/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

// for japanese encoding, obeserve characteristic:

// 1, kana character (or hankaku?) often have hight frequency of appereance

// 2, kana character often exist in group

// 3, certain combination of kana is never used in japanese language

#include "nsEUCJPProber.h"

#include "nsDebug.h"

void  nsEUCJPProber::Reset(void)

{

  mCodingSM->Reset();

  mState = eDetecting;

  mContextAnalyser.Reset();

  mDistributionAnalyser.Reset();

}

nsProbingState nsEUCJPProber::HandleData(const char* aBuf, uint32_t aLen)

{

  NS_ASSERTION(aLen, "HandleData called with empty buffer");

  uint32_t codingState;

  for (uint32_t i = 0; i < aLen; i++)

  {

    codingState = mCodingSM->NextState(aBuf[i]);

    if (codingState == eItsMe)

    {

      mState = eFoundIt;

      break;

    }

    if (codingState == eStart)

    {

      uint32_t charLen = mCodingSM->GetCurrentCharLen();

      if (i == 0)

      {

        mLastChar[1] = aBuf[0];

        mContextAnalyser.HandleOneChar(mLastChar, charLen);

        mDistributionAnalyser.HandleOneChar(mLastChar, charLen);

      }

      else

      {

        mContextAnalyser.HandleOneChar(aBuf+i-1, charLen);

        mDistributionAnalyser.HandleOneChar(aBuf+i-1, charLen);

      }

    }

  }

  mLastChar[0] = aBuf[aLen-1];

  if (mState == eDetecting)

    if (mContextAnalyser.GotEnoughData() && GetConfidence() > SHORTCUT_THRESHOLD)

      mState = eFoundIt;

  return mState;

}

float nsEUCJPProber::GetConfidence(void)

{

  float contxtCf = mContextAnalyser.GetConfidence();

  float distribCf = mDistributionAnalyser.GetConfidence();

  return (contxtCf > distribCf ? contxtCf : distribCf);

}