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 | { |
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220 | *op++ = (off >> 8) + ( 7 << 5); |
219 | *op++ = (off >> 8) + ( 7 << 5); |
221 | *op++ = len - 7; |
220 | *op++ = len - 7; |
222 | } |
221 | } |
223 | |
222 | |
224 | *op++ = off; |
223 | *op++ = off; |
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224 | lit = 0; op++; /* start run */ |
225 | |
225 | |
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226 | ip += len + 1; |
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227 | |
226 | if (expect_true (ip + len < in_end - 2)) |
228 | if (expect_false (ip >= in_end - 2)) |
227 | { |
229 | break; |
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230 | |
228 | #if ULTRA_FAST || VERY_FAST |
231 | #if ULTRA_FAST || VERY_FAST |
229 | ip += len; |
232 | --ip; |
230 | # if VERY_FAST && !ULTRA_FAST |
233 | # if VERY_FAST && !ULTRA_FAST |
231 | --ip; |
234 | --ip; |
232 | # endif |
235 | # endif |
233 | hval = FRST (ip); |
236 | hval = FRST (ip); |
234 | |
237 | |
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238 | hval = NEXT (hval, ip); |
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239 | htab[IDX (hval)] = ip; |
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240 | ip++; |
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241 | |
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242 | # if VERY_FAST && !ULTRA_FAST |
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243 | hval = NEXT (hval, ip); |
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244 | htab[IDX (hval)] = ip; |
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245 | ip++; |
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246 | # endif |
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247 | #else |
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248 | ip -= len + 1; |
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249 | |
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250 | do |
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251 | { |
235 | hval = NEXT (hval, ip); |
252 | hval = NEXT (hval, ip); |
236 | htab[IDX (hval)] = ip; |
253 | htab[IDX (hval)] = ip; |
237 | ip++; |
254 | ip++; |
238 | |
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239 | # if VERY_FAST && !ULTRA_FAST |
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240 | hval = NEXT (hval, ip); |
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241 | htab[IDX (hval)] = ip; |
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242 | ip++; |
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243 | # endif |
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244 | #else |
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245 | do |
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246 | { |
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247 | hval = NEXT (hval, ip); |
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248 | htab[IDX (hval)] = ip; |
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249 | ip++; |
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250 | } |
255 | } |
251 | while (len--); |
256 | while (len--); |
252 | #endif |
257 | #endif |
253 | } |
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254 | |
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255 | lit = 0; op++; /* start run */ |
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256 | } |
258 | } |
257 | else |
259 | else |
258 | { |
260 | { |
259 | /* one more literal byte we must copy */ |
261 | /* one more literal byte we must copy */ |
260 | if (expect_false (op >= out_end)) |
262 | if (expect_false (op >= out_end)) |