assignSymbols

        fn assignSymbols(weight_sorted_prefixed_symbols: []PrefixedSymbol, weights: [256]u4) usize {
            for (0..weight_sorted_prefixed_symbols.len) |i| {
                weight_sorted_prefixed_symbols[i] = .{
                    .symbol = @as(u8, @intCast(i)),
                    .weight = undefined,
                    .prefix = undefined,
                };
            }

            std.mem.sort(
                PrefixedSymbol,
                weight_sorted_prefixed_symbols,
                weights,
                lessThanByWeight,
            );

            var prefix: u16 = 0;
            var prefixed_symbol_count: usize = 0;
            var sorted_index: usize = 0;
            const symbol_count = weight_sorted_prefixed_symbols.len;
            while (sorted_index < symbol_count) {
                var symbol = weight_sorted_prefixed_symbols[sorted_index].symbol;
                const weight = weights[symbol];
                if (weight == 0) {
                    sorted_index += 1;
                    continue;
                }

                while (sorted_index < symbol_count) : ({
                    sorted_index += 1;
                    prefixed_symbol_count += 1;
                    prefix += 1;
                }) {
                    symbol = weight_sorted_prefixed_symbols[sorted_index].symbol;
                    if (weights[symbol] != weight) {
                        prefix = ((prefix - 1) >> (weights[symbol] - weight)) + 1;
                        break;
                    }
                    weight_sorted_prefixed_symbols[prefixed_symbol_count].symbol = symbol;
                    weight_sorted_prefixed_symbols[prefixed_symbol_count].prefix = prefix;
                    weight_sorted_prefixed_symbols[prefixed_symbol_count].weight = weight;
                }
            }
            return prefixed_symbol_count;
        }