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37
38 // for S-JIS 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 "nsSJISProber.h"
44
Reset(void)45 void nsSJISProber::Reset(void)
46 {
47 mCodingSM->Reset();
48 mState = eDetecting;
49 mContextAnalyser.Reset(mIsPreferredLanguage);
50 mDistributionAnalyser.Reset(mIsPreferredLanguage);
51 }
52
HandleData(const char * aBuf,PRUint32 aLen)53 nsProbingState nsSJISProber::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 == eItsMe)
61 {
62 mState = eFoundIt;
63 break;
64 }
65 if (codingState == eStart)
66 {
67 PRUint32 charLen = mCodingSM->GetCurrentCharLen();
68 if (i == 0)
69 {
70 mLastChar[1] = aBuf[0];
71 mContextAnalyser.HandleOneChar(mLastChar+2-charLen, charLen);
72 mDistributionAnalyser.HandleOneChar(mLastChar, charLen);
73 }
74 else
75 {
76 mContextAnalyser.HandleOneChar(aBuf+i+1-charLen, charLen);
77 mDistributionAnalyser.HandleOneChar(aBuf+i-1, charLen);
78 }
79 }
80 }
81
82 mLastChar[0] = aBuf[aLen-1];
83
84 if (mState == eDetecting)
85 if (mContextAnalyser.GotEnoughData() && GetConfidence() > SHORTCUT_THRESHOLD)
86 mState = eFoundIt;
87
88 return mState;
89 }
90
GetConfidence(void)91 float nsSJISProber::GetConfidence(void)
92 {
93 float contxtCf = mContextAnalyser.GetConfidence();
94 float distribCf = mDistributionAnalyser.GetConfidence();
95
96 return (contxtCf > distribCf ? contxtCf : distribCf);
97 }
98
99