Span

Takes a sentinel-terminated pointer and returns a slice preserving pointer attributes. [*c] pointers are assumed to be 0-terminated and assumed to not be allowzero.

Source

Implementation

fn Span(comptime T: type) type {
    switch (@typeInfo(T)) {
        .optional => |optional_info| {
            return ?Span(optional_info.child);
        },
        .pointer => |ptr_info| {
            var new_ptr_info = ptr_info;
            switch (ptr_info.size) {
                .c => {
                    new_ptr_info.sentinel_ptr = &@as(ptr_info.child, 0);
                    new_ptr_info.is_allowzero = false;
                },
                .many => if (ptr_info.sentinel() == null) @compileError("invalid type given to std.mem.span: " ++ @typeName(T)),
                .one, .slice => @compileError("invalid type given to std.mem.span: " ++ @typeName(T)),
            }
            new_ptr_info.size = .slice;
            return @Type(.{ .pointer = new_ptr_info });
        },
        else => {},
    }
    @compileError("invalid type given to std.mem.span: " ++ @typeName(T));
}