diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /lib/zlib_inflate/inffast.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'lib/zlib_inflate/inffast.c')
-rw-r--r-- | lib/zlib_inflate/inffast.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/lib/zlib_inflate/inffast.c b/lib/zlib_inflate/inffast.c new file mode 100644 index 000000000000..0bd7623fc85a --- /dev/null +++ b/lib/zlib_inflate/inffast.c | |||
@@ -0,0 +1,176 @@ | |||
1 | /* inffast.c -- process literals and length/distance pairs fast | ||
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 | struct inflate_codes_state; | ||
14 | |||
15 | /* simplify the use of the inflate_huft type with some defines */ | ||
16 | #define exop word.what.Exop | ||
17 | #define bits word.what.Bits | ||
18 | |||
19 | /* macros for bit input with no checking and for returning unused bytes */ | ||
20 | #define GRABBITS(j) {while(k<(j)){b|=((uLong)NEXTBYTE)<<k;k+=8;}} | ||
21 | #define UNGRAB {c=z->avail_in-n;c=(k>>3)<c?k>>3:c;n+=c;p-=c;k-=c<<3;} | ||
22 | |||
23 | /* Called with number of bytes left to write in window at least 258 | ||
24 | (the maximum string length) and number of input bytes available | ||
25 | at least ten. The ten bytes are six bytes for the longest length/ | ||
26 | distance pair plus four bytes for overloading the bit buffer. */ | ||
27 | |||
28 | int zlib_inflate_fast( | ||
29 | uInt bl, | ||
30 | uInt bd, | ||
31 | inflate_huft *tl, | ||
32 | inflate_huft *td, /* need separate declaration for Borland C++ */ | ||
33 | inflate_blocks_statef *s, | ||
34 | z_streamp z | ||
35 | ) | ||
36 | { | ||
37 | inflate_huft *t; /* temporary pointer */ | ||
38 | uInt e; /* extra bits or operation */ | ||
39 | uLong b; /* bit buffer */ | ||
40 | uInt k; /* bits in bit buffer */ | ||
41 | Byte *p; /* input data pointer */ | ||
42 | uInt n; /* bytes available there */ | ||
43 | Byte *q; /* output window write pointer */ | ||
44 | uInt m; /* bytes to end of window or read pointer */ | ||
45 | uInt ml; /* mask for literal/length tree */ | ||
46 | uInt md; /* mask for distance tree */ | ||
47 | uInt c; /* bytes to copy */ | ||
48 | uInt d; /* distance back to copy from */ | ||
49 | Byte *r; /* copy source pointer */ | ||
50 | |||
51 | /* load input, output, bit values */ | ||
52 | LOAD | ||
53 | |||
54 | /* initialize masks */ | ||
55 | ml = zlib_inflate_mask[bl]; | ||
56 | md = zlib_inflate_mask[bd]; | ||
57 | |||
58 | /* do until not enough input or output space for fast loop */ | ||
59 | do { /* assume called with m >= 258 && n >= 10 */ | ||
60 | /* get literal/length code */ | ||
61 | GRABBITS(20) /* max bits for literal/length code */ | ||
62 | if ((e = (t = tl + ((uInt)b & ml))->exop) == 0) | ||
63 | { | ||
64 | DUMPBITS(t->bits) | ||
65 | *q++ = (Byte)t->base; | ||
66 | m--; | ||
67 | continue; | ||
68 | } | ||
69 | do { | ||
70 | DUMPBITS(t->bits) | ||
71 | if (e & 16) | ||
72 | { | ||
73 | /* get extra bits for length */ | ||
74 | e &= 15; | ||
75 | c = t->base + ((uInt)b & zlib_inflate_mask[e]); | ||
76 | DUMPBITS(e) | ||
77 | |||
78 | /* decode distance base of block to copy */ | ||
79 | GRABBITS(15); /* max bits for distance code */ | ||
80 | e = (t = td + ((uInt)b & md))->exop; | ||
81 | do { | ||
82 | DUMPBITS(t->bits) | ||
83 | if (e & 16) | ||
84 | { | ||
85 | /* get extra bits to add to distance base */ | ||
86 | e &= 15; | ||
87 | GRABBITS(e) /* get extra bits (up to 13) */ | ||
88 | d = t->base + ((uInt)b & zlib_inflate_mask[e]); | ||
89 | DUMPBITS(e) | ||
90 | |||
91 | /* do the copy */ | ||
92 | m -= c; | ||
93 | r = q - d; | ||
94 | if (r < s->window) /* wrap if needed */ | ||
95 | { | ||
96 | do { | ||
97 | r += s->end - s->window; /* force pointer in window */ | ||
98 | } while (r < s->window); /* covers invalid distances */ | ||
99 | e = s->end - r; | ||
100 | if (c > e) | ||
101 | { | ||
102 | c -= e; /* wrapped copy */ | ||
103 | do { | ||
104 | *q++ = *r++; | ||
105 | } while (--e); | ||
106 | r = s->window; | ||
107 | do { | ||
108 | *q++ = *r++; | ||
109 | } while (--c); | ||
110 | } | ||
111 | else /* normal copy */ | ||
112 | { | ||
113 | *q++ = *r++; c--; | ||
114 | *q++ = *r++; c--; | ||
115 | do { | ||
116 | *q++ = *r++; | ||
117 | } while (--c); | ||
118 | } | ||
119 | } | ||
120 | else /* normal copy */ | ||
121 | { | ||
122 | *q++ = *r++; c--; | ||
123 | *q++ = *r++; c--; | ||
124 | do { | ||
125 | *q++ = *r++; | ||
126 | } while (--c); | ||
127 | } | ||
128 | break; | ||
129 | } | ||
130 | else if ((e & 64) == 0) | ||
131 | { | ||
132 | t += t->base; | ||
133 | e = (t += ((uInt)b & zlib_inflate_mask[e]))->exop; | ||
134 | } | ||
135 | else | ||
136 | { | ||
137 | z->msg = (char*)"invalid distance code"; | ||
138 | UNGRAB | ||
139 | UPDATE | ||
140 | return Z_DATA_ERROR; | ||
141 | } | ||
142 | } while (1); | ||
143 | break; | ||
144 | } | ||
145 | if ((e & 64) == 0) | ||
146 | { | ||
147 | t += t->base; | ||
148 | if ((e = (t += ((uInt)b & zlib_inflate_mask[e]))->exop) == 0) | ||
149 | { | ||
150 | DUMPBITS(t->bits) | ||
151 | *q++ = (Byte)t->base; | ||
152 | m--; | ||
153 | break; | ||
154 | } | ||
155 | } | ||
156 | else if (e & 32) | ||
157 | { | ||
158 | UNGRAB | ||
159 | UPDATE | ||
160 | return Z_STREAM_END; | ||
161 | } | ||
162 | else | ||
163 | { | ||
164 | z->msg = (char*)"invalid literal/length code"; | ||
165 | UNGRAB | ||
166 | UPDATE | ||
167 | return Z_DATA_ERROR; | ||
168 | } | ||
169 | } while (1); | ||
170 | } while (m >= 258 && n >= 10); | ||
171 | |||
172 | /* not enough input or output--restore pointers and return */ | ||
173 | UNGRAB | ||
174 | UPDATE | ||
175 | return Z_OK; | ||
176 | } | ||