motiejus/zig
1
Fork 0
Code Releases Activity

math: make cast return optional instead of an error

Browse Source
This commit is contained in:
Ali Chraghi
2022-05-22 19:36:59 +04:30
committed by Andrew Kelley
parent ddd5b57045
commit 0e6285c8fc
37 changed files with 152 additions and 175 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
lib/std/math.zig
View File

@@ -989,28 +989,27 @@ test "negateCast" {
}
/// Cast an integer to a different integer type. If the value doesn't fit,
/// return an error.
/// TODO make this an optional not an error.
pub fn cast(comptime T: type, x: anytype) (error{Overflow}!T) {
/// return null.
pub fn cast(comptime T: type, x: anytype) ?T {
comptime assert(@typeInfo(T) == .Int); // must pass an integer
comptime assert(@typeInfo(@TypeOf(x)) == .Int); // must pass an integer
if (maxInt(@TypeOf(x)) > maxInt(T) and x > maxInt(T)) {
return error.Overflow;
return null;
} else if (minInt(@TypeOf(x)) < minInt(T) and x < minInt(T)) {
return error.Overflow;
return null;
} else {
return @intCast(T, x);
}
}
test "cast" {
try testing.expectError(error.Overflow, cast(u8, @as(u32, 300)));
try testing.expectError(error.Overflow, cast(i8, @as(i32, -200)));
try testing.expectError(error.Overflow, cast(u8, @as(i8, -1)));
try testing.expectError(error.Overflow, cast(u64, @as(i8, -1)));
try testing.expect(cast(u8, @as(u32, 300)) == null);
try testing.expect(cast(i8, @as(i32, -200)) == null);
try testing.expect(cast(u8, @as(i8, -1)) == null);
try testing.expect(cast(u64, @as(i8, -1)) == null);
try testing.expect((try cast(u8, @as(u32, 255))) == @as(u8, 255));
try testing.expect(@TypeOf(try cast(u8, @as(u32, 255))) == u8);
try testing.expect(cast(u8, @as(u32, 255)).? == @as(u8, 255));
try testing.expect(@TypeOf(cast(u8, @as(u32, 255)).?) == u8);
}
pub const AlignCastError = error{UnalignedMemory};