// Prepare the arguments for a binary operation. The returned arguments will
// have the same type. The typ parameter specifies the allowed types for the
// operation. For example, bit-operations should specify intOp or uintOp to
// indicate that they do not operate on floating point arguments. Float
// operations may still reduce to intOp or uintOp if the operands support it.
func prepareBinaryArgs(typ opType, left, right sqlwire.Datum) (opType, sqlwire.Datum, sqlwire.Datum, error) {
var err error
switch typ {
case intOp, uintOp:
if left.UintVal != nil || right.UintVal != nil {
left, err = left.ToUint()
if err != nil {
return uintOp, null, null, err
}
right, err = right.ToUint()
if err != nil {
return uintOp, null, null, err
}
return uintOp, left, right, nil
}
left, err = left.ToInt()
if err != nil {
return intOp, null, null, err
}
right, err = right.ToInt()
if err != nil {
return intOp, null, null, err
}
return intOp, left, right, nil
case floatOp:
if (left.UintVal != nil && (right.IntVal != nil || right.UintVal != nil)) ||
(right.UintVal != nil && (left.IntVal != nil || left.UintVal != nil)) {
left, err = left.ToUint()
if err != nil {
return uintOp, null, null, err
}
right, err = right.ToUint()
if err != nil {
return uintOp, null, null, err
}
return uintOp, left, right, nil
}
if left.IntVal != nil && right.IntVal != nil {
return intOp, left, right, nil
}
}
left, err = left.ToFloat()
if err != nil {
return floatOp, null, null, err
}
right, err = right.ToFloat()
if err != nil {
return floatOp, null, null, err
}
return floatOp, left, right, nil
}
// Prepare the arguments for a comparison operation. The returned arguments
// will have the same type.
func prepareComparisonArgs(left, right sqlwire.Datum) (opType, sqlwire.Datum, sqlwire.Datum, error) {
// If both arguments are strings (or string-like), compare as strings.
if (left.BytesVal != nil || left.StringVal != nil) &&
(right.BytesVal != nil || right.StringVal != nil) {
return stringOp, left.ToString(), right.ToString(), nil
}
// If both arguments are uints, compare as unsigned.
if left.UintVal != nil && right.UintVal != nil {
return uintOp, left, right, nil
}
var err error
// If both arguments are integers (signed or unsigned), compare as integers.
if (left.BoolVal != nil || left.IntVal != nil || left.UintVal != nil) &&
(right.BoolVal != nil || right.IntVal != nil || right.UintVal != nil) {
left, err = left.ToInt()
if err != nil {
return intOp, null, null, err
}
right, err = right.ToInt()
if err != nil {
return intOp, null, null, err
}
return intOp, left, right, nil
}
// In all other cases, compare as floats.
left, err = left.ToFloat()
if err != nil {
return intOp, null, null, err
}
right, err = right.ToFloat()
if err != nil {
return intOp, null, null, err
}
return floatOp, left, right, nil
}