lib/zlib_inflate/infutil.h

   1 /* infutil.h -- types and macros common to blocks and codes
   2  * Copyright (C) 1995-1998 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 #ifndef _INFUTIL_H
  12 #define _INFUTIL_H
  13
  14 #include <linux/zconf.h>
  15 #include "inftrees.h"
  16 #include "infcodes.h"
  17
  18 typedef enum {
  19       TYPE,     /* get type bits (3, including end bit) */
  20       LENS,     /* get lengths for stored */
  21       STORED,   /* processing stored block */
  22       TABLE,    /* get table lengths */
  23       BTREE,    /* get bit lengths tree for a dynamic block */
  24       DTREE,    /* get length, distance trees for a dynamic block */
  25       CODES,    /* processing fixed or dynamic block */
  26       DRY,      /* output remaining window bytes */
  27       B_DONE,   /* finished last block, done */
  28       B_BAD}    /* got a data error--stuck here */
  29 inflate_block_mode;
  30
  31 /* inflate blocks semi-private state */
  32 struct inflate_blocks_state {
  33
  34   /* mode */
  35   inflate_block_mode  mode;     /* current inflate_block mode */
  36
  37   /* mode dependent information */
  38   union {
  39     uInt left;          /* if STORED, bytes left to copy */
  40     struct {
  41       uInt table;               /* table lengths (14 bits) */
  42       uInt index;               /* index into blens (or border) */
  43       uInt *blens;              /* bit lengths of codes */
  44       uInt bb;                  /* bit length tree depth */
  45       inflate_huft *tb;         /* bit length decoding tree */
  46     } trees;            /* if DTREE, decoding info for trees */
  47     struct {
  48       inflate_codes_statef
  49          *codes;
  50     } decode;           /* if CODES, current state */
  51   } sub;                /* submode */
  52   uInt last;            /* true if this block is the last block */
  53
  54   /* mode independent information */
  55   uInt bitk;            /* bits in bit buffer */
  56   uLong bitb;           /* bit buffer */
  57   inflate_huft *hufts;  /* single malloc for tree space */
  58   Byte *window;         /* sliding window */
  59   Byte *end;            /* one byte after sliding window */
  60   Byte *read;           /* window read pointer */
  61   Byte *write;          /* window write pointer */
  62   check_func checkfn;   /* check function */
  63   uLong check;          /* check on output */
  64
  65 };
  66
  67
  68 /* defines for inflate input/output */
  69 /*   update pointers and return */
  70 #define UPDBITS {s->bitb=b;s->bitk=k;}
  71 #define UPDIN {z->avail_in=n;z->total_in+=p-z->next_in;z->next_in=p;}
  72 #define UPDOUT {s->write=q;}
  73 #define UPDATE {UPDBITS UPDIN UPDOUT}
  74 #define LEAVE {UPDATE return zlib_inflate_flush(s,z,r);}
  75 /*   get bytes and bits */
  76 #define LOADIN {p=z->next_in;n=z->avail_in;b=s->bitb;k=s->bitk;}
  77 #define NEEDBYTE {if(n)r=Z_OK;else LEAVE}
  78 #define NEXTBYTE (n--,*p++)
  79 #define NEEDBITS(j) {while(k<(j)){NEEDBYTE;b|=((uLong)NEXTBYTE)<<k;k+=8;}}
  80 #define DUMPBITS(j) {b>>=(j);k-=(j);}
  81 /*   output bytes */
  82 #define WAVAIL (uInt)(q<s->read?s->read-q-1:s->end-q)
  83 #define LOADOUT {q=s->write;m=(uInt)WAVAIL;}
  84 #define WRAP {if(q==s->end&&s->read!=s->window){q=s->window;m=(uInt)WAVAIL;}}
  85 #define FLUSH {UPDOUT r=zlib_inflate_flush(s,z,r); LOADOUT}
  86 #define NEEDOUT {if(m==0){WRAP if(m==0){FLUSH WRAP if(m==0) LEAVE}}r=Z_OK;}
  87 #define OUTBYTE(a) {*q++=(Byte)(a);m--;}
  88 /*   load local pointers */
  89 #define LOAD {LOADIN LOADOUT}
  90
  91 /* masks for lower bits (size given to avoid silly warnings with Visual C++) */
  92 extern uInt zlib_inflate_mask[17];
  93
  94 /* copy as much as possible from the sliding window to the output area */
  95 extern int zlib_inflate_flush (
  96     inflate_blocks_statef *,
  97     z_streamp ,
  98     int);
  99
 100 /* inflate private state */
 101 typedef enum {
 102       METHOD,   /* waiting for method byte */
 103       FLAG,     /* waiting for flag byte */
 104       DICT4,    /* four dictionary check bytes to go */
 105       DICT3,    /* three dictionary check bytes to go */
 106       DICT2,    /* two dictionary check bytes to go */
 107       DICT1,    /* one dictionary check byte to go */
 108       DICT0,    /* waiting for inflateSetDictionary */
 109       BLOCKS,   /* decompressing blocks */
 110       CHECK4,   /* four check bytes to go */
 111       CHECK3,   /* three check bytes to go */
 112       CHECK2,   /* two check bytes to go */
 113       CHECK1,   /* one check byte to go */
 114       I_DONE,   /* finished check, done */
 115       I_BAD}    /* got an error--stay here */
 116 inflate_mode;
 117
 118 struct internal_state {
 119
 120   /* mode */
 121   inflate_mode  mode;   /* current inflate mode */
 122
 123   /* mode dependent information */
 124   union {
 125     uInt method;        /* if FLAGS, method byte */
 126     struct {
 127       uLong was;                /* computed check value */
 128       uLong need;               /* stream check value */
 129     } check;            /* if CHECK, check values to compare */
 130     uInt marker;        /* if BAD, inflateSync's marker bytes count */
 131   } sub;        /* submode */
 132
 133   /* mode independent information */
 134   int  nowrap;          /* flag for no wrapper */
 135   uInt wbits;           /* log2(window size)  (8..15, defaults to 15) */
 136   inflate_blocks_statef
 137     *blocks;            /* current inflate_blocks state */
 138
 139 };
 140
 141 /* inflate codes private state */
 142 typedef enum {        /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
 143       START,    /* x: set up for LEN */
 144       LEN,      /* i: get length/literal/eob next */
 145       LENEXT,   /* i: getting length extra (have base) */
 146       DIST,     /* i: get distance next */
 147       DISTEXT,  /* i: getting distance extra */
 148       COPY,     /* o: copying bytes in window, waiting for space */
 149       LIT,      /* o: got literal, waiting for output space */
 150       WASH,     /* o: got eob, possibly still output waiting */
 151       END,      /* x: got eob and all data flushed */
 152       BADCODE}  /* x: got error */
 153 inflate_codes_mode;
 154
 155 struct inflate_codes_state {
 156
 157   /* mode */
 158   inflate_codes_mode mode;      /* current inflate_codes mode */
 159
 160   /* mode dependent information */
 161   uInt len;
 162   union {
 163     struct {
 164       inflate_huft *tree;       /* pointer into tree */
 165       uInt need;                /* bits needed */
 166     } code;             /* if LEN or DIST, where in tree */
 167     uInt lit;           /* if LIT, literal */
 168     struct {
 169       uInt get;                 /* bits to get for extra */
 170       uInt dist;                /* distance back to copy from */
 171     } copy;             /* if EXT or COPY, where and how much */
 172   } sub;                /* submode */
 173
 174   /* mode independent information */
 175   Byte lbits;           /* ltree bits decoded per branch */
 176   Byte dbits;           /* dtree bits decoder per branch */
 177   inflate_huft *ltree;          /* literal/length/eob tree */
 178   inflate_huft *dtree;          /* distance tree */
 179
 180 };
 181
 182 /* memory allocation for inflation */
 183
 184 struct inflate_workspace {
 185         inflate_codes_statef working_state;
 186         struct inflate_blocks_state working_blocks_state;
 187         struct internal_state internal_state;
 188         unsigned int tree_work_area_1[19];
 189         unsigned int tree_work_area_2[288];
 190         unsigned working_blens[258 + 0x1f + 0x1f];
 191         inflate_huft working_hufts[MANY];
 192         unsigned char working_window[1 << MAX_WBITS];
 193 };
 194
 195 #define WS(z) ((struct inflate_workspace *)(z->workspace))
 196
 197 #endif