authorgravatar for quae@daurnimator.comdaurnimator <quae@daurnimator.com> 2020-03-30 21:56:09+11:00
committergravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2020-03-30 11:04:58-04:00
log3be720a729e20720a033f2cf1958311a0112d1f4
tree548ff5bcf2c39a920279968dcd464a202bbe4f1d
parentc1cc1ebc35f7a56669db2f88b6d4ff8f1603ec59

std: mem span functions can take an optional pointer

1 files changed, 38 insertions(+), 14 deletions(-)

lib/std/mem.zig+38-14
......@@ -512,36 +512,54 @@ pub fn toSlice(comptime T: type, ptr: [*:0]T) [:0]T {
512512/// the constness of the input type. `[*c]` pointers are assumed to be 0-terminated,
513513/// and assumed to not allow null.
514514pub fn Span(comptime T: type) type {
515 var ptr_info = @typeInfo(T).Pointer;
516 switch (ptr_info.size) {
517 .One => switch (@typeInfo(ptr_info.child)) {
518 .Array => |info| {
519 ptr_info.child = info.child;
520 ptr_info.sentinel = info.sentinel;
521 },
522 else => @compileError("invalid type given to std.mem.Span"),
515 switch(@typeInfo(T)) {
516 .Optional => |optional_info| {
517 return ?Span(optional_info.child);
523518 },
524 .C => {
525 ptr_info.sentinel = 0;
526 ptr_info.is_allowzero = false;
519 .Pointer => |ptr_info| {
520 var new_ptr_info = ptr_info;
521 switch (ptr_info.size) {
522 .One => switch (@typeInfo(ptr_info.child)) {
523 .Array => |info| {
524 new_ptr_info.child = info.child;
525 new_ptr_info.sentinel = info.sentinel;
526 },
527 else => @compileError("invalid type given to std.mem.Span"),
528 },
529 .C => {
530 new_ptr_info.sentinel = 0;
531 new_ptr_info.is_allowzero = false;
532 },
533 .Many, .Slice => {},
534 }
535 new_ptr_info.size = .Slice;
536 return @Type(std.builtin.TypeInfo{ .Pointer = new_ptr_info });
527537 },
528 .Many, .Slice => {},
538 else => @compileError("invalid type given to std.mem.Span"),
529539 }
530 ptr_info.size = .Slice;
531 return @Type(std.builtin.TypeInfo{ .Pointer = ptr_info });
532540}
533541
534542test "Span" {
535543 testing.expect(Span(*[5]u16) == []u16);
544 testing.expect(Span(?*[5]u16) == ?[]u16);
536545 testing.expect(Span(*const [5]u16) == []const u16);
546 testing.expect(Span(?*const [5]u16) == ?[]const u16);
537547 testing.expect(Span([]u16) == []u16);
548 testing.expect(Span(?[]u16) == ?[]u16);
538549 testing.expect(Span([]const u8) == []const u8);
550 testing.expect(Span(?[]const u8) == ?[]const u8);
539551 testing.expect(Span([:1]u16) == [:1]u16);
552 testing.expect(Span(?[:1]u16) == ?[:1]u16);
540553 testing.expect(Span([:1]const u8) == [:1]const u8);
554 testing.expect(Span(?[:1]const u8) == ?[:1]const u8);
541555 testing.expect(Span([*:1]u16) == [:1]u16);
556 testing.expect(Span(?[*:1]u16) == ?[:1]u16);
542557 testing.expect(Span([*:1]const u8) == [:1]const u8);
558 testing.expect(Span(?[*:1]const u8) == ?[:1]const u8);
543559 testing.expect(Span([*c]u16) == [:0]u16);
560 testing.expect(Span(?[*c]u16) == ?[:0]u16);
544561 testing.expect(Span([*c]const u8) == [:0]const u8);
562 testing.expect(Span(?[*c]const u8) == ?[:0]const u8);
545563}
546564
547565/// Takes a pointer to an array, a sentinel-terminated pointer, or a slice, and
......@@ -553,6 +571,9 @@ test "Span" {
553571/// length value is used instead of the sentinel.
554572pub fn span(ptr: var) Span(@TypeOf(ptr)) {
555573 const Result = Span(@TypeOf(ptr));
574 if (@typeInfo(@TypeOf(ptr)) == .Optional and ptr == null) {
575 return null;
576 }
556577 const l = len(ptr);
557578 if (@typeInfo(Result).Pointer.sentinel) |s| {
558579 return ptr[0..l :s];
......@@ -573,6 +594,9 @@ test "span" {
573594/// rather than using the length.
574595pub fn spanZ(ptr: var) Span(@TypeOf(ptr)) {
575596 const Result = Span(@TypeOf(ptr));
597 if (@typeInfo(@TypeOf(ptr)) == .Optional and ptr == null) {
598 return null;
599 }
576600 const l = lenZ(ptr);
577601 if (@typeInfo(Result).Pointer.sentinel) |s| {
578602 return ptr[0..l :s];