1 /* inftrees.h -- header to use inftrees.c 2 * Copyright (C) 1995-2005 Mark Adler 3 * For conditions of distribution and use, see copyright notice in zlib.h 4 */ 5 6 #pragma ident "%Z%%M% %I% %E% SMI" 7 8 /* WARNING: this file should *not* be used by applications. It is 9 part of the implementation of the compression library and is 10 subject to change. Applications should only use zlib.h. 11 */ 12 13 /* Structure for decoding tables. Each entry provides either the 14 information needed to do the operation requested by the code that 15 indexed that table entry, or it provides a pointer to another 16 table that indexes more bits of the code. op indicates whether 17 the entry is a pointer to another table, a literal, a length or 18 distance, an end-of-block, or an invalid code. For a table 19 pointer, the low four bits of op is the number of index bits of 20 that table. For a length or distance, the low four bits of op 21 is the number of extra bits to get after the code. bits is 22 the number of bits in this code or part of the code to drop off 23 of the bit buffer. val is the actual byte to output in the case 24 of a literal, the base length or distance, or the offset from 25 the current table to the next table. Each entry is four bytes. */ 26 typedef struct { 27 unsigned char op; /* operation, extra bits, table bits */ 28 unsigned char bits; /* bits in this part of the code */ 29 unsigned short val; /* offset in table or code value */ 30 } code; 31 32 /* op values as set by inflate_table(): 33 00000000 - literal 34 0000tttt - table link, tttt != 0 is the number of table index bits 35 0001eeee - length or distance, eeee is the number of extra bits 36 01100000 - end of block 37 01000000 - invalid code 38 */ 39 40 /* Maximum size of dynamic tree. The maximum found in a long but non- 41 exhaustive search was 1444 code structures (852 for length/literals 42 and 592 for distances, the latter actually the result of an 43 exhaustive search). The true maximum is not known, but the value 44 below is more than safe. */ 45 #define ENOUGH 2048 46 #define MAXD 592 47 48 /* Type of code to build for inftable() */ 49 typedef enum { 50 CODES, 51 LENS, 52 DISTS 53 } codetype; 54 55 extern int inflate_table OF((codetype type, unsigned short FAR *lens, 56 unsigned codes, code FAR * FAR *table, 57 unsigned FAR *bits, unsigned short FAR *work)); 58