SQLite

#define SEEK(X)
#define TRACE1(X)
#define TRACE2(X,Y)
#define TRACE3(X,Y,Z)
#define TRACE4(X,Y,Z,A)
#define TRACE5(X,Y,Z,A,B)
#define TRACE6(X,Y,Z,A,B,C)

#endif


/*
** If we compile with the SQLITE_TEST macro set, then the following block
** of code will give us the ability to simulate a disk I/O error.  This
** is used for testing the I/O recovery logic.

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.393 2004/06/28 13:09:11 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

  }

  /* If it wasn't already, P3 has been converted to the database text
  ** encoding. Fall through to OP_Concat to process this instruction.
  */
}

/* Opcode: Concat P1 P2 P3
**
** Look at the first P1 elements of the stack.  Append them all 
** together with the lowest element first.  Use P3 as a separator.  
** Put the result on the top of the stack.  The original P1 elements
** are popped from the stack if P2==0 and retained if P2==1.  If
** any element of the stack is NULL, then the result is NULL.
**
** If P3 is NULL, then use no separator.  When P1==1, this routine
** makes a copy of the top stack element into memory obtained
** from sqliteMalloc().
*/
case OP_Concat: {
  char *zNew;
  int nByte;
  int nField;
  int i, j;
  Mem *pTerm;
  Mem mSep;     /* Memory cell containing the seperator string, if any */

  if( pOp->p3 ){
    mSep.z = pOp->p3;
    if( db->enc==SQLITE_UTF8 ){
      mSep.n = strlen(mSep.z);
    }else{
      mSep.n = sqlite3utf16ByteLen(mSep.z, -1);
    }
    mSep.flags = MEM_Str|MEM_Static|MEM_Term;
    mSep.enc = db->enc;
  }else{
    mSep.flags = MEM_Null;
    mSep.n = 0;
  }

  /* Loop through the stack elements to see how long the result will be. */
  nField = pOp->p1;
  pTerm = &pTos[1-nField];
  nByte = (nField-1)*mSep.n;
  for(i=0; i<nField; i++, pTerm++){
    assert( pOp->p2==0 || (pTerm->flags&MEM_Str) );
    if( pTerm->flags&MEM_Null ){
      nByte = -1;
      break;
    }
    Stringify(pTerm, db->enc);

    j = 0;
    pTerm = &pTos[1-nField];
    for(i=j=0; i<nField; i++, pTerm++){
      int n = pTerm->n;
      assert( pTerm->flags & MEM_Str );
      memcpy(&zNew[j], pTerm->z, n);
      j += n;
      if( i<nField-1 && !(mSep.flags|MEM_Null) ){
        memcpy(&zNew[j], mSep.z, mSep.n);
        j += mSep.n;
      }
    }
    zNew[j] = 0;
    zNew[j+1] = 0;
    assert( j==nByte );

    if( pOp->p2==0 ){
      popStack(&pTos, nField);