1 | /* |
1 | /* |
2 | * Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de> |
2 | * Copyright (c) 2000-2010 Marc Alexander Lehmann <schmorp@schmorp.de> |
3 | * |
3 | * |
4 | * Redistribution and use in source and binary forms, with or without modifica- |
4 | * Redistribution and use in source and binary forms, with or without modifica- |
5 | * tion, are permitted provided that the following conditions are met: |
5 | * tion, are permitted provided that the following conditions are met: |
6 | * |
6 | * |
7 | * 1. Redistributions of source code must retain the above copyright notice, |
7 | * 1. Redistributions of source code must retain the above copyright notice, |
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38 | |
38 | |
39 | #define HSIZE (1 << (HLOG)) |
39 | #define HSIZE (1 << (HLOG)) |
40 | |
40 | |
41 | /* |
41 | /* |
42 | * don't play with this unless you benchmark! |
42 | * don't play with this unless you benchmark! |
43 | * decompression is not dependent on the hash function |
43 | * the data format is not dependent on the hash function. |
44 | * the hashing function might seem strange, just believe me |
44 | * the hash function might seem strange, just believe me, |
45 | * it works ;) |
45 | * it works ;) |
46 | */ |
46 | */ |
47 | #ifndef FRST |
47 | #ifndef FRST |
48 | # define FRST(p) (((p[0]) << 8) | p[1]) |
48 | # define FRST(p) (((p[0]) << 8) | p[1]) |
49 | # define NEXT(v,p) (((v) << 8) | p[2]) |
49 | # define NEXT(v,p) (((v) << 8) | p[2]) |
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87 | #define expect_true(expr) expect ((expr) != 0, 1) |
87 | #define expect_true(expr) expect ((expr) != 0, 1) |
88 | |
88 | |
89 | /* |
89 | /* |
90 | * compressed format |
90 | * compressed format |
91 | * |
91 | * |
92 | * 000LLLLL <L+1> ; literal |
92 | * 000LLLLL <L+1> ; literal, L+1=1..33 octets |
93 | * LLLooooo oooooooo ; backref L |
93 | * LLLooooo oooooooo ; backref L+1=1..7 octets, o+1=1..4096 offset |
94 | * 111ooooo LLLLLLLL oooooooo ; backref L+7 |
94 | * 111ooooo LLLLLLLL oooooooo ; backref L+8 octets, o+1=1..4096 offset |
95 | * |
95 | * |
96 | */ |
96 | */ |
97 | |
97 | |
98 | unsigned int |
98 | unsigned int |
99 | lzf_compress (const void *const in_data, unsigned int in_len, |
99 | lzf_compress (const void *const in_data, unsigned int in_len, |
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153 | && ref < ip /* the next test will actually take care of this, but this is faster */ |
153 | && ref < ip /* the next test will actually take care of this, but this is faster */ |
154 | #endif |
154 | #endif |
155 | && (off = ip - ref - 1) < MAX_OFF |
155 | && (off = ip - ref - 1) < MAX_OFF |
156 | && ip + 4 < in_end |
156 | && ip + 4 < in_end |
157 | && ref > (u8 *)in_data |
157 | && ref > (u8 *)in_data |
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158 | && ref[2] == ip[2] |
158 | #if STRICT_ALIGN |
159 | #if STRICT_ALIGN |
159 | && ref[0] == ip[0] |
160 | && (ref[1] << 8) | ref[0] == (ip[1] << 8) | ip[0] |
160 | && ref[1] == ip[1] |
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161 | && ref[2] == ip[2] |
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162 | #else |
161 | #else |
163 | && *(u16 *)ref == *(u16 *)ip |
162 | && *(u16 *)ref == *(u16 *)ip |
164 | && ref[2] == ip[2] |
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165 | #endif |
163 | #endif |
166 | ) |
164 | ) |
167 | { |
165 | { |
168 | /* match found at *ref++ */ |
166 | /* match found at *ref++ */ |
169 | unsigned int len = 2; |
167 | unsigned int len = 2; |
170 | unsigned int maxlen = in_end - ip - len; |
168 | unsigned int maxlen = in_end - ip - len; |
171 | maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
169 | maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
172 | |
170 | |
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171 | if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */ |
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172 | if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */ |
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173 | return 0; |
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174 | |
173 | op [- lit - 1] = lit - 1; /* stop run */ |
175 | op [- lit - 1] = lit - 1; /* stop run */ |
174 | op -= !lit; /* undo run if length is zero */ |
176 | op -= !lit; /* undo run if length is zero */ |
175 | |
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176 | if (expect_false (op + 3 + 1 >= out_end)) |
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177 | return 0; |
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178 | |
177 | |
179 | for (;;) |
178 | for (;;) |
180 | { |
179 | { |
181 | if (expect_true (maxlen > 16)) |
180 | if (expect_true (maxlen > 16)) |
182 | { |
181 | { |