1 #ifndef INFTREES_H 2 #define INFTREES_H 3 4 /* inftrees.h -- header to use inftrees.c 5 * Copyright (C) 1995-2005 Mark Adler 6 * For conditions of distribution and use, see copyright notice in zlib.h 7 */ 8 9 /* WARNING: this file should *not* be used by applications. It is 10 part of the implementation of the compression library and is 11 subject to change. Applications should only use zlib.h. 12 */ 13 14 /* Structure for decoding tables. Each entry provides either the 15 information needed to do the operation requested by the code that 16 indexed that table entry, or it provides a pointer to another 17 table that indexes more bits of the code. op indicates whether 18 the entry is a pointer to another table, a literal, a length or 19 distance, an end-of-block, or an invalid code. For a table 20 pointer, the low four bits of op is the number of index bits of 21 that table. For a length or distance, the low four bits of op 22 is the number of extra bits to get after the code. bits is 23 the number of bits in this code or part of the code to drop off 24 of the bit buffer. val is the actual byte to output in the case 25 of a literal, the base length or distance, or the offset from 26 the current table to the next table. Each entry is four bytes. */ 27 typedef struct { 28 unsigned char op; /* operation, extra bits, table bits */ 29 unsigned char bits; /* bits in this part of the code */ 30 unsigned short val; /* offset in table or code value */ 31 } code; 32 33 /* op values as set by inflate_table(): 34 00000000 - literal 35 0000tttt - table link, tttt != 0 is the number of table index bits 36 0001eeee - length or distance, eeee is the number of extra bits 37 01100000 - end of block 38 01000000 - invalid code 39 */ 40 41 /* Maximum size of dynamic tree. The maximum found in a long but non- 42 exhaustive search was 1444 code structures (852 for length/literals 43 and 592 for distances, the latter actually the result of an 44 exhaustive search). The true maximum is not known, but the value 45 below is more than safe. */ 46 #define ENOUGH 2048 47 #define MAXD 592 48 49 /* Type of code to build for inftable() */ 50 typedef enum { 51 CODES, 52 LENS, 53 DISTS 54 } codetype; 55 56 extern int zlib_inflate_table (codetype type, unsigned short *lens, 57 unsigned codes, code **table, 58 unsigned *bits, unsigned short *work); 59 #endif 60