Annotation of embedaddon/sudo/zlib/inftrees.h, revision 1.1
1.1 ! misho 1: /* inftrees.h -- header to use inftrees.c
! 2: * Copyright (C) 1995-2005, 2010 Mark Adler
! 3: * For conditions of distribution and use, see copyright notice in zlib.h
! 4: */
! 5:
! 6: /* WARNING: this file should *not* be used by applications. It is
! 7: part of the implementation of the compression library and is
! 8: subject to change. Applications should only use zlib.h.
! 9: */
! 10:
! 11: /* Structure for decoding tables. Each entry provides either the
! 12: information needed to do the operation requested by the code that
! 13: indexed that table entry, or it provides a pointer to another
! 14: table that indexes more bits of the code. op indicates whether
! 15: the entry is a pointer to another table, a literal, a length or
! 16: distance, an end-of-block, or an invalid code. For a table
! 17: pointer, the low four bits of op is the number of index bits of
! 18: that table. For a length or distance, the low four bits of op
! 19: is the number of extra bits to get after the code. bits is
! 20: the number of bits in this code or part of the code to drop off
! 21: of the bit buffer. val is the actual byte to output in the case
! 22: of a literal, the base length or distance, or the offset from
! 23: the current table to the next table. Each entry is four bytes. */
! 24: typedef struct {
! 25: unsigned char op; /* operation, extra bits, table bits */
! 26: unsigned char bits; /* bits in this part of the code */
! 27: unsigned short val; /* offset in table or code value */
! 28: } code;
! 29:
! 30: /* op values as set by inflate_table():
! 31: 00000000 - literal
! 32: 0000tttt - table link, tttt != 0 is the number of table index bits
! 33: 0001eeee - length or distance, eeee is the number of extra bits
! 34: 01100000 - end of block
! 35: 01000000 - invalid code
! 36: */
! 37:
! 38: /* Maximum size of the dynamic table. The maximum number of code structures is
! 39: 1444, which is the sum of 852 for literal/length codes and 592 for distance
! 40: codes. These values were found by exhaustive searches using the program
! 41: examples/enough.c found in the zlib distribtution. The arguments to that
! 42: program are the number of symbols, the initial root table size, and the
! 43: maximum bit length of a code. "enough 286 9 15" for literal/length codes
! 44: returns returns 852, and "enough 30 6 15" for distance codes returns 592.
! 45: The initial root table size (9 or 6) is found in the fifth argument of the
! 46: inflate_table() calls in inflate.c and infback.c. If the root table size is
! 47: changed, then these maximum sizes would be need to be recalculated and
! 48: updated. */
! 49: #define ENOUGH_LENS 852
! 50: #define ENOUGH_DISTS 592
! 51: #define ENOUGH (ENOUGH_LENS+ENOUGH_DISTS)
! 52:
! 53: /* Type of code to build for inflate_table() */
! 54: typedef enum {
! 55: CODES,
! 56: LENS,
! 57: DISTS
! 58: } codetype;
! 59:
! 60: int ZLIB_INTERNAL inflate_table OF((codetype type, unsigned short FAR *lens,
! 61: unsigned codes, code FAR * FAR *table,
! 62: unsigned FAR *bits, unsigned short FAR *work));
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>