1 | /* |
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2 | * Copyright (c) 2014 International Characters. |
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3 | * This software is licensed to the public under the Open Software License 3.0. |
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4 | * icgrep is a trademark of International Characters. |
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5 | */ |
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6 | |
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7 | #ifndef ALT_H |
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8 | #define ALT_H |
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9 | |
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10 | #include "re_re.h" |
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11 | #include "re_cc.h" |
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12 | #include <llvm/Support/Casting.h> |
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13 | |
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14 | namespace re { |
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15 | |
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16 | class Alt : public Vector { |
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17 | public: |
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18 | static inline bool classof(const RE * re) { |
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19 | return re->getClassTypeId() == ClassTypeId::Alt; |
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20 | } |
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21 | static inline bool classof(const void *) { |
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22 | return false; |
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23 | } |
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24 | protected: |
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25 | friend Alt * makeAlt(); |
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26 | template<typename iterator> friend RE * makeAlt(iterator, iterator); |
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27 | Alt() |
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28 | : Vector(ClassTypeId::Alt) { |
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29 | |
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30 | } |
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31 | Alt(iterator begin, iterator end) |
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32 | : Vector(ClassTypeId::Alt, begin, end) { |
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33 | |
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34 | } |
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35 | }; |
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36 | |
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37 | /** |
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38 | * @brief makeAlt |
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39 | * |
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40 | * Build an Alt, flattening alternative subgroups, and combining character classes and |
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41 | * move character classes towards the end of the list to ensure that all combinations are found. |
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42 | * |
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43 | * @param list |
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44 | * @return simplified RE representing the Alt |
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45 | */ |
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46 | |
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47 | inline Alt * makeAlt() { |
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48 | return new Alt(); |
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49 | } |
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50 | |
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51 | template<typename iterator> |
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52 | RE * makeAlt(iterator begin, iterator end) { |
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53 | Alt * newAlt = makeAlt(); |
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54 | CC * unionCC = nullptr; |
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55 | for (auto i = begin; i != end; ++i) { |
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56 | if (CC * cc = llvm::dyn_cast<CC>(*i)) { |
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57 | unionCC = unionCC ? makeCC(unionCC, cc) : cc; |
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58 | } else if (const Alt * alt = llvm::dyn_cast<Alt>(*i)) { |
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59 | // We have an Alt to embed within the alt. We extract the individual |
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60 | // elements to include within the new alt. Note that recursive flattening |
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61 | // is not required, if the elements themselves were created with makeAlt. |
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62 | for (RE * a : *alt) { |
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63 | if (CC * cc = llvm::dyn_cast<CC>(a)) { |
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64 | unionCC = unionCC ? makeCC(unionCC, cc) : cc; |
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65 | } else { |
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66 | newAlt->push_back(a); |
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67 | } |
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68 | } |
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69 | } |
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70 | else { |
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71 | newAlt->push_back(*i); |
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72 | } |
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73 | } |
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74 | if (unionCC) { |
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75 | newAlt->push_back(unionCC); |
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76 | } |
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77 | if (newAlt->size() == 1) return newAlt->front(); |
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78 | return newAlt; |
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79 | } |
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80 | |
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81 | inline RE * makeAlt(RE::InitializerList list) { |
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82 | return makeAlt(list.begin(), list.end()); |
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83 | } |
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84 | |
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85 | } |
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86 | |
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87 | #endif // ALT_H |
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88 | |
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