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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Universal charset detector code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Shy Shalom <shooshX@gmail.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nscore.h"
#include "nsUniversalDetector.h"
#include "nsMBCSGroupProber.h"
#include "nsSBCSGroupProber.h"
#include "nsEscCharsetProber.h"
#include "nsLatin1Prober.h"
nsUniversalDetector::nsUniversalDetector(PRUint32 aLanguageFilter)
{
mDone = PR_FALSE;
mBestGuess = -1; //illegal value as signal
mInTag = PR_FALSE;
mEscCharSetProber = nsnull;
mStart = PR_TRUE;
mDetectedCharset = nsnull;
mGotData = PR_FALSE;
mInputState = ePureAscii;
mLastChar = '\0';
mLanguageFilter = aLanguageFilter;
PRUint32 i;
for (i = 0; i < NUM_OF_CHARSET_PROBERS; i++)
mCharSetProbers[i] = nsnull;
}
nsUniversalDetector::~nsUniversalDetector()
{
for (PRInt32 i = 0; i < NUM_OF_CHARSET_PROBERS; i++)
if (mCharSetProbers[i])
delete mCharSetProbers[i];
if (mEscCharSetProber)
delete mEscCharSetProber;
}
void
nsUniversalDetector::Reset()
{
mDone = PR_FALSE;
mBestGuess = -1; //illegal value as signal
mInTag = PR_FALSE;
mStart = PR_TRUE;
mDetectedCharset = nsnull;
mGotData = PR_FALSE;
mInputState = ePureAscii;
mLastChar = '\0';
if (mEscCharSetProber)
mEscCharSetProber->Reset();
PRUint32 i;
for (i = 0; i < NUM_OF_CHARSET_PROBERS; i++)
if (mCharSetProbers[i])
mCharSetProbers[i]->Reset();
}
//---------------------------------------------------------------------
#define SHORTCUT_THRESHOLD (float)0.95
#define MINIMUM_THRESHOLD (float)0.20
nsresult nsUniversalDetector::HandleData(const char* aBuf, PRUint32 aLen)
{
if(mDone)
return NS_OK;
if (aLen > 0)
mGotData = PR_TRUE;
//If the data starts with BOM, we know it is UTF
if (mStart)
{
mStart = PR_FALSE;
if (aLen > 3)
switch (aBuf[0])
{
case '\xEF':
if (('\xBB' == aBuf[1]) && ('\xBF' == aBuf[2]))
// EF BB BF UTF-8 encoded BOM
mDetectedCharset = "UTF-8";
break;
case '\xFE':
if (('\xFF' == aBuf[1]) && ('\x00' == aBuf[2]) && ('\x00' == aBuf[3]))
// FE FF 00 00 UCS-4, unusual octet order BOM (3412)
mDetectedCharset = "X-ISO-10646-UCS-4-3412";
else if ('\xFF' == aBuf[1])
// FE FF UTF-16, big endian BOM
mDetectedCharset = "UTF-16";
break;
case '\x00':
if (('\x00' == aBuf[1]) && ('\xFE' == aBuf[2]) && ('\xFF' == aBuf[3]))
// 00 00 FE FF UTF-32, big-endian BOM
mDetectedCharset = "UTF-32";
else if (('\x00' == aBuf[1]) && ('\xFF' == aBuf[2]) && ('\xFE' == aBuf[3]))
// 00 00 FF FE UCS-4, unusual octet order BOM (2143)
mDetectedCharset = "X-ISO-10646-UCS-4-2143";
break;
case '\xFF':
if (('\xFE' == aBuf[1]) && ('\x00' == aBuf[2]) && ('\x00' == aBuf[3]))
// FF FE 00 00 UTF-32, little-endian BOM
mDetectedCharset = "UTF-32";
else if ('\xFE' == aBuf[1])
// FF FE UTF-16, little endian BOM
mDetectedCharset = "UTF-16";
break;
} // switch
if (mDetectedCharset)
{
mDone = PR_TRUE;
return NS_OK;
}
}
PRUint32 i;
for (i = 0; i < aLen; i++)
{
//other than 0xa0, if every othe character is ascii, the page is ascii
if (aBuf[i] & '\x80' && aBuf[i] != '\xA0') //Since many Ascii only page contains NBSP
{
//we got a non-ascii byte (high-byte)
if (mInputState != eHighbyte)
{
//adjust state
mInputState = eHighbyte;
//kill mEscCharSetProber if it is active
if (mEscCharSetProber) {
delete mEscCharSetProber;
mEscCharSetProber = nsnull;
}
//start multibyte and singlebyte charset prober
if (nsnull == mCharSetProbers[0])
{
mCharSetProbers[0] = new nsMBCSGroupProber(mLanguageFilter);
if (nsnull == mCharSetProbers[0])
return NS_ERROR_OUT_OF_MEMORY;
}
if (nsnull == mCharSetProbers[1] &&
(mLanguageFilter & NS_FILTER_NON_CJK))
{
mCharSetProbers[1] = new nsSBCSGroupProber;
if (nsnull == mCharSetProbers[1])
return NS_ERROR_OUT_OF_MEMORY;
}
if (nsnull == mCharSetProbers[2])
{
mCharSetProbers[2] = new nsLatin1Prober;
if (nsnull == mCharSetProbers[2])
return NS_ERROR_OUT_OF_MEMORY;
}
}
}
else
{
//ok, just pure ascii so far
if ( ePureAscii == mInputState &&
(aBuf[i] == '\033' || (aBuf[i] == '{' && mLastChar == '~')) )
{
//found escape character or HZ "~{"
mInputState = eEscAscii;
}
mLastChar = aBuf[i];
}
}
nsProbingState st;
switch (mInputState)
{
case eEscAscii:
if (nsnull == mEscCharSetProber) {
mEscCharSetProber = new nsEscCharSetProber(mLanguageFilter);
if (nsnull == mEscCharSetProber)
return NS_ERROR_OUT_OF_MEMORY;
}
st = mEscCharSetProber->HandleData(aBuf, aLen);
if (st == eFoundIt)
{
mDone = PR_TRUE;
mDetectedCharset = mEscCharSetProber->GetCharSetName();
}
break;
case eHighbyte:
for (i = 0; i < NUM_OF_CHARSET_PROBERS; i++)
{
if (mCharSetProbers[i])
{
st = mCharSetProbers[i]->HandleData(aBuf, aLen);
if (st == eFoundIt)
{
mDone = PR_TRUE;
mDetectedCharset = mCharSetProbers[i]->GetCharSetName();
return NS_OK;
}
}
}
break;
default: //pure ascii
;//do nothing here
}
return NS_OK;
}
//---------------------------------------------------------------------
void nsUniversalDetector::DataEnd()
{
if (!mGotData)
{
// we haven't got any data yet, return immediately
// caller program sometimes call DataEnd before anything has been sent to detector
return;
}
if (mDetectedCharset)
{
mDone = PR_TRUE;
Report(mDetectedCharset);
return;
}
switch (mInputState)
{
case eHighbyte:
{
float proberConfidence;
float maxProberConfidence = (float)0.0;
PRInt32 maxProber = 0;
for (PRInt32 i = 0; i < NUM_OF_CHARSET_PROBERS; i++)
{
if (mCharSetProbers[i])
{
proberConfidence = mCharSetProbers[i]->GetConfidence();
if (proberConfidence > maxProberConfidence)
{
maxProberConfidence = proberConfidence;
maxProber = i;
}
}
}
//do not report anything because we are not confident of it, that's in fact a negative answer
if (maxProberConfidence > MINIMUM_THRESHOLD)
Report(mCharSetProbers[maxProber]->GetCharSetName());
}
break;
case eEscAscii:
break;
default:
;
}
return;
}
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