const std = @import("std");

const BinaryEncoder = struct {
    buf: []u8,
    byte_index: usize = 0,
    bit_index: u8 = 0,

    pub fn init(buf: []u8) BinaryEncoder {
        const be = BinaryEncoder{ .buf = buf };
        @memset(buf, 0);

        return be;
    }

    pub fn write(this: *@This(), value: u8, bit_width: u8) void {
        const shift_left: u3 = @intCast(this.bit_index);
        this.buf[this.byte_index] |= value << shift_left;

        if (this.bit_index + bit_width > 8) {
            const shift_right: u3 = @intCast(8 - this.bit_index);
            this.buf[this.byte_index + 1] |= value >> shift_right;

            this.bit_index = bit_width - shift_right;
        } else if (this.bit_index + bit_width == 8) {
            this.bit_index = 0;
            this.byte_index += 1;
        } else {
            this.bit_index += bit_width;
        }
    }
};

pub fn main() !void {
    var buf: [16]u8 = undefined;
    var be = BinaryEncoder.init(&buf);

    be.write(0b0000000, 7);
    be.write(0b11, 2);

    std.debug.print("val: bin:{b} dec:{}\n", .{ buf[0], buf[0] });
    std.debug.print("val: bin:{b} dec:{}\n", .{ buf[1], buf[1] });
}