| 1 | /* |
1 | /* |
| 2 | * Copyright (c) 2000-2009 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, |
| … | |
… | |
| 38 | |
38 | |
| 39 | #define HSIZE (1 << (HLOG)) |
39 | #define HSIZE (1 << (HLOG)) |
| 40 | |
40 | |
| 41 | /* |
41 | /* |
| 42 | * don't play with this unless you benchmark! |
42 | * don't play with this unless you benchmark! |
| 43 | * decompression is not dependent on the hash function |
43 | * the data format is not dependent on the hash function. |
| 44 | * the hashing function might seem strange, just believe me |
44 | * the hash function might seem strange, just believe me, |
| 45 | * it works ;) |
45 | * it works ;) |
| 46 | */ |
46 | */ |
| 47 | #ifndef FRST |
47 | #ifndef FRST |
| 48 | # define FRST(p) (((p[0]) << 8) | p[1]) |
48 | # define FRST(p) (((p[0]) << 8) | p[1]) |
| 49 | # define NEXT(v,p) (((v) << 8) | p[2]) |
49 | # define NEXT(v,p) (((v) << 8) | p[2]) |
| … | |
… | |
| 104 | ) |
104 | ) |
| 105 | { |
105 | { |
| 106 | #if !LZF_STATE_ARG |
106 | #if !LZF_STATE_ARG |
| 107 | LZF_STATE htab; |
107 | LZF_STATE htab; |
| 108 | #endif |
108 | #endif |
| 109 | const u8 **hslot; |
|
|
| 110 | const u8 *ip = (const u8 *)in_data; |
109 | const u8 *ip = (const u8 *)in_data; |
| 111 | u8 *op = (u8 *)out_data; |
110 | u8 *op = (u8 *)out_data; |
| 112 | const u8 *in_end = ip + in_len; |
111 | const u8 *in_end = ip + in_len; |
| 113 | u8 *out_end = op + out_len; |
112 | u8 *out_end = op + out_len; |
| 114 | const u8 *ref; |
113 | const u8 *ref; |
| … | |
… | |
| 131 | if (!in_len || !out_len) |
130 | if (!in_len || !out_len) |
| 132 | return 0; |
131 | return 0; |
| 133 | |
132 | |
| 134 | #if INIT_HTAB |
133 | #if INIT_HTAB |
| 135 | memset (htab, 0, sizeof (htab)); |
134 | memset (htab, 0, sizeof (htab)); |
| 136 | # if 0 |
|
|
| 137 | for (hslot = htab; hslot < htab + HSIZE; hslot++) |
|
|
| 138 | *hslot++ = ip; |
|
|
| 139 | # endif |
|
|
| 140 | #endif |
135 | #endif |
| 141 | |
136 | |
| 142 | lit = 0; op++; /* start run */ |
137 | lit = 0; op++; /* start run */ |
| 143 | |
138 | |
| 144 | hval = FRST (ip); |
139 | hval = FRST (ip); |
| 145 | while (ip < in_end - 2) |
140 | while (ip < in_end - 2) |
| 146 | { |
141 | { |
|
|
142 | LZF_HSLOT *hslot; |
|
|
143 | |
| 147 | hval = NEXT (hval, ip); |
144 | hval = NEXT (hval, ip); |
| 148 | hslot = htab + IDX (hval); |
145 | hslot = htab + IDX (hval); |
| 149 | ref = *hslot; *hslot = ip; |
146 | ref = *hslot + LZF_HSLOT_BIAS; *hslot = ip - LZF_HSLOT_BIAS; |
| 150 | |
147 | |
| 151 | if (1 |
148 | if (1 |
| 152 | #if INIT_HTAB |
149 | #if INIT_HTAB |
| 153 | && ref < ip /* the next test will actually take care of this, but this is faster */ |
150 | && ref < ip /* the next test will actually take care of this, but this is faster */ |
| 154 | #endif |
151 | #endif |
| 155 | && (off = ip - ref - 1) < MAX_OFF |
152 | && (off = ip - ref - 1) < MAX_OFF |
| 156 | && ip + 4 < in_end |
153 | && ip + 4 < in_end |
| 157 | && ref > (u8 *)in_data |
154 | && ref > (u8 *)in_data |
|
|
155 | && ref[2] == ip[2] |
| 158 | #if STRICT_ALIGN |
156 | #if STRICT_ALIGN |
| 159 | && ref[0] == ip[0] |
157 | && (ref[1] << 8) | ref[0] == (ip[1] << 8) | ip[0] |
| 160 | && ref[1] == ip[1] |
|
|
| 161 | && ref[2] == ip[2] |
|
|
| 162 | #else |
158 | #else |
| 163 | && *(u16 *)ref == *(u16 *)ip |
159 | && *(u16 *)ref == *(u16 *)ip |
| 164 | && ref[2] == ip[2] |
|
|
| 165 | #endif |
160 | #endif |
| 166 | ) |
161 | ) |
| 167 | { |
162 | { |
| 168 | /* match found at *ref++ */ |
163 | /* match found at *ref++ */ |
| 169 | unsigned int len = 2; |
164 | unsigned int len = 2; |
| … | |
… | |
| 236 | --ip; |
231 | --ip; |
| 237 | # endif |
232 | # endif |
| 238 | hval = FRST (ip); |
233 | hval = FRST (ip); |
| 239 | |
234 | |
| 240 | hval = NEXT (hval, ip); |
235 | hval = NEXT (hval, ip); |
| 241 | htab[IDX (hval)] = ip; |
236 | htab[IDX (hval)] = ip - LZF_HSLOT_BIAS; |
| 242 | ip++; |
237 | ip++; |
| 243 | |
238 | |
| 244 | # if VERY_FAST && !ULTRA_FAST |
239 | # if VERY_FAST && !ULTRA_FAST |
| 245 | hval = NEXT (hval, ip); |
240 | hval = NEXT (hval, ip); |
| 246 | htab[IDX (hval)] = ip; |
241 | htab[IDX (hval)] = ip - LZF_HSLOT_BIAS; |
| 247 | ip++; |
242 | ip++; |
| 248 | # endif |
243 | # endif |
| 249 | #else |
244 | #else |
| 250 | ip -= len + 1; |
245 | ip -= len + 1; |
| 251 | |
246 | |
| 252 | do |
247 | do |
| 253 | { |
248 | { |
| 254 | hval = NEXT (hval, ip); |
249 | hval = NEXT (hval, ip); |
| 255 | htab[IDX (hval)] = ip; |
250 | htab[IDX (hval)] = ip - LZF_HSLOT_BIAS; |
| 256 | ip++; |
251 | ip++; |
| 257 | } |
252 | } |
| 258 | while (len--); |
253 | while (len--); |
| 259 | #endif |
254 | #endif |
| 260 | } |
255 | } |
