| 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 | |
| … | |
… | |
| 136 | hval = NEXT (hval, ip); |
147 | hval = NEXT (hval, ip); |
| 137 | hslot = htab + IDX (hval); |
148 | hslot = htab + IDX (hval); |
| 138 | ref = *hslot; *hslot = ip; |
149 | ref = *hslot; *hslot = ip; |
| 139 | |
150 | |
| 140 | if (1 |
151 | if (1 |
| 141 | #if INIT_HTAB && !USE_MEMCPY |
152 | #if INIT_HTAB |
| 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 |
| … | |
… | |
| 195 | while (len < maxlen && ref[len] == ip[len]); |
206 | while (len < maxlen && ref[len] == ip[len]); |
| 196 | |
207 | |
| 197 | break; |
208 | break; |
| 198 | } |
209 | } |
| 199 | |
210 | |
| 200 | len -= 2; |
211 | len -= 2; /* len is now #octets - 1 */ |
| 201 | ip++; |
212 | ip++; |
| 202 | |
213 | |
| 203 | if (len < 7) |
214 | if (len < 7) |
| 204 | { |
215 | { |
| 205 | *op++ = (off >> 8) + (len << 5); |
216 | *op++ = (off >> 8) + (len << 5); |
| … | |
… | |
| 210 | *op++ = len - 7; |
221 | *op++ = len - 7; |
| 211 | } |
222 | } |
| 212 | |
223 | |
| 213 | *op++ = off; |
224 | *op++ = off; |
| 214 | |
225 | |
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226 | if (expect_true (ip + len < in_end - 2)) |
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227 | { |
| 215 | #if ULTRA_FAST || VERY_FAST |
228 | #if ULTRA_FAST || VERY_FAST |
| 216 | ip += len; |
229 | ip += len; |
| 217 | #if VERY_FAST && !ULTRA_FAST |
230 | # if VERY_FAST && !ULTRA_FAST |
| 218 | --ip; |
231 | --ip; |
| 219 | #endif |
232 | # endif |
| 220 | hval = FRST (ip); |
233 | hval = FRST (ip); |
| 221 | |
234 | |
| 222 | hval = NEXT (hval, ip); |
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| 223 | htab[IDX (hval)] = ip; |
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| 224 | ip++; |
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| 225 | |
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| 226 | #if VERY_FAST && !ULTRA_FAST |
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| 227 | hval = NEXT (hval, ip); |
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| 228 | htab[IDX (hval)] = ip; |
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| 229 | ip++; |
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| 230 | #endif |
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| 231 | #else |
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| 232 | do |
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| 233 | { |
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| 234 | hval = NEXT (hval, ip); |
235 | hval = NEXT (hval, ip); |
| 235 | htab[IDX (hval)] = ip; |
236 | htab[IDX (hval)] = ip; |
| 236 | ip++; |
237 | ip++; |
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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; |
| 237 | } |
242 | ip++; |
| 238 | while (len--); |
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| 239 | #endif |
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 | } |
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251 | while (len--); |
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252 | #endif |
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253 | } |
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254 | |
| 240 | lit = 0; op++; /* start run */ |
255 | lit = 0; op++; /* start run */ |
| 241 | continue; |
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| 242 | } |
256 | } |
| 243 | |
257 | else |
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258 | { |
| 244 | /* one more literal byte we must copy */ |
259 | /* one more literal byte we must copy */ |
| 245 | |
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| 246 | if (expect_false (op >= out_end)) |
260 | if (expect_false (op >= out_end)) |
| 247 | return 0; |
261 | return 0; |
| 248 | |
262 | |
| 249 | lit++; |
263 | lit++; *op++ = *ip++; |
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264 | |
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265 | if (expect_false (lit == MAX_LIT)) |
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266 | { |
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267 | op [- lit - 1] = lit - 1; /* stop run */ |
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268 | lit = 0; op++; /* start run */ |
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269 | } |
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270 | } |
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271 | } |
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272 | |
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273 | if (op + 3 > out_end) /* at most 3 bytes can be missing here */ |
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274 | return 0; |
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275 | |
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276 | while (ip < in_end) |
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277 | { |
| 250 | *op++ = *ip++; |
278 | lit++; *op++ = *ip++; |
| 251 | |
279 | |
| 252 | if (expect_false (lit == MAX_LIT)) |
280 | if (expect_false (lit == MAX_LIT)) |
| 253 | { |
281 | { |
| 254 | op [- lit - 1] = lit - 1; /* stop run */ |
282 | op [- lit - 1] = lit - 1; /* stop run */ |
| 255 | lit = 0; op++; /* start run */ |
283 | lit = 0; op++; /* start run */ |
| 256 | } |
284 | } |
| 257 | } |
285 | } |
| 258 | |
286 | |
| 259 | if (op + 2 >= out_end) |
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| 260 | return 0; |
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| 261 | |
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| 262 | while (ip < in_end) |
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| 263 | { |
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| 264 | lit++; |
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| 265 | *op++ = *ip++; |
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| 266 | } |
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| 267 | |
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| 268 | op [- lit - 1] = lit - 1; /* end run */ |
287 | op [- lit - 1] = lit - 1; /* end run */ |
| 269 | op -= !lit; /* undo run if length is zero */ |
288 | op -= !lit; /* undo run if length is zero */ |
| 270 | |
289 | |
| 271 | return op - (u8 *)out_data; |
290 | return op - (u8 *)out_data; |
| 272 | } |
291 | } |
