#include "fts3.h"
#ifndef SQLITE_CORE 
# include "sqlite3ext.h"
  SQLITE_EXTENSION_INIT1
#endif

/*
** GCC does not define the offsetof() macro so we'll have to do it
** ourselves. This definition was copied from sqlite3Int.h.
*/
#ifndef offsetof
#define offsetof(STRUCTURE,FIELD) ((int)((char*)&((STRUCTURE*)0)->FIELD))
#endif

static int fts3EvalNext(Fts3Cursor *pCsr);
static int fts3EvalStart(Fts3Cursor *pCsr);
static int fts3TermSegReaderCursor(
    Fts3Cursor *, const char *, int, int, Fts3MultiSegReader **);

#ifndef SQLITE_AMALGAMATION
# if defined(SQLITE_DEBUG)

  return SQLITE_OK;
}

/*
** Implementation of xOpen method.
*/
static int fts3OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
  Fts3Table *p = (Fts3Table *)pVTab;
  Fts3Cursor *pCsr;               /* Allocated cursor */



  /* Allocate a buffer large enough for an Fts3Cursor structure. If the
  ** allocation succeeds, zero it and return SQLITE_OK. Otherwise, 
  ** if the allocation fails, return SQLITE_NOMEM.
  */
  pCsr = (Fts3Cursor*)sqlite3_malloc(sizeof(Fts3Cursor));
  *ppCsr = (sqlite3_vtab_cursor*)pCsr;
  if( !pCsr ){
    return SQLITE_NOMEM;
  }
  memset(pCsr, 0, sizeof(Fts3Cursor));

  /* Link the new cursor into the linked list at Fts3Table.pCsr. */
  pCsr->pNext = p->pAllCsr;
  p->pAllCsr = pCsr;
  pCsr->iId = ++p->iLastCsrId;

  return SQLITE_OK;
}

/*
** Finalize the statement handle at pCsr->pStmt.
**
** Or, if that statement handle is one created by fts3CursorSeekStmt(),

}

/*
** Free all resources currently held by the cursor passed as the only
** argument.
*/
static void fts3ClearCursor(Fts3Cursor *pCsr){
  const int nZero = sizeof(Fts3Cursor)-offsetof(Fts3Cursor,eSearch); 
  fts3CursorFinalizeStmt(pCsr);
  sqlite3Fts3FreeDeferredTokens(pCsr);
  sqlite3_free(pCsr->aDoclist);
  sqlite3Fts3MIBufferFree(pCsr->pMIBuffer);
  sqlite3Fts3ExprFree(pCsr->pExpr);
  memset((void*)&pCsr->eSearch, 0, nZero);
}

/*
** Close the cursor.  For additional information see the documentation
** on the xClose method of the virtual table interface.
*/
static int fts3CloseMethod(sqlite3_vtab_cursor *pCursor){
  Fts3Table *p = (Fts3Table*)pCursor->pVtab;
  Fts3Cursor *pCsr = (Fts3Cursor*)pCursor;
  Fts3Cursor **pp;
  assert( p->pSegments==0 );
  fts3ClearCursor(pCsr);
  assert( p->pSegments==0 );
  for(pp=&p->pAllCsr; (*pp)!=pCsr; pp=&(*pp)->pNext);
  *pp = 0;
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/*
** If pCsr->pStmt has not been prepared (i.e. if pCsr->pStmt==0), then
** compose and prepare an SQL statement of the form:

  /* The column value supplied by SQLite must be in range. */
  assert( iCol>=0 && iCol<=p->nColumn+2 );

  switch( iCol-p->nColumn ){
    case 0:
      /* The special 'table-name' column */
      sqlite3_result_int(pCtx, pCsr->iId);
      break;

    case 1:
      /* The docid column */
      sqlite3_result_int64(pCtx, pCsr->iPrevId);
      break;

*/
static int fts3FunctionArg(
  sqlite3_context *pContext,      /* SQL function call context */
  const char *zFunc,              /* Function name */
  sqlite3_value *pVal,            /* argv[0] passed to function */
  Fts3Cursor **ppCsr              /* OUT: Store cursor handle here */
){
  int rc = SQLITE_OK;
  int iId;
  Fts3Table *p = (Fts3Table*)sqlite3_user_data(pContext);
  iId = sqlite3_value_int(pVal);
  Fts3Cursor *pRet;

  for(pRet=p->pAllCsr; pRet; pRet=pRet->pNext){
    if( pRet->iId==iId ) break;
  }
  *ppCsr = pRet;

  if( pRet==0 ){
    char *zErr = sqlite3_mprintf("illegal first argument to %s", zFunc);
    sqlite3_result_error(pContext, zErr, -1);
    sqlite3_free(zErr);
    rc = SQLITE_ERROR;
  }
  return rc;
}

  UNUSED_PARAMETER(pVtab);
  UNUSED_PARAMETER(nArg);
  UNUSED_PARAMETER(ppArg);

  for(i=0; i<SizeofArray(aOverload); i++){
    if( strcmp(zName, aOverload[i].zName)==0 ){
      *pxFunc = aOverload[i].xFunc;
      *ppArg = (void*)pVtab;
      return 1;
    }
  }

  /* No function of the specified name was found. Return 0. */
  return 0;
}

#endif

#ifdef SQLITE_TEST
  /* True to disable the incremental doclist optimization. This is controled
  ** by special insert command 'test-no-incr-doclist'.  */
  int bNoIncrDoclist;
#endif

  Fts3Cursor *pAllCsr;            /* List of all open cursors */
  int iLastCsrId;                 /* Last cursor id assigned (or 0) */
};

/*
** When the core wants to read from the virtual table, it creates a
** virtual table cursor (an instance of the following structure) using
** the xOpen method. Cursors are destroyed using the xClose method.
*/
struct Fts3Cursor {
  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
  int iId;                        /* Numeric id of this cursor */
  Fts3Cursor *pNext;              /* Next in list of all cursors */

  /* Variables below this point are zeroed by fts3ClearCursor() */

  i16 eSearch;                    /* Search strategy (see below) */
  u8 isEof;                       /* True if at End Of Results */
  u8 isRequireSeek;               /* True if must seek pStmt to %_content row */
  u8 bSeekStmt;                   /* True if pStmt is a seek */
  sqlite3_stmt *pStmt;            /* Prepared statement in use by the cursor */
  Fts3Expr *pExpr;                /* Parsed MATCH query string */
  int iLangid;                    /* Language being queried for */