SQLite

  sqlite3_value **apOut           /* Write values to this array */
){
  int i;
  u8 *aRec = *paChange;

  for(i=0; i<nCol; i++){
    int eType = *aRec++;
    assert( !apOut || apOut[i]==0 );
    if( eType ){
      if( apOut ){
        apOut[i] = sqlite3ValueNew(0);
        if( !apOut[i] ) return SQLITE_NOMEM;
      }

      if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
        int nByte;
        int enc = (eType==SQLITE_TEXT ? SQLITE_UTF8 : 0);
        aRec += sessionVarintGet(aRec, &nByte);
        if( apOut ){
          sqlite3ValueSetStr(apOut[i], nByte, aRec, enc, SQLITE_STATIC);
        }
        aRec += nByte;
      }
      if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
        if( apOut ){
          sqlite3_int64 v = sessionGetI64(aRec);

          if( eType==SQLITE_INTEGER ){
            sqlite3VdbeMemSetInt64(apOut[i], v);
          }else{
            double d;
            memcpy(&d, &i, 8);
            sqlite3VdbeMemSetDouble(apOut[i], d);
          }
        }
        aRec += 8;
      }
    }
  }

  *paChange = aRec;
  return SQLITE_OK;
}

  int i;
  int rc = p->rc;
  for(i=0; i<p->nCol*2; i++) sqlite3ValueFree(p->apValue[i]);
  sqlite3_free(p->apValue);
  sqlite3_free(p);
  return rc;
}

/*
** Invert a changeset object.
*/
int sqlite3changeset_invert(
  int nChangeset,                 /* Number of bytes in input */
  void *pChangeset,               /* Input changeset */
  int *pnInverted,                /* OUT: Number of bytes in output changeset */
  void **ppInverted               /* OUT: Inverse of pChangeset */
){
  u8 *aOut;
  u8 *aIn;
  int i;
  int nCol = 0;

  /* Zero the output variables in case an error occurs. */
  *ppInverted = 0;
  *pnInverted = 0;
  if( nChangeset==0 ) return SQLITE_OK;

  aOut = (u8 *)sqlite3_malloc(nChangeset);
  if( !aOut ) return SQLITE_NOMEM;
  aIn = (u8 *)pChangeset;

  i = 0;
  while( i<nChangeset ){
    u8 eType = aIn[i];
    switch( eType ){
      case 'T': {
        int nByte = 1 + sessionVarintGet(&aIn[i+1], &nCol);
        nByte += 1 + strlen((char *)&aIn[i+nByte]);
        memcpy(&aOut[i], &aIn[i], nByte);
        i += nByte;
        break;
      }

      case SQLITE_INSERT:
      case SQLITE_DELETE: {
        int nByte;
        u8 *aEnd = &aIn[i+1];

        sessionReadRecord(&aEnd, nCol, 0);
        aOut[i] = (eType==SQLITE_DELETE ? SQLITE_INSERT : SQLITE_DELETE);
        nByte = aEnd - &aIn[i+1];
        memcpy(&aOut[i+1], &aIn[i+1], nByte);
        i += 1 + nByte;
        break;
      }

      case SQLITE_UPDATE: {
        int nByte1;              /* Size of old.* record in bytes */
        int nByte2;              /* Size of new.* record in bytes */
        u8 *aEnd = &aIn[i+1];    

        sessionReadRecord(&aEnd, nCol, 0);
        nByte1 = aEnd - &aIn[i+1];
        sessionReadRecord(&aEnd, nCol, 0);
        nByte2 = aEnd - &aIn[i+1] - nByte1;

        aOut[i] = SQLITE_UPDATE;
        memcpy(&aOut[i+1], &aIn[i+1+nByte1], nByte2);
        memcpy(&aOut[i+1+nByte2], &aIn[i+1], nByte1);

        i += 1 + nByte1 + nByte2;
        break;
      }

      default:
        sqlite3_free(aOut);
        return SQLITE_CORRUPT;
    }
  }

  *pnInverted = nChangeset;
  *ppInverted = (void *)aOut;
  return SQLITE_OK;
}


#endif        /* #ifdef SQLITE_ENABLE_SESSION */

/*
** Finalize an iterator allocated with sqlite3changeset_start().
**
** This function may not be called on iterators passed to a conflict handler
** callback by changeset_apply().
*/
int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);

/*
** Invert a changeset object.
*/
int sqlite3changeset_invert(
  int nIn, void *pIn,             /* Input changeset */
  int *pnOut, void **ppOut        /* OUT: Inverse of input */
);


#endif

            sqlite3_value_bytes(pVal)
        );
        break;
    }
    Tcl_ListObjAppendElement(0, pList, pObj);
  }
}

/*
** sqlite3changeset_invert CHANGESET
*/
static int test_sqlite3changeset_invert(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int rc;                         /* Return code from changeset_invert() */
  void *aChangeset;               /* Input changeset */
  int nChangeSet;                 /* Size of buffer aChangeset in bytes */
  void *aOut;                     /* Output changeset */
  int nOut;                       /* Size of buffer aOut in bytes */

  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "CHANGESET");
  }
  aChangeset = (void *)Tcl_GetByteArrayFromObj(objv[1], &nChangeSet);

  rc = sqlite3changeset_invert(nChangeSet, aChangeset, &nOut, &aOut);
  if( rc!=SQLITE_OK ){
    return test_session_error(interp, rc);
  }
  Tcl_SetObjResult(interp, Tcl_NewByteArrayObj((unsigned char *)aOut, nOut));
  sqlite3_free(aOut);
  return TCL_OK;
}

/*
** sqlite3session_foreach VARNAME CHANGESET SCRIPT
*/
static int test_sqlite3session_foreach(
  void * clientData,
  Tcl_Interp *interp,

}

int TestSession_Init(Tcl_Interp *interp){
  Tcl_CreateObjCommand(interp, "sqlite3session", test_sqlite3session, 0, 0);
  Tcl_CreateObjCommand(
      interp, "sqlite3session_foreach", test_sqlite3session_foreach, 0, 0
  );
  Tcl_CreateObjCommand(
      interp, "sqlite3changeset_invert", test_sqlite3changeset_invert, 0, 0
  );
  return TCL_OK;
}

#endif

#***********************************************************************
# This file implements regression tests for SQLite library.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set ::testprefix session1

proc do_changeset_test {tn session res} {
  set r [list]
  foreach x $res {lappend r $x}
  uplevel do_test $tn [list [subst -nocommands {
    set x [list]
    sqlite3session_foreach c [$session changeset] { lappend x [set c] }
    set x
  }]] [list $r]
}

proc do_changeset_invert_test {tn session res} {
  set r [list]
  foreach x $res {lappend r $x}
  uplevel do_test $tn [list [subst -nocommands {
    set x [list]
    set changeset [sqlite3changeset_invert [$session changeset]]
    sqlite3session_foreach c [set changeset] { lappend x [set c] }
    set x
  }]] [list $r]
}

do_execsql_test 1.0 {
  CREATE TABLE t1(x, y);
  INSERT INTO t1 VALUES('abc', 'def');
}

#-------------------------------------------------------------------------
# Test creating, attaching tables to and deleting session objects.
#
do_test 1.1 { sqlite3session S db main } {S}
do_test 1.2 { S delete } {}
do_test 1.3 { sqlite3session S db main } {S}
do_test 1.4 { S attach t1 } {}
do_test 1.5 { S delete } {}
do_test 1.6 { sqlite3session S db main } {S}
do_test 1.7 { S attach t1 ; S attach t2 ; S attach t3 } {}

  execsql { DELETE FROM t1 WHERE rowid = 2 }
} {}
do_test 1.13 {
  S changeset
  S delete
} {}

#-------------------------------------------------------------------------
# Simple changeset tests. Also test the sqlite3changeset_invert() 





# function.


#
do_test 2.1.1 {
  execsql { DELETE FROM t1 }
  sqlite3session S db main
  S attach t1
  execsql { INSERT INTO t1 VALUES(1, 'Sukhothai') }
  execsql { INSERT INTO t1 VALUES(2, 'Ayutthaya') }
  execsql { INSERT INTO t1 VALUES(3, 'Thonburi') }
} {}
do_changeset_test 2.1.2 S {
  {INSERT t1 {} {i 1 t Sukhothai}}
  {INSERT t1 {} {i 2 t Ayutthaya}}
  {INSERT t1 {} {i 3 t Thonburi}}
}
do_changeset_invert_test 2.1.3 S {
  {DELETE t1 {i 1 t Sukhothai} {}}
  {DELETE t1 {i 2 t Ayutthaya} {}}
  {DELETE t1 {i 3 t Thonburi} {}}
}
do_test 2.1.4 { S delete } {}

do_test 2.2.1 {
  sqlite3session S db main
  S attach t1
  execsql { DELETE FROM t1 WHERE 1 }
} {}
do_changeset_test 2.2.2 S {
  {DELETE t1 {i 1 t Sukhothai} {}}
  {DELETE t1 {i 2 t Ayutthaya} {}}
  {DELETE t1 {i 3 t Thonburi} {}}
}
do_changeset_invert_test 2.2.3 S {
  {INSERT t1 {} {i 1 t Sukhothai}}
  {INSERT t1 {} {i 2 t Ayutthaya}}
  {INSERT t1 {} {i 3 t Thonburi}}
}
do_test 2.2.4 { S delete } {}

do_test 2.3.1 {
  sqlite3session S db main
  execsql { INSERT INTO t1 VALUES(1, 'Sukhothai') }
  execsql { INSERT INTO t1 VALUES(2, 'Ayutthaya') }
  execsql { INSERT INTO t1 VALUES(3, 'Thonburi') }
  S attach t1
  execsql { 
    UPDATE t1 SET x = 10 WHERE x = 1;
    UPDATE t1 SET y = 'Surin' WHERE x = 2;
    UPDATE t1 SET x = 20, y = 'Thapae' WHERE x = 3;
  }
} {}

do_changeset_test 2.3.2 S {
  {UPDATE t1 {i 1 {} {}} {i 10 {} {}}} 
  {UPDATE t1 {{} {} t Ayutthaya} {{} {} t Surin}} 
  {UPDATE t1 {i 3 t Thonburi} {i 20 t Thapae}}
}
do_changeset_invert_test 2.3.3 S {
  {UPDATE t1 {i 10 {} {}} {i 1 {} {}}} 
  {UPDATE t1 {{} {} t Surin} {{} {} t Ayutthaya}} 
  {UPDATE t1 {i 20 t Thapae} {i 3 t Thonburi}}
}
do_test 2.3.4 { S delete } {}

do_test 2.4.1 {
  sqlite3session S db main
  S attach t1
  execsql { INSERT INTO t1 VALUES(100, 'Bangkok') }
  execsql { DELETE FROM t1 WHERE x = 100 }
} {}


do_changeset_test 2.4.2 S {}
do_changeset_invert_test 2.4.3 S {}
do_test 2.4.4 { S delete } {}

finish_test