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bed459c6e7
Some languages are not meant to have multibyte characters. For instance, English would typically have none. Yet you can still have UTF-8 English text (with a few special characters, or foreign words…). So anyway let's make it less of a deal breaker. To be even fairer, the whole logics is biased of course and I believe that eventually we should get rid of these lines of code dropping confidence on a number of character. This is a ridiculous rule (we base on our whole logics on language statistics and suddenly we add some weird rule with a completely random number). But for now, I'll keep this as-is until we make the whole library even more robust.
114 lines
3.5 KiB
C++
114 lines
3.5 KiB
C++
/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is mozilla.org code.
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*
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* The Initial Developer of the Original Code is
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* Netscape Communications Corporation.
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* Portions created by the Initial Developer are Copyright (C) 1998
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#include "nsUTF8Prober.h"
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void nsUTF8Prober::Reset(void)
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{
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mCodingSM->Reset();
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mNumOfMBChar = 0;
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mState = eDetecting;
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currentCodePoint = 0;
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}
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#define ENOUGH_CHAR_THRESHOLD 256
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nsProbingState nsUTF8Prober::HandleData(const char* aBuf, PRUint32 aLen,
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int** codePointBuffer,
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int* codePointBufferIdx)
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{
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PRUint32 codingState;
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for (PRUint32 i = 0; i < aLen; i++)
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{
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codingState = mCodingSM->NextState(aBuf[i]);
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if (codingState == eItsMe)
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{
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mState = eFoundIt;
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break;
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}
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if (codingState == eStart)
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{
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if (mCodingSM->GetCurrentCharLen() >= 2)
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{
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mNumOfMBChar++;
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currentCodePoint = ((0xff & aBuf[i]) & 0x3fu) | (currentCodePoint << 6);
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if (mCodingSM->GetCurrentCharLen() == 2)
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currentCodePoint &= 0x7ff;
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else if (mCodingSM->GetCurrentCharLen() == 3)
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currentCodePoint &= 0xffff;
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else
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currentCodePoint &= 0x1fffff;
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}
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else
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{
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currentCodePoint = 0xff & (char) aBuf[i];
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}
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(*codePointBuffer)[(*codePointBufferIdx)++] = currentCodePoint;
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currentCodePoint = 0;
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}
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else
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{
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currentCodePoint = ((0xff & aBuf[i]) & 0x3fu) | (currentCodePoint << 6);
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}
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}
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if (mState == eDetecting)
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if (mNumOfMBChar > ENOUGH_CHAR_THRESHOLD && GetConfidence(0) > SHORTCUT_THRESHOLD)
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mState = eFoundIt;
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return mState;
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}
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#define ONE_CHAR_PROB (float)0.50
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float nsUTF8Prober::GetConfidence(int candidate)
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{
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if (mNumOfMBChar < 6)
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{
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float unlike = 0.5f;
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for (PRUint32 i = 0; i < mNumOfMBChar; i++)
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unlike *= ONE_CHAR_PROB;
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return (float)1.0 - unlike;
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}
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else
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return (float)0.99;
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}
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