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huffman_table.h

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+#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