// Calculate determines the number of apples that Klaudia and Natalia have.
func (calc *Calculator) Calculate() {
var remainder big.Int
// Solving 2x + diff = total for x, where Klaudia has x + diff apples and
// Natalia has x apples. Since we're working with integers for efficient
// but we may halve odd numbers, we need to account for a "0.5" being
// introduced.
calc.natalia.Sub(calc.total, calc.diff).QuoRem(&calc.natalia, big.NewInt(2), &remainder)
calc.klaudia.Add(&calc.natalia, calc.diff)
calc.odd = remainder.Int64() == 1
}
//encodes big.Int to base58 string
func Big2Base58(val *big.Int) Base58 {
answer := ""
valCopy := new(big.Int).Abs(val) //copies big.Int
if val.Cmp(big.NewInt(0)) <= 0 { //if it is less than 0, returns empty string
return Base58("")
}
tmpStr := ""
tmp := new(big.Int)
for valCopy.Cmp(big.NewInt(0)) > 0 { //converts the number into base58
tmp.Mod(valCopy, big.NewInt(58)) //takes modulo 58 value
valCopy.Div(valCopy, big.NewInt(58)) //divides the rest by 58
tmpStr += alphabet[tmp.Int64() : tmp.Int64()+1] //encodes
}
for i := (len(tmpStr) - 1); i > -1; i-- {
answer += tmpStr[i : i+1] //reverses the order
}
return Base58(answer) //returns
}
// a.convertTo(t) converts the value of the analyzed expression a,
// which must be a constant, ideal number, to a new analyzed
// expression with a constant value of type t.
//
// TODO(austin) Rename to resolveIdeal or something?
func (a *expr) convertTo(t Type) *expr {
if !a.t.isIdeal() {
log.Panicf("attempted to convert from %v, expected ideal", a.t)
}
var rat *big.Rat
// XXX(Spec) The spec says "It is erroneous".
//
// It is an error to assign a value with a non-zero fractional
// part to an integer, or if the assignment would overflow or
// underflow, or in general if the value cannot be represented
// by the type of the variable.
switch a.t {
case IdealFloatType:
rat = a.asIdealFloat()()
if t.isInteger() && !rat.IsInt() {
a.diag("constant %v truncated to integer", rat.FloatString(6))
return nil
}
case IdealIntType:
i := a.asIdealInt()()
rat = new(big.Rat).SetInt(i)
default:
log.Panicf("unexpected ideal type %v", a.t)
}
// Check bounds
if t, ok := t.lit().(BoundedType); ok {
if rat.Cmp(t.minVal()) < 0 {
a.diag("constant %v underflows %v", rat.FloatString(6), t)
return nil
}
if rat.Cmp(t.maxVal()) > 0 {
a.diag("constant %v overflows %v", rat.FloatString(6), t)
return nil
}
}
// Convert rat to type t.
res := a.newExpr(t, a.desc)
switch t := t.lit().(type) {
case *uintType:
n, d := rat.Num(), rat.Denom()
f := new(big.Int).Quo(n, d)
f = f.Abs(f)
v := uint64(f.Int64())
res.eval = func(*Thread) uint64 { return v }
case *intType:
n, d := rat.Num(), rat.Denom()
f := new(big.Int).Quo(n, d)
v := f.Int64()
res.eval = func(*Thread) int64 { return v }
case *idealIntType:
n, d := rat.Num(), rat.Denom()
f := new(big.Int).Quo(n, d)
res.eval = func() *big.Int { return f }
case *floatType:
n, d := rat.Num(), rat.Denom()
v := float64(n.Int64()) / float64(d.Int64())
res.eval = func(*Thread) float64 { return v }
case *idealFloatType:
res.eval = func() *big.Rat { return rat }
default:
log.Panicf("cannot convert to type %T", t)
}
return res
}
func simpBig(x *big.Int) Obj {
if x.Cmp(fixnum_min_Int) >= 0 && x.Cmp(fixnum_max_Int) <= 0 {
return Make_fixnum(int(x.Int64()))
}
return wrap(x)
}
