1 /* infcodes.c -- process literals and length/distance pairs
2 * Copyright (C) 1995-1998 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
4 */
5
6 #include <linux/zutil.h>
7 #include "inftrees.h"
8 #include "infblock.h"
9 #include "infcodes.h"
10 #include "infutil.h"
11 #include "inffast.h"
12
13 /* simplify the use of the inflate_huft type with some defines */
14 #define exop word.what.Exop
15 #define bits word.what.Bits
16
zlib_inflate_codes_new(bl,bd,tl,td,z)17 inflate_codes_statef *zlib_inflate_codes_new(bl, bd, tl, td, z)
18 uInt bl, bd;
19 inflate_huft *tl;
20 inflate_huft *td; /* need separate declaration for Borland C++ */
21 z_streamp z;
22 {
23 inflate_codes_statef *c;
24
25 c = &WS(z)->working_state;
26 {
27 c->mode = START;
28 c->lbits = (Byte)bl;
29 c->dbits = (Byte)bd;
30 c->ltree = tl;
31 c->dtree = td;
32 }
33 return c;
34 }
35
36
zlib_inflate_codes(s,z,r)37 int zlib_inflate_codes(s, z, r)
38 inflate_blocks_statef *s;
39 z_streamp z;
40 int r;
41 {
42 uInt j; /* temporary storage */
43 inflate_huft *t; /* temporary pointer */
44 uInt e; /* extra bits or operation */
45 uLong b; /* bit buffer */
46 uInt k; /* bits in bit buffer */
47 Bytef *p; /* input data pointer */
48 uInt n; /* bytes available there */
49 Bytef *q; /* output window write pointer */
50 uInt m; /* bytes to end of window or read pointer */
51 Bytef *f; /* pointer to copy strings from */
52 inflate_codes_statef *c = s->sub.decode.codes; /* codes state */
53
54 /* copy input/output information to locals (UPDATE macro restores) */
55 LOAD
56
57 /* process input and output based on current state */
58 while (1) switch (c->mode)
59 { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
60 case START: /* x: set up for LEN */
61 #ifndef SLOW
62 if (m >= 258 && n >= 10)
63 {
64 UPDATE
65 r = zlib_inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z);
66 LOAD
67 if (r != Z_OK)
68 {
69 c->mode = r == Z_STREAM_END ? WASH : BADCODE;
70 break;
71 }
72 }
73 #endif /* !SLOW */
74 c->sub.code.need = c->lbits;
75 c->sub.code.tree = c->ltree;
76 c->mode = LEN;
77 case LEN: /* i: get length/literal/eob next */
78 j = c->sub.code.need;
79 NEEDBITS(j)
80 t = c->sub.code.tree + ((uInt)b & zlib_inflate_mask[j]);
81 DUMPBITS(t->bits)
82 e = (uInt)(t->exop);
83 if (e == 0) /* literal */
84 {
85 c->sub.lit = t->base;
86 c->mode = LIT;
87 break;
88 }
89 if (e & 16) /* length */
90 {
91 c->sub.copy.get = e & 15;
92 c->len = t->base;
93 c->mode = LENEXT;
94 break;
95 }
96 if ((e & 64) == 0) /* next table */
97 {
98 c->sub.code.need = e;
99 c->sub.code.tree = t + t->base;
100 break;
101 }
102 if (e & 32) /* end of block */
103 {
104 c->mode = WASH;
105 break;
106 }
107 c->mode = BADCODE; /* invalid code */
108 z->msg = (char*)"invalid literal/length code";
109 r = Z_DATA_ERROR;
110 LEAVE
111 case LENEXT: /* i: getting length extra (have base) */
112 j = c->sub.copy.get;
113 NEEDBITS(j)
114 c->len += (uInt)b & zlib_inflate_mask[j];
115 DUMPBITS(j)
116 c->sub.code.need = c->dbits;
117 c->sub.code.tree = c->dtree;
118 c->mode = DIST;
119 case DIST: /* i: get distance next */
120 j = c->sub.code.need;
121 NEEDBITS(j)
122 t = c->sub.code.tree + ((uInt)b & zlib_inflate_mask[j]);
123 DUMPBITS(t->bits)
124 e = (uInt)(t->exop);
125 if (e & 16) /* distance */
126 {
127 c->sub.copy.get = e & 15;
128 c->sub.copy.dist = t->base;
129 c->mode = DISTEXT;
130 break;
131 }
132 if ((e & 64) == 0) /* next table */
133 {
134 c->sub.code.need = e;
135 c->sub.code.tree = t + t->base;
136 break;
137 }
138 c->mode = BADCODE; /* invalid code */
139 z->msg = (char*)"invalid distance code";
140 r = Z_DATA_ERROR;
141 LEAVE
142 case DISTEXT: /* i: getting distance extra */
143 j = c->sub.copy.get;
144 NEEDBITS(j)
145 c->sub.copy.dist += (uInt)b & zlib_inflate_mask[j];
146 DUMPBITS(j)
147 c->mode = COPY;
148 case COPY: /* o: copying bytes in window, waiting for space */
149 #ifndef __TURBOC__ /* Turbo C bug for following expression */
150 f = (uInt)(q - s->window) < c->sub.copy.dist ?
151 s->end - (c->sub.copy.dist - (q - s->window)) :
152 q - c->sub.copy.dist;
153 #else
154 f = q - c->sub.copy.dist;
155 if ((uInt)(q - s->window) < c->sub.copy.dist)
156 f = s->end - (c->sub.copy.dist - (uInt)(q - s->window));
157 #endif
158 while (c->len)
159 {
160 NEEDOUT
161 OUTBYTE(*f++)
162 if (f == s->end)
163 f = s->window;
164 c->len--;
165 }
166 c->mode = START;
167 break;
168 case LIT: /* o: got literal, waiting for output space */
169 NEEDOUT
170 OUTBYTE(c->sub.lit)
171 c->mode = START;
172 break;
173 case WASH: /* o: got eob, possibly more output */
174 if (k > 7) /* return unused byte, if any */
175 {
176 k -= 8;
177 n++;
178 p--; /* can always return one */
179 }
180 FLUSH
181 if (s->read != s->write)
182 LEAVE
183 c->mode = END;
184 case END:
185 r = Z_STREAM_END;
186 LEAVE
187 case BADCODE: /* x: got error */
188 r = Z_DATA_ERROR;
189 LEAVE
190 default:
191 r = Z_STREAM_ERROR;
192 LEAVE
193 }
194 #ifdef NEED_DUMMY_RETURN
195 return Z_STREAM_ERROR; /* Some dumb compilers complain without this */
196 #endif
197 }
198
199
zlib_inflate_codes_free(c,z)200 void zlib_inflate_codes_free(c, z)
201 inflate_codes_statef *c;
202 z_streamp z;
203 {
204 }
205