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author | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
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committer | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
commit | a031b83a09a8628435317a03f199cdc18b78262f (patch) | |
tree | bc017a96769ce6de33745b8b0b1304ccf38e9df0 /vendor/gopkg.in/inf.v0/rounder.go | |
parent | 2b74391cd5281f6fdf391ff8ad50fd1490f6bf89 (diff) | |
download | podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.gz podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.bz2 podman-a031b83a09a8628435317a03f199cdc18b78262f.zip |
Initial checkin from CRI-O repo
Signed-off-by: Matthew Heon <matthew.heon@gmail.com>
Diffstat (limited to 'vendor/gopkg.in/inf.v0/rounder.go')
-rw-r--r-- | vendor/gopkg.in/inf.v0/rounder.go | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/vendor/gopkg.in/inf.v0/rounder.go b/vendor/gopkg.in/inf.v0/rounder.go new file mode 100644 index 000000000..3a97ef529 --- /dev/null +++ b/vendor/gopkg.in/inf.v0/rounder.go @@ -0,0 +1,145 @@ +package inf + +import ( + "math/big" +) + +// Rounder represents a method for rounding the (possibly infinite decimal) +// result of a division to a finite Dec. It is used by Dec.Round() and +// Dec.Quo(). +// +// See the Example for results of using each Rounder with some sample values. +// +type Rounder rounder + +// See http://speleotrove.com/decimal/damodel.html#refround for more detailed +// definitions of these rounding modes. +var ( + RoundDown Rounder // towards 0 + RoundUp Rounder // away from 0 + RoundFloor Rounder // towards -infinity + RoundCeil Rounder // towards +infinity + RoundHalfDown Rounder // to nearest; towards 0 if same distance + RoundHalfUp Rounder // to nearest; away from 0 if same distance + RoundHalfEven Rounder // to nearest; even last digit if same distance +) + +// RoundExact is to be used in the case when rounding is not necessary. +// When used with Quo or Round, it returns the result verbatim when it can be +// expressed exactly with the given precision, and it returns nil otherwise. +// QuoExact is a shorthand for using Quo with RoundExact. +var RoundExact Rounder + +type rounder interface { + + // When UseRemainder() returns true, the Round() method is passed the + // remainder of the division, expressed as the numerator and denominator of + // a rational. + UseRemainder() bool + + // Round sets the rounded value of a quotient to z, and returns z. + // quo is rounded down (truncated towards zero) to the scale obtained from + // the Scaler in Quo(). + // + // When the remainder is not used, remNum and remDen are nil. + // When used, the remainder is normalized between -1 and 1; that is: + // + // -|remDen| < remNum < |remDen| + // + // remDen has the same sign as y, and remNum is zero or has the same sign + // as x. + Round(z, quo *Dec, remNum, remDen *big.Int) *Dec +} + +type rndr struct { + useRem bool + round func(z, quo *Dec, remNum, remDen *big.Int) *Dec +} + +func (r rndr) UseRemainder() bool { + return r.useRem +} + +func (r rndr) Round(z, quo *Dec, remNum, remDen *big.Int) *Dec { + return r.round(z, quo, remNum, remDen) +} + +var intSign = []*big.Int{big.NewInt(-1), big.NewInt(0), big.NewInt(1)} + +func roundHalf(f func(c int, odd uint) (roundUp bool)) func(z, q *Dec, rA, rB *big.Int) *Dec { + return func(z, q *Dec, rA, rB *big.Int) *Dec { + z.Set(q) + brA, brB := rA.BitLen(), rB.BitLen() + if brA < brB-1 { + // brA < brB-1 => |rA| < |rB/2| + return z + } + roundUp := false + srA, srB := rA.Sign(), rB.Sign() + s := srA * srB + if brA == brB-1 { + rA2 := new(big.Int).Lsh(rA, 1) + if s < 0 { + rA2.Neg(rA2) + } + roundUp = f(rA2.Cmp(rB)*srB, z.UnscaledBig().Bit(0)) + } else { + // brA > brB-1 => |rA| > |rB/2| + roundUp = true + } + if roundUp { + z.UnscaledBig().Add(z.UnscaledBig(), intSign[s+1]) + } + return z + } +} + +func init() { + RoundExact = rndr{true, + func(z, q *Dec, rA, rB *big.Int) *Dec { + if rA.Sign() != 0 { + return nil + } + return z.Set(q) + }} + RoundDown = rndr{false, + func(z, q *Dec, rA, rB *big.Int) *Dec { + return z.Set(q) + }} + RoundUp = rndr{true, + func(z, q *Dec, rA, rB *big.Int) *Dec { + z.Set(q) + if rA.Sign() != 0 { + z.UnscaledBig().Add(z.UnscaledBig(), intSign[rA.Sign()*rB.Sign()+1]) + } + return z + }} + RoundFloor = rndr{true, + func(z, q *Dec, rA, rB *big.Int) *Dec { + z.Set(q) + if rA.Sign()*rB.Sign() < 0 { + z.UnscaledBig().Add(z.UnscaledBig(), intSign[0]) + } + return z + }} + RoundCeil = rndr{true, + func(z, q *Dec, rA, rB *big.Int) *Dec { + z.Set(q) + if rA.Sign()*rB.Sign() > 0 { + z.UnscaledBig().Add(z.UnscaledBig(), intSign[2]) + } + return z + }} + RoundHalfDown = rndr{true, roundHalf( + func(c int, odd uint) bool { + return c > 0 + })} + RoundHalfUp = rndr{true, roundHalf( + func(c int, odd uint) bool { + return c >= 0 + })} + RoundHalfEven = rndr{true, roundHalf( + func(c int, odd uint) bool { + return c > 0 || c == 0 && odd == 1 + })} +} |