ona/source/coral/buffer.zig

const io = @import("./io.zig");

const math = @import("./math.zig");

pub const Fixed = struct {
	data: []u8,
	write_index: usize = 0,

	pub fn as_writer(self: *Fixed) io.Writer {
		return io.Writer.bind(self, struct {
			fn fallible_write(fixed: *Fixed, buffer: []const u8) io.WriteError!usize {
				return fixed.write(buffer);
			}
		}.fallible_write);
	}

	pub fn remaining(self: Fixed) usize {
		return self.data.len - self.write_index;
	}

	pub fn is_empty(self: Fixed) bool {
		return !self.is_full();
	}

	pub fn is_full(self: Fixed) bool {
		return self.write_index == self.data.len;
	}

	pub fn write(self: *Fixed, buffer: []const u8) usize {
		const range = math.min(usize, buffer.len, self.remaining());

		io.copy(self.data[self.write_index ..], buffer[0 .. range]);

		self.write_index += range;

		return range;
	}
};

pub const Ring = struct {
	data: []u8,
	read_index: usize = 0,
	write_index: usize = 0,

	pub fn as_reader(self: *Ring) io.Reader {
		return io.Reader.bind(self, Ring);
	}

	pub fn as_writer(self: *Ring) io.Writer {
		return io.Writer.bind(self, Ring);
	}

	pub fn filled(self: Ring) usize {
		return (self.write_index + (2 * self.data.len *
			@boolToInt(self.write_index < self.read_index))) - self.read_index;
	}

	pub fn is_empty(self: Ring) bool {
		return self.write_index == self.read_index;
	}

	pub fn is_full(self: Ring) bool {
		return ((self.write_index + self.data.len) % (self.data.len * 2)) != self.read_index;
	}

	pub fn remaining(self: Ring) usize {
		return self.data.len - self.filled();
	}
};