/* -*- Mode: C; tab-width: 4; 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 nsCodingStateMachine_h__
#define nsCodingStateMachine_h__

#include "mozilla/ArrayUtils.h"

#include "nsPkgInt.h"

/* Apart from these 3 generic states, machine states are specific to
 * each charset prober.
 */
#define eStart 0
#define eError 1
#define eItsMe 2

#define GETCLASS(c) GETFROMPCK(((unsigned char)(c)), mModel->classTable)

//state machine model
typedef struct
{
  nsPkgInt classTable;
  uint32_t classFactor;
  nsPkgInt stateTable;
  const uint32_t* charLenTable;
#ifdef DEBUG
  const size_t charLenTableLength;
#endif
  const char* name;
} SMModel;

class nsCodingStateMachine {
public:
  explicit nsCodingStateMachine(const SMModel* sm) : mModel(sm) { mCurrentState = eStart; }
  uint32_t NextState(char c){
    //for each byte we get its class , if it is first byte, we also get byte length
    uint32_t byteCls = GETCLASS(c);
    if (mCurrentState == eStart)
    {
      mCurrentBytePos = 0;
      MOZ_ASSERT(byteCls < mModel->charLenTableLength);
      mCurrentCharLen = mModel->charLenTable[byteCls];
    }
    //from byte's class and stateTable, we get its next state
    mCurrentState = GETFROMPCK(mCurrentState * mModel->classFactor + byteCls,
                               mModel->stateTable);
    mCurrentBytePos++;
    return mCurrentState;
  }
  uint32_t  GetCurrentCharLen(void) {return mCurrentCharLen;}
  void      Reset(void) {mCurrentState = eStart;}
  const char * GetCodingStateMachine() {return mModel->name;}

protected:
  uint32_t mCurrentState;
  uint32_t mCurrentCharLen;
  uint32_t mCurrentBytePos;

  const SMModel *mModel;
};

extern const SMModel UTF8SMModel;
extern const SMModel Big5SMModel;
extern const SMModel EUCJPSMModel;
extern const SMModel EUCKRSMModel;
extern const SMModel EUCTWSMModel;
extern const SMModel GB18030SMModel;
extern const SMModel SJISSMModel;


extern const SMModel HZSMModel;
extern const SMModel ISO2022CNSMModel;
extern const SMModel ISO2022JPSMModel;
extern const SMModel ISO2022KRSMModel;

#undef CHAR_LEN_TABLE
#ifdef DEBUG
#define CHAR_LEN_TABLE(x) x, mozilla::ArrayLength(x)
#else
#define CHAR_LEN_TABLE(x) x
#endif

#endif /* nsCodingStateMachine_h__ */

