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/* -*- 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 S-JIS 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 "nsSJISProber.h"
#include "nsDebug.h"
void nsSJISProber::Reset(void)
{
mCodingSM->Reset();
mState = eDetecting;
mContextAnalyser.Reset();
mDistributionAnalyser.Reset();
}
nsProbingState nsSJISProber::HandleData(const char* aBuf, uint32_t aLen)
{
NS_ASSERTION(aLen, "HandleData called with empty buffer");
nsSMState 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+2-charLen, charLen);
mDistributionAnalyser.HandleOneChar(mLastChar, charLen);
}
else
{
mContextAnalyser.HandleOneChar(aBuf+i+1-charLen, 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 nsSJISProber::GetConfidence(void)
{
float contxtCf = mContextAnalyser.GetConfidence();
float distribCf = mDistributionAnalyser.GetConfidence();
return (contxtCf > distribCf ? contxtCf : distribCf);
}
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