1 /* infutil.h -- types and macros common to blocks and codes
2 * Copyright (C) 1995-1996 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
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.
15 TYPE, /* get type bits (3, including end bit) */
16 LENS, /* get lengths for stored */
17 STORED, /* processing stored block */
18 TABLE, /* get table lengths */
19 BTREE, /* get bit lengths tree for a dynamic block */
20 DTREE, /* get length, distance trees for a dynamic block */
21 CODES, /* processing fixed or dynamic block */
22 DRY, /* output remaining window bytes */
23 DONE, /* finished last block, done */
24 BAD} /* got a data error--stuck here */
27 /* inflate blocks semi-private state */
28 struct inflate_blocks_state {
31 inflate_block_mode mode; /* current inflate_block mode */
33 /* mode dependent information */
35 uInt left; /* if STORED, bytes left to copy */
37 uInt table; /* table lengths (14 bits) */
38 uInt index; /* index into blens (or border) */
39 uIntf *blens; /* bit lengths of codes */
40 uInt bb; /* bit length tree depth */
41 inflate_huft *tb; /* bit length decoding tree */
42 } trees; /* if DTREE, decoding info for trees */
45 inflate_huft *td; /* trees to free */
48 } decode; /* if CODES, current state */
50 uInt last; /* true if this block is the last block */
52 /* mode independent information */
53 uInt bitk; /* bits in bit buffer */
54 uLong bitb; /* bit buffer */
55 Bytef *window; /* sliding window */
56 Bytef *end; /* one byte after sliding window */
57 Bytef *read; /* window read pointer */
58 Bytef *write; /* window write pointer */
59 check_func checkfn; /* check function */
60 uLong check; /* check on output */
65 /* defines for inflate input/output */
66 /* update pointers and return */
67 #define UPDBITS {s->bitb=b;s->bitk=k;}
68 #define UPDIN {z->avail_in=n;z->total_in+=p-z->next_in;z->next_in=p;}
69 #define UPDOUT {s->write=q;}
70 #define UPDATE {UPDBITS UPDIN UPDOUT}
71 #define LEAVE {UPDATE return inflate_flush(s,z,r);}
72 /* get bytes and bits */
73 #define LOADIN {p=z->next_in;n=z->avail_in;b=s->bitb;k=s->bitk;}
74 #define NEEDBYTE {if(n)r=Z_OK;else LEAVE}
75 #define NEXTBYTE (n--,*p++)
76 #define NEEDBITS(j) {while(k<(j)){NEEDBYTE;b|=((uLong)NEXTBYTE)<<k;k+=8;}}
77 #define DUMPBITS(j) {b>>=(j);k-=(j);}
79 #define WAVAIL (uInt)(q<s->read?s->read-q-1:s->end-q)
80 #define LOADOUT {q=s->write;m=(uInt)WAVAIL;}
81 #define WRAP {if(q==s->end&&s->read!=s->window){q=s->window;m=(uInt)WAVAIL;}}
82 #define FLUSH {UPDOUT r=inflate_flush(s,z,r); LOADOUT}
83 #define NEEDOUT {if(m==0){WRAP if(m==0){FLUSH WRAP if(m==0) LEAVE}}r=Z_OK;}
84 #define OUTBYTE(a) {*q++=(Byte)(a);m--;}
85 /* load local pointers */
86 #define LOAD {LOADIN LOADOUT}
88 /* masks for lower bits (size given to avoid silly warnings with Visual C++) */
89 extern uInt inflate_mask[17];
91 /* copy as much as possible from the sliding window to the output area */
92 extern int inflate_flush OF((
93 inflate_blocks_statef *,
97 struct internal_state {int dummy;}; /* for buggy compilers */