65  *                      - Catch missing end-of-block symbol error
202  * symbol[] are the symbol values in canonical order, where the number of
208     short *symbol;      /* canonically ordered symbols */  member
212  * Decode a code from the stream s using huffman table h.  Return the symbol or
241     int index;          /* index of first code of length len in symbol table */  in decode()
247         if (code - count < first)       /* if length len, return symbol */  in decode()
248             return h->symbol[index + (code - first)];  in decode()
269     int index;          /* index of first code of length len in symbol table */  in decode()
284             if (code - count < first) { /* if length len, return symbol */  in decode()
287                 return h->symbol[index + (code - first)];  in decode()
318  * enough bits will resolve to a symbol.  If the return value is positive, then
325  * one symbol, which is an error in a dynamic block.
334  *   codes and any code with a single symbol which in deflate is coded as one
342     int symbol;         /* current symbol when stepping through length[] */  in construct()  local
345     short offs[MAXBITS+1];      /* offsets in symbol table for each length */  in construct()
350     for (symbol = 0; symbol < n; symbol++)  in construct()
351         (h->count[length[symbol]])++;   /* assumes lengths are within bounds */  in construct()
364     /* generate offsets into symbol table for each length for sorting */  in construct()
370      * put symbols in table sorted by length, by symbol order within each  in construct()
373     for (symbol = 0; symbol < n; symbol++)  in construct()
374         if (length[symbol] != 0)  in construct()
375             h->symbol[offs[length[symbol]]++] = symbol;  in construct()
395  *   symbols (257..285), and the end-of-block symbol (256).
399  *   by just a length symbol.  Lengths 11..257 are represented as a symbol and
401  *   of the length symbol.  The number of extra bits is determined by the base
402  *   length symbol.  These are in the static arrays below, lens[] for the base
405  * - The reason that 258 gets its own symbol is that the longest length is used
413  *   to a base value represented by the symbol.  The distances 1..4 get their
414  *   own symbol, but the rest require extra bits.  The base distances and
440     int symbol;         /* decoded symbol */  in codes()  local
460         symbol = decode(s, lencode);  in codes()
461         if (symbol < 0)  in codes()
462             return symbol;              /* invalid symbol */  in codes()
463         if (symbol < 256) {             /* literal: symbol is the byte */  in codes()
468                 s->out[s->outcnt] = symbol;  in codes()
472         else if (symbol > 256) {        /* length */  in codes()
474             symbol -= 257;  in codes()
475             if (symbol >= 29)  in codes()
477             len = lens[symbol] + bits(s, lext[symbol]);  in codes()
480             symbol = decode(s, distcode);  in codes()
481             if (symbol < 0)  in codes()
482                 return symbol;          /* invalid symbol */  in codes()
483             dist = dists[symbol] + bits(s, dext[symbol]);  in codes()
506     } while (symbol != 256);            /* end of block symbol */  in codes()
521  *   codes and distance codes are fixed.  The specific lengths for each symbol
545         int symbol;  in fixed()  local
550         lencode.symbol = lensym;  in fixed()
552         distcode.symbol = distsym;  in fixed()
555         for (symbol = 0; symbol < 144; symbol++)  in fixed()
556             lengths[symbol] = 8;  in fixed()
557         for (; symbol < 256; symbol++)  in fixed()
558             lengths[symbol] = 9;  in fixed()
559         for (; symbol < 280; symbol++)  in fixed()
560             lengths[symbol] = 7;  in fixed()
561         for (; symbol < FIXLCODES; symbol++)  in fixed()
562             lengths[symbol] = 8;  in fixed()
566         for (symbol = 0; symbol < MAXDCODES; symbol++)  in fixed()
567             lengths[symbol] = 5;  in fixed()
590  *   are simply a list of code lengths for each symbol.
596  * - If a symbol is not used in the block, this is represented by a zero as
598  *   that no code should be created for this symbol.  There is no way in the
605  *   interesting consequence.  Normally if only one symbol is used for a given
608  *   only a single distance base symbol appears in a block, then it will be
611  *   and should result in an error.  So incomplete distance codes of one symbol
618  *   literal/length codes of one symbol should also be permitted.
625  *   the list of code lengths, a 0 symbol means no code, a 1..15 symbol means
634  *   representing no code (0) or the code length for that symbol (1..7).
679     lencode.symbol = lensym;  in dynamic()
681     distcode.symbol = distsym;  in dynamic()
704         int symbol;             /* decoded value */  in dynamic()  local
707         symbol = decode(s, &lencode);  in dynamic()
708         if (symbol < 0)  in dynamic()
709             return symbol;          /* invalid symbol */  in dynamic()
710         if (symbol < 16)                /* length in 0..15 */  in dynamic()
711             lengths[index++] = symbol;  in dynamic()
714             if (symbol == 16) {         /* repeat last length 3..6 times */  in dynamic()
718                 symbol = 3 + bits(s, 2);  in dynamic()
720             else if (symbol == 17)      /* repeat zero 3..10 times */  in dynamic()
721                 symbol = 3 + bits(s, 3);  in dynamic()
723                 symbol = 11 + bits(s, 7);  in dynamic()
724             if (index + symbol > nlen + ndist)  in dynamic()
726             while (symbol--)            /* repeat last or zero symbol times */  in dynamic()