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1da177e4 LT |
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 | ||
17 | inflate_codes_statef *zlib_inflate_codes_new( | |
18 | uInt bl, | |
19 | uInt bd, | |
20 | inflate_huft *tl, | |
21 | inflate_huft *td, /* need separate declaration for Borland C++ */ | |
22 | z_streamp z | |
23 | ) | |
24 | { | |
25 | inflate_codes_statef *c; | |
26 | ||
27 | c = &WS(z)->working_state; | |
28 | { | |
29 | c->mode = START; | |
30 | c->lbits = (Byte)bl; | |
31 | c->dbits = (Byte)bd; | |
32 | c->ltree = tl; | |
33 | c->dtree = td; | |
34 | } | |
35 | return c; | |
36 | } | |
37 | ||
38 | ||
39 | int zlib_inflate_codes( | |
40 | inflate_blocks_statef *s, | |
41 | z_streamp z, | |
42 | int r | |
43 | ) | |
44 | { | |
45 | uInt j; /* temporary storage */ | |
46 | inflate_huft *t; /* temporary pointer */ | |
47 | uInt e; /* extra bits or operation */ | |
48 | uLong b; /* bit buffer */ | |
49 | uInt k; /* bits in bit buffer */ | |
50 | Byte *p; /* input data pointer */ | |
51 | uInt n; /* bytes available there */ | |
52 | Byte *q; /* output window write pointer */ | |
53 | uInt m; /* bytes to end of window or read pointer */ | |
54 | Byte *f; /* pointer to copy strings from */ | |
55 | inflate_codes_statef *c = s->sub.decode.codes; /* codes state */ | |
56 | ||
57 | /* copy input/output information to locals (UPDATE macro restores) */ | |
58 | LOAD | |
59 | ||
60 | /* process input and output based on current state */ | |
61 | while (1) switch (c->mode) | |
62 | { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */ | |
63 | case START: /* x: set up for LEN */ | |
64 | #ifndef SLOW | |
65 | if (m >= 258 && n >= 10) | |
66 | { | |
67 | UPDATE | |
68 | r = zlib_inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z); | |
69 | LOAD | |
70 | if (r != Z_OK) | |
71 | { | |
72 | c->mode = r == Z_STREAM_END ? WASH : BADCODE; | |
73 | break; | |
74 | } | |
75 | } | |
76 | #endif /* !SLOW */ | |
77 | c->sub.code.need = c->lbits; | |
78 | c->sub.code.tree = c->ltree; | |
79 | c->mode = LEN; | |
80 | case LEN: /* i: get length/literal/eob next */ | |
81 | j = c->sub.code.need; | |
82 | NEEDBITS(j) | |
83 | t = c->sub.code.tree + ((uInt)b & zlib_inflate_mask[j]); | |
84 | DUMPBITS(t->bits) | |
85 | e = (uInt)(t->exop); | |
86 | if (e == 0) /* literal */ | |
87 | { | |
88 | c->sub.lit = t->base; | |
89 | c->mode = LIT; | |
90 | break; | |
91 | } | |
92 | if (e & 16) /* length */ | |
93 | { | |
94 | c->sub.copy.get = e & 15; | |
95 | c->len = t->base; | |
96 | c->mode = LENEXT; | |
97 | break; | |
98 | } | |
99 | if ((e & 64) == 0) /* next table */ | |
100 | { | |
101 | c->sub.code.need = e; | |
102 | c->sub.code.tree = t + t->base; | |
103 | break; | |
104 | } | |
105 | if (e & 32) /* end of block */ | |
106 | { | |
107 | c->mode = WASH; | |
108 | break; | |
109 | } | |
110 | c->mode = BADCODE; /* invalid code */ | |
111 | z->msg = (char*)"invalid literal/length code"; | |
112 | r = Z_DATA_ERROR; | |
113 | LEAVE | |
114 | case LENEXT: /* i: getting length extra (have base) */ | |
115 | j = c->sub.copy.get; | |
116 | NEEDBITS(j) | |
117 | c->len += (uInt)b & zlib_inflate_mask[j]; | |
118 | DUMPBITS(j) | |
119 | c->sub.code.need = c->dbits; | |
120 | c->sub.code.tree = c->dtree; | |
121 | c->mode = DIST; | |
122 | case DIST: /* i: get distance next */ | |
123 | j = c->sub.code.need; | |
124 | NEEDBITS(j) | |
125 | t = c->sub.code.tree + ((uInt)b & zlib_inflate_mask[j]); | |
126 | DUMPBITS(t->bits) | |
127 | e = (uInt)(t->exop); | |
128 | if (e & 16) /* distance */ | |
129 | { | |
130 | c->sub.copy.get = e & 15; | |
131 | c->sub.copy.dist = t->base; | |
132 | c->mode = DISTEXT; | |
133 | break; | |
134 | } | |
135 | if ((e & 64) == 0) /* next table */ | |
136 | { | |
137 | c->sub.code.need = e; | |
138 | c->sub.code.tree = t + t->base; | |
139 | break; | |
140 | } | |
141 | c->mode = BADCODE; /* invalid code */ | |
142 | z->msg = (char*)"invalid distance code"; | |
143 | r = Z_DATA_ERROR; | |
144 | LEAVE | |
145 | case DISTEXT: /* i: getting distance extra */ | |
146 | j = c->sub.copy.get; | |
147 | NEEDBITS(j) | |
148 | c->sub.copy.dist += (uInt)b & zlib_inflate_mask[j]; | |
149 | DUMPBITS(j) | |
150 | c->mode = COPY; | |
151 | case COPY: /* o: copying bytes in window, waiting for space */ | |
152 | f = q - c->sub.copy.dist; | |
153 | while (f < s->window) /* modulo window size-"while" instead */ | |
154 | f += s->end - s->window; /* of "if" handles invalid distances */ | |
155 | while (c->len) | |
156 | { | |
157 | NEEDOUT | |
158 | OUTBYTE(*f++) | |
159 | if (f == s->end) | |
160 | f = s->window; | |
161 | c->len--; | |
162 | } | |
163 | c->mode = START; | |
164 | break; | |
165 | case LIT: /* o: got literal, waiting for output space */ | |
166 | NEEDOUT | |
167 | OUTBYTE(c->sub.lit) | |
168 | c->mode = START; | |
169 | break; | |
170 | case WASH: /* o: got eob, possibly more output */ | |
171 | if (k > 7) /* return unused byte, if any */ | |
172 | { | |
173 | k -= 8; | |
174 | n++; | |
175 | p--; /* can always return one */ | |
176 | } | |
177 | FLUSH | |
178 | if (s->read != s->write) | |
179 | LEAVE | |
180 | c->mode = END; | |
181 | case END: | |
182 | r = Z_STREAM_END; | |
183 | LEAVE | |
184 | case BADCODE: /* x: got error */ | |
185 | r = Z_DATA_ERROR; | |
186 | LEAVE | |
187 | default: | |
188 | r = Z_STREAM_ERROR; | |
189 | LEAVE | |
190 | } | |
191 | #ifdef NEED_DUMMY_RETURN | |
192 | return Z_STREAM_ERROR; /* Some dumb compilers complain without this */ | |
193 | #endif | |
194 | } | |
195 | ||
196 | ||
197 | void zlib_inflate_codes_free( | |
198 | inflate_codes_statef *c, | |
199 | z_streamp z | |
200 | ) | |
201 | { | |
202 | } |