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Diffstat (limited to 'include/linux/zutil.h')
-rw-r--r-- | include/linux/zutil.h | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/include/linux/zutil.h b/include/linux/zutil.h new file mode 100644 index 000000000000..fdfd5ed41ec4 --- /dev/null +++ b/include/linux/zutil.h | |||
@@ -0,0 +1,119 @@ | |||
1 | /* zutil.h -- internal interface and configuration of the compression library | ||
2 | * Copyright (C) 1995-1998 Jean-loup Gailly. | ||
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 | /* @(#) $Id: zutil.h,v 1.1 2000/01/01 03:32:23 davem Exp $ */ | ||
12 | |||
13 | #ifndef _Z_UTIL_H | ||
14 | #define _Z_UTIL_H | ||
15 | |||
16 | #include <linux/zlib.h> | ||
17 | #include <linux/string.h> | ||
18 | #include <linux/errno.h> | ||
19 | #include <linux/kernel.h> | ||
20 | |||
21 | typedef unsigned char uch; | ||
22 | typedef unsigned short ush; | ||
23 | typedef unsigned long ulg; | ||
24 | |||
25 | /* common constants */ | ||
26 | |||
27 | #ifndef DEF_WBITS | ||
28 | # define DEF_WBITS MAX_WBITS | ||
29 | #endif | ||
30 | /* default windowBits for decompression. MAX_WBITS is for compression only */ | ||
31 | |||
32 | #if MAX_MEM_LEVEL >= 8 | ||
33 | # define DEF_MEM_LEVEL 8 | ||
34 | #else | ||
35 | # define DEF_MEM_LEVEL MAX_MEM_LEVEL | ||
36 | #endif | ||
37 | /* default memLevel */ | ||
38 | |||
39 | #define STORED_BLOCK 0 | ||
40 | #define STATIC_TREES 1 | ||
41 | #define DYN_TREES 2 | ||
42 | /* The three kinds of block type */ | ||
43 | |||
44 | #define MIN_MATCH 3 | ||
45 | #define MAX_MATCH 258 | ||
46 | /* The minimum and maximum match lengths */ | ||
47 | |||
48 | #define PRESET_DICT 0x20 /* preset dictionary flag in zlib header */ | ||
49 | |||
50 | /* target dependencies */ | ||
51 | |||
52 | /* Common defaults */ | ||
53 | |||
54 | #ifndef OS_CODE | ||
55 | # define OS_CODE 0x03 /* assume Unix */ | ||
56 | #endif | ||
57 | |||
58 | /* functions */ | ||
59 | |||
60 | typedef uLong (*check_func) (uLong check, const Byte *buf, | ||
61 | uInt len); | ||
62 | |||
63 | |||
64 | /* checksum functions */ | ||
65 | |||
66 | #define BASE 65521L /* largest prime smaller than 65536 */ | ||
67 | #define NMAX 5552 | ||
68 | /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */ | ||
69 | |||
70 | #define DO1(buf,i) {s1 += buf[i]; s2 += s1;} | ||
71 | #define DO2(buf,i) DO1(buf,i); DO1(buf,i+1); | ||
72 | #define DO4(buf,i) DO2(buf,i); DO2(buf,i+2); | ||
73 | #define DO8(buf,i) DO4(buf,i); DO4(buf,i+4); | ||
74 | #define DO16(buf) DO8(buf,0); DO8(buf,8); | ||
75 | |||
76 | /* ========================================================================= */ | ||
77 | /* | ||
78 | Update a running Adler-32 checksum with the bytes buf[0..len-1] and | ||
79 | return the updated checksum. If buf is NULL, this function returns | ||
80 | the required initial value for the checksum. | ||
81 | An Adler-32 checksum is almost as reliable as a CRC32 but can be computed | ||
82 | much faster. Usage example: | ||
83 | |||
84 | uLong adler = adler32(0L, NULL, 0); | ||
85 | |||
86 | while (read_buffer(buffer, length) != EOF) { | ||
87 | adler = adler32(adler, buffer, length); | ||
88 | } | ||
89 | if (adler != original_adler) error(); | ||
90 | */ | ||
91 | static inline uLong zlib_adler32(uLong adler, | ||
92 | const Byte *buf, | ||
93 | uInt len) | ||
94 | { | ||
95 | unsigned long s1 = adler & 0xffff; | ||
96 | unsigned long s2 = (adler >> 16) & 0xffff; | ||
97 | int k; | ||
98 | |||
99 | if (buf == NULL) return 1L; | ||
100 | |||
101 | while (len > 0) { | ||
102 | k = len < NMAX ? len : NMAX; | ||
103 | len -= k; | ||
104 | while (k >= 16) { | ||
105 | DO16(buf); | ||
106 | buf += 16; | ||
107 | k -= 16; | ||
108 | } | ||
109 | if (k != 0) do { | ||
110 | s1 += *buf++; | ||
111 | s2 += s1; | ||
112 | } while (--k); | ||
113 | s1 %= BASE; | ||
114 | s2 %= BASE; | ||
115 | } | ||
116 | return (s2 << 16) | s1; | ||
117 | } | ||
118 | |||
119 | #endif /* _Z_UTIL_H */ | ||