1 | /* |
1 | /* |
2 | * Copyright (c) 2000-2007 Marc Alexander Lehmann <schmorp@schmorp.de> |
2 | * Copyright (c) 2000-2009 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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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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111 | u8 *op = (u8 *)out_data; |
111 | u8 *op = (u8 *)out_data; |
112 | const u8 *in_end = ip + in_len; |
112 | const u8 *in_end = ip + in_len; |
113 | u8 *out_end = op + out_len; |
113 | u8 *out_end = op + out_len; |
114 | const u8 *ref; |
114 | const u8 *ref; |
115 | |
115 | |
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116 | /* off requires a type wide enough to hold a general pointer difference. |
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117 | * ISO C doesn't have that (size_t might not be enough and ptrdiff_t only |
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118 | * works for differences within a single object). We also assume that no |
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119 | * no bit pattern traps. Since the only platform that is both non-POSIX |
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120 | * and fails to support both assumptions is windows 64 bit, we make a |
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121 | * special workaround for it. |
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122 | */ |
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123 | #if defined (WIN32) && defined (_M_X64) |
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124 | unsigned _int64 off; /* workaround for missing POSIX compliance */ |
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125 | #else |
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126 | unsigned long off; |
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127 | #endif |
116 | unsigned int hval; |
128 | unsigned int hval; |
117 | unsigned long off; |
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118 | int lit; |
129 | int lit; |
119 | |
130 | |
120 | if (!in_len || !out_len) |
131 | if (!in_len || !out_len) |
121 | return 0; |
132 | return 0; |
122 | |
133 | |
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157 | /* match found at *ref++ */ |
168 | /* match found at *ref++ */ |
158 | unsigned int len = 2; |
169 | unsigned int len = 2; |
159 | unsigned int maxlen = in_end - ip - len; |
170 | unsigned int maxlen = in_end - ip - len; |
160 | maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
171 | maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
161 | |
172 | |
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173 | if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */ |
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174 | if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */ |
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175 | return 0; |
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176 | |
162 | op [- lit - 1] = lit - 1; /* stop run */ |
177 | op [- lit - 1] = lit - 1; /* stop run */ |
163 | op -= !lit; /* undo run if length is zero */ |
178 | op -= !lit; /* undo run if length is zero */ |
164 | |
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165 | if (expect_false (op + 3 + 1 >= out_end)) |
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166 | return 0; |
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167 | |
179 | |
168 | for (;;) |
180 | for (;;) |
169 | { |
181 | { |
170 | if (expect_true (maxlen > 16)) |
182 | if (expect_true (maxlen > 16)) |
171 | { |
183 | { |
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195 | while (len < maxlen && ref[len] == ip[len]); |
207 | while (len < maxlen && ref[len] == ip[len]); |
196 | |
208 | |
197 | break; |
209 | break; |
198 | } |
210 | } |
199 | |
211 | |
200 | len -= 2; |
212 | len -= 2; /* len is now #octets - 1 */ |
201 | ip++; |
213 | ip++; |
202 | |
214 | |
203 | if (len < 7) |
215 | if (len < 7) |
204 | { |
216 | { |
205 | *op++ = (off >> 8) + (len << 5); |
217 | *op++ = (off >> 8) + (len << 5); |
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209 | *op++ = (off >> 8) + ( 7 << 5); |
221 | *op++ = (off >> 8) + ( 7 << 5); |
210 | *op++ = len - 7; |
222 | *op++ = len - 7; |
211 | } |
223 | } |
212 | |
224 | |
213 | *op++ = off; |
225 | *op++ = off; |
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226 | lit = 0; op++; /* start run */ |
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227 | |
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228 | ip += len + 1; |
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229 | |
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230 | if (expect_false (ip >= in_end - 2)) |
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231 | break; |
214 | |
232 | |
215 | #if ULTRA_FAST || VERY_FAST |
233 | #if ULTRA_FAST || VERY_FAST |
216 | ip += len; |
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217 | #if VERY_FAST && !ULTRA_FAST |
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218 | --ip; |
234 | --ip; |
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235 | # if VERY_FAST && !ULTRA_FAST |
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236 | --ip; |
219 | #endif |
237 | # endif |
220 | hval = FRST (ip); |
238 | hval = FRST (ip); |
221 | |
239 | |
222 | hval = NEXT (hval, ip); |
240 | hval = NEXT (hval, ip); |
223 | htab[IDX (hval)] = ip; |
241 | htab[IDX (hval)] = ip; |
224 | ip++; |
242 | ip++; |
225 | |
243 | |
226 | #if VERY_FAST && !ULTRA_FAST |
244 | # if VERY_FAST && !ULTRA_FAST |
227 | hval = NEXT (hval, ip); |
245 | hval = NEXT (hval, ip); |
228 | htab[IDX (hval)] = ip; |
246 | htab[IDX (hval)] = ip; |
229 | ip++; |
247 | ip++; |
230 | #endif |
248 | # endif |
231 | #else |
249 | #else |
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250 | ip -= len + 1; |
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251 | |
232 | do |
252 | do |
233 | { |
253 | { |
234 | hval = NEXT (hval, ip); |
254 | hval = NEXT (hval, ip); |
235 | htab[IDX (hval)] = ip; |
255 | htab[IDX (hval)] = ip; |
236 | ip++; |
256 | ip++; |
237 | } |
257 | } |
238 | while (len--); |
258 | while (len--); |
239 | #endif |
259 | #endif |
240 | |
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241 | lit = 0; op++; /* start run */ |
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242 | } |
260 | } |
243 | else |
261 | else |
244 | { |
262 | { |
245 | /* one more literal byte we must copy */ |
263 | /* one more literal byte we must copy */ |
246 | if (expect_false (op >= out_end)) |
264 | if (expect_false (op >= out_end)) |