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/*                                                                      *
 * File Name:    SKP_Silk_resample_2_3.c                              *
 *                                                                      *
 * Resamples by a factor 2/3                                            *
 *                                                                      *
 * Copyright 2008 (c), Skype Limited                                    *
 * All rights reserved.                                                 *
 *                                                                      *
 * Date: 081113                                                         *
 *                                                                      */

#include "SKP_Silk_SigProc_FIX.h"

#define OUT_SUBFR_LEN        80

/* Resamples by a factor 2/3 */
void SKP_Silk_resample_2_3(
    SKP_int16            *out,       /* O:   Fs_low signal    [inLen * 2/3]           */
    SKP_int32            *S,         /* I/O: State vector     [7+4]                   */
    const SKP_int16      *in,        /* I:   Fs_high signal   [inLen]                 */
    const SKP_int        inLen       /* I:   Input length, must be a multiple of 3    */
)
{
    SKP_int      outLen, LSubFrameIn, LSubFrameOut;
    SKP_int16    outH[      3 * OUT_SUBFR_LEN ];
    SKP_int32    scratch[ ( 9 * OUT_SUBFR_LEN ) / 2 ];

    /* Check that input length is multiple of 3 */
    SKP_assert( inLen % 3 == 0 );

    outLen = SKP_DIV32_16( SKP_LSHIFT( inLen, 1 ), 3 );
    while( outLen > 0 ) {
        LSubFrameOut = SKP_min_int( OUT_SUBFR_LEN, outLen );
        LSubFrameIn  = SKP_SMULWB( 98304, LSubFrameOut ); /* 98304_Q16 = 3/2_Q0 */
            
        /* Upsample by a factor 2 */
        /* Scratch size needs to be: 3 * LSubFrameIn * sizeof( SKP_int32 ) */
        SKP_Silk_resample_2_1_coarse( in, &S[ 0 ], outH, scratch, LSubFrameIn );

        /* Downsample by a factor 3 */
        SKP_Silk_resample_1_3( out, &S[ 4 ], outH, SKP_LSHIFT( LSubFrameIn, 1 ) );

        in     += LSubFrameIn;
        out    += LSubFrameOut;
        outLen -= LSubFrameOut;
    }
}
