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37
38 // for japanese encoding, obeserve characteristic:
39 // 1, kana character (or hankaku?) often have hight frequency of appereance
40 // 2, kana character often exist in group
41 // 3, certain combination of kana is never used in japanese language
42
43 #include "nsEUCJPProber.h"
44
Reset(void)45 void nsEUCJPProber::Reset(void)
46 {
47 mCodingSM->Reset();
48 mState = eDetecting;
49 mContextAnalyser.Reset();
50 mDistributionAnalyser.Reset();
51 }
52
HandleData(const char * aBuf,PRUint32 aLen)53 nsProbingState nsEUCJPProber::HandleData(const char* aBuf, PRUint32 aLen)
54 {
55 nsSMState codingState;
56
57 for (PRUint32 i = 0; i < aLen; i++)
58 {
59 codingState = mCodingSM->NextState(aBuf[i]);
60 if (codingState == eError)
61 {
62 mState = eNotMe;
63 break;
64 }
65 if (codingState == eItsMe)
66 {
67 mState = eFoundIt;
68 break;
69 }
70 if (codingState == eStart)
71 {
72 PRUint32 charLen = mCodingSM->GetCurrentCharLen();
73
74 if (i == 0)
75 {
76 mLastChar[1] = aBuf[0];
77 mContextAnalyser.HandleOneChar(mLastChar, charLen);
78 mDistributionAnalyser.HandleOneChar(mLastChar, charLen);
79 }
80 else
81 {
82 mContextAnalyser.HandleOneChar(aBuf+i-1, charLen);
83 mDistributionAnalyser.HandleOneChar(aBuf+i-1, charLen);
84 }
85 }
86 }
87
88 mLastChar[0] = aBuf[aLen-1];
89
90 if (mState == eDetecting)
91 if (mContextAnalyser.GotEnoughData() && GetConfidence() > SHORTCUT_THRESHOLD)
92 mState = eFoundIt;
93
94 return mState;
95 }
96
GetConfidence(void)97 float nsEUCJPProber::GetConfidence(void)
98 {
99 float contxtCf = mContextAnalyser.GetConfidence();
100 float distribCf = mDistributionAnalyser.GetConfidence();
101
102 return (contxtCf > distribCf ? contxtCf : distribCf);
103 }
104
105