/*

*	Blade DLL Interface for LAME.

*

*	Copyright (c) 1999 - 2002 A.L. Faber

*

* This library is free software; you can redistribute it and/or

* modify it under the terms of the GNU Library General Public

* License as published by the Free Software Foundation; either

* version 2 of the License, or (at your option) any later version.

* 

* This library is distributed in the hope that it will be useful,

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

* Library General Public License for more details.

* 

* You should have received a copy of the GNU Library General Public

* License along with this library; if not, write to the

* Free Software Foundation, Inc., 59 Temple Place - Suite 330,

* Boston, MA  02111-1307, USA.

*/

#include <windows.h>

#include <Windef.h>

#include "BladeMP3EncDLL.h"

#include <assert.h>

#include <stdio.h>

#include <lame.h>

#ifdef	__cplusplus

extern "C" {

#endif

#define         Min(A, B)       ((A) < (B) ? (A) : (B))

#define         Max(A, B)       ((A) > (B) ? (A) : (B))

#define _RELEASEDEBUG 0

// lame_enc DLL version number

const BYTE MAJORVERSION = 1;

const BYTE MINORVERSION = 32;

// Local variables

static DWORD				dwSampleBufferSize=0;

static HMODULE				gs_hModule=NULL;

static BOOL					gs_bLogFile=FALSE;

static lame_global_flags*	gfp_save = NULL;

// Local function prototypes

static void dump_config( 	lame_global_flags*	gfp );

static void DebugPrintf( const char* pzFormat, ... );

static void DispErr( char const* strErr );

static void PresetOptions( lame_global_flags *gfp, LONG myPreset );

static void DebugPrintf(const char* pzFormat, ...)

{

    char	szBuffer[1024]={'\0',};

    char	szFileName[MAX_PATH+1]={'\0',};

    va_list ap;

    // Get the full module (DLL) file name

    GetModuleFileNameA(	gs_hModule, 

        szFileName,

        sizeof( szFileName ) );

    // change file name extention

    szFileName[ strlen(szFileName) - 3 ] = 't';

    szFileName[ strlen(szFileName) - 2 ] = 'x';

    szFileName[ strlen(szFileName) - 1 ] = 't';

    // start at beginning of the list

    va_start(ap, pzFormat);

    // copy it to the string buffer

    _vsnprintf(szBuffer, sizeof(szBuffer), pzFormat, ap);

    // log it to the file?

    if ( gs_bLogFile ) 

    {	

        FILE* fp = NULL;

        // try to open the log file

        fp=fopen( szFileName, "a+" );

        // check file open result

        if (fp)

        {

            // write string to the file

            fputs(szBuffer,fp);

            // close the file

            fclose(fp);

        }

    }

#if defined _DEBUG || defined _RELEASEDEBUG

    OutputDebugStringA( szBuffer );

#endif

    va_end(ap);

}

static void PresetOptions( lame_global_flags *gfp, LONG myPreset )

{

    switch (myPreset)

    {

        /*-1*/case LQP_NOPRESET:

            break;

        /*0*/case LQP_NORMAL_QUALITY:

            /*	lame_set_quality( gfp, 5 );*/

            break;

        /*1*/case LQP_LOW_QUALITY:

             lame_set_quality( gfp, 9 );

             break;

        /*2*/case LQP_HIGH_QUALITY:

             lame_set_quality( gfp, 2 );

             break;

        /*3*/case LQP_VOICE_QUALITY:				// --voice flag for experimental voice mode

             lame_set_mode( gfp, MONO );

             lame_set_preset( gfp, 56);

             break;

        /*4*/case LQP_R3MIX:					// --R3MIX

             lame_set_preset( gfp, R3MIX);

             break;

        /*5*/case LQP_VERYHIGH_QUALITY:

             lame_set_quality( gfp, 0 );

             break;

        /*6*/case LQP_STANDARD:				// --PRESET STANDARD

            lame_set_preset( gfp, STANDARD);

            break;

        /*7*/case LQP_FAST_STANDARD:				// --PRESET FAST STANDARD

            lame_set_preset( gfp, STANDARD_FAST);

            break;

        /*8*/case LQP_EXTREME:				// --PRESET EXTREME

            lame_set_preset( gfp, EXTREME);

            break;

        /*9*/case LQP_FAST_EXTREME:				// --PRESET FAST EXTREME:

            lame_set_preset( gfp, EXTREME_FAST);

            break;

        /*10*/case LQP_INSANE:				// --PRESET INSANE

            lame_set_preset( gfp, INSANE);

            break;

        /*11*/case LQP_ABR:					// --PRESET ABR

            // handled in beInitStream

            break;

        /*12*/case LQP_CBR:					// --PRESET CBR

            // handled in beInitStream

            break;

        /*13*/case LQP_MEDIUM:					// --PRESET MEDIUM

            lame_set_preset( gfp, MEDIUM);

            break;

        /*14*/case LQP_FAST_MEDIUM:					// --PRESET FAST MEDIUM

            lame_set_preset( gfp, MEDIUM_FAST);

            break;

        /*1000*/case LQP_PHONE:

            lame_set_mode( gfp, MONO );

            lame_set_preset( gfp, 16);

            break;

        /*2000*/case LQP_SW:

            lame_set_mode( gfp, MONO );

            lame_set_preset( gfp, 24);

            break;

        /*3000*/case LQP_AM:

            lame_set_mode( gfp, MONO );

            lame_set_preset( gfp, 40);

            break;

        /*4000*/case LQP_FM:

            lame_set_preset( gfp, 112);

            break;

        /*5000*/case LQP_VOICE:

            lame_set_mode( gfp, MONO );

            lame_set_preset( gfp, 56);

            break;

        /*6000*/case LQP_RADIO:

            lame_set_preset( gfp, 112);

            break;

        /*7000*/case LQP_TAPE:

            lame_set_preset( gfp, 112);

            break;

        /*8000*/case LQP_HIFI:

            lame_set_preset( gfp, 160);

            break;

        /*9000*/case LQP_CD:

            lame_set_preset( gfp, 192);

            break;

        /*10000*/case LQP_STUDIO:

            lame_set_preset( gfp, 256);

            break;

    }

}

__declspec(dllexport) BE_ERR	beInitStream(PBE_CONFIG pbeConfig, PDWORD dwSamples, PDWORD dwBufferSize, PHBE_STREAM phbeStream)

{

    int actual_bitrate;

    //2001-12-18

    BE_CONFIG			lameConfig = { 0, };

    int					nInitReturn = 0;

    lame_global_flags*	gfp = NULL;

    // Init the global flags structure

    gfp = lame_init();

    *phbeStream = (HBE_STREAM)gfp;

    // clear out structure

    memset(&lameConfig,0x00,CURRENT_STRUCT_SIZE);

    // Check if this is a regular BLADE_ENCODER header

    if (pbeConfig->dwConfig!=BE_CONFIG_LAME)

    {

        int nCRC=pbeConfig->format.mp3.bCRC;

        int nVBR=(nCRC>>12)&0x0F;

        // Copy parameter from old Blade structure

        lameConfig.format.LHV1.dwSampleRate	=pbeConfig->format.mp3.dwSampleRate;

        //for low bitrates, LAME will automatically downsample for better

        //sound quality.  Forcing output samplerate = input samplerate is not a good idea 

        //unless the user specifically requests it:

        //lameConfig.format.LHV1.dwReSampleRate=pbeConfig->format.mp3.dwSampleRate;

        lameConfig.format.LHV1.nMode		=(pbeConfig->format.mp3.byMode&0x0F);

        lameConfig.format.LHV1.dwBitrate	=pbeConfig->format.mp3.wBitrate;

        lameConfig.format.LHV1.bPrivate		=pbeConfig->format.mp3.bPrivate;

        lameConfig.format.LHV1.bOriginal	=pbeConfig->format.mp3.bOriginal;

        lameConfig.format.LHV1.bCRC		=nCRC&0x01;

        lameConfig.format.LHV1.bCopyright	=pbeConfig->format.mp3.bCopyright;

        // Fill out the unknowns

        lameConfig.format.LHV1.dwStructSize=CURRENT_STRUCT_SIZE;

        lameConfig.format.LHV1.dwStructVersion=CURRENT_STRUCT_VERSION;

        // Get VBR setting from fourth nibble

        if ( nVBR>0 )

        {

            lameConfig.format.LHV1.bWriteVBRHeader = TRUE;

            lameConfig.format.LHV1.bEnableVBR = TRUE;

            lameConfig.format.LHV1.nVBRQuality = nVBR-1;

        }

        // Get Quality from third nibble

        lameConfig.format.LHV1.nPreset=((nCRC>>8)&0x0F);

    }

    else

    {

        // Copy the parameters

        memcpy(&lameConfig,pbeConfig,pbeConfig->format.LHV1.dwStructSize);

    }

    // --------------- Set arguments to LAME encoder -------------------------

    // Set input sample frequency

    lame_set_in_samplerate( gfp, lameConfig.format.LHV1.dwSampleRate );

    // disable INFO/VBR tag by default.  

    // if this tag is used, the calling program must call beWriteVBRTag()

    // after encoding.  But the original DLL documentation does not 

    // require the 

    // app to call beWriteVBRTag() unless they have specifically

    // set LHV1.bWriteVBRHeader=TRUE.  Thus the default setting should

    // be disabled.  

    lame_set_bWriteVbrTag( gfp, 0 );

    //2001-12-18 Dibrom's ABR preset stuff

    if(lameConfig.format.LHV1.nPreset == LQP_ABR)		// --ALT-PRESET ABR

    {

        actual_bitrate = lameConfig.format.LHV1.dwVbrAbr_bps / 1000;

        // limit range

        if( actual_bitrate > 320)

        {

            actual_bitrate = 320;

        }

        if( actual_bitrate < 8 )

        {

            actual_bitrate = 8;

        }

        lame_set_preset( gfp, actual_bitrate );

    }    

    // end Dibrom's ABR preset 2001-12-18 ****** START OF CBR

    if(lameConfig.format.LHV1.nPreset == LQP_CBR)		// --ALT-PRESET CBR

    {

        actual_bitrate = lameConfig.format.LHV1.dwBitrate;

        lame_set_preset(gfp, actual_bitrate);

        lame_set_VBR(gfp, vbr_off);

    }

    // end Dibrom's CBR preset 2001-12-18

    // The following settings only used when preset is not one of the LAME QUALITY Presets

    if ( (int)lameConfig.format.LHV1.nPreset < (int) LQP_STANDARD )

    {

        switch ( lameConfig.format.LHV1.nMode )

        {

        case BE_MP3_MODE_STEREO:

            lame_set_mode( gfp, STEREO );

            lame_set_num_channels( gfp, 2 );

            break;

        case BE_MP3_MODE_JSTEREO:

            lame_set_mode( gfp, JOINT_STEREO );

            //lame_set_force_ms( gfp, bForceMS ); // no check box to force this?

            lame_set_num_channels( gfp, 2 );

            break;

        case BE_MP3_MODE_MONO:

            lame_set_mode( gfp, MONO );

            lame_set_num_channels( gfp, 1 );

            break;

        case BE_MP3_MODE_DUALCHANNEL:

            lame_set_mode( gfp, DUAL_CHANNEL );

            lame_set_num_channels( gfp, 2 );

            break;

        default:

            {

                DebugPrintf("Invalid lameConfig.format.LHV1.nMode, value is %d\n",lameConfig.format.LHV1.nMode);

                return BE_ERR_INVALID_FORMAT_PARAMETERS;

            }

        }

        if ( lameConfig.format.LHV1.bEnableVBR )

        {

            /* set VBR quality */

            lame_set_VBR_q( gfp, lameConfig.format.LHV1.nVBRQuality );

            /* select proper VBR method */

            switch ( lameConfig.format.LHV1.nVbrMethod)

            {

            case VBR_METHOD_NONE:

                lame_set_VBR( gfp, vbr_off );

                break;

            case VBR_METHOD_DEFAULT:

                lame_set_VBR( gfp, vbr_default ); 

                break;

            case VBR_METHOD_OLD:

                lame_set_VBR( gfp, vbr_rh ); 

                break;

            case VBR_METHOD_MTRH:

            case VBR_METHOD_NEW:

                /*                                

                * the --vbr-mtrh commandline switch is obsolete. 

                * now --vbr-mtrh is known as --vbr-new

                */

                lame_set_VBR( gfp, vbr_mtrh ); 

                break;

            case VBR_METHOD_ABR:

                lame_set_VBR( gfp, vbr_abr ); 

                break;

            default:

                /* unsupported VBR method */

                assert( FALSE );

            }

        }

        else

        {

            /* use CBR encoding method, so turn off VBR */

            lame_set_VBR( gfp, vbr_off );

        }

        /* Set bitrate.  (CDex users always specify bitrate=Min bitrate when using VBR) */

        lame_set_brate( gfp, lameConfig.format.LHV1.dwBitrate );

        /* check if we have to use ABR, in order to backwards compatible, this

        * condition should still be checked indepedent of the nVbrMethod method

        */

        if (lameConfig.format.LHV1.dwVbrAbr_bps > 0 )

        {

            /* set VBR method to ABR */

            lame_set_VBR( gfp, vbr_abr );

            /* calculate to kbps, round to nearest kbps */

            lame_set_VBR_mean_bitrate_kbps( gfp, ( lameConfig.format.LHV1.dwVbrAbr_bps + 500 ) / 1000 );

            /* limit range */

            if( lame_get_VBR_mean_bitrate_kbps( gfp ) > 320)

            {

                lame_set_VBR_mean_bitrate_kbps( gfp, 320 );

            }

            if( lame_get_VBR_mean_bitrate_kbps( gfp ) < 8 )

            {

                lame_set_VBR_mean_bitrate_kbps( gfp, 8 );

            }

        }

    }

    // First set all the preset options

    if ( LQP_NOPRESET !=  lameConfig.format.LHV1.nPreset )

    {

        PresetOptions( gfp, lameConfig.format.LHV1.nPreset );

    }

    // Set frequency resampling rate, if specified

    if ( lameConfig.format.LHV1.dwReSampleRate > 0 )

    {

        lame_set_out_samplerate( gfp, lameConfig.format.LHV1.dwReSampleRate );

    }

    switch ( lameConfig.format.LHV1.nMode )

    {

    case BE_MP3_MODE_MONO:

        lame_set_mode( gfp, MONO );

        lame_set_num_channels( gfp, 1 );

        break;

    default:

        break;

    }

    // Use strict ISO encoding?

    lame_set_strict_ISO( gfp, ( lameConfig.format.LHV1.bStrictIso ) ? 1 : 0 );

    // Set copyright flag?

    if ( lameConfig.format.LHV1.bCopyright )

    {

        lame_set_copyright( gfp, 1 );

    }

    // Do we have to tag  it as non original 

    if ( !lameConfig.format.LHV1.bOriginal )

    {

        lame_set_original( gfp, 0 );

    }

    else

    {

        lame_set_original( gfp, 1 );

    }

    // Add CRC?

    if ( lameConfig.format.LHV1.bCRC )

    {

        lame_set_error_protection( gfp, 1 );

    }

    else

    {

        lame_set_error_protection( gfp, 0 );

    }

    // Set private bit?

    if ( lameConfig.format.LHV1.bPrivate )

    {

        lame_set_extension( gfp, 1 );

    }

    else

    {

        lame_set_extension( gfp, 0 );

    }

    // Set VBR min bitrate, if specified

    if ( lameConfig.format.LHV1.dwBitrate > 0 )

    {

        lame_set_VBR_min_bitrate_kbps( gfp, lameConfig.format.LHV1.dwBitrate );

    }

    // Set Maxbitrate, if specified

    if ( lameConfig.format.LHV1.dwMaxBitrate > 0 )

    {

        lame_set_VBR_max_bitrate_kbps( gfp, lameConfig.format.LHV1.dwMaxBitrate );

    }

    // Set bit resovoir option

    if ( lameConfig.format.LHV1.bNoRes )

    {

        lame_set_disable_reservoir( gfp,1 );

    }

    // check if the VBR tag is required

    if ( lameConfig.format.LHV1.bWriteVBRHeader ) 

    {

        lame_set_bWriteVbrTag( gfp, 1 );

    }

    else

    {

        lame_set_bWriteVbrTag( gfp, 0 );

    }

    // Override Quality setting, use HIGHBYTE = NOT LOWBYTE to be backwards compatible

    if (	( lameConfig.format.LHV1.nQuality & 0xFF ) ==

        ((~( lameConfig.format.LHV1.nQuality >> 8 )) & 0xFF) )

    {

        lame_set_quality( gfp, lameConfig.format.LHV1.nQuality & 0xFF );

    }

    if ( 0 != ( nInitReturn = lame_init_params( gfp ) ) )

    {

        return nInitReturn;

    }

    //LAME encoding call will accept any number of samples.  

    if ( 0 == lame_get_version( gfp ) )

    {

        // For MPEG-II, only 576 samples per frame per channel

        *dwSamples= 576 * lame_get_num_channels( gfp );

    }

    else

    {

        // For MPEG-I, 1152 samples per frame per channel

        *dwSamples= 1152 * lame_get_num_channels( gfp );

    }

    // Set the input sample buffer size, so we know what we can expect

    dwSampleBufferSize = *dwSamples;

    // Set MP3 buffer size, conservative estimate

    *dwBufferSize=(DWORD)( 1.25 * ( *dwSamples / lame_get_num_channels( gfp ) ) + 7200 );

    // For debugging purposes

    dump_config( gfp );

    // Everything went OK, thus return SUCCESSFUL

    return BE_ERR_SUCCESSFUL;

}

__declspec(dllexport) BE_ERR	beFlushNoGap(HBE_STREAM hbeStream, PBYTE pOutput, PDWORD pdwOutput)

{

    int nOutputSamples = 0;

    lame_global_flags*	gfp = (lame_global_flags*)hbeStream;

    // Init the global flags structure

    nOutputSamples = lame_encode_flush_nogap( gfp, pOutput, LAME_MAXMP3BUFFER );

    if ( nOutputSamples < 0 )

    {

        *pdwOutput = 0;

        return BE_ERR_BUFFER_TOO_SMALL;

    }

    else

    {

        *pdwOutput = nOutputSamples;

    }

    return BE_ERR_SUCCESSFUL;

}

__declspec(dllexport) BE_ERR	beDeinitStream(HBE_STREAM hbeStream, PBYTE pOutput, PDWORD pdwOutput)

{

    int nOutputSamples = 0;

    lame_global_flags*	gfp = (lame_global_flags*)hbeStream;

    nOutputSamples = lame_encode_flush( gfp, pOutput, 0 );

    if ( nOutputSamples < 0 )

    {

        *pdwOutput = 0;

        return BE_ERR_BUFFER_TOO_SMALL;

    }

    else

    {

        *pdwOutput = nOutputSamples;

    }

    return BE_ERR_SUCCESSFUL;

}

__declspec(dllexport) BE_ERR	beCloseStream(HBE_STREAM hbeStream)

{

    lame_global_flags*	gfp = (lame_global_flags*)hbeStream;

    // lame will be close in VbrWriteTag function

    if ( !lame_get_bWriteVbrTag( gfp ) )

    {

        // clean up of allocated memory

        lame_close( gfp );

        gfp_save = NULL;

    }

    else

    {

        gfp_save = (lame_global_flags*)hbeStream;

    }

    // DeInit encoder

    return BE_ERR_SUCCESSFUL;

}

__declspec(dllexport) VOID		beVersion(PBE_VERSION pbeVersion)

{

    // DLL Release date

    char lpszDate[20]	= { '\0', };

    char lpszTemp[5]	= { '\0', };

    lame_version_t lv   = { 0, };

    // Set DLL interface version

    pbeVersion->byDLLMajorVersion=MAJORVERSION;

    pbeVersion->byDLLMinorVersion=MINORVERSION;

    get_lame_version_numerical ( &lv );

    // Set Engine version number (Same as Lame version)

    pbeVersion->byMajorVersion = (BYTE)lv.major;

    pbeVersion->byMinorVersion = (BYTE)lv.minor;

    pbeVersion->byAlphaLevel   = (BYTE)lv.alpha;

    pbeVersion->byBetaLevel    = (BYTE)lv.beta;

#ifdef MMX_choose_table

    pbeVersion->byMMXEnabled=1;

#else

    pbeVersion->byMMXEnabled=0;

#endif

    memset( pbeVersion->btReserved, 0, sizeof( pbeVersion->btReserved ) );

    // Get compilation date

    strcpy(lpszDate,__DATE__);

    // Get the first three character, which is the month

    strncpy(lpszTemp,lpszDate,3);

    lpszTemp[3] = '\0';

    pbeVersion->byMonth=1;

    // Set month

    if (strcmp(lpszTemp,"Jan")==0)	pbeVersion->byMonth = 1;

    if (strcmp(lpszTemp,"Feb")==0)	pbeVersion->byMonth = 2;

    if (strcmp(lpszTemp,"Mar")==0)	pbeVersion->byMonth = 3;

    if (strcmp(lpszTemp,"Apr")==0)	pbeVersion->byMonth = 4;

    if (strcmp(lpszTemp,"May")==0)	pbeVersion->byMonth = 5;

    if (strcmp(lpszTemp,"Jun")==0)	pbeVersion->byMonth = 6;

    if (strcmp(lpszTemp,"Jul")==0)	pbeVersion->byMonth = 7;

    if (strcmp(lpszTemp,"Aug")==0)	pbeVersion->byMonth = 8;

    if (strcmp(lpszTemp,"Sep")==0)	pbeVersion->byMonth = 9;

    if (strcmp(lpszTemp,"Oct")==0)	pbeVersion->byMonth = 10;

    if (strcmp(lpszTemp,"Nov")==0)	pbeVersion->byMonth = 11;

    if (strcmp(lpszTemp,"Dec")==0)	pbeVersion->byMonth = 12;

    // Get day of month string (char [4..5])

    pbeVersion->byDay = (BYTE) atoi( lpszDate + 4 );

    // Get year of compilation date (char [7..10])

    pbeVersion->wYear = (WORD) atoi( lpszDate + 7 );

    memset( pbeVersion->zHomepage, 0x00, BE_MAX_HOMEPAGE );

    strcpy( pbeVersion->zHomepage, "http://www.mp3dev.org/" );

}

__declspec(dllexport) BE_ERR	beEncodeChunk(HBE_STREAM hbeStream, DWORD nSamples, 

                                              PSHORT pSamples, PBYTE pOutput, PDWORD pdwOutput)

{

    // Encode it

    int dwSamples;

    int	nOutputSamples = 0;

    lame_global_flags*	gfp = (lame_global_flags*)hbeStream;

    dwSamples = nSamples / lame_get_num_channels( gfp );

    // old versions of lame_enc.dll required exactly 1152 samples

    // and worked even if nSamples accidently set to 2304 

    // simulate this behavoir:

    if ( 1 == lame_get_num_channels( gfp ) && nSamples == 2304)

    {

        dwSamples/= 2;

    }

    if ( 1 == lame_get_num_channels( gfp ) )

    {

        nOutputSamples = lame_encode_buffer(gfp,pSamples,pSamples,dwSamples,pOutput,0);

    }

    else

    {

        nOutputSamples = lame_encode_buffer_interleaved(gfp,pSamples,dwSamples,pOutput,0);

    }

    if ( nOutputSamples < 0 )

    {

        *pdwOutput=0;

        return BE_ERR_BUFFER_TOO_SMALL;

    }

    else

    {

        *pdwOutput = (DWORD)nOutputSamples;

    }

    return BE_ERR_SUCCESSFUL;

}

// accept floating point audio samples, scaled to the range of a signed 16-bit

//  integer (within +/- 32768), in non-interleaved channels  -- DSPguru, jd

__declspec(dllexport) BE_ERR	beEncodeChunkFloatS16NI(HBE_STREAM hbeStream, DWORD nSamples, 

                                                        PFLOAT buffer_l, PFLOAT buffer_r, PBYTE pOutput, PDWORD pdwOutput)

{

    int nOutputSamples;

    lame_global_flags*	gfp = (lame_global_flags*)hbeStream;

    nOutputSamples = lame_encode_buffer_float(gfp,buffer_l,buffer_r,nSamples,pOutput,0);

    if ( nOutputSamples >= 0 )

    {

        *pdwOutput = (DWORD) nOutputSamples;

    }

    else

    {

        *pdwOutput=0;

        return BE_ERR_BUFFER_TOO_SMALL;

    }

    return BE_ERR_SUCCESSFUL;

}

static int

maybeSyncWord(FILE* fpStream)

{

    unsigned char mp3_frame_header[4];

    size_t nbytes = fread(mp3_frame_header, 1, sizeof(mp3_frame_header), fpStream);

    if ( nbytes != sizeof(mp3_frame_header) ) {

        return -1;

    }

    if ( mp3_frame_header[0] != 0xffu ) {

        return -1; /* doesn't look like a sync word */

    }

    if ( (mp3_frame_header[1] & 0xE0u) != 0xE0u ) {

        return -1; /* doesn't look like a sync word */

    }

    return 0;

}

static int

skipId3v2(FILE * fpStream, size_t lametag_frame_size)

{

    size_t  nbytes;

    size_t  id3v2TagSize = 0;

    unsigned char id3v2Header[10];

    /* seek to the beginning of the stream */

    if (fseek(fpStream, 0, SEEK_SET) != 0) {

        return -2;  /* not seekable, abort */

    }

    /* read 10 bytes in case there's an ID3 version 2 header here */

    nbytes = fread(id3v2Header, 1, sizeof(id3v2Header), fpStream);

    if (nbytes != sizeof(id3v2Header)) {

        return -3;  /* not readable, maybe opened Write-Only */

    }

    /* does the stream begin with the ID3 version 2 file identifier? */

    if (!strncmp((char *) id3v2Header, "ID3", 3)) {

        /* the tag size (minus the 10-byte header) is encoded into four

        * bytes where the most significant bit is clear in each byte

        */

        id3v2TagSize = (((id3v2Header[6] & 0x7f) << 21)

            | ((id3v2Header[7] & 0x7f) << 14)

            | ((id3v2Header[8] & 0x7f) << 7)

            | (id3v2Header[9] & 0x7f))

            + sizeof id3v2Header;

    }

    /* Seek to the beginning of the audio stream */

    if ( fseek(fpStream, id3v2TagSize, SEEK_SET) != 0 ) {

        return -2;

    }

    if ( maybeSyncWord(fpStream) != 0) {

        return -1;

    }

    if ( fseek(fpStream, id3v2TagSize+lametag_frame_size, SEEK_SET) != 0 ) {

        return -2;

    }

    if ( maybeSyncWord(fpStream) != 0) {

        return -1;

    }

    /* OK, it seems we found our LAME-Tag/Xing frame again */

    /* Seek to the beginning of the audio stream */

    if ( fseek(fpStream, id3v2TagSize, SEEK_SET) != 0 ) {

        return -2;

    }

    return 0;

}

static BE_ERR

updateLameTagFrame(lame_global_flags* gfp, FILE* fpStream)

{

    size_t n = lame_get_lametag_frame( gfp, 0, 0 ); /* ask for bufer size */

    if ( n > 0 )

    {

        unsigned char* buffer = 0;

        size_t m = 1;

        if ( 0 != skipId3v2(fpStream, n) ) 

        {

            DispErr( "Error updating LAME-tag frame:\n\n"

                     "can't locate old frame\n" );

            return BE_ERR_INVALID_FORMAT_PARAMETERS;

        }

        buffer = (unsigned char*)malloc( n );

        if ( buffer == 0 ) 

        {

            DispErr( "Error updating LAME-tag frame:\n\n"

                     "can't allocate frame buffer\n" );

            return BE_ERR_INVALID_FORMAT_PARAMETERS;

        }

        /* Put it all to disk again */

        n = lame_get_lametag_frame( gfp, buffer, n );

        if ( n > 0 ) 

        {

            m = fwrite( buffer, n, 1, fpStream );        

        }

        free( buffer );

        if ( m != 1 ) 

        {

            DispErr( "Error updating LAME-tag frame:\n\n"

                     "couldn't write frame into file\n" );

            return BE_ERR_INVALID_FORMAT_PARAMETERS;

        }

    }

    return BE_ERR_SUCCESSFUL;

}

__declspec(dllexport) BE_ERR beWriteInfoTag( HBE_STREAM hbeStream,

                                            LPCSTR lpszFileName )

{

    FILE* fpStream	= NULL;

    BE_ERR beResult	= BE_ERR_SUCCESSFUL;

    lame_global_flags*	gfp = (lame_global_flags*)hbeStream;

    if ( NULL != gfp )

    {

        // Do we have to write the VBR tag?

        if ( lame_get_bWriteVbrTag( gfp ) )

        {

            // Try to open the file

            fpStream=fopen( lpszFileName, "rb+" );

            // Check file open result

            if ( NULL == fpStream )

            {

                beResult = BE_ERR_INVALID_FORMAT_PARAMETERS;

                DispErr( "Error updating LAME-tag frame:\n\n"

                         "can't open file for reading and writing\n" );