func (z *Big) needsInc(x, r int64, pos, odd bool) bool {
m := 1
if r > math.MinInt64/2 || r <= math.MaxInt64/2 {
m = arith.AbsCmp(r<<1, x)
}
return z.ctx.mode.needsInc(m, pos, odd)
}
// cmpNorm compares x and y in the range [0.1, 0.999...] and
// returns true if x > y.
func cmpNorm(x int64, xs int32, y int64, ys int32) (ok bool) {
if debug && (x == 0 || y == 0) {
panic("x and/or y cannot be zero")
}
if diff := xs - ys; diff != 0 {
if diff < 0 {
x, ok = checked.MulPow10(x, -diff)
} else {
y, ok = checked.MulPow10(y, diff)
}
}
if x != c.Inflated {
if y != c.Inflated {
return arith.AbsCmp(x, y) > 0
}
return false
}
return true
}
// Cmp compares d and x and returns:
//
// -1 if z < x
// 0 if z == x
// +1 if z > x
//
// It does not modify d or x.
func (z *Big) Cmp(x *Big) int {
// Check for same pointers.
if z == x {
return 0
}
// Same scales means we can compare straight across.
if z.scale == x.scale {
if z.isCompact() && x.isCompact() {
if z.compact > x.compact {
return +1
}
if z.compact < x.compact {
return -1
}
return 0
}
if z.isInflated() && x.isInflated() {
if z.mantissa.Sign() != x.mantissa.Sign() {
return z.mantissa.Sign()
}
if z.scale < 0 {
return z.mantissa.Cmp(&x.mantissa)
}
zb := z.mantissa.Bits()
xb := x.mantissa.Bits()
min := len(zb)
if len(xb) < len(zb) {
min = len(xb)
}
i := 0
for i < min-1 && zb[i] == xb[i] {
i++
}
if zb[i] > xb[i] {
return +1
}
if zb[i] < xb[i] {
return -1
}
return 0
}
}
// Different scales -- check signs and/or if they're
// both zero.
ds := z.Sign()
xs := x.Sign()
switch {
case ds > xs:
return +1
case ds < xs:
return -1
case ds == 0 && xs == 0:
return 0
}
// Scales aren't equal, the signs are the same, and both
// are non-zero.
dl := int32(z.Prec()) - z.scale
xl := int32(x.Prec()) - x.scale
if dl > xl {
return +1
}
if dl < xl {
return -1
}
// We need to inflate one of the numbers.
dc := z.compact // hi
xc := x.compact // lo
var swap bool
hi, lo := z, x
if hi.scale < lo.scale {
hi, lo = lo, hi
dc, xc = xc, dc
swap = true // d is lo
}
diff := hi.scale - lo.scale
if diff <= c.BadScale {
var ok bool
xc, ok = checked.MulPow10(xc, diff)
if !ok && dc == c.Inflated {
// d is lo
if swap {
zm := new(big.Int).Set(&z.mantissa)
return checked.MulBigPow10(zm, diff).Cmp(&x.mantissa)
}
// x is lo
xm := new(big.Int).Set(&x.mantissa)
return z.mantissa.Cmp(checked.MulBigPow10(xm, diff))
}
}
if swap {
dc, xc = xc, dc
}
if dc != c.Inflated {
if xc != c.Inflated {
return arith.AbsCmp(dc, xc)
}
return big.NewInt(dc).Cmp(&x.mantissa)
}
if xc != c.Inflated {
return z.mantissa.Cmp(big.NewInt(xc))
}
return z.mantissa.Cmp(&x.mantissa)
}