func (r BigRat) floatString(verb byte, prec int) string {
switch verb {
case 'f', 'F':
return r.Rat.FloatString(prec)
case 'e', 'E':
// The exponent will alway be >= 0.
sign := ""
var x, t big.Rat
x.Set(r.Rat)
if x.Sign() < 0 {
sign = "-"
x.Neg(&x)
}
t.Set(&x)
exp := ratExponent(&x)
ratScale(&t, exp)
str := t.FloatString(prec + 1) // +1 because first digit might be zero.
// Drop the decimal.
if str[0] == '0' {
str = str[2:]
exp--
} else if len(str) > 1 && str[1] == '.' {
str = str[0:1] + str[2:]
}
return eFormat(verb, prec, sign, str, exp)
case 'g', 'G':
var x big.Rat
x.Set(r.Rat)
exp := ratExponent(&x)
// Exponent could be positive or negative
if exp < -4 || prec <= exp {
// Use e format.
verb -= 2 // g becomes e.
return trimEZeros(verb, r.floatString(verb, prec-1))
}
// Use f format.
// If it's got zeros right of the decimal, they count as digits in the precision.
// If it's got digits left of the decimal, they count as digits in the precision.
// Both are handled by adjusting prec by exp.
str := r.floatString(verb-1, prec-exp-1) // -1 for the one digit left of the decimal.
// Trim trailing decimals.
point := strings.IndexByte(str, '.')
if point > 0 {
n := len(str)
for str[n-1] == '0' {
n--
}
str = str[:n]
if str[n-1] == '.' {
str = str[:n-1]
}
}
return str
default:
Errorf("can't handle verb %c for rational", verb)
}
return ""
}
// MulRat returns a new Currency value c = x * y, where y is a big.Rat.
func (x Currency) MulRat(y *big.Rat) (c Currency) {
if y.Sign() < 0 {
build.Critical(ErrNegativeCurrency)
} else {
c.i.Mul(&x.i, y.Num())
c.i.Div(&c.i, y.Denom())
}
return
}
// MulRat returns a new Currency value c = x * y, where y is a big.Rat.
func (x Currency) MulRat(y *big.Rat) (c Currency) {
if y.Sign() < 0 {
if build.DEBUG {
panic(ErrNegativeCurrency)
}
} else {
c.i.Mul(&x.i, y.Num())
c.i.Div(&c.i, y.Denom())
}
return
}
// Takes a transaction and balances it. This is mainly to fill in the empty part
// with the remaining balance.
func balanceTransaction(input *Transaction) error {
balance := new(big.Rat)
var emptyAccPtr *Account
var emptyAccIndex int
for accIndex, accChange := range input.AccountChanges {
if accChange.Balance == nil {
if emptyAccPtr != nil {
return fmt.Errorf("More than one account change empty!")
}
emptyAccPtr = &accChange
emptyAccIndex = accIndex
} else {
balance = balance.Add(balance, accChange.Balance)
}
}
if balance.Sign() != 0 {
if emptyAccPtr == nil {
return fmt.Errorf("No empty account change to place extra balance!")
}
input.AccountChanges[emptyAccIndex].Balance = balance.Neg(balance)
}
return nil
}
// ratExponent returns the power of ten that x would display in scientific notation.
func ratExponent(x *big.Rat) int {
if x.Sign() < 0 {
x.Neg(x)
}
e := 0
invert := false
if x.Num().Cmp(x.Denom()) < 0 {
invert = true
x.Inv(x)
e++
}
for x.Cmp(bigRatBillion) >= 0 {
e += 9
x.Quo(x, bigRatBillion)
}
for x.Cmp(bigRatTen) > 0 {
e++
x.Quo(x, bigRatTen)
}
if invert {
return -e
}
return e
}
// newComplex returns the smallest constant representation
// for the specific value re + im*i; either an int64, *big.Int,
// *big.Rat, or complex value.
//
func newComplex(re, im *big.Rat) interface{} {
if im.Sign() == 0 {
return normalizeRatConst(re)
}
return Complex{re, im}
}
func normComplex(re, im *big.Rat) Value {
if im.Sign() == 0 {
return normFloat(re)
}
return complexVal{re, im}
}