diff --git a/lib/std/math.zig b/lib/std/math.zig index b76c4694b2..de9f5e349d 100644 --- a/lib/std/math.zig +++ b/lib/std/math.zig @@ -596,6 +596,59 @@ fn testDivFloor() void { testing.expect((divFloor(f32, -5.0, 3.0) catch unreachable) == -2.0); } +pub fn divCeil(comptime T: type, numerator: T, denominator: T) !T { + @setRuntimeSafety(false); + if (comptime std.meta.trait.isNumber(T) and denominator == 0) return error.DivisionByZero; + const info = @typeInfo(T); + switch (info) { + .ComptimeFloat, .Float => return @ceil(numerator / denominator), + .ComptimeInt, .Int => { + if (numerator < 0 and denominator < 0) { + if (info == .Int and numerator == minInt(T) and denominator == -1) + return error.Overflow; + return @divFloor(numerator + 1, denominator) + 1; + } + if (numerator > 0 and denominator > 0) + return @divFloor(numerator - 1, denominator) + 1; + return @divTrunc(numerator, denominator); + }, + else => @compileError("divCeil unsupported on " ++ @typeName(T)), + } +} + +test "math.divCeil" { + testDivCeil(); + comptime testDivCeil(); +} +fn testDivCeil() void { + testing.expectEqual(@as(i32, 2), divCeil(i32, 5, 3) catch unreachable); + testing.expectEqual(@as(i32, -1), divCeil(i32, -5, 3) catch unreachable); + testing.expectEqual(@as(i32, -1), divCeil(i32, 5, -3) catch unreachable); + testing.expectEqual(@as(i32, 2), divCeil(i32, -5, -3) catch unreachable); + testing.expectEqual(@as(i32, 0), divCeil(i32, 0, 5) catch unreachable); + testing.expectEqual(@as(u32, 0), divCeil(u32, 0, 5) catch unreachable); + testing.expectError(error.DivisionByZero, divCeil(i8, -5, 0)); + testing.expectError(error.Overflow, divCeil(i8, -128, -1)); + + testing.expectEqual(@as(f32, 0.0), divCeil(f32, 0.0, 5.0) catch unreachable); + testing.expectEqual(@as(f32, 2.0), divCeil(f32, 5.0, 3.0) catch unreachable); + testing.expectEqual(@as(f32, -1.0), divCeil(f32, -5.0, 3.0) catch unreachable); + testing.expectEqual(@as(f32, -1.0), divCeil(f32, 5.0, -3.0) catch unreachable); + testing.expectEqual(@as(f32, 2.0), divCeil(f32, -5.0, -3.0) catch unreachable); + + testing.expectEqual(6, divCeil(comptime_int, 23, 4) catch unreachable); + testing.expectEqual(-5, divCeil(comptime_int, -23, 4) catch unreachable); + testing.expectEqual(-5, divCeil(comptime_int, 23, -4) catch unreachable); + testing.expectEqual(6, divCeil(comptime_int, -23, -4) catch unreachable); + testing.expectError(error.DivisionByZero, divCeil(comptime_int, 23, 0)); + + testing.expectEqual(6.0, divCeil(comptime_float, 23.0, 4.0) catch unreachable); + testing.expectEqual(-5.0, divCeil(comptime_float, -23.0, 4.0) catch unreachable); + testing.expectEqual(-5.0, divCeil(comptime_float, 23.0, -4.0) catch unreachable); + testing.expectEqual(6.0, divCeil(comptime_float, -23.0, -4.0) catch unreachable); + testing.expectError(error.DivisionByZero, divCeil(comptime_float, 23.0, 0.0)); +} + pub fn divExact(comptime T: type, numerator: T, denominator: T) !T { @setRuntimeSafety(false); if (denominator == 0) return error.DivisionByZero;