File indexing completed on 2024-04-28 03:53:04

 /*  -*- C++ -*-
     SPDX-FileCopyrightText: 2008 Wang Kai <wkai@gmail.com>
 
     SPDX-License-Identifier: MIT
 */
 
 #include "UnicodeGroupProber.h"
 
 #include <QChar>
 #include <math.h>
 
 namespace kencodingprober
 {
 UnicodeGroupProber::UnicodeGroupProber(void)
 {
     mCodingSM[0] = new nsCodingStateMachine(&UTF8SMModel);
     mCodingSM[1] = new nsCodingStateMachine(&UCS2LESMModel);
     mCodingSM[2] = new nsCodingStateMachine(&UCS2BESMModel);
     mActiveSM = NUM_OF_UNICODE_CHARSETS;
     mState = eDetecting;
     mDetectedCharset = "UTF-8";
 }
 
 UnicodeGroupProber::~UnicodeGroupProber(void)
 {
     for (unsigned int i = 0; i < NUM_OF_UNICODE_CHARSETS; i++) {
         delete mCodingSM[i];
     }
 }
 
 void UnicodeGroupProber::Reset(void)
 {
     mState = eDetecting;
     for (unsigned int i = 0; i < NUM_OF_UNICODE_CHARSETS; i++) {
         mCodingSM[i]->Reset();
     }
     mActiveSM = NUM_OF_UNICODE_CHARSETS;
     mDetectedCharset = "UTF-8";
 }
 
 nsProbingState UnicodeGroupProber::HandleData(const char *aBuf, unsigned int aLen)
 {
     nsSMState codingState;
     static bool disableUTF16LE = false;
     static bool disableUTF16BE = false;
 
     if (mActiveSM == 0 || aLen < 2) {
         mState = eNotMe;
         return mState;
     }
 
     if (!(disableUTF16LE || disableUTF16BE)) {
         if (aLen % 2 != 0) {
             disableUTF16LE = true;
             disableUTF16BE = true;
         }
         const uint weight_BOM = sqrt((double)aLen) + aLen / 10.0;
         uint counts[5] = {0, 0, 0, 0, 0};
         for (uint i = 0; i < 5; i++) {
             counts[i] = std::count(aBuf, aBuf + aLen, char(i));
         }
         const double weight_zero = (2.0 * (counts[0] + counts[1] + counts[2] + counts[3] + counts[4]) + weight_BOM) / aLen;
         if (weight_zero < log(1.4142)) {
             disableUTF16LE = true;
             disableUTF16BE = true;
         }
         if (4 >= aBuf[1] && aBuf[1] >= 0 && QChar::isPrint(static_cast<uint>(aBuf[0]))) {
             disableUTF16BE = true;
         } else {
             disableUTF16LE = true;
         }
         if (disableUTF16BE) {
             mActiveSM--;
         }
         if (disableUTF16LE) {
             nsCodingStateMachine *t;
             t = mCodingSM[1];
             mCodingSM[1] = mCodingSM[2];
             mCodingSM[2] = t;
             mActiveSM--;
         }
     }
 
     for (uint i = 0; i < aLen; ++i) {
         for (int j = mActiveSM - 1; j >= 0; --j) {
             // byte is feed to all active state machine
             codingState = mCodingSM[j]->NextState(aBuf[i]);
             if (codingState == eError) {
                 // got negative answer for this state machine, make it inactive
                 mActiveSM--;
                 if (mActiveSM == 0) {
                     mState = eNotMe;
                     return mState;
                 } else if (j != (int)mActiveSM) {
                     nsCodingStateMachine *t;
                     t = mCodingSM[mActiveSM];
                     mCodingSM[mActiveSM] = mCodingSM[j];
                     mCodingSM[j] = t;
                 }
             } else if (codingState == eItsMe) {
                 mState = eFoundIt;
                 mDetectedCharset = mCodingSM[j]->GetCodingStateMachine();
                 return mState;
             } else if (mState == eDetecting) {
                 mDetectedCharset = mCodingSM[j]->GetCodingStateMachine();
             };
         }
     }
     return mState;
 }
 
 float UnicodeGroupProber::GetConfidence()
 {
     if (mState == eFoundIt) {
         return 0.99f;
     } else {
         return 0.0f;
     }
 }
 
 #ifdef DEBUG_PROBE
 void UnicodeGroupProber::DumpStatus()
 {
     GetConfidence();
     for (uint i = 0; i < mActiveSM; i++) {
         qDebug() << "Unicode group" << mCodingSM[i]->DumpCurrentState() << mCodingSM[i]->GetCodingStateMachine();
     }
 }
 #endif
 
 }