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// notice, this list of conditions and the following disclaimer.
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// in the documentation and/or other materials provided with the
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#include "base/text_converter.h"

#include <cstring>
#include <string>
#include "base/string_piece.h"
#include "base/util.h"

namespace mozc {

namespace {

int Lookup(const mozc::TextConverter::DoubleArray *array,
           const char *key, int len, int *result) {
  int32 seekto = 0;
  int n = 0;
  int b = array[0].base;
  uint32 p = 0;
  *result = -1;
  uint32 num = 0;

  for (int i = 0; i < len; ++i) {
    p = b;
    n = array[p].base;
    if (static_cast<uint32>(b) == array[p].check && n < 0) {
      seekto = i;
      *result = - n - 1;
      ++num;
    }
    p = b + static_cast<uint8>(key[i]) + 1;
    if (static_cast<uint32 >(b) == array[p].check) {
      b = array[p].base;
    } else {
      return seekto;
    }
  }
  p = b;
  n = array[p].base;
  if (static_cast<uint32>(b) == array[p].check && n < 0) {
    seekto = len;
    *result = -n - 1;
  }

  return seekto;
}

}  // namespace

void TextConverter::Convert(const DoubleArray *da,
                            const char *ctable,
                            const StringPiece input,
                            string *output) {
  output->clear();
  const char *begin = input.data();
  const char *const end = input.data() + input.size();
  while (begin < end) {
    int result = 0;
    size_t mblen = Lookup(da, begin, static_cast<int>(end - begin), &result);
    if (mblen > 0) {
      const char *p = &ctable[result];
      const size_t len = strlen(p);
      output->append(p, len);
      mblen -= static_cast<int32>(p[len + 1]);
      begin += mblen;
    } else {
      mblen = Util::OneCharLen(begin);
      output->append(begin, mblen);
      begin += mblen;
    }
  }
}

}  // namespace mozc