diff options
Diffstat (limited to 'zlib/inftrees.h')
| -rw-r--r-- | zlib/inftrees.h | 91 |
1 files changed, 44 insertions, 47 deletions
diff --git a/zlib/inftrees.h b/zlib/inftrees.h index 04b73b7296a..82d365a7e90 100644 --- a/zlib/inftrees.h +++ b/zlib/inftrees.h @@ -1,6 +1,6 @@ /* inftrees.h -- header to use inftrees.c - * Copyright (C) 1995-2002 Mark Adler - * For conditions of distribution and use, see copyright notice in zlib.h + * Copyright (C) 1995-2003 Mark Adler + * For conditions of distribution and use, see copyright notice in zlib.h */ /* WARNING: this file should *not* be used by applications. It is @@ -8,51 +8,48 @@ subject to change. Applications should only use zlib.h. */ -/* Huffman code lookup table entry--this entry is four bytes for machines - that have 16-bit pointers (e.g. PC's in the small or medium model). */ - -typedef struct inflate_huft_s FAR inflate_huft; - -struct inflate_huft_s { - union { - struct { - Byte Exop; /* number of extra bits or operation */ - Byte Bits; /* number of bits in this code or subcode */ - } what; - uInt pad; /* pad structure to a power of 2 (4 bytes for */ - } word; /* 16-bit, 8 bytes for 32-bit int's) */ - uInt base; /* literal, length base, distance base, - or table offset */ -}; +/* Structure for decoding tables. Each entry provides either the + information needed to do the operation requested by the code that + indexed that table entry, or it provides a pointer to another + table that indexes more bits of the code. op indicates whether + the entry is a pointer to another table, a literal, a length or + distance, an end-of-block, or an invalid code. For a table + pointer, the low four bits of op is the number of index bits of + that table. For a length or distance, the low four bits of op + is the number of extra bits to get after the code. bits is + the number of bits in this code or part of the code to drop off + of the bit buffer. val is the actual byte to output in the case + of a literal, the base length or distance, or the offset from + the current table to the next table. Each entry is four bytes. */ +typedef struct { + unsigned char op; /* operation, extra bits, table bits */ + unsigned char bits; /* bits in this part of the code */ + unsigned short val; /* offset in table or code value */ +} code; + +/* op values as set by inflate_table(): + 00000000 - literal + 0000tttt - table link, tttt != 0 is the number of table index bits + 0001eeee - length or distance, eeee is the number of extra bits + 01100000 - end of block + 01000000 - invalid code + */ /* Maximum size of dynamic tree. The maximum found in a long but non- - exhaustive search was 1004 huft structures (850 for length/literals + exhaustive search was 1004 code structures (850 for length/literals and 154 for distances, the latter actually the result of an - exhaustive search). The actual maximum is not known, but the - value below is more than safe. */ -#define MANY 1440 - -extern int inflate_trees_bits OF(( - uIntf *, /* 19 code lengths */ - uIntf *, /* bits tree desired/actual depth */ - inflate_huft * FAR *, /* bits tree result */ - inflate_huft *, /* space for trees */ - z_streamp)); /* for messages */ - -extern int inflate_trees_dynamic OF(( - uInt, /* number of literal/length codes */ - uInt, /* number of distance codes */ - uIntf *, /* that many (total) code lengths */ - uIntf *, /* literal desired/actual bit depth */ - uIntf *, /* distance desired/actual bit depth */ - inflate_huft * FAR *, /* literal/length tree result */ - inflate_huft * FAR *, /* distance tree result */ - inflate_huft *, /* space for trees */ - z_streamp)); /* for messages */ - -extern int inflate_trees_fixed OF(( - uIntf *, /* literal desired/actual bit depth */ - uIntf *, /* distance desired/actual bit depth */ - inflate_huft * FAR *, /* literal/length tree result */ - inflate_huft * FAR *, /* distance tree result */ - z_streamp)); /* for memory allocation */ + exhaustive search). The true maximum is not known, but the value + below is more than safe. */ +#define ENOUGH 1440 +#define MAXD 154 + +/* Type of code to build for inftable() */ +typedef enum { + CODES, + LENS, + DISTS +} codetype; + +extern int inflate_table OF((codetype type, unsigned short FAR *lens, + unsigned codes, code FAR * FAR *table, + unsigned FAR *bits, unsigned short FAR *work)); |