1 | /* |
1 | /* |
2 | * Copyright (c) 2000-2010 Marc Alexander Lehmann <schmorp@schmorp.de> |
2 | * Copyright (c) 2000-2010,2012 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, |
8 | * this list of conditions and the following disclaimer. |
8 | * this list of conditions and the following disclaimer. |
9 | * |
9 | * |
10 | * 2. Redistributions in binary form must reproduce the above copyright |
10 | * 2. Redistributions in binary form must reproduce the above copyright |
11 | * notice, this list of conditions and the following disclaimer in the |
11 | * notice, this list of conditions and the following disclaimer in the |
12 | * documentation and/or other materials provided with the distribution. |
12 | * documentation and/or other materials provided with the distribution. |
13 | * |
13 | * |
14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
15 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER- |
15 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER- |
16 | * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
16 | * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
17 | * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE- |
17 | * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE- |
18 | * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
18 | * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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… | |
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]) |
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50 | # if MULTIPLICATION_IS_SLOW |
50 | # if ULTRA_FAST |
51 | # if ULTRA_FAST |
51 | # define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1)) |
52 | # define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1)) |
52 | # elif VERY_FAST |
53 | # elif VERY_FAST |
53 | # define IDX(h) ((( h >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
54 | # define IDX(h) ((( h >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
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55 | # else |
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56 | # define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
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57 | # endif |
54 | # else |
58 | # else |
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59 | /* this one was developed with sesse, |
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60 | * and is very similar to the one in snappy. |
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61 | * it does need a modern enough cpu with a fast multiplication. |
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62 | */ |
55 | # define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
63 | # define IDX(h) (((h * 0x1e35a7bdU) >> (32 - HLOG - 8)) & (HSIZE - 1)) |
56 | # endif |
64 | # endif |
57 | #endif |
65 | #endif |
58 | /* |
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59 | * IDX works because it is very similar to a multiplicative hash, e.g. |
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60 | * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) |
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61 | * the latter is also quite fast on newer CPUs, and compresses similarly. |
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62 | * |
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63 | * the next one is also quite good, albeit slow ;) |
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64 | * (int)(cos(h & 0xffffff) * 1e6) |
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65 | */ |
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66 | |
66 | |
67 | #if 0 |
67 | #if 0 |
68 | /* original lzv-like hash function, much worse and thus slower */ |
68 | /* original lzv-like hash function, much worse and thus slower */ |
69 | # define FRST(p) (p[0] << 5) ^ p[1] |
69 | # define FRST(p) (p[0] << 5) ^ p[1] |
70 | # define NEXT(v,p) ((v) << 5) ^ p[2] |
70 | # define NEXT(v,p) ((v) << 5) ^ p[2] |
71 | # define IDX(h) ((h) & (HSIZE - 1)) |
71 | # define IDX(h) ((h) & (HSIZE - 1)) |
72 | #endif |
72 | #endif |
73 | |
73 | |
74 | #define MAX_LIT (1 << 5) |
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75 | #define MAX_OFF (1 << 13) |
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76 | #define MAX_REF ((1 << 8) + (1 << 3)) |
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77 | |
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78 | #if __GNUC__ >= 3 |
74 | #if __GNUC__ >= 3 |
79 | # define expect(expr,value) __builtin_expect ((expr),(value)) |
75 | # define expect(expr,value) __builtin_expect ((expr),(value)) |
80 | # define inline inline |
76 | # define inline inline |
81 | #else |
77 | #else |
82 | # define expect(expr,value) (expr) |
78 | # define expect(expr,value) (expr) |
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112 | u8 *out_end = op + out_len; |
108 | u8 *out_end = op + out_len; |
113 | const u8 *ref; |
109 | const u8 *ref; |
114 | |
110 | |
115 | /* off requires a type wide enough to hold a general pointer difference. |
111 | /* off requires a type wide enough to hold a general pointer difference. |
116 | * ISO C doesn't have that (size_t might not be enough and ptrdiff_t only |
112 | * ISO C doesn't have that (size_t might not be enough and ptrdiff_t only |
117 | * works for differences within a single object). We also assume that no |
113 | * works for differences within a single object). We also assume that |
118 | * no bit pattern traps. Since the only platform that is both non-POSIX |
114 | * no bit pattern traps. Since the only platform that is both non-POSIX |
119 | * and fails to support both assumptions is windows 64 bit, we make a |
115 | * and fails to support both assumptions is windows 64 bit, we make a |
120 | * special workaround for it. |
116 | * special workaround for it. |
121 | */ |
117 | */ |
122 | #if defined (WIN32) && defined (_M_X64) |
118 | #if defined (_WIN32) && defined (_M_X64) |
123 | unsigned _int64 off; /* workaround for missing POSIX compliance */ |
119 | /* workaround for missing POSIX compliance */ |
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120 | #if __GNUC__ |
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121 | unsigned long long off; |
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122 | #else |
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123 | unsigned __int64 off; |
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124 | #endif |
124 | #else |
125 | #else |
125 | unsigned long off; |
126 | unsigned long off; |
126 | #endif |
127 | #endif |
127 | unsigned int hval; |
128 | unsigned int hval; |
128 | int lit; |
129 | int lit; |
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147 | |
148 | |
148 | if (1 |
149 | if (1 |
149 | #if INIT_HTAB |
150 | #if INIT_HTAB |
150 | && ref < ip /* the next test will actually take care of this, but this is faster */ |
151 | && ref < ip /* the next test will actually take care of this, but this is faster */ |
151 | #endif |
152 | #endif |
152 | && (off = ip - ref - 1) < MAX_OFF |
153 | && (off = ip - ref - 1) < LZF_MAX_OFF |
153 | && ip + 4 < in_end |
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154 | && ref > (u8 *)in_data |
154 | && ref > (u8 *)in_data |
155 | && ref[2] == ip[2] |
155 | && ref[2] == ip[2] |
156 | #if STRICT_ALIGN |
156 | #if STRICT_ALIGN |
157 | && (ref[1] << 8) | ref[0] == (ip[1] << 8) | ip[0] |
157 | && ((ref[1] << 8) | ref[0]) == ((ip[1] << 8) | ip[0]) |
158 | #else |
158 | #else |
159 | && *(u16 *)ref == *(u16 *)ip |
159 | && *(u16 *)ref == *(u16 *)ip |
160 | #endif |
160 | #endif |
161 | ) |
161 | ) |
162 | { |
162 | { |
163 | /* match found at *ref++ */ |
163 | /* match found at *ref++ */ |
164 | unsigned int len = 2; |
164 | unsigned int len = 2; |
165 | unsigned int maxlen = in_end - ip - len; |
165 | unsigned int maxlen = in_end - ip - len; |
166 | maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
166 | maxlen = maxlen > LZF_MAX_REF ? LZF_MAX_REF : maxlen; |
167 | |
167 | |
168 | if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */ |
168 | if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */ |
169 | if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */ |
169 | if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */ |
170 | return 0; |
170 | return 0; |
171 | |
171 | |
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216 | *op++ = (off >> 8) + ( 7 << 5); |
216 | *op++ = (off >> 8) + ( 7 << 5); |
217 | *op++ = len - 7; |
217 | *op++ = len - 7; |
218 | } |
218 | } |
219 | |
219 | |
220 | *op++ = off; |
220 | *op++ = off; |
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221 | |
221 | lit = 0; op++; /* start run */ |
222 | lit = 0; op++; /* start run */ |
222 | |
223 | |
223 | ip += len + 1; |
224 | ip += len + 1; |
224 | |
225 | |
225 | if (expect_false (ip >= in_end - 2)) |
226 | if (expect_false (ip >= in_end - 2)) |
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259 | if (expect_false (op >= out_end)) |
260 | if (expect_false (op >= out_end)) |
260 | return 0; |
261 | return 0; |
261 | |
262 | |
262 | lit++; *op++ = *ip++; |
263 | lit++; *op++ = *ip++; |
263 | |
264 | |
264 | if (expect_false (lit == MAX_LIT)) |
265 | if (expect_false (lit == LZF_MAX_LIT)) |
265 | { |
266 | { |
266 | op [- lit - 1] = lit - 1; /* stop run */ |
267 | op [- lit - 1] = lit - 1; /* stop run */ |
267 | lit = 0; op++; /* start run */ |
268 | lit = 0; op++; /* start run */ |
268 | } |
269 | } |
269 | } |
270 | } |
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274 | |
275 | |
275 | while (ip < in_end) |
276 | while (ip < in_end) |
276 | { |
277 | { |
277 | lit++; *op++ = *ip++; |
278 | lit++; *op++ = *ip++; |
278 | |
279 | |
279 | if (expect_false (lit == MAX_LIT)) |
280 | if (expect_false (lit == LZF_MAX_LIT)) |
280 | { |
281 | { |
281 | op [- lit - 1] = lit - 1; /* stop run */ |
282 | op [- lit - 1] = lit - 1; /* stop run */ |
282 | lit = 0; op++; /* start run */ |
283 | lit = 0; op++; /* start run */ |
283 | } |
284 | } |
284 | } |
285 | } |