mirror of
https://github.com/luxfi/math.git
synced 2026-07-27 03:38:49 +00:00
Zach Kelling
fd27f2ecb0
- Create math/big for big.Int utilities (HexOrDecimal256, U256, parsing) - Create math/safe for overflow-safe arithmetic (SafeAdd, SafeMul, etc.) - Move averager files to root package level - Add re-exports in root package for backwards compatibility - Update README with new package structure documentation - Remove old math/meter directory (consolidated elsewhere) - Remove redundant math/ subdirectory structure
82 lines
1.6 KiB
Go
82 lines
1.6 KiB
Go
// Copyright (C) 2019-2025, Lux Industries Inc. All rights reserved.
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// See the file LICENSE for licensing terms.
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// Package safe provides overflow-safe arithmetic operations.
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package safe
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import (
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"errors"
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"math"
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"math/bits"
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"golang.org/x/exp/constraints"
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)
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var (
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ErrOverflow = errors.New("overflow")
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ErrUnderflow = errors.New("underflow")
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)
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// Add64 returns a + b, or error if overflow.
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func Add64(a, b uint64) (uint64, error) {
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if a > math.MaxUint64-b {
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return 0, ErrOverflow
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}
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return a + b, nil
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}
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// Sub returns a - b, or error if underflow.
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func Sub[T constraints.Unsigned](a, b T) (T, error) {
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if a < b {
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return 0, ErrUnderflow
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}
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return a - b, nil
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}
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// Mul64 returns a * b, or error if overflow.
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func Mul64(a, b uint64) (uint64, error) {
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if b != 0 && a > math.MaxUint64/b {
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return 0, ErrOverflow
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}
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return a * b, nil
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}
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// SafeAdd returns x+y and whether overflow occurred.
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func SafeAdd(x, y uint64) (uint64, bool) {
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sum, carryOut := bits.Add64(x, y, 0)
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return sum, carryOut != 0
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}
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// SafeSub returns x-y and whether underflow occurred.
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func SafeSub(x, y uint64) (uint64, bool) {
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diff, borrowOut := bits.Sub64(x, y, 0)
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return diff, borrowOut != 0
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}
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// SafeMul returns x*y and whether overflow occurred.
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func SafeMul(x, y uint64) (uint64, bool) {
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hi, lo := bits.Mul64(x, y)
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return lo, hi != 0
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}
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// AbsDiff returns |a - b|.
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func AbsDiff[T constraints.Unsigned](a, b T) T {
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return max(a, b) - min(a, b)
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}
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// Min returns the minimum of two uint64 values.
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func Min(a, b uint64) uint64 {
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if a < b {
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return a
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}
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return b
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}
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// Max returns the maximum of two uint64 values.
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func Max(a, b uint64) uint64 {
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if a > b {
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return a
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}
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return b
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}
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