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#include "dictionary/rx/rx_trie.h"

#include <string>
#include <vector>

#include "base/base.h"
#include "third_party/rx/v1_0rc2/rx.h"

namespace mozc {
namespace rx {
namespace {
const int kMaxTokensPerLookup = 10000;

struct RxResults {
  int limit;
  vector<RxEntry> *result;
};

static int RxCallback(void *cookie, const char *s, int len, int id) {
  RxResults *res = reinterpret_cast<RxResults *>(cookie);
  DCHECK(res);
  if (res->limit <= 0) {
    // stops traversal.
    return -1;
  }
  --(res->limit);
  // truncates to len byte.
  RxEntry entry;
  entry.key = string(s, len);
  entry.id = id;
  res->result->push_back(entry);
  return 0;
}
}  // namespace

RxTrie::RxTrie() : rx_trie_(NULL) {}

RxTrie::~RxTrie() {
  rx_close(rx_trie_);
}

bool RxTrie::OpenImage(const unsigned char *image) {
  rx_trie_ = rx_open(image);
  return (rx_trie_ != NULL);
}

void RxTrie::PredictiveSearch(const string &key,
                              vector<RxEntry> *result) const {
  DCHECK(result);
  SearchInternal(key, PREDICTIVE, kMaxTokensPerLookup, result);
}

void RxTrie::PrefixSearch(const string &key,
                          vector<RxEntry> *result) const {
  DCHECK(result);
  SearchInternal(key, PREFIX, kMaxTokensPerLookup, result);
}

void RxTrie::PredictiveSearchWithLimit(const string &key,
                                       int limit,
                                       vector<RxEntry> *result) const {
  DCHECK(result);
  SearchInternal(key, PREDICTIVE, limit, result);
}

void RxTrie::PrefixSearchWithLimit(const string &key,
                                   int limit,
                                   vector<RxEntry> *result) const {
  DCHECK(result);
  SearchInternal(key, PREFIX, limit, result);
}

void RxTrie::ReverseLookup(int id, string *key) const {
  DCHECK(key);
  char buf[256];
  rx_reverse(rx_trie_, id, buf, sizeof(buf));
  key->assign(buf);
}

void RxTrie::SearchInternal(const string &key, SearchType type,
                            int limit,
                            vector<RxEntry> *result) const {
  DCHECK(result);
  RxResults rx_results;
  rx_results.limit = limit;
  rx_results.result = result;
  if (type == PREDICTIVE) {
    rx_search(rx_trie_, 1, key.c_str(), RxCallback, &rx_results);
  } else if (type == PREFIX) {
    rx_search(rx_trie_, 0, key.c_str(), RxCallback, &rx_results);
  } else {
    DLOG(FATAL) << "should not come here.";
  }
}
}  // namespace rx
}  // namespace mozc