From bd1412b764bc9ae25f8271de8e76cacb0a614cc0 Mon Sep 17 00:00:00 2001 From: Alexandr Stefurishin Date: Mon, 9 Dec 2024 14:25:56 +0300 Subject: [PATCH] Convert function, minor improvements (#1) * Convert function, minor improvements * fix readme * Should probably just retain the original license without adding all contributors --- LICENSE | 2 +- README.md | 25 +++----- overflow.go | 26 +++++--- overflow_test.go | 152 ++++++++++++++++++++++++++++++++++++++++++++++- 4 files changed, 177 insertions(+), 28 deletions(-) diff --git a/LICENSE b/LICENSE index c42e2ee..23f7bdf 100644 --- a/LICENSE +++ b/LICENSE @@ -1,6 +1,6 @@ MIT License -Copyright (c) 2023 Antonio Cheong +Copyright (c) 2024 John C. Griffin Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal diff --git a/README.md b/README.md index 93c2cdd..c55bab7 100644 --- a/README.md +++ b/README.md @@ -25,31 +25,20 @@ Function signatures: https://pkg.go.dev/github.com/g-utils/overflow ```go package overflow -type number interface { +type Int interface { int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64 } -func Add[T number](a, b T) (T, bool) -func Sub[T number](a, b T) (T, bool) -func Mul[T number](a, b T) (T, bool) -func Div[T number](a, b T) (T, bool) -func Quotient[T number](a, b T) (T, T, bool) +func Add[T Int](a, b T) (T, bool) +func Sub[T Int](a, b T) (T, bool) +func Mul[T Int](a, b T) (T, bool) +func Div[T Int](a, b T) (T, bool) +func Quotient[T Int](a, b T) (T, T, bool) +func Convert[T Int, U Int](a T) (U, bool) ``` - - # Copyright / License This is a fork of https://github.com/JohnCGriffin/overflow. Generics were added to Golang in Go 1.18 (2022) and is used in place of build time code generators. Tests for unsigned integers have also been added from github.com/rwxe/overflow in case my logic is incorrect. - -``` -Copyright (c) 2017 John C. Griffin, - -Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: - -The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. - -THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. -``` diff --git a/overflow.go b/overflow.go index 0d43fde..fa64cdd 100644 --- a/overflow.go +++ b/overflow.go @@ -1,10 +1,10 @@ package overflow -type number interface { +type Int interface { int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64 } -func Add[T number](a, b T) (T, bool) { +func Add[T Int](a, b T) (T, bool) { c := a + b if (c > a) == (b > 0) { return c, true @@ -12,7 +12,7 @@ func Add[T number](a, b T) (T, bool) { return c, false } -func Sub[T number](a, b T) (T, bool) { +func Sub[T Int](a, b T) (T, bool) { c := a - b if (c < a) == (b > 0) { return c, true @@ -20,7 +20,7 @@ func Sub[T number](a, b T) (T, bool) { return c, false } -func Mul[T number](a, b T) (T, bool) { +func Mul[T Int](a, b T) (T, bool) { if a == 0 || b == 0 { return 0, true } @@ -32,15 +32,25 @@ func Mul[T number](a, b T) (T, bool) { } return c, false } -func Div[T number](a, b T) (T, bool) { + +func Div[T Int](a, b T) (T, bool) { q, _, ok := Quotient(a, b) return q, ok } -func Quotient[T number](a, b T) (T, T, bool) { + +func Quotient[T Int](a, b T) (T, T, bool) { if b == 0 { return 0, 0, false } c := a / b - status := (c < 0) == ((a < 0) != (b < 0)) - return c, a % b, status + ok := (c < 0) == ((a < 0) != (b < 0)) + return c, a % b, ok +} + +func Convert[T Int, U Int](a T) (U, bool) { + b := U(a) + if T(b) == a && (a < 0) == (b < 0) { + return b, true + } + return b, false } diff --git a/overflow_test.go b/overflow_test.go index bf5d9d9..04259b2 100644 --- a/overflow_test.go +++ b/overflow_test.go @@ -3,8 +3,9 @@ package overflow_test import ( "math" "testing" + + "github.com/g-utils/overflow" ) -import "github.com/g-utils/overflow" // sample all possibilities of 8 bit numbers // by checking against 64 bit numbers @@ -287,3 +288,152 @@ func TestAlgorithmsUintImpl2(t *testing.T) { } } + +func TestConvert(t *testing.T) { + // int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 + + t.Run("positive: uint64->unsigned", func(t *testing.T) { + t.Parallel() + for i := uint64(0); i <= math.MaxUint8; i++ { + testConvert4[uint64, uint64, uint32, uint16, uint8](t, i, true) + } + testConvert3[uint64, uint64, uint32, uint16](t, math.MaxUint16-1, true) + testConvert3[uint64, uint64, uint32, uint16](t, math.MaxUint16, true) + testConvert2[uint64, uint64, uint32](t, math.MaxUint32-1, true) + testConvert2[uint64, uint64, uint32](t, math.MaxUint32, true) + testConvert1[uint64, uint64](t, math.MaxUint64-1, true) + testConvert1[uint64, uint64](t, math.MaxUint64, true) + }) + + t.Run("negative: uint64->unsigned", func(t *testing.T) { + for i := uint64(math.MaxUint32 + 1); i <= uint64(math.MaxUint32+math.MaxUint8+1); i++ { + testConvert3[uint64, uint32, uint16, uint8](t, i, false) + } + testConvert2[uint64, uint16, uint8](t, math.MaxUint16+1, false) + testConvert1[uint64, uint8](t, math.MaxUint8+1, false) + }) + + t.Run("positive: uint64->signed", func(t *testing.T) { + for i := uint64(0); i <= math.MaxInt8; i++ { + testConvert4[uint64, int64, int32, int16, int8](t, i, true) + } + testConvert3[uint64, int64, int32, int16](t, math.MaxInt16-1, true) + testConvert3[uint64, int64, int32, int16](t, math.MaxInt16, true) + testConvert2[uint64, int64, int32](t, math.MaxInt32-1, true) + testConvert2[uint64, int64, int32](t, math.MaxInt32, true) + testConvert1[uint64, int64](t, math.MaxInt64-1, true) + testConvert1[uint64, int64](t, math.MaxInt64, true) + }) + + t.Run("negative: uint64->signed", func(t *testing.T) { + for i := uint64(math.MaxInt64 + 1); i <= uint64(math.MaxInt64+math.MaxUint8+1); i++ { + testConvert4[uint64, int64, int32, int16, int8](t, i, false) + } + testConvert4[uint64, int64, int32, int16, int8](t, math.MaxUint64, false) + testConvert4[uint64, int64, int32, int16, int8](t, math.MaxUint64-1, false) + testConvert3[uint64, int32, int16, int8](t, math.MaxInt32+1, false) + testConvert2[uint64, int16, int8](t, math.MaxInt16+1, false) + testConvert1[uint64, int8](t, math.MaxInt8+1, false) + }) + + t.Run("positive: int64->signed", func(t *testing.T) { + for i := int64(math.MinInt8); i <= math.MaxInt8; i++ { + testConvert4[int64, int64, int32, int16, int8](t, i, true) + } + testConvert3[int64, int64, int32, int16](t, math.MinInt16, true) + testConvert3[int64, int64, int32, int16](t, math.MinInt16+1, true) + testConvert3[int64, int64, int32, int16](t, math.MaxInt16-1, true) + testConvert3[int64, int64, int32, int16](t, math.MaxInt16, true) + testConvert2[int64, int64, int32](t, math.MinInt32, true) + testConvert2[int64, int64, int32](t, math.MinInt32+1, true) + testConvert2[int64, int64, int32](t, math.MaxInt32-1, true) + testConvert2[int64, int64, int32](t, math.MaxInt32, true) + testConvert1[int64, int64](t, math.MinInt64, true) + testConvert1[int64, int64](t, math.MinInt64+1, true) + testConvert1[int64, int64](t, math.MaxInt64-1, true) + testConvert1[int64, int64](t, math.MaxInt64, true) + }) + + t.Run("negative: int64->signed", func(t *testing.T) { + for i := int64(math.MaxInt32 + 1); i <= int64(math.MaxInt32+math.MaxInt8+1); i++ { + testConvert3[int64, int32, int16, int8](t, i, false) + } + testConvert2[int64, int16, int8](t, math.MaxInt16+1, false) + testConvert1[int64, int8](t, math.MaxInt8+1, false) + }) + + t.Run("positive: int64->unsigned", func(t *testing.T) { + for i := int64(0); i <= math.MaxUint8; i++ { + testConvert4[int64, uint64, uint32, uint16, uint8](t, i, true) + } + testConvert3[int64, uint64, uint32, uint16](t, math.MaxUint16-1, true) + testConvert3[int64, uint64, uint32, uint16](t, math.MaxUint16, true) + testConvert2[int64, uint64, uint32](t, math.MaxUint32-1, true) + testConvert2[int64, uint64, uint32](t, math.MaxUint32, true) + testConvert1[int64, uint64](t, math.MaxInt64-1, true) + testConvert1[int64, uint64](t, math.MaxInt64, true) + }) + + t.Run("negative: int64->unsigned", func(t *testing.T) { + testConvert4[int64, uint64, uint32, uint16, uint8](t, math.MinInt64, false) + testConvert4[int64, uint64, uint32, uint16, uint8](t, math.MinInt64+1, false) + testConvert4[int64, uint64, uint32, uint16, uint8](t, -1, false) + testConvert3[int64, uint32, uint16, uint8](t, math.MaxUint32+1, false) + testConvert2[int64, uint16, int8](t, math.MaxUint16+1, false) + for i := int64(math.MaxUint8 + 1); i <= math.MaxUint8+math.MaxUint8+2; i++ { + testConvert1[int64, uint8](t, i, false) + } + }) + + t.Run("negative: int32|16|8->uint64", func(t *testing.T) { + testConvert1[int32, uint64](t, -1, false) + testConvert1[int32, uint64](t, math.MinInt32, false) + testConvert1[int16, uint64](t, -1, false) + testConvert1[int16, uint64](t, math.MinInt16, false) + testConvert1[int8, uint64](t, -1, false) + testConvert1[int8, uint64](t, math.MinInt8, false) + }) + + // already covered by reverse conversion checks: + // - "positive [u]int32|16|8 -> [u]int64" + + // impossible cases: + // "negative uint32|16|8 -> [u]int64" + // "negative [u]int32|16|8 -> int64" +} + +func testConvert4[T overflow.Int, U1 overflow.Int, U2 overflow.Int, U3 overflow.Int, U4 overflow.Int](t *testing.T, a T, expectOk bool) { + t.Helper() + testConvert2[T, U1, U2](t, a, expectOk) + testConvert2[T, U3, U4](t, a, expectOk) +} + +func testConvert3[T overflow.Int, U1 overflow.Int, U2 overflow.Int, U3 overflow.Int](t *testing.T, a T, expectOk bool) { + t.Helper() + testConvert1[T, U1](t, a, expectOk) + testConvert1[T, U2](t, a, expectOk) + testConvert1[T, U3](t, a, expectOk) +} + +func testConvert2[T overflow.Int, U1 overflow.Int, U2 overflow.Int](t *testing.T, a T, expectOk bool) { + t.Helper() + testConvert1[T, U1](t, a, expectOk) + testConvert1[T, U2](t, a, expectOk) +} + +func testConvert1[T overflow.Int, U overflow.Int](t *testing.T, a T, expectOk bool) { + t.Helper() + if b, ok := overflow.Convert[T, U](a); expectOk && !ok { + t.Error("expected ok, got overflow: ", b) + } else if !expectOk && ok { + t.Error("expected overflow, got ok: ", b) + } else if a2, ok2 := overflow.Convert[U, T](b); ok && !ok2 { + t.Error("expected ok, got ok, but reverse conversion overflowed: ", a2) + } +} + +func BenchmarkConvert(b *testing.B) { + for i := int64(-1_000_000_000); i < 1_000_000_000; i++ { + _, _ = overflow.Convert[int64, uint64](i) + } +}