| 1 | #ifndef UTIL_H__ |
1 | #ifndef UTIL_H__ |
| 2 | #define UTIL_H__ |
2 | #define UTIL_H__ |
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3 | |
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4 | #if __GNUC__ >= 3 |
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5 | # define is_constant(c) __builtin_constant_p (c) |
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6 | #else |
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7 | # define is_constant(c) 0 |
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8 | #endif |
| 3 | |
9 | |
| 4 | // makes dynamically allocated objects zero-initialised |
10 | // makes dynamically allocated objects zero-initialised |
| 5 | struct zero_initialised |
11 | struct zero_initialised |
| 6 | { |
12 | { |
| 7 | void *operator new (size_t s); |
13 | void *operator new (size_t s); |
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14 | void *operator new [] (size_t s); |
| 8 | void operator delete (void *p, size_t s); |
15 | void operator delete (void *p, size_t s); |
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16 | void operator delete [] (void *p, size_t s); |
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17 | }; |
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18 | |
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19 | struct str_hash |
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20 | { |
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21 | std::size_t operator ()(const char *s) const |
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22 | { |
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23 | unsigned long hash = 0; |
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24 | |
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25 | /* use the one-at-a-time hash function, which supposedly is |
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26 | * better than the djb2-like one used by perl5.005, but |
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27 | * certainly is better then the bug used here before. |
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28 | * see http://burtleburtle.net/bob/hash/doobs.html |
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29 | */ |
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30 | while (*s) |
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31 | { |
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32 | hash += *s++; |
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33 | hash += hash << 10; |
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34 | hash ^= hash >> 6; |
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35 | } |
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36 | |
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37 | hash += hash << 3; |
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38 | hash ^= hash >> 11; |
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39 | hash += hash << 15; |
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40 | |
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41 | return hash; |
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42 | } |
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43 | }; |
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44 | |
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45 | struct str_equal |
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46 | { |
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47 | bool operator ()(const char *a, const char *b) const |
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48 | { |
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49 | return !strcmp (a, b); |
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50 | } |
| 9 | }; |
51 | }; |
| 10 | |
52 | |
| 11 | #endif |
53 | #endif |
| 12 | |
54 | |
