assignWeights

        fn assignWeights(
            huff_bits_buffer: []const u8,
            accuracy_log: u16,
            entries: *[1 << 6]Table.Fse,
            weights: *[256]u4,
        ) !usize {
            var huff_bits = try ReverseBitReader.init(huff_bits_buffer);

            var i: usize = 0;
            var even_state: u32 = try huff_bits.readBitsNoEof(u32, accuracy_log);
            var odd_state: u32 = try huff_bits.readBitsNoEof(u32, accuracy_log);

            while (i < 254) {
                const even_data = entries[even_state];
                var read_bits: u16 = 0;
                const even_bits = huff_bits.readBits(u32, even_data.bits, &read_bits) catch unreachable;
                weights[i] = std.math.cast(u4, even_data.symbol) orelse return error.MalformedHuffmanTree;
                i += 1;
                if (read_bits < even_data.bits) {
                    weights[i] = std.math.cast(u4, entries[odd_state].symbol) orelse return error.MalformedHuffmanTree;
                    i += 1;
                    break;
                }
                even_state = even_data.baseline + even_bits;

                read_bits = 0;
                const odd_data = entries[odd_state];
                const odd_bits = huff_bits.readBits(u32, odd_data.bits, &read_bits) catch unreachable;
                weights[i] = std.math.cast(u4, odd_data.symbol) orelse return error.MalformedHuffmanTree;
                i += 1;
                if (read_bits < odd_data.bits) {
                    if (i == 255) return error.MalformedHuffmanTree;
                    weights[i] = std.math.cast(u4, entries[even_state].symbol) orelse return error.MalformedHuffmanTree;
                    i += 1;
                    break;
                }
                odd_state = odd_data.baseline + odd_bits;
            } else return error.MalformedHuffmanTree;

            if (!huff_bits.isEmpty()) {
                return error.MalformedHuffmanTree;
            }

            return i + 1; // stream contains all but the last symbol
        }