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37 :
38 : #ifndef __JPCNTX_H__
39 : #define __JPCNTX_H__
40 :
41 : #define NUM_OF_CATEGORY 6
42 :
43 : #include "nscore.h"
44 :
45 : #define ENOUGH_REL_THRESHOLD 100
46 : #define MAX_REL_THRESHOLD 1000
47 :
48 : //hiragana frequency category table
49 : extern const PRUint8 jp2CharContext[83][83];
50 :
51 : class JapaneseContextAnalysis
52 : {
53 : public:
54 0 : JapaneseContextAnalysis() {Reset(false);}
55 :
56 : void HandleData(const char* aBuf, PRUint32 aLen);
57 :
58 0 : void HandleOneChar(const char* aStr, PRUint32 aCharLen)
59 : {
60 : PRInt32 order;
61 :
62 : //if we received enough data, stop here
63 0 : if (mTotalRel > MAX_REL_THRESHOLD) mDone = true;
64 0 : if (mDone) return;
65 :
66 : //Only 2-bytes characters are of our interest
67 0 : order = (aCharLen == 2) ? GetOrder(aStr) : -1;
68 0 : if (order != -1 && mLastCharOrder != -1)
69 : {
70 0 : mTotalRel++;
71 : //count this sequence to its category counter
72 0 : mRelSample[jp2CharContext[mLastCharOrder][order]]++;
73 : }
74 0 : mLastCharOrder = order;
75 : }
76 :
77 : float GetConfidence(void);
78 : void Reset(bool aIsPreferredLanguage);
79 : void SetOpion(){}
80 0 : bool GotEnoughData() {return mTotalRel > ENOUGH_REL_THRESHOLD;}
81 :
82 : protected:
83 : virtual PRInt32 GetOrder(const char* str, PRUint32 *charLen) = 0;
84 : virtual PRInt32 GetOrder(const char* str) = 0;
85 :
86 : //category counters, each integer counts sequences in its category
87 : PRUint32 mRelSample[NUM_OF_CATEGORY];
88 :
89 : //total sequence received
90 : PRUint32 mTotalRel;
91 :
92 : //Number of sequences needed to trigger detection
93 : PRUint32 mDataThreshold;
94 :
95 : //The order of previous char
96 : PRInt32 mLastCharOrder;
97 :
98 : //if last byte in current buffer is not the last byte of a character, we
99 : //need to know how many byte to skip in next buffer.
100 : PRUint32 mNeedToSkipCharNum;
101 :
102 : //If this flag is set to true, detection is done and conclusion has been made
103 : bool mDone;
104 : };
105 :
106 :
107 : class SJISContextAnalysis : public JapaneseContextAnalysis
108 0 : {
109 : //SJISContextAnalysis(){};
110 : protected:
111 : PRInt32 GetOrder(const char* str, PRUint32 *charLen);
112 :
113 0 : PRInt32 GetOrder(const char* str)
114 : {
115 : //We only interested in Hiragana, so first byte is '\202'
116 0 : if (*str == '\202' &&
117 0 : (unsigned char)*(str+1) >= (unsigned char)0x9f &&
118 0 : (unsigned char)*(str+1) <= (unsigned char)0xf1)
119 0 : return (unsigned char)*(str+1) - (unsigned char)0x9f;
120 0 : return -1;
121 : }
122 : };
123 :
124 : class EUCJPContextAnalysis : public JapaneseContextAnalysis
125 0 : {
126 : protected:
127 : PRInt32 GetOrder(const char* str, PRUint32 *charLen);
128 0 : PRInt32 GetOrder(const char* str)
129 : //We only interested in Hiragana, so first byte is '\244'
130 : {
131 0 : if (*str == '\244' &&
132 0 : (unsigned char)*(str+1) >= (unsigned char)0xa1 &&
133 0 : (unsigned char)*(str+1) <= (unsigned char)0xf3)
134 0 : return (unsigned char)*(str+1) - (unsigned char)0xa1;
135 0 : return -1;
136 : }
137 : };
138 :
139 : #endif /* __JPCNTX_H__ */
140 :
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