Navit SVN

/work/compile/navit/src/navit/support/zlib/inftrees.h

00001 /* inftrees.h -- header to use inftrees.c
00002  * Copyright (C) 1995-2005 Mark Adler
00003  * For conditions of distribution and use, see copyright notice in zlib.h
00004  */
00005 
00006 /* WARNING: this file should *not* be used by applications. It is
00007    part of the implementation of the compression library and is
00008    subject to change. Applications should only use zlib.h.
00009  */
00010 
00011 /* Structure for decoding tables.  Each entry provides either the
00012    information needed to do the operation requested by the code that
00013    indexed that table entry, or it provides a pointer to another
00014    table that indexes more bits of the code.  op indicates whether
00015    the entry is a pointer to another table, a literal, a length or
00016    distance, an end-of-block, or an invalid code.  For a table
00017    pointer, the low four bits of op is the number of index bits of
00018    that table.  For a length or distance, the low four bits of op
00019    is the number of extra bits to get after the code.  bits is
00020    the number of bits in this code or part of the code to drop off
00021    of the bit buffer.  val is the actual byte to output in the case
00022    of a literal, the base length or distance, or the offset from
00023    the current table to the next table.  Each entry is four bytes. */
00024 typedef struct {
00025     unsigned char op;           /* operation, extra bits, table bits */
00026     unsigned char bits;         /* bits in this part of the code */
00027     unsigned short val;         /* offset in table or code value */
00028 } code;
00029 
00030 /* op values as set by inflate_table():
00031     00000000 - literal
00032     0000tttt - table link, tttt != 0 is the number of table index bits
00033     0001eeee - length or distance, eeee is the number of extra bits
00034     01100000 - end of block
00035     01000000 - invalid code
00036  */
00037 
00038 /* Maximum size of dynamic tree.  The maximum found in a long but non-
00039    exhaustive search was 1444 code structures (852 for length/literals
00040    and 592 for distances, the latter actually the result of an
00041    exhaustive search).  The true maximum is not known, but the value
00042    below is more than safe. */
00043 #define ENOUGH 2048
00044 #define MAXD 592
00045 
00046 /* Type of code to build for inftable() */
00047 typedef enum {
00048     CODES,
00049     LENS,
00050     DISTS
00051 } codetype;
00052 
00053 extern int inflate_table OF((codetype type, unsigned short FAR *lens,
00054                              unsigned codes, code FAR * FAR *table,
00055                              unsigned FAR *bits, unsigned short FAR *work));