func floatOrDecimalBuiltin1(f func(float64) (Datum, error)) []builtin {
return []builtin{
{
types: argTypes{floatType},
returnType: typeFloat,
fn: func(_ EvalContext, args DTuple) (Datum, error) {
return f(float64(args[0].(DFloat)))
},
}, {
types: argTypes{decimalType},
returnType: typeDecimal,
fn: func(_ EvalContext, args DTuple) (Datum, error) {
dec := args[0].(*DDecimal)
v, err := decimal.Float64FromDec(&dec.Dec)
if err != nil {
return nil, err
}
r, err := f(v)
if err != nil {
return r, err
}
rf := float64(r.(DFloat))
if math.IsNaN(rf) || math.IsInf(rf, 0) {
// TODO(nvanbenschoten) NaN semmantics should be introduced
// into the decimal library to support it here.
return nil, fmt.Errorf("decimal does not support NaN")
}
dd := &DDecimal{}
decimal.SetFromFloat(&dd.Dec, rf)
return dd, nil
},
},
}
}
// Eval implements the Expr interface.
func (expr *CastExpr) Eval(ctx EvalContext) (Datum, error) {
d, err := expr.Expr.Eval(ctx)
if err != nil {
return nil, err
}
// NULL cast to anything is NULL.
if d == DNull {
return d, nil
}
switch expr.Type.(type) {
case *BoolType:
switch v := d.(type) {
case DBool:
return d, nil
case DInt:
return DBool(v != 0), nil
case DFloat:
return DBool(v != 0), nil
case *DDecimal:
return DBool(v.Sign() != 0), nil
case DString:
// TODO(pmattis): strconv.ParseBool is more permissive than the SQL
// spec. Is that ok?
b, err := strconv.ParseBool(string(v))
if err != nil {
return nil, err
}
return DBool(b), nil
}
case *IntType:
switch v := d.(type) {
case DBool:
if v {
return DInt(1), nil
}
return DInt(0), nil
case DInt:
return d, nil
case DFloat:
f, err := round(float64(v), 0)
if err != nil {
panic(fmt.Sprintf("round should never fail with digits hardcoded to 0: %s", err))
}
return DInt(f.(DFloat)), nil
case *DDecimal:
dec := new(inf.Dec)
dec.Round(&v.Dec, 0, inf.RoundHalfUp)
i, ok := dec.Unscaled()
if !ok {
return nil, errIntOutOfRange
}
return DInt(i), nil
case DString:
i, err := strconv.ParseInt(string(v), 0, 64)
if err != nil {
return nil, err
}
return DInt(i), nil
}
case *FloatType:
switch v := d.(type) {
case DBool:
if v {
return DFloat(1), nil
}
return DFloat(0), nil
case DInt:
return DFloat(v), nil
case DFloat:
return d, nil
case *DDecimal:
f, err := decimal.Float64FromDec(&v.Dec)
if err != nil {
return nil, errFloatOutOfRange
}
return DFloat(f), nil
case DString:
f, err := strconv.ParseFloat(string(v), 64)
if err != nil {
return nil, err
}
return DFloat(f), nil
}
case *DecimalType:
dd := &DDecimal{}
switch v := d.(type) {
case DBool:
if v {
dd.SetUnscaled(1)
}
return dd, nil
case DInt:
dd.SetUnscaled(int64(v))
return dd, nil
case DFloat:
decimal.SetFromFloat(&dd.Dec, float64(v))
return dd, nil
case *DDecimal:
return d, nil
case DString:
if _, ok := dd.SetString(string(v)); !ok {
return nil, fmt.Errorf("could not parse string %q as decimal", v)
}
return dd, nil
}
case *StringType:
var s DString
switch t := d.(type) {
case DBool, DInt, DFloat, *DDecimal, dNull:
s = DString(d.String())
case DString:
s = t
case DBytes:
if !utf8.ValidString(string(t)) {
return nil, fmt.Errorf("invalid utf8: %q", string(t))
}
s = DString(t)
}
if c, ok := expr.Type.(*StringType); ok {
// If the CHAR type specifies a limit we truncate to that limit:
// 'hello'::CHAR(2) -> 'he'
if c.N > 0 && c.N < len(s) {
s = s[:c.N]
}
}
return s, nil
case *BytesType:
switch t := d.(type) {
case DString:
return DBytes(t), nil
case DBytes:
return d, nil
}
case *DateType:
switch d := d.(type) {
case DString:
return ParseDate(d)
case DTimestamp:
return ctx.makeDDate(d.Time)
}
case *TimestampType:
switch d := d.(type) {
case DString:
return ctx.ParseTimestamp(d)
case DDate:
loc, err := ctx.GetLocation()
if err != nil {
return nil, err
}
year, month, day := time.Unix(int64(d)*secondsInDay, 0).UTC().Date()
return DTimestamp{Time: time.Date(year, month, day, 0, 0, 0, 0, loc)}, nil
}
case *IntervalType:
switch d.(type) {
case DString:
// We use the Golang format for specifying duration.
// TODO(vivek): we might consider using the postgres format as well.
d, err := time.ParseDuration(string(d.(DString)))
return DInterval{Duration: d}, err
case DInt:
// An integer duration represents a duration in nanoseconds.
return DInterval{Duration: time.Duration(d.(DInt))}, nil
}
}
return nil, fmt.Errorf("invalid cast: %s -> %s", d.Type(), expr.Type)
}