Chris@69: /***********************************************************************
Chris@69: Copyright (c) 2006-2011, Skype Limited. All rights reserved.
Chris@69: Redistribution and use in source and binary forms, with or without
Chris@69: modification, are permitted provided that the following conditions
Chris@69: are met:
Chris@69: - Redistributions of source code must retain the above copyright notice,
Chris@69: this list of conditions and the following disclaimer.
Chris@69: - Redistributions in binary form must reproduce the above copyright
Chris@69: notice, this list of conditions and the following disclaimer in the
Chris@69: documentation and/or other materials provided with the distribution.
Chris@69: - Neither the name of Internet Society, IETF or IETF Trust, nor the
Chris@69: names of specific contributors, may be used to endorse or promote
Chris@69: products derived from this software without specific prior written
Chris@69: permission.
Chris@69: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
Chris@69: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
Chris@69: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
Chris@69: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
Chris@69: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
Chris@69: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
Chris@69: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
Chris@69: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
Chris@69: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
Chris@69: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
Chris@69: POSSIBILITY OF SUCH DAMAGE.
Chris@69: ***********************************************************************/
Chris@69: 
Chris@69: #ifdef HAVE_CONFIG_H
Chris@69: #include "config.h"
Chris@69: #endif
Chris@69: 
Chris@69: /* Insertion sort (fast for already almost sorted arrays):  */
Chris@69: /* Best case:  O(n)   for an already sorted array           */
Chris@69: /* Worst case: O(n^2) for an inversely sorted array         */
Chris@69: 
Chris@69: #include "typedef.h"
Chris@69: #include "SigProc_FLP.h"
Chris@69: 
Chris@69: void silk_insertion_sort_decreasing_FLP(
Chris@69:     silk_float          *a,                 /* I/O  Unsorted / Sorted vector                                    */
Chris@69:     opus_int            *idx,               /* O    Index vector for the sorted elements                        */
Chris@69:     const opus_int      L,                  /* I    Vector length                                               */
Chris@69:     const opus_int      K                   /* I    Number of correctly sorted positions                        */
Chris@69: )
Chris@69: {
Chris@69:     silk_float value;
Chris@69:     opus_int   i, j;
Chris@69: 
Chris@69:     /* Safety checks */
Chris@69:     celt_assert( K >  0 );
Chris@69:     celt_assert( L >  0 );
Chris@69:     celt_assert( L >= K );
Chris@69: 
Chris@69:     /* Write start indices in index vector */
Chris@69:     for( i = 0; i < K; i++ ) {
Chris@69:         idx[ i ] = i;
Chris@69:     }
Chris@69: 
Chris@69:     /* Sort vector elements by value, decreasing order */
Chris@69:     for( i = 1; i < K; i++ ) {
Chris@69:         value = a[ i ];
Chris@69:         for( j = i - 1; ( j >= 0 ) && ( value > a[ j ] ); j-- ) {
Chris@69:             a[ j + 1 ]   = a[ j ];      /* Shift value */
Chris@69:             idx[ j + 1 ] = idx[ j ];    /* Shift index */
Chris@69:         }
Chris@69:         a[ j + 1 ]   = value;   /* Write value */
Chris@69:         idx[ j + 1 ] = i;       /* Write index */
Chris@69:     }
Chris@69: 
Chris@69:     /* If less than L values are asked check the remaining values,      */
Chris@69:     /* but only spend CPU to ensure that the K first values are correct */
Chris@69:     for( i = K; i < L; i++ ) {
Chris@69:         value = a[ i ];
Chris@69:         if( value > a[ K - 1 ] ) {
Chris@69:             for( j = K - 2; ( j >= 0 ) && ( value > a[ j ] ); j-- ) {
Chris@69:                 a[ j + 1 ]   = a[ j ];      /* Shift value */
Chris@69:                 idx[ j + 1 ] = idx[ j ];    /* Shift index */
Chris@69:             }
Chris@69:             a[ j + 1 ]   = value;   /* Write value */
Chris@69:             idx[ j + 1 ] = i;       /* Write index */
Chris@69:         }
Chris@69:     }
Chris@69: }