vdbe.c

sqlite数据库管理系统开放源码

/* Opcode: Eq P1 P2 *
**
** Pop the top two elements from the stack.  If they are equal, then
** jump to instruction P2.  Otherwise, continue to the next instruction.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** If both values are numeric, they are converted to doubles using atof()
** and compared for equality that way.  Otherwise the strcmp() library
** routine is used for the comparison.  For a pure text comparison
** use OP_StrEq.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
/* Opcode: Ne P1 P2 *
**
** Pop the top two elements from the stack.  If they are not equal, then
** jump to instruction P2.  Otherwise, continue to the next instruction.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** If both values are numeric, they are converted to doubles using atof()
** and compared in that format.  Otherwise the strcmp() library
** routine is used for the comparison.  For a pure text comparison
** use OP_StrNe.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
/* Opcode: Lt P1 P2 *
**
** Pop the top two elements from the stack.  If second element (the
** next on stack) is less than the first (the top of stack), then
** jump to instruction P2.  Otherwise, continue to the next instruction.
** In other words, jump if NOS<TOS.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** If both values are numeric, they are converted to doubles using atof()
** and compared in that format.  Numeric values are always less than
** non-numeric values.  If both operands are non-numeric, the strcmp() library
** routine is used for the comparison.  For a pure text comparison
** use OP_StrLt.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
/* Opcode: Le P1 P2 *
**
** Pop the top two elements from the stack.  If second element (the
** next on stack) is less than or equal to the first (the top of stack),
** then jump to instruction P2. In other words, jump if NOS<=TOS.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** If both values are numeric, they are converted to doubles using atof()
** and compared in that format.  Numeric values are always less than
** non-numeric values.  If both operands are non-numeric, the strcmp() library
** routine is used for the comparison.  For a pure text comparison
** use OP_StrLe.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
/* Opcode: Gt P1 P2 *
**
** Pop the top two elements from the stack.  If second element (the
** next on stack) is greater than the first (the top of stack),
** then jump to instruction P2. In other words, jump if NOS>TOS.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** If both values are numeric, they are converted to doubles using atof()
** and compared in that format.  Numeric values are always less than
** non-numeric values.  If both operands are non-numeric, the strcmp() library
** routine is used for the comparison.  For a pure text comparison
** use OP_StrGt.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
/* Opcode: Ge P1 P2 *
**
** Pop the top two elements from the stack.  If second element (the next
** on stack) is greater than or equal to the first (the top of stack),
** then jump to instruction P2. In other words, jump if NOS>=TOS.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** If both values are numeric, they are converted to doubles using atof()
** and compared in that format.  Numeric values are always less than
** non-numeric values.  If both operands are non-numeric, the strcmp() library
** routine is used for the comparison.  For a pure text comparison
** use OP_StrGe.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
case OP_Eq:
case OP_Ne:
case OP_Lt:
case OP_Le:
case OP_Gt:
case OP_Ge: {
  Mem *pNos = &pTos[-1];
  int c, v;
  int ft, fn;
  assert( pNos>=p->aStack );
  ft = pTos->flags;
  fn = pNos->flags;
  if( (ft | fn) & MEM_Null ){
    popStack(&pTos, 2);
    if( pOp->p2 ){
      if( pOp->p1 ) pc = pOp->p2-1;
    }else{
      pTos++;
      pTos->flags = MEM_Null;
    }
    break;
  }else if( (ft & fn & MEM_Int)==MEM_Int ){
    c = pNos->i - pTos->i;
  }else if( (ft & MEM_Int)!=0 && (fn & MEM_Str)!=0 && toInt(pNos->z,&v) ){
    c = v - pTos->i;
  }else if( (fn & MEM_Int)!=0 && (ft & MEM_Str)!=0 && toInt(pTos->z,&v) ){
    c = pNos->i - v;
  }else{
    Stringify(pTos);
    Stringify(pNos);
    c = sqliteCompare(pNos->z, pTos->z);
  }
  switch( pOp->opcode ){
    case OP_Eq:    c = c==0;     break;
    case OP_Ne:    c = c!=0;     break;
    case OP_Lt:    c = c<0;      break;
    case OP_Le:    c = c<=0;     break;
    case OP_Gt:    c = c>0;      break;
    default:       c = c>=0;     break;
  }
  popStack(&pTos, 2);
  if( pOp->p2 ){
    if( c ) pc = pOp->p2-1;
  }else{
    pTos++;
    pTos->i = c;
    pTos->flags = MEM_Int;
  }
  break;
}
/* INSERT NO CODE HERE!
**
** The opcode numbers are extracted from this source file by doing
**
**    grep '^case OP_' vdbe.c | ... >opcodes.h
**
** The opcodes are numbered in the order that they appear in this file.
** But in order for the expression generating code to work right, the
** string comparison operators that follow must be numbered exactly 6
** greater than the numeric comparison opcodes above.  So no other
** cases can appear between the two.
*/
/* Opcode: StrEq P1 P2 *
**
** Pop the top two elements from the stack.  If they are equal, then
** jump to instruction P2.  Otherwise, continue to the next instruction.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** The strcmp() library routine is used for the comparison.  For a
** numeric comparison, use OP_Eq.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
/* Opcode: StrNe P1 P2 *
**
** Pop the top two elements from the stack.  If they are not equal, then
** jump to instruction P2.  Otherwise, continue to the next instruction.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** The strcmp() library routine is used for the comparison.  For a
** numeric comparison, use OP_Ne.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
/* Opcode: StrLt P1 P2 *
**
** Pop the top two elements from the stack.  If second element (the
** next on stack) is less than the first (the top of stack), then
** jump to instruction P2.  Otherwise, continue to the next instruction.
** In other words, jump if NOS<TOS.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** The strcmp() library routine is used for the comparison.  For a
** numeric comparison, use OP_Lt.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
/* Opcode: StrLe P1 P2 *
**
** Pop the top two elements from the stack.  If second element (the
** next on stack) is less than or equal to the first (the top of stack),
** then jump to instruction P2. In other words, jump if NOS<=TOS.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** The strcmp() library routine is used for the comparison.  For a
** numeric comparison, use OP_Le.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
/* Opcode: StrGt P1 P2 *
**
** Pop the top two elements from the stack.  If second element (the
** next on stack) is greater than the first (the top of stack),
** then jump to instruction P2. In other words, jump if NOS>TOS.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** The strcmp() library routine is used for the comparison.  For a
** numeric comparison, use OP_Gt.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
/* Opcode: StrGe P1 P2 *
**
** Pop the top two elements from the stack.  If second element (the next
** on stack) is greater than or equal to the first (the top of stack),
** then jump to instruction P2. In other words, jump if NOS>=TOS.
**
** If either operand is NULL (and thus if the result is unknown) then
** take the jump if P1 is true.
**
** The strcmp() library routine is used for the comparison.  For a
** numeric comparison, use OP_Ge.
**
** If P2 is zero, do not jump.  Instead, push an integer 1 onto the
** stack if the jump would have been taken, or a 0 if not.  Push a
** NULL if either operand was NULL.
*/
case OP_StrEq:
case OP_StrNe:
case OP_StrLt:
case OP_StrLe:
case OP_StrGt:
case OP_StrGe: {
  Mem *pNos = &pTos[-1];
  int c;
  assert( pNos>=p->aStack );
  if( (pNos->flags | pTos->flags) & MEM_Null ){
    popStack(&pTos, 2);
    if( pOp->p2 ){
      if( pOp->p1 ) pc = pOp->p2-1;
    }else{
      pTos++;
      pTos->flags = MEM_Null;
    }
    break;
  }else{
    Stringify(pTos);
    Stringify(pNos);
    c = strcmp(pNos->z, pTos->z);
  }
  /* The asserts on each case of the following switch are there to verify
  ** that string comparison opcodes are always exactly 6 greater than the
  ** corresponding numeric comparison opcodes.  The code generator depends
  ** on this fact.
  */
  switch( pOp->opcode ){
    case OP_StrEq:    c = c==0;    assert( pOp->opcode-6==OP_Eq );   break;
    case OP_StrNe:    c = c!=0;    assert( pOp->opcode-6==OP_Ne );   break;
    case OP_StrLt:    c = c<0;     assert( pOp->opcode-6==OP_Lt );   break;
    case OP_StrLe:    c = c<=0;    assert( pOp->opcode-6==OP_Le );   break;
    case OP_StrGt:    c = c>0;     assert( pOp->opcode-6==OP_Gt );   break;
    default:          c = c>=0;    assert( pOp->opcode-6==OP_Ge );   break;
  }
  popStack(&pTos, 2);
  if( pOp->p2 ){
    if( c ) pc = pOp->p2-1;
  }else{
    pTos++;
    pTos->flags = MEM_Int;
    pTos->i = c;
  }
  break;
}

/* Opcode: And * * *
**
** Pop two values off the stack.  Take the logical AND of the
** two values and push the resulting boolean value back onto the
** stack. 
*/
/* Opcode: Or * * *
**
** Pop two values off the stack.  Take the logical OR of the
** two values and push the resulting boolean value back onto the
** stack. 
*/
case OP_And:
case OP_Or: {
  Mem *pNos = &pTos[-1];
  int v1, v2;    /* 0==TRUE, 1==FALSE, 2==UNKNOWN or NULL */

  assert( pNos>=p->aStack );
  if( pTos->flags & MEM_Null ){
    v1 = 2;
  }else{
    Integerify(pTos);
    v1 = pTos->i==0;
  }
  if( pNos->flags & MEM_Null ){
    v2 = 2;
  }else{
    Integerify(pNos);
    v2 = pNos->i==0;
  }
  if( pOp->opcode==OP_And ){
    static const unsigned char and_logic[] = { 0, 1, 2, 1, 1, 1, 2, 1, 2 };
    v1 = and_logic[v1*3+v2];
  }else{
    static const unsigned char or_logic[] = { 0, 0, 0, 0, 1, 2, 0, 2, 2 };
    v1 = or_logic[v1*3+v2];
  }
  popStack(&pTos, 2);
  pTos++;
  if( v1==2 ){
    pTos->flags = MEM_Null;
  }else{
    pTos->i = v1==0;
    pTos->flags = MEM_Int;
  }
  break;
}

/* Opcode: Negative * * *
**
** Treat the top of the stack as a numeric quantity.  Replace it
** with its additive inverse.  If the top of the stack is NULL
** its value is unchanged.
*/
/* Opcode: AbsValue * * *
**
** Treat the top of the stack as a numeric quantity.  Replace it
** with its absolute value. If the top of the stack is NULL
** its value is unchanged.
*/
case OP_Negative:
case OP_AbsValue: {
  assert( pTos>=p->aStack );
  if( pTos->flags & MEM_Real ){
    Release(pTos);
    if( pOp->opcode==OP_Negative || pTos->r<0.0 ){
      pTos->r = -pTos->r;
    }
    pTos->flags = MEM_Real;
  }else if( pTos->flags & MEM_Int ){
    Release(pTos);
    if( pOp->opcode==OP_Negative || pTos->i<0 ){
      pTos->i = -pTos->i;
    }
    pTos->flags = MEM_Int;
  }else if( pTos->flags & MEM_Null ){
    /* Do nothing */
  }else{
    Realify(pTos);
    Release(pTos);
    if( pOp->opcode==OP_Negative || pTos->r<0.0 ){
      pTos->r = -pTos->r;
    }
    pTos->flags = MEM_Real;
  }
  break;
}

/* Opcode: Not * * *
**
** Interpret the top of the stack as a boolean value.  Replace it
** with its complement.  If the top of the stack is NULL its value
** is unchanged.
*/
case OP_Not: {
  assert( pTos>=p->aStack );
  if( pTos->flags & MEM_Null ) break;  /* Do nothing to NULLs */
  Integerify(pTos);
  Release(pTos);
  pTos->i = !pTos->i;
  pTos->flags = MEM_Int;
  break;
}

/* Opcode: BitNot * * *
**
** Interpret the top of the stack as an value.  Replace it
** with its ones-complement.  If the top of the stack is NULL its
** value is unchanged.
*/
case OP_BitNot: {
  assert( pTos>=p->aStack );
  if( pTos->flags & MEM_Null ) break;  /* Do nothing to NULLs */
  Integerify(pTos);
  Release(pTos);