/*******************************************************************************

;*******************************************************************************

;**                                                                           **

;**                    COPYRIGHT 2004-2011 NUANCE COMMUNICATIONS              **

;**                                                                           **

;**               NUANCE COMMUNICATIONS PROPRIETARY INFORMATION               **

;**                                                                           **

;**     This software is supplied under the terms of a license agreement      **

;**     or non-disclosure agreement with Nuance Communications and may not    **

;**     be copied or disclosed except in accordance with the terms of that    **

;**     agreement.                                                            **

;**                                                                           **

;**                                                                           **

;*******************************************************************************

;**                                                                           **

;**     FileName: et9cpcntx.c                                                  **

;**                                                                           **

;**  Description: Chinese XT9 context predication module.                     **

;**               Conforming to the development version of Chinese XT9.               **

;**                                                                           **

;*******************************************************************************

;******************************************************************************/



#include "et9cpapi.h"

#include "et9cpldb.h"

#include "et9cppbuf.h"

#include "et9cpkey.h"

#include "et9cpinit.h"

#include "et9cpsys.h"

#include "et9cpspel.h"

#include "et9cpcntx.h"

#include "et9cpname.h"

#include "et9cpwdls.h"

#include "et9cpmisc.h"



/*

   update the context buffer after a phrase is selected

   input: psPhrase - the selected phrase (in PID/SID)

 */

void ET9FARCALL ET9_CP_UpdateContextBuf(ET9CPLingInfo *pET9CPLingInfo,

                                     ET9CPPhrase *psPhrase)

{

    ET9U16 *pwSrc, *pwDst;

    ET9U8 *pbContextLen;

    ET9U8 b, bLen, bCount;



    pbContextLen = pET9CPLingInfo->CommonInfo.pbContextLen;

    /* flush any external context so that internal/external context won't

     * coexist in the context history */

    if (pET9CPLingInfo->CommonInfo.bExtContext) {

        ET9_CP_ClrContextBuf(pET9CPLingInfo);

    }

    bLen = psPhrase->bLen;

    if (bLen >= ET9CPMAXPHRASESIZE) {

        /* clr context if the selection has max phrase length. */

        ET9_CP_ClrContextBuf(pET9CPLingInfo);

        return;

    }

    /* find the oldest history to keep */

    bCount = 0;

    for (b = 0; pbContextLen[b]; b++) {

        ET9Assert(b < ET9_CP_MAX_CONTEXT_HISTORY);

    }

    for (; b; b--) {

        ET9Assert(pbContextLen[b - 1]);

        if (((bLen + pbContextLen[b - 1]) < ET9CPMAXPHRASESIZE) &&

            (bCount < ET9_CP_MAX_CONTEXT_HISTORY - 1)) {

            bLen = (ET9U8)(bLen + pbContextLen[b - 1]);

            bCount++;

        }

        else {

            break;

        }

    }

    pwDst = pET9CPLingInfo->CommonInfo.pwContextBuf;

    if (0 == b) {

        /* keep all history, append selection after the newest history */

        for (b = 0; b < bCount; b++) {

            ET9Assert(pbContextLen[b]);

            pwDst += pbContextLen[b];

        }

    }

    else {

        ET9U8 bOldest;

        /* shift wanted history to left, displace unwanted ones */

        bOldest = b;

        pwSrc = pwDst;

        for (b = 0; b < bOldest; b++) {

            ET9Assert(pbContextLen[b]);

            pwSrc += pbContextLen[b];

        }

        for (b = bOldest; b < bOldest + bCount; b++) {

            for (bLen = pbContextLen[b]; bLen; bLen--) {

                *pwDst++ = *pwSrc++;

            }

            pbContextLen[b - bOldest] = pbContextLen[b];

        }

        b = bCount;

    }

    /* copy current selection into context buf */

    pwSrc = psPhrase->pSymbs;

    bLen = psPhrase->bLen;

    ET9Assert(b < ET9_CP_MAX_CONTEXT_HISTORY);

    pbContextLen[b] = bLen; /* copy current selection len into context len */

    pbContextLen[b + 1] = 0; /* 0-termination */

    for (b = 0; b < bLen; b++) {

        *pwDst++ = *pwSrc++;

    }

} /* ET9_CP_UpdateContextBuf() */



void ET9FARCALL ET9_CP_ClrContextBuf(ET9CPLingInfo *pET9CPLingInfo)

{

    pET9CPLingInfo->CommonInfo.pbContextLen[0] = 0;

    pET9CPLingInfo->CommonInfo.bExtContext = 0; /* clr external context flag */

}



/* ----------------------------------< eof >--------------------------------- */