1 | #ifndef INC_CircularQueue_hpp__ |
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2 | #define INC_CircularQueue_hpp__ |
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3 | |
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4 | /* ANTLR Translator Generator |
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5 | * Project led by Terence Parr at http://www.jGuru.com |
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6 | * Software rights: http://www.antlr.org/license.html |
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7 | * |
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8 | * $Id: //depot/code/org.antlr/release/antlr-2.7.7/lib/cpp/antlr/CircularQueue.hpp#2 $ |
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9 | */ |
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10 | |
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11 | #include <antlr/config.hpp> |
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12 | #include <antlr/Token.hpp> |
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13 | #include <vector> |
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14 | #include <cassert> |
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15 | |
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16 | #ifdef ANTLR_CXX_SUPPORTS_NAMESPACE |
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17 | namespace antlr { |
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18 | #endif |
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19 | |
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20 | // Resize every 5000 items |
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21 | #define OFFSET_MAX_RESIZE 5000 |
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22 | |
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23 | template <class T> |
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24 | class ANTLR_API CircularQueue { |
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25 | public: |
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26 | CircularQueue() |
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27 | : storage() |
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28 | , m_offset(0) |
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29 | { |
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30 | } |
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31 | ~CircularQueue() |
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32 | { |
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33 | } |
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34 | |
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35 | /// Clear the queue |
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36 | inline void clear( void ) |
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37 | { |
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38 | m_offset = 0; |
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39 | storage.clear(); |
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40 | } |
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41 | |
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42 | /// @todo this should use at or should have a check |
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43 | inline T elementAt( size_t idx ) const |
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44 | { |
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45 | return storage[idx+m_offset]; |
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46 | } |
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47 | void removeFirst() |
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48 | { |
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49 | if (m_offset >= OFFSET_MAX_RESIZE) |
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50 | { |
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51 | storage.erase( storage.begin(), storage.begin() + m_offset + 1 ); |
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52 | m_offset = 0; |
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53 | } |
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54 | else |
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55 | ++m_offset; |
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56 | } |
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57 | inline void removeItems( size_t nb ) |
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58 | { |
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59 | // it would be nice if we would not get called with nb > entries |
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60 | // (or to be precise when entries() == 0) |
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61 | // This case is possible when lexer/parser::recover() calls |
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62 | // consume+consumeUntil when the queue is empty. |
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63 | // In recover the consume says to prepare to read another |
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64 | // character/token. Then in the subsequent consumeUntil the |
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65 | // LA() call will trigger |
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66 | // syncConsume which calls this method *before* the same queue |
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67 | // has been sufficiently filled. |
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68 | if( nb > entries() ) |
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69 | nb = entries(); |
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70 | |
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71 | if (m_offset >= OFFSET_MAX_RESIZE) |
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72 | { |
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73 | storage.erase( storage.begin(), storage.begin() + m_offset + nb ); |
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74 | m_offset = 0; |
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75 | } |
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76 | else |
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77 | m_offset += nb; |
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78 | } |
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79 | inline void append(const T& t) |
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80 | { |
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81 | storage.push_back(t); |
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82 | } |
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83 | inline size_t entries() const |
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84 | { |
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85 | return storage.size() - m_offset; |
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86 | } |
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87 | |
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88 | private: |
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89 | ANTLR_USE_NAMESPACE(std)vector<T> storage; |
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90 | size_t m_offset; |
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91 | |
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92 | CircularQueue(const CircularQueue&); |
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93 | const CircularQueue& operator=(const CircularQueue&); |
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94 | }; |
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95 | |
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96 | #ifdef ANTLR_CXX_SUPPORTS_NAMESPACE |
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97 | } |
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98 | #endif |
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99 | |
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100 | #endif //INC_CircularQueue_hpp__ |
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