inputConverter.cpp

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#include "inputConverter.h"
#include <string>


struct InputConverter::pImpl {
  const Uint16* convert_table;
  unsigned int max_length;
  std::basic_string<Uint16> converted;

  pImpl(const Uint16* convertTable, unsigned int maxLength)
    : convert_table(convertTable), max_length(maxLength) {
  }

  size_t ptnlen(const int index, const Uint16* table) {
    int length = 0;
    while (table[index + length] != 0x0) {
      ++length;
    }
    return length;
  }

  size_t replace(size_t match_index, int table_index) {
    int ptn_length = ptnlen(table_index, convert_table);
    converted.replace(match_index, ptn_length,
                      &convert_table[table_index + max_length]);

    return ptn_length - ptnlen(table_index + max_length, convert_table);
  }
};


InputConverter::InputConverter(const Uint16* convertTable,
                               unsigned int maxLength)
  : pimpl(new pImpl(convertTable, maxLength)) {
}


InputConverter::~InputConverter(void) {
}


const Uint16* InputConverter::convert(const char* input) {
  pimpl->converted.clear();

  // 変換文字列を代入
  int input_length = strlen(input);
  for (int i = 0; i < input_length; ++i) {
    pimpl->converted.push_back(input[i]);
  }

  int steps = pimpl->max_length * 2;
  for (size_t i = 0; i < pimpl->converted.size(); ++i) {
    // 一致したパターンを置換する
    for (int j = 0; pimpl->convert_table[j] != 0x0; j += steps) {
      size_t match =
        pimpl->converted.compare(i, pimpl->ptnlen(j, pimpl->convert_table),
                                 &pimpl->convert_table[j]);
      if (match == 0) {
        pimpl->replace(i, j);

        // か + (濁点) といった変換用のために、１文字分戻る
        --i;
        break;
      }
    }
  }

  pimpl->converted.push_back(0x0);
  return &pimpl->converted[0];
}