120 lines
3.4 KiB
C++
120 lines
3.4 KiB
C++
/*
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*****************************************************************************************
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*
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* Copyright © {1997-1999}, International Business Machines Corporation and others. All Rights Reserved.
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*****************************************************************************************
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*
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* File WDBKTBL.H
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*
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* WordBreakTable implements a state transition table.
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*
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* @package Text and International
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* @category Text Scanning
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*
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* Modification History:
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*
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* Date Name Description
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* 02/18/97 aliu Converted from OpenClass. Made statics const.
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*****************************************************************************************
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*/
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#ifndef WDBKTBL_H
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#define WDBKTBL_H
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#include "utypes.h"
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#include "txtbdat.h"
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/**
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* This class implements a state transition table.
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* After each transition, using the get method, the
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* new state is returned along with information about
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* the state change (ex. was it a "marked" transition").
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* For efficiency, none of the arguments to any of these
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* methods are validated.
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*/
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class WordBreakTable {
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public:
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// For convenience
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typedef TextBoundaryData::Node Node;
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typedef TextBoundaryData::Type Type;
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/**
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* Construct a table from the provided data. See CharacterBreakData or
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* the other TextBoundaryData subclasses for examples. Each row represents
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* a state, each column within a row represents a transition. The values
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* in the table represent the new state and mark information.
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* @param cols number of columns in the table (transitions)
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* @param data an encoded byte array containing state and transition data
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* @param data_length the length of the byte array data
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*/
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WordBreakTable(int32_t cols, const Node data[], int32_t data_length);
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/**
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* Get the resulting state moving from oldState accepting input.
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* @param oldState current state
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* @param input input
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* @return resulting state and transition data
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*/
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Node get(Node oldState, Type input) const;
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/**
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* Checks to see if the transition into the specified state was "marked."
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* @param state the state as returned by get, initialState, or endState
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* @return true if transition into state was marked.
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*/
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bool_t isMarkState(Node state) const;
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/**
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* Check to see if the state is the end state
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* @param state the state to check
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* @return true if state is an end state
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*/
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bool_t isEndState(Node state) const;
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/**
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* Get the initial state
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* @return the initial state
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*/
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Node initialState(void) const;
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private:
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static const Node kMark_mask;
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static const Node kIndex_mask;
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static const Node kInitial_state;
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static const Node kEnd_state;
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const TextBoundaryData::Node* fData;
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int32_t fData_length;
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int32_t fCols;
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};
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// -------------------------------------
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inline WordBreakTable::Node
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WordBreakTable::get(WordBreakTable::Node oldState, WordBreakTable::Type input) const
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{
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return fData[(oldState & kIndex_mask) * fCols + input];
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}
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inline bool_t
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WordBreakTable::isMarkState(WordBreakTable::Node state) const
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{
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return (state & kMark_mask) != 0;
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}
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inline bool_t
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WordBreakTable::isEndState(WordBreakTable::Node state) const
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{
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return (state & kIndex_mask) == kEnd_state;
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}
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inline WordBreakTable::Node
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WordBreakTable::initialState() const
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{
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return kInitial_state;
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}
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#endif // _WDBKTBL
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//eof
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