91 lines
3.4 KiB
C
91 lines
3.4 KiB
C
/* infutil.h -- types and macros common to blocks and codes
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* Copyright (C) 1995 Mark Adler
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* For conditions of distribution and use, see copyright notice in zlib.h
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*/
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/* WARNING: this file should *not* be used by applications. It is
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part of the implementation of the compression library and is
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subject to change. Applications should only use zlib.h.
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*/
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/* inflate blocks semi-private state */
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struct inflate_blocks_state {
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/* mode */
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enum {
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TYPE, /* get type bits (3, including end bit) */
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LENS, /* get lengths for stored */
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STORED, /* processing stored block */
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TABLE, /* get table lengths */
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BTREE, /* get bit lengths tree for a dynamic block */
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DTREE, /* get length, distance trees for a dynamic block */
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CODES, /* processing fixed or dynamic block */
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DRY, /* output remaining window bytes */
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DONE, /* finished last block, done */
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BAD} /* got a data error--stuck here */
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mode; /* current inflate_block mode */
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/* mode dependent information */
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union {
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uInt left; /* if STORED, bytes left to copy */
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struct {
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uInt table; /* table lengths (14 bits) */
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uInt index; /* index into blens (or border) */
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uInt *blens; /* bit lengths of codes */
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uInt bb; /* bit length tree depth */
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inflate_huft *tb; /* bit length decoding tree */
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} trees; /* if DTREE, decoding info for trees */
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struct {
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inflate_huft *tl, *td; /* trees to free */
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struct inflate_codes_state
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*codes;
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} decode; /* if CODES, current state */
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} sub; /* submode */
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uInt last; /* true if this block is the last block */
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/* mode independent information */
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uInt bitk; /* bits in bit buffer */
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uLong bitb; /* bit buffer */
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Byte *window; /* sliding window */
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Byte *end; /* one byte after sliding window */
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Byte *read; /* window read pointer */
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Byte *write; /* window write pointer */
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check_func checkfn; /* check function */
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uLong check; /* check on output */
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};
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/* defines for inflate input/output */
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/* update pointers and return */
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#define UPDBITS {s->bitb=b;s->bitk=k;}
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#define UPDIN {z->avail_in=n;z->total_in+=p-z->next_in;z->next_in=p;}
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#define UPDOUT {s->write=q;}
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#define UPDATE {UPDBITS UPDIN UPDOUT}
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#define LEAVE {UPDATE return inflate_flush(s,z,r);}
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/* get bytes and bits */
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#define LOADIN {p=z->next_in;n=z->avail_in;b=s->bitb;k=s->bitk;}
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#define NEEDBYTE {if(n)r=Z_OK;else LEAVE}
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#define NEXTBYTE (n--,*p++)
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#define NEEDBITS(j) {while(k<(j)){NEEDBYTE;b|=((uLong)NEXTBYTE)<<k;k+=8;}}
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#define DUMPBITS(j) {b>>=(j);k-=(j);}
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/* output bytes */
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#define WAVAIL (q<s->read?s->read-q-1:s->end-q)
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#define LOADOUT {q=s->write;m=WAVAIL;}
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#define WRAP {if(q==s->end&&s->read!=s->window){q=s->window;m=WAVAIL;}}
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#define FLUSH {UPDOUT r=inflate_flush(s,z,r); LOADOUT}
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#define NEEDOUT {if(m==0){WRAP if(m==0){FLUSH WRAP if(m==0) LEAVE}}r=Z_OK;}
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#define OUTBYTE(a) {*q++=(Byte)(a);m--;}
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/* load local pointers */
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#define LOAD {LOADIN LOADOUT}
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/* masks for lower bits */
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extern uInt inflate_mask[];
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/* copy as much as possible from the sliding window to the output area */
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extern int inflate_flush __P((
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struct inflate_blocks_state *,
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z_stream *,
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int));
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struct internal_state {int dummy;}; /* for buggy compilers */
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