authorgravatar for quae@daurnimator.comdaurnimator <quae@daurnimator.com> 2020-04-27 02:50:32+10:00
committergravatar for quae@daurnimator.comdaurnimator <quae@daurnimator.com> 2020-04-27 02:50:32+10:00
log122b992a958d339e9331319db6788e44ee6591b2
treefeb5fe3164e3343e460de80e54757346fa5f7add
parentd44c9bdbd9c6add603997a834506ddd165a70cd4
signature Commit is signed but in an unrecognized format.

std: add io.MultiOutStream

2 files changed, 57 insertions(+), 0 deletions(-)

lib/std/io.zig+3
...@@ -110,6 +110,9 @@ pub const cOutStream = @import("io/c_out_stream.zig").cOutStream;...@@ -110,6 +110,9 @@ pub const cOutStream = @import("io/c_out_stream.zig").cOutStream;
110pub const CountingOutStream = @import("io/counting_out_stream.zig").CountingOutStream;110pub const CountingOutStream = @import("io/counting_out_stream.zig").CountingOutStream;
111pub const countingOutStream = @import("io/counting_out_stream.zig").countingOutStream;111pub const countingOutStream = @import("io/counting_out_stream.zig").countingOutStream;
112112
113pub const MultiOutStream = @import("io/multi_out_stream.zig").MultiOutStream;
114pub const multiOutStream = @import("io/multi_out_stream.zig").multiOutStream;
115
113pub const BitInStream = @import("io/bit_in_stream.zig").BitInStream;116pub const BitInStream = @import("io/bit_in_stream.zig").BitInStream;
114pub const bitInStream = @import("io/bit_in_stream.zig").bitInStream;117pub const bitInStream = @import("io/bit_in_stream.zig").bitInStream;
115118
lib/std/io/multi_out_stream.zig created+54
...@@ -0,0 +1,54 @@
1const std = @import("../std.zig");
2const io = std.io;
3const testing = std.testing;
4
5/// Takes a tuple of streams, and constructs a new stream that writes to all of them
6pub fn MultiOutStream(comptime OutStreams: type) type {
7 comptime var ErrSet = error{};
8 inline for (@typeInfo(OutStreams).Struct.fields) |field| {
9 const StreamType = field.field_type;
10 ErrSet = ErrSet || StreamType.Error;
11 }
12
13 return struct {
14 const Self = @This();
15
16 streams: OutStreams,
17
18 pub const Error = ErrSet;
19 pub const OutStream = io.OutStream(*Self, Error, write);
20 pub fn outStream(self: *Self) OutStream {
21 return .{ .context = self };
22 }
23
24 pub fn write(self: *Self, bytes: []const u8) Error!usize {
25 if (comptime self.streams.len == 0) return bytes.len;
26
27 // only first stream is allowed to do a partial write
28 // all subsequent streams do a `.writeAll`
29 const bytes_to_write = try self.streams[0].write(bytes);
30 const slice_to_write = bytes[0..bytes_to_write];
31 comptime var i = 1;
32 inline while (i < self.streams.len) : (i += 1) {
33 const stream = self.streams[i];
34 try stream.writeAll(slice_to_write);
35 }
36 return bytes_to_write;
37 }
38 };
39}
40
41pub fn multiOutStream(streams: var) MultiOutStream(@TypeOf(streams)) {
42 return .{ .streams = streams };
43}
44
45test "MultiOutStream" {
46 var buf1: [255]u8 = undefined;
47 var fbs1 = io.fixedBufferStream(&buf1);
48 var buf2: [255]u8 = undefined;
49 var fbs2 = io.fixedBufferStream(&buf2);
50 var stream = multiOutStream(.{fbs1.outStream(), fbs2.outStream()});
51 try stream.outStream().print("HI", .{});
52 testing.expectEqualSlices(u8, "HI", fbs1.getWritten());
53 testing.expectEqualSlices(u8, "HI", fbs2.getWritten());
54}