1 | /* |
1 | /* |
2 | * Copyright (c) 2000-2007 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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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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142 | && 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 */ |
143 | #endif |
154 | #endif |
144 | && (off = ip - ref - 1) < MAX_OFF |
155 | && (off = ip - ref - 1) < MAX_OFF |
145 | && ip + 4 < in_end |
156 | && ip + 4 < in_end |
146 | && ref > (u8 *)in_data |
157 | && ref > (u8 *)in_data |
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158 | && ref[2] == ip[2] |
147 | #if STRICT_ALIGN |
159 | #if STRICT_ALIGN |
148 | && ref[0] == ip[0] |
160 | && (ref[1] << 8) | ref[0] == (ip[1] << 8) | ip[0] |
149 | && ref[1] == ip[1] |
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150 | && ref[2] == ip[2] |
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151 | #else |
161 | #else |
152 | && *(u16 *)ref == *(u16 *)ip |
162 | && *(u16 *)ref == *(u16 *)ip |
153 | && ref[2] == ip[2] |
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154 | #endif |
163 | #endif |
155 | ) |
164 | ) |
156 | { |
165 | { |
157 | /* match found at *ref++ */ |
166 | /* match found at *ref++ */ |
158 | unsigned int len = 2; |
167 | unsigned int len = 2; |
159 | unsigned int maxlen = in_end - ip - len; |
168 | unsigned int maxlen = in_end - ip - len; |
160 | maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
169 | maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
161 | |
170 | |
162 | if (maxlen > 8) maxlen = 8;//D |
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; |
163 | |
174 | |
164 | op [- lit - 1] = lit - 1; /* stop run */ |
175 | op [- lit - 1] = lit - 1; /* stop run */ |
165 | op -= !lit; /* undo run if length is zero */ |
176 | op -= !lit; /* undo run if length is zero */ |
166 | |
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167 | if (expect_false (op + 3 + 1 >= out_end)) |
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168 | return 0; |
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169 | |
177 | |
170 | for (;;) |
178 | for (;;) |
171 | { |
179 | { |
172 | if (expect_true (maxlen > 16)) |
180 | if (expect_true (maxlen > 16)) |
173 | { |
181 | { |
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197 | while (len < maxlen && ref[len] == ip[len]); |
205 | while (len < maxlen && ref[len] == ip[len]); |
198 | |
206 | |
199 | break; |
207 | break; |
200 | } |
208 | } |
201 | |
209 | |
202 | len -= 2; |
210 | len -= 2; /* len is now #octets - 1 */ |
203 | ip++; |
211 | ip++; |
204 | |
212 | |
205 | if (len < 7) |
213 | if (len < 7) |
206 | { |
214 | { |
207 | *op++ = (off >> 8) + (len << 5); |
215 | *op++ = (off >> 8) + (len << 5); |
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211 | *op++ = (off >> 8) + ( 7 << 5); |
219 | *op++ = (off >> 8) + ( 7 << 5); |
212 | *op++ = len - 7; |
220 | *op++ = len - 7; |
213 | } |
221 | } |
214 | |
222 | |
215 | *op++ = off; |
223 | *op++ = off; |
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224 | lit = 0; op++; /* start run */ |
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225 | |
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226 | ip += len + 1; |
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227 | |
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228 | if (expect_false (ip >= in_end - 2)) |
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229 | break; |
216 | |
230 | |
217 | #if ULTRA_FAST || VERY_FAST |
231 | #if ULTRA_FAST || VERY_FAST |
218 | ip += len; |
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219 | #if VERY_FAST && !ULTRA_FAST |
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220 | --ip; |
232 | --ip; |
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233 | # if VERY_FAST && !ULTRA_FAST |
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234 | --ip; |
221 | #endif |
235 | # endif |
222 | hval = FRST (ip); |
236 | hval = FRST (ip); |
223 | |
237 | |
224 | hval = NEXT (hval, ip); |
238 | hval = NEXT (hval, ip); |
225 | htab[IDX (hval)] = ip; |
239 | htab[IDX (hval)] = ip; |
226 | ip++; |
240 | ip++; |
227 | |
241 | |
228 | #if VERY_FAST && !ULTRA_FAST |
242 | # if VERY_FAST && !ULTRA_FAST |
229 | hval = NEXT (hval, ip); |
243 | hval = NEXT (hval, ip); |
230 | htab[IDX (hval)] = ip; |
244 | htab[IDX (hval)] = ip; |
231 | ip++; |
245 | ip++; |
232 | #endif |
246 | # endif |
233 | #else |
247 | #else |
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248 | ip -= len + 1; |
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249 | |
234 | do |
250 | do |
235 | { |
251 | { |
236 | hval = NEXT (hval, ip); |
252 | hval = NEXT (hval, ip); |
237 | htab[IDX (hval)] = ip; |
253 | htab[IDX (hval)] = ip; |
238 | ip++; |
254 | ip++; |
239 | } |
255 | } |
240 | while (len--); |
256 | while (len--); |
241 | #endif |
257 | #endif |
242 | |
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243 | lit = 0; op++; /* start run */ |
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244 | } |
258 | } |
245 | else |
259 | else |
246 | { |
260 | { |
247 | /* one more literal byte we must copy */ |
261 | /* one more literal byte we must copy */ |
248 | if (expect_false (op >= out_end)) |
262 | if (expect_false (op >= out_end)) |