| … | |
… | |
| 44 | * don't play with this unless you benchmark! |
44 | * don't play with this unless you benchmark! |
| 45 | * decompression is not dependent on the hash function |
45 | * decompression is not dependent on the hash function |
| 46 | * the hashing function might seem strange, just believe me |
46 | * the hashing function might seem strange, just believe me |
| 47 | * it works ;) |
47 | * it works ;) |
| 48 | */ |
48 | */ |
| 49 | #define FRST(p) (((p[0]) << 8) + p[1]) |
49 | #define FRST(p) (((p[0]) << 8) | p[1]) |
| 50 | #define NEXT(v,p) (((v) << 8) + p[2]) |
50 | #define NEXT(v,p) (((v) << 8) | p[2]) |
| 51 | #define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
51 | #define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
| 52 | /* |
52 | /* |
| 53 | * IDX works because it is very similar to a multiplicative hash, e.g. |
53 | * IDX works because it is very similar to a multiplicative hash, e.g. |
| 54 | * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) |
54 | * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) |
| 55 | * the latter is also quite fast on newer CPUs, and sligthly better |
55 | * the latter is also quite fast on newer CPUs, and sligthly better |
| … | |
… | |
| 137 | /* match found at *ref++ */ |
137 | /* match found at *ref++ */ |
| 138 | unsigned int len = 2; |
138 | unsigned int len = 2; |
| 139 | unsigned int maxlen = in_end - ip - len; |
139 | unsigned int maxlen = in_end - ip - len; |
| 140 | maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
140 | maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
| 141 | |
141 | |
|
|
142 | if (op + lit + 1 + 3 >= out_end) |
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143 | return 0; |
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144 | |
| 142 | do |
145 | do |
| 143 | len++; |
146 | len++; |
| 144 | while (len < maxlen && ref[len] == ip[len]); |
147 | while (len < maxlen && ref[len] == ip[len]); |
| 145 | |
|
|
| 146 | if (op + lit + 1 + 3 >= out_end) |
|
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| 147 | return 0; |
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|
| 148 | |
148 | |
| 149 | if (lit) |
149 | if (lit) |
| 150 | { |
150 | { |
| 151 | *op++ = lit - 1; |
151 | *op++ = lit - 1; |
| 152 | lit = -lit; |
152 | lit = -lit; |
| … | |
… | |
| 168 | *op++ = len - 7; |
168 | *op++ = len - 7; |
| 169 | } |
169 | } |
| 170 | |
170 | |
| 171 | *op++ = off; |
171 | *op++ = off; |
| 172 | |
172 | |
| 173 | #if ULTRA_FAST |
173 | #if ULTRA_FAST || VERY_FAST |
| 174 | ip += len; |
174 | ip += len; |
|
|
175 | #if VERY_FAST && !ULTRA_FAST |
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176 | --ip; |
|
|
177 | #endif |
| 175 | hval = FRST (ip); |
178 | hval = FRST (ip); |
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179 | |
| 176 | hval = NEXT (hval, ip); |
180 | hval = NEXT (hval, ip); |
| 177 | htab[IDX (hval)] = ip; |
181 | htab[IDX (hval)] = ip; |
| 178 | ip++; |
182 | ip++; |
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183 | |
|
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184 | #if VERY_FAST && !ULTRA_FAST |
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185 | hval = NEXT (hval, ip); |
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186 | htab[IDX (hval)] = ip; |
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187 | ip++; |
|
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188 | #endif |
| 179 | #else |
189 | #else |
| 180 | do |
190 | do |
| 181 | { |
191 | { |
| 182 | hval = NEXT (hval, ip); |
192 | hval = NEXT (hval, ip); |
| 183 | htab[IDX (hval)] = ip; |
193 | htab[IDX (hval)] = ip; |
