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Add uint256 package and int256 wrapper (#1320)
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,194 @@ | ||
| package int256 | ||
|
|
||
| import ( | ||
| "math/big" | ||
|
|
||
| "github.com/holiman/uint256" | ||
| ) | ||
|
|
||
| // Signed wrapper for github.com/holiman/uint256. | ||
| // | ||
| // WARNING: Do not write to pointers until reading from all pointers is complete. This will cause incorrect | ||
| // behavior if the same pointer is passed in through multiple arguments. | ||
|
|
||
| type Int uint256.Int | ||
|
|
||
| var ( | ||
| OneInt256 = NewInt(1) | ||
| TenInt256 = NewInt(10) | ||
| OneMillionInt256 = NewInt(1_000_000) | ||
|
|
||
| exp10Lookup = createExp10Lookup() | ||
| ) | ||
|
|
||
| func (z *Int) String() string { | ||
| if z.Sign() >= 0 { | ||
| return (*uint256.Int)(z).Dec() | ||
| } | ||
| return "-" + (*uint256.Int)(new(uint256.Int).Neg((*uint256.Int)(z))).Dec() | ||
| } | ||
|
|
||
| // NewInt creates a new Int from an int64. | ||
| func NewInt(val int64) *Int { | ||
| if val < 0 { | ||
| u := uint256.NewInt(uint64(-val)) | ||
| return (*Int)(u.Neg(u)) | ||
| } | ||
| return (*Int)(uint256.NewInt(uint64(val))) | ||
| } | ||
|
|
||
| // NewUnsignedInt creates a new Int from a uint64. | ||
| func NewUnsignedInt(val uint64) *Int { | ||
| return (*Int)(uint256.NewInt(uint64(val))) | ||
| } | ||
|
|
||
| // MustFromBig creates a new Int from a big.Int. Panics on failure. | ||
| func MustFromBig(b *big.Int) *Int { | ||
| return (*Int)(uint256.MustFromBig(b)) | ||
| } | ||
|
|
||
| // ToBig converts z to a big.Int. | ||
| func (z *Int) ToBig() *big.Int { | ||
| if z.Sign() >= 0 { | ||
| return (*uint256.Int)(z).ToBig() | ||
| } | ||
| r := new(uint256.Int).Neg((*uint256.Int)(z)).ToBig() | ||
| return r.Neg(r) | ||
| } | ||
|
|
||
| // Set sets z to the value of x. | ||
| func (z *Int) Set(x *Int) *Int { | ||
| return (*Int)((*uint256.Int)(z).Set((*uint256.Int)(x))) | ||
| } | ||
|
|
||
| // Set sets z to the value of a uint256. | ||
| func (z *Int) SetUint64(x uint64) *Int { | ||
| return (*Int)((*uint256.Int)(z).SetUint64(x)) | ||
| } | ||
|
|
||
| // Sign returns -1 if z is negative, 0 if z is zero, and 1 if z is positive. | ||
| func (z *Int) Sign() int { | ||
| return (*uint256.Int)(z).Sign() | ||
| } | ||
|
|
||
| // IsZero returns true iff z is equal to 0. | ||
| func (z *Int) IsZero() bool { | ||
| return (*uint256.Int)(z).IsZero() | ||
| } | ||
|
|
||
| // Eq returns z == x. | ||
| func (z *Int) Eq(x *Int) bool { | ||
| return (*uint256.Int)(z).Eq((*uint256.Int)(x)) | ||
| } | ||
|
|
||
| // Cmp returns -1 if z < x, 0 if z == x, and +1 if z > x. | ||
| func (z *Int) Cmp(x *Int) (r int) { | ||
| if z.Sign() >= 0 { | ||
| if x.Sign() >= 0 { | ||
| return (*uint256.Int)(z).Cmp((*uint256.Int)(x)) | ||
| } else { | ||
| return 1 | ||
| } | ||
| } | ||
| if x.Sign() >= 0 { | ||
| return -1 | ||
| } | ||
| return (*uint256.Int)(z).Cmp((*uint256.Int)(x)) | ||
| } | ||
|
|
||
| // Neg sets z to -x and returns z. | ||
| func (z *Int) Neg(x *Int) *Int { | ||
| return (*Int)((*uint256.Int)(z).Neg((*uint256.Int)(x))) | ||
| } | ||
|
|
||
| // Abs sets z to the absolute value of x and returns z. | ||
| func (z *Int) Abs(x *Int) *Int { | ||
| return (*Int)((*uint256.Int)(z).Abs((*uint256.Int)(x))) | ||
| } | ||
|
|
||
| // Add sets z = x + y and returns z. | ||
| func (z *Int) Add(x, y *Int) *Int { | ||
| return (*Int)((*uint256.Int)(z).Add((*uint256.Int)(x), (*uint256.Int)(y))) | ||
| } | ||
|
|
||
| // Sub sets z = x - y and returns z. | ||
| func (z *Int) Sub(x, y *Int) *Int { | ||
| return (*Int)((*uint256.Int)(z).Sub((*uint256.Int)(x), (*uint256.Int)(y))) | ||
| } | ||
|
|
||
| // Mul sets z = x * y and returns z. | ||
| func (z *Int) Mul(x, y *Int) *Int { | ||
| if x.Sign() > 0 { | ||
| if y.Sign() > 0 { | ||
| return (*Int)( | ||
| (*uint256.Int)(z).Mul( | ||
| (*uint256.Int)(x), | ||
| (*uint256.Int)(y), | ||
| ), | ||
| ) | ||
| } else { | ||
| return z.Neg((*Int)( | ||
| (*uint256.Int)(z).Mul( | ||
| (*uint256.Int)(x), | ||
| new(uint256.Int).Neg((*uint256.Int)(y)), | ||
| ), | ||
| )) | ||
| } | ||
| } | ||
| if y.Sign() > 0 { | ||
| return z.Neg((*Int)( | ||
| (*uint256.Int)(z).Mul( | ||
| new(uint256.Int).Neg((*uint256.Int)(x)), | ||
| (*uint256.Int)(y), | ||
| ), | ||
| )) | ||
| } | ||
| return (*Int)((*uint256.Int)(z).Mul( | ||
| new(uint256.Int).Neg((*uint256.Int)(x)), | ||
| new(uint256.Int).Neg((*uint256.Int)(y)), | ||
| )) | ||
| } | ||
|
|
||
| // Div sets z = x / y and returns z. If y is 0, z is set to 0. | ||
| func (z *Int) Div(x, y *Int) *Int { | ||
| return (*Int)((*uint256.Int)(z).SDiv((*uint256.Int)(x), (*uint256.Int)(y))) | ||
| } | ||
|
|
||
| func createExp10Lookup() map[uint64]uint256.Int { | ||
| lookup := make(map[uint64]uint256.Int, 100) | ||
| value := uint256.NewInt(1) | ||
| for i := 0; i < 100; i++ { | ||
| lookup[uint64(i)] = *new(uint256.Int).Set(value) | ||
| value.Mul(value, (*uint256.Int)(TenInt256)) | ||
| } | ||
| return lookup | ||
| } | ||
|
|
||
| func mulExp10(z *uint256.Int, x *uint256.Int, y int64) *uint256.Int { | ||
| var abs uint64 | ||
| if y < 0 { | ||
| abs = uint64(-y) | ||
| } else { | ||
| abs = uint64(y) | ||
| } | ||
| lookup, ok := exp10Lookup[abs] | ||
| var exp10 *uint256.Int | ||
| if ok { | ||
| exp10 = &lookup | ||
| } else { | ||
| exp10.Exp((*uint256.Int)(TenInt256), uint256.NewInt(abs)) | ||
| } | ||
| if y < 0 { | ||
| return z.Div(x, exp10) | ||
| } else { | ||
| return z.Mul(x, exp10) | ||
| } | ||
| } | ||
|
|
||
| // MulExp10 sets z = x * 10^y and returns z. | ||
| func (z *Int) MulExp10(x *Int, y int64) *Int { | ||
| if x.Sign() >= 0 { | ||
| return (*Int)(mulExp10((*uint256.Int)(z), (*uint256.Int)(x), y)) | ||
| } | ||
| return z.Neg((*Int)(mulExp10((*uint256.Int)(z), (*uint256.Int)(z.Neg(x)), y))) | ||
| } |
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