#include <istream>
#include <unordered_map>

#include "bitstream.h"

#ifndef HUFFMAN_TABLE
#define HUFFMAN_TABLE

class HuffmanTable
{
private:
    std::unordered_map<char, std::pair<int, short> > huffmanCodes;
public:
// Given the list of code lengths length[0..n-1] representing a canonical
// Huffman code for n symbols, construct the tables required to decode those
// codes.
    HuffmanTable(uint8_t *header);

    // Build from input stream
    HuffmanTable(std::basic_istream<char> &is);

    uint8_t *to_header();

    std::pair<int, short> operator[](const char &c);

    void write_symbol(obitstream &os, const char &c);

// Decode a code from the stream s using huffman table h. Return the symbol or
// a negative value if there is an error. If all of the lengths are zero, i.e.
// an empty code, or if the code is incomplete and an invalid code is received,
// then IG_BAD_CODE_ERR is returned after reading MAXBITS bits.
    int decode_one_symbol(ibitstream &bs);
};

#endif