		** Routine sqlite3AlterFinishAddColumn() will be called to complete
		** coding the "ALTER TABLE ... ADD" statement.
		*/

		private static void sqlite3AlterBeginAddColumn(Parse pParse, SrcList pSrc)
		{
			Table pNew;
			Table pTab;
			Vdbe v;
			int iDb;
			int i;
			int nAlloc;
			sqlite3 db = pParse.db;

			/* Look up the table being altered. */
			Debug.Assert(pParse.pNewTable == null);
			Debug.Assert(sqlite3BtreeHoldsAllMutexes(db));
			//      if ( db.mallocFailed != 0 ) goto exit_begin_add_column;
			pTab = sqlite3LocateTable(pParse, 0, pSrc.a[0].zName, pSrc.a[0].zDatabase);
			if (pTab == null)
				goto exit_begin_add_column;

			if (IsVirtual(pTab))
			{
				sqlite3ErrorMsg(pParse, "virtual tables may not be altered");
				goto exit_begin_add_column;
			}

			/* Make sure this is not an attempt to ALTER a view. */
			if (pTab.pSelect != null)
			{
				sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
				goto exit_begin_add_column;
			}
			if (SQLITE_OK != isSystemTable(pParse, pTab.zName))
			{
				goto exit_begin_add_column;
			}

			Debug.Assert(pTab.addColOffset > 0);
			iDb = sqlite3SchemaToIndex(db, pTab.pSchema);

			/* Put a copy of the Table struct in Parse.pNewTable for the
			** sqlite3AddColumn() function and friends to modify.  But modify
			** the name by adding an "sqlite_altertab_" prefix.  By adding this
			** prefix, we insure that the name will not collide with an existing
			** table because user table are not allowed to have the "sqlite_"
			** prefix on their name.
			*/
			pNew = new Table();// (Table*)sqlite3DbMallocZero( db, sizeof(Table))
			if (pNew == null)
				goto exit_begin_add_column;
			pParse.pNewTable = pNew;
			pNew.nRef = 1;
			pNew.nCol = pTab.nCol;
			Debug.Assert(pNew.nCol > 0);
			nAlloc = (((pNew.nCol - 1) / 8) * 8) + 8;
			Debug.Assert(nAlloc >= pNew.nCol && nAlloc % 8 == 0 && nAlloc - pNew.nCol < 8);
			pNew.aCol = new Column[nAlloc];// (Column*)sqlite3DbMallocZero( db, sizeof(Column) * nAlloc );
			pNew.zName = sqlite3MPrintf(db, "sqlite_altertab_%s", pTab.zName);
			if (pNew.aCol == null || pNew.zName == null)
			{
				//        db.mallocFailed = 1;
				goto exit_begin_add_column;
			}
			// memcpy( pNew.aCol, pTab.aCol, sizeof(Column) * pNew.nCol );
			for (i = 0; i < pNew.nCol; i++)
			{
				Column pCol = pTab.aCol[i].Copy();
				// sqlite3DbStrDup( db, pCol.zName );
				pCol.zColl = null;
				pCol.zType = null;
				pCol.pDflt = null;
				pCol.zDflt = null;
				pNew.aCol[i] = pCol;
			}
			pNew.pSchema = db.aDb[iDb].pSchema;
			pNew.addColOffset = pTab.addColOffset;
			pNew.nRef = 1;

			/* Begin a transaction and increment the schema cookie.  */
			sqlite3BeginWriteOperation(pParse, 0, iDb);
			v = sqlite3GetVdbe(pParse);
			if (v == null)
				goto exit_begin_add_column;
			sqlite3ChangeCookie(pParse, iDb);

		exit_begin_add_column:
			sqlite3SrcListDelete(db, ref pSrc);
			return;
		}

#endif  // * SQLITE_ALTER_TABLE */
	}
}