17dd7cddfSDavid du Colombier /* inftrees.h -- header to use inftrees.c 2*593dc095SDavid du Colombier * Copyright (C) 1995-2003 Mark Adler 37dd7cddfSDavid du Colombier * For conditions of distribution and use, see copyright notice in zlib.h 47dd7cddfSDavid du Colombier */ 57dd7cddfSDavid du Colombier 67dd7cddfSDavid du Colombier /* WARNING: this file should *not* be used by applications. It is 77dd7cddfSDavid du Colombier part of the implementation of the compression library and is 87dd7cddfSDavid du Colombier subject to change. Applications should only use zlib.h. 97dd7cddfSDavid du Colombier */ 107dd7cddfSDavid du Colombier 11*593dc095SDavid du Colombier /* Structure for decoding tables. Each entry provides either the 12*593dc095SDavid du Colombier information needed to do the operation requested by the code that 13*593dc095SDavid du Colombier indexed that table entry, or it provides a pointer to another 14*593dc095SDavid du Colombier table that indexes more bits of the code. op indicates whether 15*593dc095SDavid du Colombier the entry is a pointer to another table, a literal, a length or 16*593dc095SDavid du Colombier distance, an end-of-block, or an invalid code. For a table 17*593dc095SDavid du Colombier pointer, the low four bits of op is the number of index bits of 18*593dc095SDavid du Colombier that table. For a length or distance, the low four bits of op 19*593dc095SDavid du Colombier is the number of extra bits to get after the code. bits is 20*593dc095SDavid du Colombier the number of bits in this code or part of the code to drop off 21*593dc095SDavid du Colombier of the bit buffer. val is the actual byte to output in the case 22*593dc095SDavid du Colombier of a literal, the base length or distance, or the offset from 23*593dc095SDavid du Colombier the current table to the next table. Each entry is four bytes. */ 24*593dc095SDavid du Colombier typedef struct { 25*593dc095SDavid du Colombier unsigned char op; /* operation, extra bits, table bits */ 26*593dc095SDavid du Colombier unsigned char bits; /* bits in this part of the code */ 27*593dc095SDavid du Colombier unsigned short val; /* offset in table or code value */ 28*593dc095SDavid du Colombier } code; 297dd7cddfSDavid du Colombier 30*593dc095SDavid du Colombier /* op values as set by inflate_table(): 31*593dc095SDavid du Colombier 00000000 - literal 32*593dc095SDavid du Colombier 0000tttt - table link, tttt != 0 is the number of table index bits 33*593dc095SDavid du Colombier 0001eeee - length or distance, eeee is the number of extra bits 34*593dc095SDavid du Colombier 01100000 - end of block 35*593dc095SDavid du Colombier 01000000 - invalid code 36*593dc095SDavid du Colombier */ 377dd7cddfSDavid du Colombier 38*593dc095SDavid du Colombier /* Maximum size of dynamic tree. The maximum found in a long but non- 39*593dc095SDavid du Colombier exhaustive search was 1004 code structures (850 for length/literals 40*593dc095SDavid du Colombier and 154 for distances, the latter actually the result of an 41*593dc095SDavid du Colombier exhaustive search). The true maximum is not known, but the value 42*593dc095SDavid du Colombier below is more than safe. */ 43*593dc095SDavid du Colombier #define ENOUGH 1440 44*593dc095SDavid du Colombier #define MAXD 154 457dd7cddfSDavid du Colombier 46*593dc095SDavid du Colombier /* Type of code to build for inftable() */ 47*593dc095SDavid du Colombier typedef enum { 48*593dc095SDavid du Colombier CODES, 49*593dc095SDavid du Colombier LENS, 50*593dc095SDavid du Colombier DISTS 51*593dc095SDavid du Colombier } codetype; 527dd7cddfSDavid du Colombier 53*593dc095SDavid du Colombier extern int inflate_table OF((codetype type, unsigned short FAR *lens, 54*593dc095SDavid du Colombier unsigned codes, code FAR * FAR *table, 55*593dc095SDavid du Colombier unsigned FAR *bits, unsigned short FAR *work)); 56