1 | /* |
1 | /* |
2 | * Copyright (c) 2000-2007 Marc Alexander Lehmann <schmorp@schmorp.de> |
2 | * Copyright (c) 2000-2008 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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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 | |
162 | if (maxlen > 8) maxlen = 8;//D |
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163 | |
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164 | op [- lit - 1] = lit - 1; /* stop run */ |
173 | op [- lit - 1] = lit - 1; /* stop run */ |
165 | op -= !lit; /* undo run if length is zero */ |
174 | op -= !lit; /* undo run if length is zero */ |
166 | |
175 | |
167 | if (expect_false (op + 3 + 1 >= out_end)) |
176 | if (expect_false (op + 3 + 1 >= out_end)) |
168 | return 0; |
177 | return 0; |
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197 | while (len < maxlen && ref[len] == ip[len]); |
206 | while (len < maxlen && ref[len] == ip[len]); |
198 | |
207 | |
199 | break; |
208 | break; |
200 | } |
209 | } |
201 | |
210 | |
202 | len -= 2; |
211 | len -= 2; /* len is now #octets - 1 */ |
203 | ip++; |
212 | ip++; |
204 | |
213 | |
205 | if (len < 7) |
214 | if (len < 7) |
206 | { |
215 | { |
207 | *op++ = (off >> 8) + (len << 5); |
216 | *op++ = (off >> 8) + (len << 5); |
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211 | *op++ = (off >> 8) + ( 7 << 5); |
220 | *op++ = (off >> 8) + ( 7 << 5); |
212 | *op++ = len - 7; |
221 | *op++ = len - 7; |
213 | } |
222 | } |
214 | |
223 | |
215 | *op++ = off; |
224 | *op++ = off; |
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225 | lit = 0; op++; /* start run */ |
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226 | |
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227 | ip += len + 1; |
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228 | |
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229 | if (expect_false (ip >= in_end - 2)) |
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230 | break; |
216 | |
231 | |
217 | #if ULTRA_FAST || VERY_FAST |
232 | #if ULTRA_FAST || VERY_FAST |
218 | ip += len; |
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219 | #if VERY_FAST && !ULTRA_FAST |
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220 | --ip; |
233 | --ip; |
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234 | # if VERY_FAST && !ULTRA_FAST |
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235 | --ip; |
221 | #endif |
236 | # endif |
222 | hval = FRST (ip); |
237 | hval = FRST (ip); |
223 | |
238 | |
224 | hval = NEXT (hval, ip); |
239 | hval = NEXT (hval, ip); |
225 | htab[IDX (hval)] = ip; |
240 | htab[IDX (hval)] = ip; |
226 | ip++; |
241 | ip++; |
227 | |
242 | |
228 | #if VERY_FAST && !ULTRA_FAST |
243 | # if VERY_FAST && !ULTRA_FAST |
229 | hval = NEXT (hval, ip); |
244 | hval = NEXT (hval, ip); |
230 | htab[IDX (hval)] = ip; |
245 | htab[IDX (hval)] = ip; |
231 | ip++; |
246 | ip++; |
232 | #endif |
247 | # endif |
233 | #else |
248 | #else |
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249 | ip -= len + 1; |
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250 | |
234 | do |
251 | do |
235 | { |
252 | { |
236 | hval = NEXT (hval, ip); |
253 | hval = NEXT (hval, ip); |
237 | htab[IDX (hval)] = ip; |
254 | htab[IDX (hval)] = ip; |
238 | ip++; |
255 | ip++; |
239 | } |
256 | } |
240 | while (len--); |
257 | while (len--); |
241 | #endif |
258 | #endif |
242 | |
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243 | lit = 0; op++; /* start run */ |
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244 | } |
259 | } |
245 | else |
260 | else |
246 | { |
261 | { |
247 | /* one more literal byte we must copy */ |
262 | /* one more literal byte we must copy */ |
248 | if (expect_false (op >= out_end)) |
263 | if (expect_false (op >= out_end)) |
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256 | lit = 0; op++; /* start run */ |
271 | lit = 0; op++; /* start run */ |
257 | } |
272 | } |
258 | } |
273 | } |
259 | } |
274 | } |
260 | |
275 | |
261 | if (op + 2 > out_end) /* at most 2 bytes can be missing here */ |
276 | if (op + 3 > out_end) /* at most 3 bytes can be missing here */ |
262 | return 0; |
277 | return 0; |
263 | |
278 | |
264 | while (ip < in_end) |
279 | while (ip < in_end) |
265 | { |
280 | { |
266 | lit++; *op++ = *ip++; |
281 | lit++; *op++ = *ip++; |