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//#ifdef HAVE_CONFIG_H
#include "../config.h"
//#endif

#include "SigProc_FIX.h"
#include "resampler_private.h"
#include "../celt/stack_alloc.h"

static OPUS_INLINE opus_int16 *silk_resampler_private_down_FIR_INTERPOL(
    opus_int16          *out,
    opus_int32          *buf,
    const opus_int16    *FIR_Coefs,
    opus_int            FIR_Order,
    opus_int            FIR_Fracs,
    opus_int32          max_index_Q16,
    opus_int32          index_increment_Q16
) {
    opus_int32 index_Q16, res_Q6;
    opus_int32 *buf_ptr;
    opus_int32 interpol_ind;
    const opus_int16 *interpol_ptr;

    switch (FIR_Order) {
    case RESAMPLER_DOWN_ORDER_FIR0:
        for (index_Q16 = 0; index_Q16 < max_index_Q16; index_Q16 += index_increment_Q16) {
            /* Integer part gives pointer to buffered input */
            buf_ptr = buf + silk_RSHIFT(index_Q16, 16);

            /* Fractional part gives interpolation coefficients */
            interpol_ind = silk_SMULWB(index_Q16 & 0xFFFF, FIR_Fracs);

            /* Inner product */
            interpol_ptr = &FIR_Coefs[ RESAMPLER_DOWN_ORDER_FIR0 / 2 * interpol_ind ];
            res_Q6 = silk_SMULWB(buf_ptr[ 0 ], interpol_ptr[ 0 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 1 ], interpol_ptr[ 1 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 2 ], interpol_ptr[ 2 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 3 ], interpol_ptr[ 3 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 4 ], interpol_ptr[ 4 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 5 ], interpol_ptr[ 5 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 6 ], interpol_ptr[ 6 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 7 ], interpol_ptr[ 7 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 8 ], interpol_ptr[ 8 ]);
            interpol_ptr = &FIR_Coefs[ RESAMPLER_DOWN_ORDER_FIR0 / 2 * (FIR_Fracs - 1 - interpol_ind) ];
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 17 ], interpol_ptr[ 0 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 16 ], interpol_ptr[ 1 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 15 ], interpol_ptr[ 2 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 14 ], interpol_ptr[ 3 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 13 ], interpol_ptr[ 4 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 12 ], interpol_ptr[ 5 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 11 ], interpol_ptr[ 6 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[ 10 ], interpol_ptr[ 7 ]);
            res_Q6 = silk_SMLAWB(res_Q6, buf_ptr[  9 ], interpol_ptr[ 8 ]);

            /* Scale down, saturate and store in output array */
            *out++ = (opus_int16)silk_SAT16(silk_RSHIFT_ROUND(res_Q6, 6));
        }
        break;
    case RESAMPLER_DOWN_ORDER_FIR1:
        for (index_Q16 = 0; index_Q16 < max_index_Q16; index_Q16 += index_increment_Q16) {
            /* Integer part gives pointer to buffered input */
            buf_ptr = buf + silk_RSHIFT(index_Q16, 16);

            /* Inner product */
            res_Q6 = silk_SMULWB(silk_ADD32(buf_ptr[  0 ], buf_ptr[ 23 ]), FIR_Coefs[  0 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  1 ], buf_ptr[ 22 ]), FIR_Coefs[  1 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  2 ], buf_ptr[ 21 ]), FIR_Coefs[  2 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  3 ], buf_ptr[ 20 ]), FIR_Coefs[  3 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  4 ], buf_ptr[ 19 ]), FIR_Coefs[  4 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  5 ], buf_ptr[ 18 ]), FIR_Coefs[  5 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  6 ], buf_ptr[ 17 ]), FIR_Coefs[  6 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  7 ], buf_ptr[ 16 ]), FIR_Coefs[  7 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  8 ], buf_ptr[ 15 ]), FIR_Coefs[  8 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  9 ], buf_ptr[ 14 ]), FIR_Coefs[  9 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[ 10 ], buf_ptr[ 13 ]), FIR_Coefs[ 10 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[ 11 ], buf_ptr[ 12 ]), FIR_Coefs[ 11 ]);

            /* Scale down, saturate and store in output array */
            *out++ = (opus_int16)silk_SAT16(silk_RSHIFT_ROUND(res_Q6, 6));
        }
        break;
    case RESAMPLER_DOWN_ORDER_FIR2:
        for (index_Q16 = 0; index_Q16 < max_index_Q16; index_Q16 += index_increment_Q16) {
            /* Integer part gives pointer to buffered input */
            buf_ptr = buf + silk_RSHIFT(index_Q16, 16);

            /* Inner product */
            res_Q6 = silk_SMULWB(silk_ADD32(buf_ptr[  0 ], buf_ptr[ 35 ]), FIR_Coefs[  0 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  1 ], buf_ptr[ 34 ]), FIR_Coefs[  1 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  2 ], buf_ptr[ 33 ]), FIR_Coefs[  2 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  3 ], buf_ptr[ 32 ]), FIR_Coefs[  3 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  4 ], buf_ptr[ 31 ]), FIR_Coefs[  4 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  5 ], buf_ptr[ 30 ]), FIR_Coefs[  5 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  6 ], buf_ptr[ 29 ]), FIR_Coefs[  6 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  7 ], buf_ptr[ 28 ]), FIR_Coefs[  7 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  8 ], buf_ptr[ 27 ]), FIR_Coefs[  8 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[  9 ], buf_ptr[ 26 ]), FIR_Coefs[  9 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[ 10 ], buf_ptr[ 25 ]), FIR_Coefs[ 10 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[ 11 ], buf_ptr[ 24 ]), FIR_Coefs[ 11 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[ 12 ], buf_ptr[ 23 ]), FIR_Coefs[ 12 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[ 13 ], buf_ptr[ 22 ]), FIR_Coefs[ 13 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[ 14 ], buf_ptr[ 21 ]), FIR_Coefs[ 14 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[ 15 ], buf_ptr[ 20 ]), FIR_Coefs[ 15 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[ 16 ], buf_ptr[ 19 ]), FIR_Coefs[ 16 ]);
            res_Q6 = silk_SMLAWB(res_Q6, silk_ADD32(buf_ptr[ 17 ], buf_ptr[ 18 ]), FIR_Coefs[ 17 ]);

            /* Scale down, saturate and store in output array */
            *out++ = (opus_int16)silk_SAT16(silk_RSHIFT_ROUND(res_Q6, 6));
        }
        break;
    default:
        celt_assert(0);
    }
    return out;
}

/* Resample with a 2nd order AR filter followed by FIR interpolation */
void silk_resampler_private_down_FIR(
    void                            *SS,            /* I/O  Resampler state             */
    opus_int16                      out[],          /* O    Output signal               */
    const opus_int16                in[],           /* I    Input signal                */
    opus_int32                      inLen           /* I    Number of input samples     */
) {
    silk_resampler_state_struct *S = (silk_resampler_state_struct *)SS;
    opus_int32 nSamplesIn;
    opus_int32 max_index_Q16, index_increment_Q16;
    VARDECL(opus_int32, buf);
    const opus_int16 *FIR_Coefs;
    SAVE_STACK;

    ALLOC(buf, S->batchSize + S->FIR_Order, opus_int32);

    /* Copy buffered samples to start of buffer */
    silk_memcpy(buf, S->sFIR.i32, S->FIR_Order * sizeof(opus_int32));

    FIR_Coefs = &S->Coefs[ 2 ];

    /* Iterate over blocks of frameSizeIn input samples */
    index_increment_Q16 = S->invRatio_Q16;
    while (1) {
        nSamplesIn = silk_min(inLen, S->batchSize);

        /* Second-order AR filter (output in Q8) */
        silk_resampler_private_AR2(S->sIIR, &buf[ S->FIR_Order ], in, S->Coefs, nSamplesIn);

        max_index_Q16 = silk_LSHIFT32(nSamplesIn, 16);

        /* Interpolate filtered signal */
        out = silk_resampler_private_down_FIR_INTERPOL(out, buf, FIR_Coefs, S->FIR_Order,
                S->FIR_Fracs, max_index_Q16, index_increment_Q16);

        in += nSamplesIn;
        inLen -= nSamplesIn;

        if (inLen > 1) {
            /* More iterations to do; copy last part of filtered signal to beginning of buffer */
            silk_memcpy(buf, &buf[ nSamplesIn ], S->FIR_Order * sizeof(opus_int32));
        } else {
            break;
        }
    }

    /* Copy last part of filtered signal to the state for the next call */
    silk_memcpy(S->sFIR.i32, &buf[ nSamplesIn ], S->FIR_Order * sizeof(opus_int32));
    RESTORE_STACK;
}
