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#include "composer/internal/typing_model.h"

#include <limits>

#include "base/port.h"
#include "base/scoped_ptr.h"
#include "base/string_piece.h"

namespace mozc {
namespace composer {

namespace {

// These header files are automatically generated by gen_typing_model.py.
#include "composer/internal/typing_model_12keys-hiragana.h"
#include "composer/internal/typing_model_flick-hiragana.h"
#include "composer/internal/typing_model_godan-hiragana.h"
#include "composer/internal/typing_model_qwerty_mobile-hiragana.h"
#include "composer/internal/typing_model_toggle_flick-hiragana.h"

scoped_ptr<TypingModel> g_typing_model_12keys_hiragana;
scoped_ptr<TypingModel> g_typing_model_flick_hiragana;
scoped_ptr<TypingModel> g_typing_model_godan_hiragana;
scoped_ptr<TypingModel> g_typing_model_qwerty_mobile_hiragana;
scoped_ptr<TypingModel> g_typing_model_toggle_flick_hiragana;
}  // namespace

const uint8 TypingModel::kNoData = numeric_limits<uint8>::max();
const int TypingModel::kInfinity = (2 << 20);  // approximately equals 1e+6

TypingModel::TypingModel(const char *characters,
                         size_t characters_size,
                         const uint8 *cost_table,
                         size_t cost_table_size,
                         const int32 *mapping_table) :
    character_to_radix_table_(
        new unsigned char[numeric_limits<unsigned char>::max()]),
    characters_size_(characters_size),
    cost_table_(cost_table),
    cost_table_size_(cost_table_size),
    mapping_table_(mapping_table) {
  for (size_t i = 0; i < characters_size; ++i) {
    character_to_radix_table_[characters[i]] = i + 1;
  }
}

int TypingModel::GetCost(StringPiece key) const {
  size_t index = GetIndex(key);
  if (index >= cost_table_size_) {
    return kInfinity;
  }
  uint8 cost_index = cost_table_[index];
  return cost_index == kNoData ? kInfinity : mapping_table_[cost_index];
}

size_t TypingModel::GetIndex(StringPiece key) const {
  const unsigned int radix = characters_size_ + 1;
  size_t index = 0;
  for (size_t i = 0; i < key.length(); ++i) {
    index = index * radix + character_to_radix_table_[key[i]];
  }
  return index;
}

// static
const TypingModel *TypingModel::GetTypingModel(
    const mozc::commands::Request::SpecialRomanjiTable &special_romanji_table) {
  switch (special_romanji_table) {
    case mozc::commands::Request::TWELVE_KEYS_TO_HIRAGANA:
      if (!g_typing_model_12keys_hiragana.get()) {
        g_typing_model_12keys_hiragana.reset(new TypingModel(
              kKeyCharacters_12keysHiragana,
              kKeyCharactersSize_12keysHiragana,
              kCostTable_12keysHiragana,
              kCostTableSize_12keysHiragana,
              kCostMappingTable_12keysHiragana));
      }
      return g_typing_model_12keys_hiragana.get();
    case mozc::commands::Request::FLICK_TO_HIRAGANA:
      if (!g_typing_model_flick_hiragana.get()) {
        g_typing_model_flick_hiragana.reset(new TypingModel(
              kKeyCharacters_FlickHiragana,
              kKeyCharactersSize_FlickHiragana,
              kCostTable_FlickHiragana,
              kCostTableSize_FlickHiragana,
              kCostMappingTable_FlickHiragana));
      }
      return g_typing_model_flick_hiragana.get();
    case mozc::commands::Request::TOGGLE_FLICK_TO_HIRAGANA:
      if (!g_typing_model_toggle_flick_hiragana.get()) {
        g_typing_model_toggle_flick_hiragana.reset(new TypingModel(
              kKeyCharacters_ToggleFlickHiragana,
              kKeyCharactersSize_ToggleFlickHiragana,
              kCostTable_ToggleFlickHiragana,
              kCostTableSize_ToggleFlickHiragana,
              kCostMappingTable_ToggleFlickHiragana));
      }
      return g_typing_model_toggle_flick_hiragana.get();
    case mozc::commands::Request::QWERTY_MOBILE_TO_HIRAGANA:
      if (!g_typing_model_qwerty_mobile_hiragana.get()) {
        g_typing_model_qwerty_mobile_hiragana.reset(new TypingModel(
              kKeyCharacters_QwertyMobileHiragana,
              kKeyCharactersSize_QwertyMobileHiragana,
              kCostTable_QwertyMobileHiragana,
              kCostTableSize_QwertyMobileHiragana,
              kCostMappingTable_QwertyMobileHiragana));
      }
      return g_typing_model_qwerty_mobile_hiragana.get();
    case mozc::commands::Request::GODAN_TO_HIRAGANA:
      if (!g_typing_model_godan_hiragana.get()) {
        g_typing_model_godan_hiragana.reset(new TypingModel(
              kKeyCharacters_GodanHiragana,
              kKeyCharactersSize_GodanHiragana,
              kCostTable_GodanHiragana,
              kCostTableSize_GodanHiragana,
              kCostMappingTable_GodanHiragana));
      }
      return g_typing_model_godan_hiragana.get();
    default:
      return NULL;
  }
}

}  // namespace composer
}  // namespace mozc