vendor files

vendor/k8s.io/apimachinery/pkg/api/resource/math.go

@@ -0,0 +1,314 @@
+/*
+Copyright 2014 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package resource
+
+import (
+	"math/big"
+
+	inf "gopkg.in/inf.v0"
+)
+
+const (
+	// maxInt64Factors is the highest value that will be checked when removing factors of 10 from an int64.
+	// It is also the maximum decimal digits that can be represented with an int64.
+	maxInt64Factors = 18
+)
+
+var (
+	// Commonly needed big.Int values-- treat as read only!
+	bigTen      = big.NewInt(10)
+	bigZero     = big.NewInt(0)
+	bigOne      = big.NewInt(1)
+	bigThousand = big.NewInt(1000)
+	big1024     = big.NewInt(1024)
+
+	// Commonly needed inf.Dec values-- treat as read only!
+	decZero      = inf.NewDec(0, 0)
+	decOne       = inf.NewDec(1, 0)
+	decMinusOne  = inf.NewDec(-1, 0)
+	decThousand  = inf.NewDec(1000, 0)
+	dec1024      = inf.NewDec(1024, 0)
+	decMinus1024 = inf.NewDec(-1024, 0)
+
+	// Largest (in magnitude) number allowed.
+	maxAllowed = infDecAmount{inf.NewDec((1<<63)-1, 0)} // == max int64
+
+	// The maximum value we can represent milli-units for.
+	// Compare with the return value of Quantity.Value() to
+	// see if it's safe to use Quantity.MilliValue().
+	MaxMilliValue = int64(((1 << 63) - 1) / 1000)
+)
+
+const mostNegative = -(mostPositive + 1)
+const mostPositive = 1<<63 - 1
+
+// int64Add returns a+b, or false if that would overflow int64.
+func int64Add(a, b int64) (int64, bool) {
+	c := a + b
+	switch {
+	case a > 0 && b > 0:
+		if c < 0 {
+			return 0, false
+		}
+	case a < 0 && b < 0:
+		if c > 0 {
+			return 0, false
+		}
+		if a == mostNegative && b == mostNegative {
+			return 0, false
+		}
+	}
+	return c, true
+}
+
+// int64Multiply returns a*b, or false if that would overflow or underflow int64.
+func int64Multiply(a, b int64) (int64, bool) {
+	if a == 0 || b == 0 || a == 1 || b == 1 {
+		return a * b, true
+	}
+	if a == mostNegative || b == mostNegative {
+		return 0, false
+	}
+	c := a * b
+	return c, c/b == a
+}
+
+// int64MultiplyScale returns a*b, assuming b is greater than one, or false if that would overflow or underflow int64.
+// Use when b is known to be greater than one.
+func int64MultiplyScale(a int64, b int64) (int64, bool) {
+	if a == 0 || a == 1 {
+		return a * b, true
+	}
+	if a == mostNegative && b != 1 {
+		return 0, false
+	}
+	c := a * b
+	return c, c/b == a
+}
+
+// int64MultiplyScale10 multiplies a by 10, or returns false if that would overflow. This method is faster than
+// int64Multiply(a, 10) because the compiler can optimize constant factor multiplication.
+func int64MultiplyScale10(a int64) (int64, bool) {
+	if a == 0 || a == 1 {
+		return a * 10, true
+	}
+	if a == mostNegative {
+		return 0, false
+	}
+	c := a * 10
+	return c, c/10 == a
+}
+
+// int64MultiplyScale100 multiplies a by 100, or returns false if that would overflow. This method is faster than
+// int64Multiply(a, 100) because the compiler can optimize constant factor multiplication.
+func int64MultiplyScale100(a int64) (int64, bool) {
+	if a == 0 || a == 1 {
+		return a * 100, true
+	}
+	if a == mostNegative {
+		return 0, false
+	}
+	c := a * 100
+	return c, c/100 == a
+}
+
+// int64MultiplyScale1000 multiplies a by 1000, or returns false if that would overflow. This method is faster than
+// int64Multiply(a, 1000) because the compiler can optimize constant factor multiplication.
+func int64MultiplyScale1000(a int64) (int64, bool) {
+	if a == 0 || a == 1 {
+		return a * 1000, true
+	}
+	if a == mostNegative {
+		return 0, false
+	}
+	c := a * 1000
+	return c, c/1000 == a
+}
+
+// positiveScaleInt64 multiplies base by 10^scale, returning false if the
+// value overflows. Passing a negative scale is undefined.
+func positiveScaleInt64(base int64, scale Scale) (int64, bool) {
+	switch scale {
+	case 0:
+		return base, true
+	case 1:
+		return int64MultiplyScale10(base)
+	case 2:
+		return int64MultiplyScale100(base)
+	case 3:
+		return int64MultiplyScale1000(base)
+	case 6:
+		return int64MultiplyScale(base, 1000000)
+	case 9:
+		return int64MultiplyScale(base, 1000000000)
+	default:
+		value := base
+		var ok bool
+		for i := Scale(0); i < scale; i++ {
+			if value, ok = int64MultiplyScale(value, 10); !ok {
+				return 0, false
+			}
+		}
+		return value, true
+	}
+}
+
+// negativeScaleInt64 reduces base by the provided scale, rounding up, until the
+// value is zero or the scale is reached. Passing a negative scale is undefined.
+// The value returned, if not exact, is rounded away from zero.
+func negativeScaleInt64(base int64, scale Scale) (result int64, exact bool) {
+	if scale == 0 {
+		return base, true
+	}
+
+	value := base
+	var fraction bool
+	for i := Scale(0); i < scale; i++ {
+		if !fraction && value%10 != 0 {
+			fraction = true
+		}
+		value = value / 10
+		if value == 0 {
+			if fraction {
+				if base > 0 {
+					return 1, false
+				}
+				return -1, false
+			}
+			return 0, true
+		}
+	}
+	if fraction {
+		if base > 0 {
+			value += 1
+		} else {
+			value += -1
+		}
+	}
+	return value, !fraction
+}
+
+func pow10Int64(b int64) int64 {
+	switch b {
+	case 0:
+		return 1
+	case 1:
+		return 10
+	case 2:
+		return 100
+	case 3:
+		return 1000
+	case 4:
+		return 10000
+	case 5:
+		return 100000
+	case 6:
+		return 1000000
+	case 7:
+		return 10000000
+	case 8:
+		return 100000000
+	case 9:
+		return 1000000000
+	case 10:
+		return 10000000000
+	case 11:
+		return 100000000000
+	case 12:
+		return 1000000000000
+	case 13:
+		return 10000000000000
+	case 14:
+		return 100000000000000
+	case 15:
+		return 1000000000000000
+	case 16:
+		return 10000000000000000
+	case 17:
+		return 100000000000000000
+	case 18:
+		return 1000000000000000000
+	default:
+		return 0
+	}
+}
+
+// negativeScaleInt64 returns the result of dividing base by scale * 10 and the remainder, or
+// false if no such division is possible. Dividing by negative scales is undefined.
+func divideByScaleInt64(base int64, scale Scale) (result, remainder int64, exact bool) {
+	if scale == 0 {
+		return base, 0, true
+	}
+	// the max scale representable in base 10 in an int64 is 18 decimal places
+	if scale >= 18 {
+		return 0, base, false
+	}
+	divisor := pow10Int64(int64(scale))
+	return base / divisor, base % divisor, true
+}
+
+// removeInt64Factors divides in a loop; the return values have the property that
+// value == result * base ^ scale
+func removeInt64Factors(value int64, base int64) (result int64, times int32) {
+	times = 0
+	result = value
+	negative := result < 0
+	if negative {
+		result = -result
+	}
+	switch base {
+	// allow the compiler to optimize the common cases
+	case 10:
+		for result >= 10 && result%10 == 0 {
+			times++
+			result = result / 10
+		}
+	// allow the compiler to optimize the common cases
+	case 1024:
+		for result >= 1024 && result%1024 == 0 {
+			times++
+			result = result / 1024
+		}
+	default:
+		for result >= base && result%base == 0 {
+			times++
+			result = result / base
+		}
+	}
+	if negative {
+		result = -result
+	}
+	return result, times
+}
+
+// removeBigIntFactors divides in a loop; the return values have the property that
+// d == result * factor ^ times
+// d may be modified in place.
+// If d == 0, then the return values will be (0, 0)
+func removeBigIntFactors(d, factor *big.Int) (result *big.Int, times int32) {
+	q := big.NewInt(0)
+	m := big.NewInt(0)
+	for d.Cmp(bigZero) != 0 {
+		q.DivMod(d, factor, m)
+		if m.Cmp(bigZero) != 0 {
+			break
+		}
+		times++
+		d, q = q, d
+	}
+	return d, times
+}