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Annotation of sys/lib/libz/inftrees.h, Revision 1.1.1.1

1.1       nbrk        1: /*     $OpenBSD: inftrees.h,v 1.8 2005/07/20 15:56:46 millert Exp $    */
                      2: /* inftrees.h -- header to use inftrees.c
                      3:  * Copyright (C) 1995-2005 Mark Adler
                      4:  * For conditions of distribution and use, see copyright notice in zlib.h
                      5:  */
                      6:
                      7: /* WARNING: this file should *not* be used by applications. It is
                      8:    part of the implementation of the compression library and is
                      9:    subject to change. Applications should only use zlib.h.
                     10:  */
                     11:
                     12: /* Structure for decoding tables.  Each entry provides either the
                     13:    information needed to do the operation requested by the code that
                     14:    indexed that table entry, or it provides a pointer to another
                     15:    table that indexes more bits of the code.  op indicates whether
                     16:    the entry is a pointer to another table, a literal, a length or
                     17:    distance, an end-of-block, or an invalid code.  For a table
                     18:    pointer, the low four bits of op is the number of index bits of
                     19:    that table.  For a length or distance, the low four bits of op
                     20:    is the number of extra bits to get after the code.  bits is
                     21:    the number of bits in this code or part of the code to drop off
                     22:    of the bit buffer.  val is the actual byte to output in the case
                     23:    of a literal, the base length or distance, or the offset from
                     24:    the current table to the next table.  Each entry is four bytes. */
                     25: typedef struct {
                     26:     unsigned char op;           /* operation, extra bits, table bits */
                     27:     unsigned char bits;         /* bits in this part of the code */
                     28:     unsigned short val;         /* offset in table or code value */
                     29: } code;
                     30:
                     31: /* op values as set by inflate_table():
                     32:     00000000 - literal
                     33:     0000tttt - table link, tttt != 0 is the number of table index bits
                     34:     0001eeee - length or distance, eeee is the number of extra bits
                     35:     01100000 - end of block
                     36:     01000000 - invalid code
                     37:  */
                     38:
                     39: /* Maximum size of dynamic tree.  The maximum found in a long but non-
                     40:    exhaustive search was 1444 code structures (852 for length/literals
                     41:    and 592 for distances, the latter actually the result of an
                     42:    exhaustive search).  The true maximum is not known, but the value
                     43:    below is more than safe. */
                     44: #define ENOUGH 2048
                     45: #define MAXD 592
                     46:
                     47: /* Type of code to build for inftable() */
                     48: typedef enum {
                     49:     CODES,
                     50:     LENS,
                     51:     DISTS
                     52: } codetype;
                     53:
                     54: extern int inflate_table OF((codetype type, unsigned short FAR *lens,
                     55:                              unsigned codes, code FAR * FAR *table,
                     56:                              unsigned FAR *bits, unsigned short FAR *work));