| 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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| 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 | |
| … | |
… | |
| 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 |
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; |
| 163 | |
176 | |
| 164 | op [- lit - 1] = lit - 1; /* stop run */ |
177 | op [- lit - 1] = lit - 1; /* stop run */ |
| 165 | op -= !lit; /* undo run if length is zero */ |
178 | 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 | |
179 | |
| 170 | for (;;) |
180 | for (;;) |
| 171 | { |
181 | { |
| 172 | if (expect_true (maxlen > 16)) |
182 | if (expect_true (maxlen > 16)) |
| 173 | { |
183 | { |
| … | |
… | |
| 197 | while (len < maxlen && ref[len] == ip[len]); |
207 | while (len < maxlen && ref[len] == ip[len]); |
| 198 | |
208 | |
| 199 | break; |
209 | break; |
| 200 | } |
210 | } |
| 201 | |
211 | |
| 202 | len -= 2; |
212 | len -= 2; /* len is now #octets - 1 */ |
| 203 | ip++; |
213 | ip++; |
| 204 | |
214 | |
| 205 | if (len < 7) |
215 | if (len < 7) |
| 206 | { |
216 | { |
| 207 | *op++ = (off >> 8) + (len << 5); |
217 | *op++ = (off >> 8) + (len << 5); |
| … | |
… | |
| 211 | *op++ = (off >> 8) + ( 7 << 5); |
221 | *op++ = (off >> 8) + ( 7 << 5); |
| 212 | *op++ = len - 7; |
222 | *op++ = len - 7; |
| 213 | } |
223 | } |
| 214 | |
224 | |
| 215 | *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; |
| 216 | |
232 | |
| 217 | #if ULTRA_FAST || VERY_FAST |
233 | #if ULTRA_FAST || VERY_FAST |
| 218 | ip += len; |
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| 219 | #if VERY_FAST && !ULTRA_FAST |
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| 220 | --ip; |
234 | --ip; |
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235 | # if VERY_FAST && !ULTRA_FAST |
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236 | --ip; |
| 221 | #endif |
237 | # endif |
| 222 | hval = FRST (ip); |
238 | hval = FRST (ip); |
| 223 | |
239 | |
| 224 | hval = NEXT (hval, ip); |
240 | hval = NEXT (hval, ip); |
| 225 | htab[IDX (hval)] = ip; |
241 | htab[IDX (hval)] = ip; |
| 226 | ip++; |
242 | ip++; |
| 227 | |
243 | |
| 228 | #if VERY_FAST && !ULTRA_FAST |
244 | # if VERY_FAST && !ULTRA_FAST |
| 229 | hval = NEXT (hval, ip); |
245 | hval = NEXT (hval, ip); |
| 230 | htab[IDX (hval)] = ip; |
246 | htab[IDX (hval)] = ip; |
| 231 | ip++; |
247 | ip++; |
| 232 | #endif |
248 | # endif |
| 233 | #else |
249 | #else |
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250 | ip -= len + 1; |
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251 | |
| 234 | do |
252 | do |
| 235 | { |
253 | { |
| 236 | hval = NEXT (hval, ip); |
254 | hval = NEXT (hval, ip); |
| 237 | htab[IDX (hval)] = ip; |
255 | htab[IDX (hval)] = ip; |
| 238 | ip++; |
256 | ip++; |
| 239 | } |
257 | } |
| 240 | while (len--); |
258 | while (len--); |
| 241 | #endif |
259 | #endif |
| 242 | |
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| 243 | lit = 0; op++; /* start run */ |
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| 244 | } |
260 | } |
| 245 | else |
261 | else |
| 246 | { |
262 | { |
| 247 | /* one more literal byte we must copy */ |
263 | /* one more literal byte we must copy */ |
| 248 | if (expect_false (op >= out_end)) |
264 | if (expect_false (op >= out_end)) |
| … | |
… | |
| 256 | lit = 0; op++; /* start run */ |
272 | lit = 0; op++; /* start run */ |
| 257 | } |
273 | } |
| 258 | } |
274 | } |
| 259 | } |
275 | } |
| 260 | |
276 | |
| 261 | if (op + 2 > out_end) /* at most 2 bytes can be missing here */ |
277 | if (op + 3 > out_end) /* at most 3 bytes can be missing here */ |
| 262 | return 0; |
278 | return 0; |
| 263 | |
279 | |
| 264 | while (ip < in_end) |
280 | while (ip < in_end) |
| 265 | { |
281 | { |
| 266 | lit++; *op++ = *ip++; |
282 | lit++; *op++ = *ip++; |
