SQLite

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**
** $Id: vdbe.c,v 1.317 2004/05/22 07:27:46 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

  }

  pVal = &pVm->pTos[(1-vals)+i];
  if( pVal->flags&MEM_Null ){
    return 0;
  }

  if( !(pVal->flags&MEM_Blob) ){
    Stringify(pVal);
    SetEncoding(pVal, MEM_Utf8|MEM_Term);
  }

  return pVal->z;
}

*/
case OP_Integer: {
  pTos++;
  pTos->i = pOp->p1;
  pTos->flags = MEM_Int;
  if( pOp->p3 ){
    pTos->z = pOp->p3;
    pTos->flags |= MEM_Utf8 | MEM_Str | MEM_Static | MEM_Term;
    pTos->n = strlen(pOp->p3)+1;
    if( pTos->i==0 ){
      sqlite3GetInt64(pTos->z, &pTos->i);
    }
  }
  break;
}

  assert( z );
  assert( sqlite3IsNumber(z, 0) );

  pTos++;
  pTos->r = sqlite3AtoF(z, 0);
  pTos->z = z;
  pTos->n = strlen(z)+1;
  pTos->flags = MEM_Real|MEM_Str|MEM_Static|MEM_Utf8|MEM_Term;
  break;
}

/* Opcode: Variable P1 * *
**
** Push the value of variable P1 onto the stack.  A variable is
** an unknown in the original SQL string as handed to sqlite3_compile().

  int i;
  Mem ts;

  ts = *pFrom;
  Deephemeralize(pTos);
  for(i=0; i<pOp->p1; i++, pFrom++){
    Deephemeralize(&pFrom[1]);

    assert( (pFrom->flags & MEM_Ephem)==0 );
    *pFrom = pFrom[1];
    if( pFrom->flags & MEM_Short ){
      assert( pFrom->flags & (MEM_Str|MEM_Blob) );
      assert( pFrom->z==pFrom[1].zShort );
      pFrom->z = pFrom->zShort;
    }
  }
  *pTos = ts;

    {MEM_Int, "INTEGER"},
    {MEM_Real, "REAL"},
    {MEM_Str, "TEXT"},
    {MEM_Blob, "BLOB"}
  };

  Release(pTos);
  pTos->flags = MEM_Str|MEM_Static|MEM_Utf8|MEM_Term;

  for(i=0; i<5; i++){
    if( classes[i].mask&flags ){
      pTos->z = classes[i].zClass;
      break;
    }
  }
  assert( i<5 );
  pTos->n = strlen(classes[i].zClass);
  break;
}

/* Opcode: SetNumColumns P1 P2 *
**
** Before the OP_Column opcode can be executed on a cursor, this
** opcode must be called to set the number of fields in the table.

  if( i<0 ){
    char *zRec;     /* Pointer to record data from the stack. */
    int off = 0;    /* Offset in zRec to start of the columns data. */
    int off2 = 0;   /* Offset in zRec to the next serial type to read */
    u64 colType;    /* The serial type of the value being read. */

    assert( &pTos[i-1]>=p->aStack );

    /* FIX ME: I don't understand this either. How is it related to
    ** OP_SortNext? (I thought it would be the commented out assert())
    */
    /* assert( pTos[i].flags & MEM_Blob ); */
    assert( pTos[i].flags & (MEM_Blob|MEM_Str) );
    assert( pTos[i-1].flags & MEM_Int );

    if( pTos[i].n==0 ){
      pTos->flags = MEM_Null;
      break;
    }

  Sorter *pSorter = p->pSort;
  CHECK_FOR_INTERRUPT;
  if( pSorter!=0 ){
    p->pSort = pSorter->pNext;
    pTos++;
    pTos->z = pSorter->pData;
    pTos->n = pSorter->nData;
    /* FIX ME: I don't understand this. What does the sorter return? 
    ** I thought it would be the commented out flags.
    */
    /* pTos->flags = MEM_Blob|MEM_Dyn; */
    pTos->flags = MEM_Str|MEM_Dyn|MEM_Utf8|MEM_Term;
    sqliteFree(pSorter->zKey);
    sqliteFree(pSorter);
  }else{
    pc = pOp->p2 - 1;
  }
  break;
}

  }else{
    z = 0;
  }
  pTos++;
  if( z ){
    pTos->n = strlen(z) + 1;
    pTos->z = z;
    pTos->flags = MEM_Utf8 | MEM_Str | MEM_Ephem | MEM_Term;
  }else{
    pTos->flags = MEM_Null;
  }
  break;
}

/* Opcode: MemStore P1 P2 *

  int rc = SQLITE_OK;
  static char *azColumnNames[] = {
     "addr", "opcode", "p1",  "p2",  "p3", 
     "int",  "text",   "int", "int", "text",
     0
  };


  assert( p->explain );

  /* Even though this opcode does not put dynamic strings onto the
  ** the stack, they may become dynamic if the user calls
  ** sqlite3_column_data16(), causing a translation to UTF-16 encoding.
  */
  if( p->pTos==&p->aStack[4] ){
    for(i=0; i<5; i++){
      if( p->aStack[i].flags & MEM_Dyn ){
        sqliteFree(p->aStack[i].z);
      }
      p->aStack[i].flags = 0;
    }
  }

  p->azColName = azColumnNames;
  p->resOnStack = 0;

  i = p->pc++;
  if( i>=p->nOp ){
    p->rc = SQLITE_OK;
    rc = SQLITE_DONE;
  }else if( db->flags & SQLITE_Interrupt ){
    db->flags &= ~SQLITE_Interrupt;
    if( db->magic!=SQLITE_MAGIC_BUSY ){
      p->rc = SQLITE_MISUSE;
    }else{
      p->rc = SQLITE_INTERRUPT;
    }
    rc = SQLITE_ERROR;
    sqlite3SetString(&p->zErrMsg, sqlite3_error_string(p->rc), (char*)0);
  }else{
    Op *pOp = &p->aOp[i];
    p->aStack[0].flags = MEM_Int;
    p->aStack[0].i = i;                                /* Program counter */


    p->aStack[1].flags = MEM_Static|MEM_Str|MEM_Utf8|MEM_Term;
    p->aStack[1].z = sqlite3OpcodeNames[pOp->opcode];  /* Opcode */
    p->aStack[2].flags = MEM_Int;
    p->aStack[2].i = pOp->p1;                          /* P1 */
    p->aStack[3].flags = MEM_Int;
    p->aStack[3].i = pOp->p2;                          /* P2 */
    p->aStack[4].flags = MEM_Str|MEM_Utf8|MEM_Term;    /* P3 */
    p->aStack[4].z = displayP3(pOp, p->aStack[4].zShort, NBFS);
    if( p->aStack[4].z==p->aStack[4].zShort ){
      p->aStack[4].flags |= MEM_Short;
    }else{
      p->aStack[4].flags |= MEM_Static;
    }
    p->nResColumn = 5;
    p->pTos = &p->aStack[4];
    p->rc = SQLITE_OK;
    p->resOnStack = 1;
    rc = SQLITE_ROW;
  }
  return rc;
}

/*
** Prepare a virtual machine for execution.  This involves things such