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1 /* infutil.h -- types and macros common to blocks and codes
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2 * Copyright (C) 1995 Mark Adler
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3 * For conditions of distribution and use, see copyright notice in zlib.h
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4 */
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5
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6 /* WARNING: this file should *not* be used by applications. It is
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7 part of the implementation of the compression library and is
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8 subject to change. Applications should only use zlib.h.
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9 */
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10
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11 /* inflate blocks semi-private state */
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12 struct inflate_blocks_state {
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13
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14 /* mode */
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15 enum {
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16 TYPE, /* get type bits (3, including end bit) */
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17 LENS, /* get lengths for stored */
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18 STORED, /* processing stored block */
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19 TABLE, /* get table lengths */
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20 BTREE, /* get bit lengths tree for a dynamic block */
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21 DTREE, /* get length, distance trees for a dynamic block */
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22 CODES, /* processing fixed or dynamic block */
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23 DRY, /* output remaining window bytes */
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24 DONE, /* finished last block, done */
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25 BAD} /* got a data error--stuck here */
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26 mode; /* current inflate_block mode */
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27
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28 /* mode dependent information */
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29 union {
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30 uInt left; /* if STORED, bytes left to copy */
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31 struct {
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32 uInt table; /* table lengths (14 bits) */
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33 uInt index; /* index into blens (or border) */
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34 uInt *blens; /* bit lengths of codes */
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35 uInt bb; /* bit length tree depth */
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36 inflate_huft *tb; /* bit length decoding tree */
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37 } trees; /* if DTREE, decoding info for trees */
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38 struct inflate_codes_state
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39 *codes; /* if CODES, current state */
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40 } sub; /* submode */
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41 uInt last; /* true if this block is the last block */
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42
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43 /* mode independent information */
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44 uInt bitk; /* bits in bit buffer */
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45 uLong bitb; /* bit buffer */
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46 Byte *window; /* sliding window */
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47 Byte *end; /* one byte after sliding window */
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48 Byte *read; /* window read pointer */
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49 Byte *write; /* window write pointer */
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50 check_func checkfn; /* check function */
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51 uLong check; /* check on output */
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52
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53 };
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54
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55 /* defines for inflate input/output */
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56 /* update pointers and return */
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57 #define UPDBITS {s->bitb=b;s->bitk=k;}
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58 #define UPDIN {z->avail_in=n;z->total_in+=p-z->next_in;z->next_in=p;}
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59 #define UPDOUT {s->write=q;}
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60 #define UPDATE {UPDBITS UPDIN UPDOUT}
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61 #define LEAVE {UPDATE return inflate_flush(s,z,r);}
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62 /* get bytes and bits */
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63 #define LOADIN {p=z->next_in;n=z->avail_in;b=s->bitb;k=s->bitk;}
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64 #define NEEDBYTE {if(n)r=Z_OK;else LEAVE}
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65 #define NEXTBYTE (n--,*p++)
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66 #define NEEDBITS(j) {while(k<(j)){NEEDBYTE;b|=((uLong)NEXTBYTE)<<k;k+=8;}}
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67 #define DUMPBITS(j) {b>>=(j);k-=(j);}
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68 /* output bytes */
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69 #define WAVAIL (q<s->read?s->read-q-1:s->end-q)
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70 #define LOADOUT {q=s->write;m=WAVAIL;}
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71 #define WRAP {if(q==s->end&&s->read!=s->window){q=s->window;m=WAVAIL;}}
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72 #define FLUSH {UPDOUT r=inflate_flush(s,z,r); LOADOUT}
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73 #define NEEDOUT {if(m==0){WRAP if(m==0){FLUSH WRAP if(m==0) LEAVE}}r=Z_OK;}
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74 #define OUTBYTE(a) {*q++=(Byte)(a);m--;}
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75 /* load local pointers */
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76 #define LOAD {LOADIN LOADOUT}
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77
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78 /* masks for lower bits */
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79 extern uInt inflate_mask[];
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80
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81 /* copy as much as possible from the sliding window to the output area */
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82 extern int inflate_flush __P((
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83 struct inflate_blocks_state *,
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84 z_stream *,
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85 int));
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86
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87 struct internal_state {int dummy;}; /* for buggy compilers */
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