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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef __JPCNTX_H__
#define __JPCNTX_H__
#define NUM_OF_CATEGORY 6
#include "nscore.h"
#define ENOUGH_REL_THRESHOLD 100
#define MAX_REL_THRESHOLD 1000
//hiragana frequency category table
extern const uint8_t jp2CharContext[83][83];
class JapaneseContextAnalysis
{
public:
JapaneseContextAnalysis() {Reset();}
void HandleData(const char* aBuf, uint32_t aLen);
void HandleOneChar(const char* aStr, uint32_t aCharLen)
{
int32_t order;
//if we received enough data, stop here
if (mTotalRel > MAX_REL_THRESHOLD) mDone = true;
if (mDone) return;
//Only 2-bytes characters are of our interest
order = (aCharLen == 2) ? GetOrder(aStr) : -1;
if (order != -1 && mLastCharOrder != -1)
{
mTotalRel++;
//count this sequence to its category counter
mRelSample[jp2CharContext[mLastCharOrder][order]]++;
}
mLastCharOrder = order;
}
float GetConfidence(void);
void Reset();
bool GotEnoughData() {return mTotalRel > ENOUGH_REL_THRESHOLD;}
protected:
virtual int32_t GetOrder(const char* str, uint32_t *charLen) = 0;
virtual int32_t GetOrder(const char* str) = 0;
//category counters, each integer counts sequences in its category
uint32_t mRelSample[NUM_OF_CATEGORY];
//total sequence received
uint32_t mTotalRel;
//Number of sequences needed to trigger detection
uint32_t mDataThreshold;
//The order of previous char
int32_t mLastCharOrder;
//if last byte in current buffer is not the last byte of a character, we
//need to know how many byte to skip in next buffer.
uint32_t mNeedToSkipCharNum;
//If this flag is set to true, detection is done and conclusion has been made
bool mDone;
};
class SJISContextAnalysis : public JapaneseContextAnalysis
{
//SJISContextAnalysis(){};
protected:
int32_t GetOrder(const char* str, uint32_t *charLen);
int32_t GetOrder(const char* str)
{
//We only interested in Hiragana, so first byte is '\202'
if (*str == '\202' &&
(unsigned char)*(str+1) >= (unsigned char)0x9f &&
(unsigned char)*(str+1) <= (unsigned char)0xf1)
return (unsigned char)*(str+1) - (unsigned char)0x9f;
return -1;
}
};
class EUCJPContextAnalysis : public JapaneseContextAnalysis
{
protected:
int32_t GetOrder(const char* str, uint32_t *charLen);
int32_t GetOrder(const char* str)
//We only interested in Hiragana, so first byte is '\244'
{
if (*str == '\244' &&
(unsigned char)*(str+1) >= (unsigned char)0xa1 &&
(unsigned char)*(str+1) <= (unsigned char)0xf3)
return (unsigned char)*(str+1) - (unsigned char)0xa1;
return -1;
}
};
#endif /* __JPCNTX_H__ */
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