| // Copyright 2026 The Go 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 spec |
| |
| import ( |
| "math" |
| "testing" |
| ) |
| |
| func assertEq[T comparable](t *testing.T, got, want T, msg string) { |
| t.Helper() |
| if got != want { |
| t.Errorf("%s: got %v, want %v", msg, got, want) |
| } |
| } |
| |
| func TestIsSigned(t *testing.T) { |
| assertEq(t, isSigned[int8](), true, "isSigned[int8]()") |
| assertEq(t, isSigned[uint8](), false, "isSigned[uint8]()") |
| assertEq(t, isSigned[int16](), true, "isSigned[int16]()") |
| assertEq(t, isSigned[uint16](), false, "isSigned[uint16]()") |
| assertEq(t, isSigned[int32](), true, "isSigned[int32]()") |
| assertEq(t, isSigned[uint32](), false, "isSigned[uint32]()") |
| assertEq(t, isSigned[int64](), true, "isSigned[int64]()") |
| assertEq(t, isSigned[uint64](), false, "isSigned[uint64]()") |
| } |
| |
| func TestMaxVal(t *testing.T) { |
| assertEq(t, maxVal[int8](), int8(math.MaxInt8), "maxVal[int8]") |
| assertEq(t, maxVal[uint8](), uint8(math.MaxUint8), "maxVal[uint8]") |
| assertEq(t, maxVal[int16](), int16(math.MaxInt16), "maxVal[int16]") |
| assertEq(t, maxVal[uint16](), uint16(math.MaxUint16), "maxVal[uint16]") |
| assertEq(t, maxVal[int32](), int32(math.MaxInt32), "maxVal[int32]") |
| assertEq(t, maxVal[uint32](), uint32(math.MaxUint32), "maxVal[uint32]") |
| assertEq(t, maxVal[int64](), int64(math.MaxInt64), "maxVal[int64]") |
| assertEq(t, maxVal[uint64](), uint64(math.MaxUint64), "maxVal[uint64]") |
| } |
| |
| func TestMinVal(t *testing.T) { |
| assertEq(t, minVal[int8](), int8(math.MinInt8), "minVal[int8]") |
| assertEq(t, minVal[uint8](), uint8(0), "minVal[uint8]") |
| assertEq(t, minVal[int16](), int16(math.MinInt16), "minVal[int16]") |
| assertEq(t, minVal[uint16](), uint16(0), "minVal[uint16]") |
| assertEq(t, minVal[int32](), int32(math.MinInt32), "minVal[int32]") |
| assertEq(t, minVal[uint32](), uint32(0), "minVal[uint32]") |
| assertEq(t, minVal[int64](), int64(math.MinInt64), "minVal[int64]") |
| assertEq(t, minVal[uint64](), uint64(0), "minVal[uint64]") |
| } |
| |
| func TestSaturate(t *testing.T) { |
| // saturate[T Ints | Uints, U Ints | Uints](x T) U |
| |
| // Signed to signed: int16 -> int8 |
| assertEq(t, saturate[int16, int8](126), int8(126), "saturate[int16, int8](126)") |
| assertEq(t, saturate[int16, int8](-127), int8(-127), "saturate[int16, int8](-127)") |
| assertEq(t, saturate[int16, int8](128), int8(math.MaxInt8), "saturate[int16, int8](128) overflow") |
| assertEq(t, saturate[int16, int8](-129), int8(math.MinInt8), "saturate[int16, int8](-129) underflow") |
| |
| // Unsigned to unsigned: uint16 -> uint8 |
| assertEq(t, saturate[uint16, uint8](254), uint8(254), "saturate[uint16, uint8](254)") |
| assertEq(t, saturate[uint16, uint8](256), uint8(math.MaxUint8), "saturate[uint16, uint8](256) overflow") |
| |
| // Signed to unsigned: int16 -> uint8 |
| assertEq(t, saturate[int16, uint8](1), uint8(1), "saturate[int16, uint8](1)") |
| assertEq(t, saturate[int16, uint8](-1), uint8(0), "saturate[int16, uint8](-1) underflow") |
| assertEq(t, saturate[int16, uint8](254), uint8(254), "saturate[int16, uint8](254)") |
| assertEq(t, saturate[int16, uint8](256), uint8(math.MaxUint8), "saturate[int16, uint8](256) overflow") |
| |
| // Unsigned to signed: uint16 -> int8 |
| assertEq(t, saturate[uint16, int8](126), int8(126), "saturate[uint16, int8](126)") |
| assertEq(t, saturate[uint16, int8](128), int8(math.MaxInt8), "saturate[uint16, int8](128) overflow") |
| |
| // Wider bounds: int64 to int32 |
| assertEq(t, saturate[int64, int32](math.MaxInt32-1), int32(math.MaxInt32-1), "saturate[int64, int32](MaxInt32-1)") |
| assertEq(t, saturate[int64, int32](math.MaxInt32+1), int32(math.MaxInt32), "saturate[int64, int32](MaxInt32+1) overflow") |
| assertEq(t, saturate[int64, int32](math.MinInt32+1), int32(math.MinInt32+1), "saturate[int64, int32](MinInt32+1)") |
| assertEq(t, saturate[int64, int32](math.MinInt32-1), int32(math.MinInt32), "saturate[int64, int32](MinInt32-1) underflow") |
| } |
| |
| func TestAddSaturated(t *testing.T) { |
| // Signed int8 |
| assertEq(t, addSaturated[int8](125, 1), int8(126), "addSaturated[int8](125, 1)") |
| assertEq(t, addSaturated[int8](120, 10), int8(math.MaxInt8), "addSaturated[int8](120, 10) overflow") |
| assertEq(t, addSaturated[int8](-126, -1), int8(-127), "addSaturated[int8](-126, -1)") |
| assertEq(t, addSaturated[int8](-120, -10), int8(math.MinInt8), "addSaturated[int8](-120, -10) underflow") |
| |
| // Unsigned uint8 |
| assertEq(t, addSaturated[uint8](253, 1), uint8(254), "addSaturated[uint8](253, 1)") |
| assertEq(t, addSaturated[uint8](250, 10), uint8(math.MaxUint8), "addSaturated[uint8](250, 10) overflow") |
| assertEq(t, addSaturated[uint8](254, 0), uint8(254), "addSaturated[uint8](254, 0)") |
| |
| // Signed int64 |
| assertEq(t, addSaturated[int64](math.MaxInt64-2, 1), int64(math.MaxInt64-1), "addSaturated[int64](MaxInt64-2, 1)") |
| assertEq(t, addSaturated[int64](math.MaxInt64-5, 10), int64(math.MaxInt64), "addSaturated[int64](max-5, 10) overflow") |
| assertEq(t, addSaturated[int64](math.MinInt64+2, -1), int64(math.MinInt64+1), "addSaturated[int64](MinInt64+2, -1)") |
| assertEq(t, addSaturated[int64](math.MinInt64+5, -10), int64(math.MinInt64), "addSaturated[int64](min+5, -10) underflow") |
| |
| // Unsigned uint64 |
| assertEq(t, addSaturated[uint64](math.MaxUint64-2, 1), uint64(math.MaxUint64-1), "addSaturated[uint64](MaxUint64-2, 1)") |
| assertEq(t, addSaturated[uint64](math.MaxUint64-5, 10), uint64(math.MaxUint64), "addSaturated[uint64](max-5, 10) overflow") |
| } |
| |
| func TestMulSaturatedUSS(t *testing.T) { |
| // mulSaturatedUSS[X Uints, Y Ints](x X, y Y) Y |
| |
| // uint8, int8 |
| assertEq(t, mulSaturatedUSS[uint8, int8](0, 10), int8(0), "mulSaturatedUSS[uint8, int8](0, 10)") |
| assertEq(t, mulSaturatedUSS[uint8, int8](10, 0), int8(0), "mulSaturatedUSS[uint8, int8](10, 0)") |
| assertEq(t, mulSaturatedUSS[uint8, int8](2, 63), int8(126), "mulSaturatedUSS[uint8, int8](2, 63)") |
| assertEq(t, mulSaturatedUSS[uint8, int8](1, 126), int8(126), "mulSaturatedUSS[uint8, int8](1, 126)") |
| assertEq(t, mulSaturatedUSS[uint8, int8](1, -127), int8(-127), "mulSaturatedUSS[uint8, int8](1, -127)") |
| assertEq(t, mulSaturatedUSS[uint8, int8](10, 20), int8(math.MaxInt8), "mulSaturatedUSS[uint8, int8](10, 20) positive overflow") |
| assertEq(t, mulSaturatedUSS[uint8, int8](10, -20), int8(math.MinInt8), "mulSaturatedUSS[uint8, int8](10, -20) negative overflow") |
| |
| // uint64, int64 |
| assertEq(t, mulSaturatedUSS[uint64, int64](2, (math.MaxInt64-1)/2), int64(math.MaxInt64-1), "mulSaturatedUSS[uint64, int64](2, (MaxInt64-1)/2)") |
| assertEq(t, mulSaturatedUSS[uint64, int64](2, math.MaxInt64), int64(math.MaxInt64), "mulSaturatedUSS[uint64, int64](2, MaxInt64) overflow") |
| assertEq(t, mulSaturatedUSS[uint64, int64](2, (math.MinInt64/2)+1), int64(math.MinInt64+2), "mulSaturatedUSS[uint64, int64](2, (MinInt64/2)+1)") |
| assertEq(t, mulSaturatedUSS[uint64, int64](2, math.MinInt64), int64(math.MinInt64), "mulSaturatedUSS[uint64, int64](2, MinInt64) underflow") |
| assertEq(t, mulSaturatedUSS[uint64, int64](math.MaxUint64, 1), int64(math.MaxInt64), "mulSaturatedUSS[uint64, int64](MaxUint64, 1) overflow") |
| assertEq(t, mulSaturatedUSS[uint64, int64](math.MaxUint64, -1), int64(math.MinInt64), "mulSaturatedUSS[uint64, int64](MaxUint64, -1) underflow") |
| } |
