cannam@154: /***********************************************************************
cannam@154: Copyright (c) 2006-2011, Skype Limited. All rights reserved.
cannam@154: Redistribution and use in source and binary forms, with or without
cannam@154: modification, are permitted provided that the following conditions
cannam@154: are met:
cannam@154: - Redistributions of source code must retain the above copyright notice,
cannam@154: this list of conditions and the following disclaimer.
cannam@154: - Redistributions in binary form must reproduce the above copyright
cannam@154: notice, this list of conditions and the following disclaimer in the
cannam@154: documentation and/or other materials provided with the distribution.
cannam@154: - Neither the name of Internet Society, IETF or IETF Trust, nor the
cannam@154: names of specific contributors, may be used to endorse or promote
cannam@154: products derived from this software without specific prior written
cannam@154: permission.
cannam@154: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
cannam@154: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
cannam@154: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
cannam@154: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
cannam@154: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
cannam@154: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
cannam@154: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
cannam@154: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
cannam@154: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
cannam@154: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
cannam@154: POSSIBILITY OF SUCH DAMAGE.
cannam@154: ***********************************************************************/
cannam@154: 
cannam@154: #ifdef HAVE_CONFIG_H
cannam@154: #include "config.h"
cannam@154: #endif
cannam@154: 
cannam@154: #include "SigProc_FLP.h"
cannam@154: 
cannam@154: /* step up function, converts reflection coefficients to prediction coefficients */
cannam@154: void silk_k2a_FLP(
cannam@154:     silk_float          *A,                 /* O     prediction coefficients [order]                            */
cannam@154:     const silk_float    *rc,                /* I     reflection coefficients [order]                            */
cannam@154:     opus_int32          order               /* I     prediction order                                           */
cannam@154: )
cannam@154: {
cannam@154:     opus_int   k, n;
cannam@154:     silk_float rck, tmp1, tmp2;
cannam@154: 
cannam@154:     for( k = 0; k < order; k++ ) {
cannam@154:         rck = rc[ k ];
cannam@154:         for( n = 0; n < (k + 1) >> 1; n++ ) {
cannam@154:             tmp1 = A[ n ];
cannam@154:             tmp2 = A[ k - n - 1 ];
cannam@154:             A[ n ]         = tmp1 + tmp2 * rck;
cannam@154:             A[ k - n - 1 ] = tmp2 + tmp1 * rck;
cannam@154:         }
cannam@154:         A[ k ] = -rck;
cannam@154:     }
cannam@154: }