Chris@43: /* inftree9.h -- header to use inftree9.c
Chris@43:  * Copyright (C) 1995-2008 Mark Adler
Chris@43:  * For conditions of distribution and use, see copyright notice in zlib.h
Chris@43:  */
Chris@43: 
Chris@43: /* WARNING: this file should *not* be used by applications. It is
Chris@43:    part of the implementation of the compression library and is
Chris@43:    subject to change. Applications should only use zlib.h.
Chris@43:  */
Chris@43: 
Chris@43: /* Structure for decoding tables.  Each entry provides either the
Chris@43:    information needed to do the operation requested by the code that
Chris@43:    indexed that table entry, or it provides a pointer to another
Chris@43:    table that indexes more bits of the code.  op indicates whether
Chris@43:    the entry is a pointer to another table, a literal, a length or
Chris@43:    distance, an end-of-block, or an invalid code.  For a table
Chris@43:    pointer, the low four bits of op is the number of index bits of
Chris@43:    that table.  For a length or distance, the low four bits of op
Chris@43:    is the number of extra bits to get after the code.  bits is
Chris@43:    the number of bits in this code or part of the code to drop off
Chris@43:    of the bit buffer.  val is the actual byte to output in the case
Chris@43:    of a literal, the base length or distance, or the offset from
Chris@43:    the current table to the next table.  Each entry is four bytes. */
Chris@43: typedef struct {
Chris@43:     unsigned char op;           /* operation, extra bits, table bits */
Chris@43:     unsigned char bits;         /* bits in this part of the code */
Chris@43:     unsigned short val;         /* offset in table or code value */
Chris@43: } code;
Chris@43: 
Chris@43: /* op values as set by inflate_table():
Chris@43:     00000000 - literal
Chris@43:     0000tttt - table link, tttt != 0 is the number of table index bits
Chris@43:     100eeeee - length or distance, eeee is the number of extra bits
Chris@43:     01100000 - end of block
Chris@43:     01000000 - invalid code
Chris@43:  */
Chris@43: 
Chris@43: /* Maximum size of the dynamic table.  The maximum number of code structures is
Chris@43:    1446, which is the sum of 852 for literal/length codes and 594 for distance
Chris@43:    codes.  These values were found by exhaustive searches using the program
Chris@43:    examples/enough.c found in the zlib distribtution.  The arguments to that
Chris@43:    program are the number of symbols, the initial root table size, and the
Chris@43:    maximum bit length of a code.  "enough 286 9 15" for literal/length codes
Chris@43:    returns returns 852, and "enough 32 6 15" for distance codes returns 594.
Chris@43:    The initial root table size (9 or 6) is found in the fifth argument of the
Chris@43:    inflate_table() calls in infback9.c.  If the root table size is changed,
Chris@43:    then these maximum sizes would be need to be recalculated and updated. */
Chris@43: #define ENOUGH_LENS 852
Chris@43: #define ENOUGH_DISTS 594
Chris@43: #define ENOUGH (ENOUGH_LENS+ENOUGH_DISTS)
Chris@43: 
Chris@43: /* Type of code to build for inflate_table9() */
Chris@43: typedef enum {
Chris@43:     CODES,
Chris@43:     LENS,
Chris@43:     DISTS
Chris@43: } codetype;
Chris@43: 
Chris@43: extern int inflate_table9 OF((codetype type, unsigned short FAR *lens,
Chris@43:                              unsigned codes, code FAR * FAR *table,
Chris@43:                              unsigned FAR *bits, unsigned short FAR *work));