Zig 0.17.0-dev (Split by item)

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readVecPositional

Reader.readVecPositional

fn readVecPositional(r: *Reader, data: [][]u8) Io.Reader.Error!usize

File

lib/std/Io/File/Reader.zig:241

Code

fn readVecPositional(r: *Reader, data: [][]u8) Io.Reader.Error!usize {
    const io = r.io;
    var iovecs_buffer: [max_buffers_len][]u8 = undefined;
    const dest_n, const data_size = try r.interface.writableVector(&iovecs_buffer, data);
    const dest = iovecs_buffer[0..dest_n];
    assert(dest[0].len > 0);
    const n = io.vtable.fileReadPositional(io.userdata, r.file, dest, r.pos) catch |err| switch (err) {
        error.Unseekable => {
            r.mode = r.mode.toStreaming();
            const pos = r.pos;
            if (pos != 0) {
                r.pos = 0;
                r.seekBy(@intCast(pos)) catch {
                    r.mode = .failure;
                    return error.ReadFailed;
                };
            }
            return 0;
        },
        else => |e| {
            r.err = e;
            return error.ReadFailed;
        },
    };
    if (n == 0) {
        r.size = r.pos;
        return error.EndOfStream;
    }
    r.pos += n;
    if (n > data_size) {
        r.interface.end += n - data_size;
        return data_size;
    }
    return n;
}