1 files changed, 279 insertions, 0 deletions
diff --git a/vendor/modernc.org/mathutil/int.go b/vendor/modernc.org/mathutil/int.go
new file mode 100644
index 00000000..7c357876
--- /dev/null
+++ b/vendor/modernc.org/mathutil/int.go
@@ -0,0 +1,279 @@
+// Copyright (c) 2018 The mathutil Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package mathutil // import "modernc.org/mathutil"
+
+import (
+	"fmt"
+	"math"
+	"math/big"
+)
+
+var (
+	// MaxInt128 represents the maximun Int128 value as big.Int
+	MaxInt128 *big.Int
+	// MinInt128 represents the minimun Int128 value as big.Int
+	MinInt128 *big.Int
+	// MaxUint128 represents the maximun Uint128 value as big.Int
+	MaxUint128 *big.Int
+)
+
+func init() {
+	var ok bool
+	MaxInt128, ok = big.NewInt(0).SetString("0x7fffffff_ffffffff_ffffffff_ffffffff", 0)
+	if !ok {
+		panic("internal error")
+	}
+
+	MinInt128 = big.NewInt(0).Set(MaxInt128)
+	MinInt128.Add(MinInt128, _1)
+	MinInt128.Neg(MinInt128)
+
+	MaxUint128, ok = big.NewInt(0).SetString("0xffffffff_ffffffff_ffffffff_ffffffff", 0)
+	if !ok {
+		panic("internal error")
+	}
+}
+
+const (
+	maxInt128  = 1<<127 - 1
+	maxUint128 = 1<<128 - 1
+	minInt128  = -maxInt128 - 1
+)
+
+// Int128 is an 128 bit signed integer.
+type Int128 struct {
+	Lo int64 // Bits 63..0.
+	Hi int64 // Bits 127..64.
+}
+
+// Add returns the sum of x and y and a carry indication.
+func (x Int128) Add(y Int128) (r Int128, cy bool) {
+	r.Lo = x.Lo + y.Lo
+	r.Hi = x.Hi + y.Hi
+	if uint64(r.Lo) < uint64(x.Lo) {
+		r.Hi++
+	}
+	return r, (r.Cmp(x) < 0) == (y.Sign() >= 0)
+}
+
+// BigInt returns x in the form of a big.Int.
+func (x Int128) BigInt() *big.Int {
+	r := big.NewInt(x.Hi)
+	r.Lsh(r, 64)
+	lo := big.NewInt(0)
+	lo.SetUint64(uint64(x.Lo))
+	return r.Add(r, lo)
+}
+
+// Cmp compares x and y and returns:
+//
+//	-1 if x <  y
+//	 0 if x == y
+//	+1 if x >  y
+func (x Int128) Cmp(y Int128) int {
+	if x.Hi > y.Hi {
+		return 1
+	}
+
+	if x.Hi < y.Hi {
+		return -1
+	}
+
+	if uint64(x.Lo) > uint64(y.Lo) {
+		return 1
+	}
+
+	if uint64(x.Lo) < uint64(y.Lo) {
+		return -1
+	}
+
+	return 0
+}
+
+// Neg returns -x and an indication that x was not equal to MinInt128.
+func (x Int128) Neg() (r Int128, ok bool) {
+	if x == (Int128{Hi: math.MinInt64}) {
+		return x, false
+	}
+
+	x.Lo = ^x.Lo
+	x.Hi = ^x.Hi
+	r, _ = x.Add(Int128{Lo: 1})
+	return r, true
+}
+
+// SetBigInt sets x to y, returns x and an error, if any.
+func (x *Int128) SetBigInt(y *big.Int) (r Int128, err error) {
+	if y.Cmp(MaxInt128) > 0 {
+		return *x, fmt.Errorf("%T.SetInt: overflow", x)
+	}
+	if y.Cmp(MinInt128) < 0 {
+		return *x, fmt.Errorf("%T.SetInt: underflow", x)
+	}
+	neg := y.Sign() < 0
+	var z big.Int
+	z.Set(y)
+	if neg {
+		z.Neg(&z)
+	}
+	r.Lo = z.Int64()
+	z.Rsh(&z, 64)
+	r.Hi = z.Int64()
+	if neg {
+		r, _ = r.Neg()
+	}
+	*x = r
+	return r, nil
+}
+
+// SetInt64 sets x to y and returns x.
+func (x *Int128) SetInt64(y int64) (r Int128) {
+	r.Lo = y
+	if y >= 0 {
+		r.Hi = 0
+		*x = r
+		return r
+	}
+
+	r.Hi = -1
+	*x = r
+	return r
+}
+
+// SetUint64 sets x to y and returns x.
+func (x *Int128) SetUint64(y uint64) (r Int128) {
+	r = Int128{Lo: int64(y)}
+	*x = r
+	return r
+}
+
+// Sign returns:
+//
+//	-1 if x <  0
+//	 0 if x == 0
+//	+1 if x >  0
+func (x Int128) Sign() int {
+	if x.Hi < 0 {
+		return -1
+	}
+
+	if x.Hi != 0 || x.Lo != 0 {
+		return 1
+	}
+
+	return 0
+}
+
+// String implements fmt.Stringer()
+func (x Int128) String() string { return x.BigInt().String() }
+
+// NewInt128FromInt64 return a new Int128 value initialized to n.
+func NewInt128FromInt64(n int64) (r Int128) {
+	r.Lo = n
+	if n < 0 {
+		r.Hi = -1
+	}
+	return r
+}
+
+// NewInt128FromUint64 return a new Int128 value initialized to n.
+func NewInt128FromUint64(n uint64) (r Int128) { return Int128{Lo: int64(n)} }
+
+// NewInt128FromFloat32 returns a new Int128 value initialized to n. Result is
+// not specified in n does not represent a number within the range of Int128
+// values.
+func NewInt128FromFloat32(n float32) (r Int128) {
+	if n >= minInt128 && n <= maxInt128 {
+		if n >= math.MinInt64 && n <= math.MaxInt64 {
+			return NewInt128FromInt64(int64(n))
+		}
+
+		f := big.NewFloat(float64(n))
+		bi, _ := f.Int(nil)
+		r.SetBigInt(bi)
+	}
+	return r
+}
+
+// NewInt128FromFloat64 returns a new Int128 value initialized to n. Result is
+// not specified in n does not represent a number within the range of Int128
+// values.
+func NewInt128FromFloat64(n float64) (r Int128) {
+	if n >= minInt128 && n <= maxInt128 {
+		if n >= math.MinInt64 && n <= math.MaxInt64 {
+			return NewInt128FromInt64(int64(n))
+		}
+
+		f := big.NewFloat(n)
+		bi, _ := f.Int(nil)
+		r.SetBigInt(bi)
+	}
+	return r
+}
+
+// Uint128 is an 128 bit unsigned integer.
+type Uint128 struct {
+	Lo uint64 // Bits 63..0.
+	Hi uint64 // Bits 127..64.
+}
+
+// NewUint128FromInt64 return a new Uint128 value initialized to n.
+func NewUint128FromInt64(n int64) (r Uint128) {
+	r.Lo = uint64(n)
+	if n < 0 {
+		r.Hi = ^uint64(0)
+	}
+	return r
+}
+
+// NewUint128FromUint64 return a new Uint128 value initialized to n.
+func NewUint128FromUint64(n uint64) (r Uint128) { return Uint128{Lo: n} }
+
+// NewUint128FromFloat32 returns a new Uint128 value initialized to n. Result is
+// not specified in n does not represent a number within the range of Uint128
+// values.
+func NewUint128FromFloat32(n float32) (r Uint128) {
+	if n >= 0 {
+		if n <= math.MaxUint64 {
+			return NewUint128FromUint64(uint64(n))
+		}
+
+		f := big.NewFloat(float64(n))
+		bi, _ := f.Int(nil)
+		r.SetBigInt(bi)
+	}
+	return r
+}
+
+// NewUint128FromFloat64 returns a new Uint128 value initialized to n. Result is
+// not specified in n does not represent a number within the range of Uint128
+// values.
+func NewUint128FromFloat64(n float64) (r Uint128) {
+	if n >= 0 && n <= maxUint128 {
+		if n <= math.MaxUint64 {
+			return NewUint128FromUint64(uint64(n))
+		}
+
+		f := big.NewFloat(n)
+		bi, _ := f.Int(nil)
+		r.SetBigInt(bi)
+	}
+	return r
+}
+
+// SetBigInt sets x to y, returns x and an error, if any.
+func (x *Uint128) SetBigInt(y *big.Int) (r Uint128, err error) {
+	if y.Sign() < 0 || y.Cmp(MaxUint128) > 0 {
+		return *x, fmt.Errorf("%T.SetInt: overflow", x)
+	}
+
+	var z big.Int
+	z.Set(y)
+	r.Lo = z.Uint64()
+	z.Rsh(&z, 64)
+	r.Hi = z.Uint64()
+	*x = r
+	return r, nil
+}