michael@0: /***********************************************************************
michael@0: Copyright (c) 2006-2011, Skype Limited. All rights reserved.
michael@0: Redistribution and use in source and binary forms, with or without
michael@0: modification, are permitted provided that the following conditions
michael@0: are met:
michael@0: - Redistributions of source code must retain the above copyright notice,
michael@0: this list of conditions and the following disclaimer.
michael@0: - Redistributions in binary form must reproduce the above copyright
michael@0: notice, this list of conditions and the following disclaimer in the
michael@0: documentation and/or other materials provided with the distribution.
michael@0: - Neither the name of Internet Society, IETF or IETF Trust, nor the
michael@0: names of specific contributors, may be used to endorse or promote
michael@0: products derived from this software without specific prior written
michael@0: permission.
michael@0: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
michael@0: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
michael@0: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
michael@0: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
michael@0: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
michael@0: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
michael@0: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
michael@0: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
michael@0: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
michael@0: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
michael@0: POSSIBILITY OF SUCH DAMAGE.
michael@0: ***********************************************************************/
michael@0: 
michael@0: #ifdef HAVE_CONFIG_H
michael@0: #include "config.h"
michael@0: #endif
michael@0: 
michael@0: /* Insertion sort (fast for already almost sorted arrays):   */
michael@0: /* Best case:  O(n)   for an already sorted array            */
michael@0: /* Worst case: O(n^2) for an inversely sorted array          */
michael@0: /*                                                           */
michael@0: /* Shell short:    http://en.wikipedia.org/wiki/Shell_sort   */
michael@0: 
michael@0: #include "SigProc_FIX.h"
michael@0: 
michael@0: void silk_insertion_sort_increasing(
michael@0:     opus_int32           *a,             /* I/O   Unsorted / Sorted vector               */
michael@0:     opus_int             *idx,           /* O     Index vector for the sorted elements   */
michael@0:     const opus_int       L,              /* I     Vector length                          */
michael@0:     const opus_int       K               /* I     Number of correctly sorted positions   */
michael@0: )
michael@0: {
michael@0:     opus_int32    value;
michael@0:     opus_int        i, j;
michael@0: 
michael@0:     /* Safety checks */
michael@0:     silk_assert( K >  0 );
michael@0:     silk_assert( L >  0 );
michael@0:     silk_assert( L >= K );
michael@0: 
michael@0:     /* Write start indices in index vector */
michael@0:     for( i = 0; i < K; i++ ) {
michael@0:         idx[ i ] = i;
michael@0:     }
michael@0: 
michael@0:     /* Sort vector elements by value, increasing order */
michael@0:     for( i = 1; i < K; i++ ) {
michael@0:         value = a[ i ];
michael@0:         for( j = i - 1; ( j >= 0 ) && ( value < a[ j ] ); j-- ) {
michael@0:             a[ j + 1 ]   = a[ j ];       /* Shift value */
michael@0:             idx[ j + 1 ] = idx[ j ];     /* Shift index */
michael@0:         }
michael@0:         a[ j + 1 ]   = value;   /* Write value */
michael@0:         idx[ j + 1 ] = i;       /* Write index */
michael@0:     }
michael@0: 
michael@0:     /* If less than L values are asked for, check the remaining values, */
michael@0:     /* but only spend CPU to ensure that the K first values are correct */
michael@0:     for( i = K; i < L; i++ ) {
michael@0:         value = a[ i ];
michael@0:         if( value < a[ K - 1 ] ) {
michael@0:             for( j = K - 2; ( j >= 0 ) && ( value < a[ j ] ); j-- ) {
michael@0:                 a[ j + 1 ]   = a[ j ];       /* Shift value */
michael@0:                 idx[ j + 1 ] = idx[ j ];     /* Shift index */
michael@0:             }
michael@0:             a[ j + 1 ]   = value;   /* Write value */
michael@0:             idx[ j + 1 ] = i;       /* Write index */
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: #ifdef FIXED_POINT
michael@0: /* This function is only used by the fixed-point build */
michael@0: void silk_insertion_sort_decreasing_int16(
michael@0:     opus_int16                  *a,                 /* I/O   Unsorted / Sorted vector                                   */
michael@0:     opus_int                    *idx,               /* O     Index vector for the sorted elements                       */
michael@0:     const opus_int              L,                  /* I     Vector length                                              */
michael@0:     const opus_int              K                   /* I     Number of correctly sorted positions                       */
michael@0: )
michael@0: {
michael@0:     opus_int i, j;
michael@0:     opus_int value;
michael@0: 
michael@0:     /* Safety checks */
michael@0:     silk_assert( K >  0 );
michael@0:     silk_assert( L >  0 );
michael@0:     silk_assert( L >= K );
michael@0: 
michael@0:     /* Write start indices in index vector */
michael@0:     for( i = 0; i < K; i++ ) {
michael@0:         idx[ i ] = i;
michael@0:     }
michael@0: 
michael@0:     /* Sort vector elements by value, decreasing order */
michael@0:     for( i = 1; i < K; i++ ) {
michael@0:         value = a[ i ];
michael@0:         for( j = i - 1; ( j >= 0 ) && ( value > a[ j ] ); j-- ) {
michael@0:             a[ j + 1 ]   = a[ j ];     /* Shift value */
michael@0:             idx[ j + 1 ] = idx[ j ];   /* Shift index */
michael@0:         }
michael@0:         a[ j + 1 ]   = value;   /* Write value */
michael@0:         idx[ j + 1 ] = i;       /* Write index */
michael@0:     }
michael@0: 
michael@0:     /* If less than L values are asked for, check the remaining values, */
michael@0:     /* but only spend CPU to ensure that the K first values are correct */
michael@0:     for( i = K; i < L; i++ ) {
michael@0:         value = a[ i ];
michael@0:         if( value > a[ K - 1 ] ) {
michael@0:             for( j = K - 2; ( j >= 0 ) && ( value > a[ j ] ); j-- ) {
michael@0:                 a[ j + 1 ]   = a[ j ];     /* Shift value */
michael@0:                 idx[ j + 1 ] = idx[ j ];   /* Shift index */
michael@0:             }
michael@0:             a[ j + 1 ]   = value;   /* Write value */
michael@0:             idx[ j + 1 ] = i;       /* Write index */
michael@0:         }
michael@0:     }
michael@0: }
michael@0: #endif
michael@0: 
michael@0: void silk_insertion_sort_increasing_all_values_int16(
michael@0:      opus_int16                 *a,                 /* I/O   Unsorted / Sorted vector                                   */
michael@0:      const opus_int             L                   /* I     Vector length                                              */
michael@0: )
michael@0: {
michael@0:     opus_int    value;
michael@0:     opus_int    i, j;
michael@0: 
michael@0:     /* Safety checks */
michael@0:     silk_assert( L >  0 );
michael@0: 
michael@0:     /* Sort vector elements by value, increasing order */
michael@0:     for( i = 1; i < L; i++ ) {
michael@0:         value = a[ i ];
michael@0:         for( j = i - 1; ( j >= 0 ) && ( value < a[ j ] ); j-- ) {
michael@0:             a[ j + 1 ] = a[ j ]; /* Shift value */
michael@0:         }
michael@0:         a[ j + 1 ] = value; /* Write value */
michael@0:     }
michael@0: }