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      1 /***********************************************************************
      2 Copyright (c) 2006-2011, Skype Limited. All rights reserved.
      3 Redistribution and use in source and binary forms, with or without
      4 modification, are permitted provided that the following conditions
      5 are met:
      6 - Redistributions of source code must retain the above copyright notice,
      7 this list of conditions and the following disclaimer.
      8 - Redistributions in binary form must reproduce the above copyright
      9 notice, this list of conditions and the following disclaimer in the
     10 documentation and/or other materials provided with the distribution.
     11 - Neither the name of Internet Society, IETF or IETF Trust, nor the
     12 names of specific contributors, may be used to endorse or promote
     13 products derived from this software without specific prior written
     14 permission.
     15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
     16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
     19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     25 POSSIBILITY OF SUCH DAMAGE.
     26 ***********************************************************************/
     27 
     28 #ifdef HAVE_CONFIG_H
     29 #include "config.h"
     30 #endif
     31 
     32 /* Insertion sort (fast for already almost sorted arrays):   */
     33 /* Best case:  O(n)   for an already sorted array            */
     34 /* Worst case: O(n^2) for an inversely sorted array          */
     35 /*                                                           */
     36 /* Shell short:    http://en.wikipedia.org/wiki/Shell_sort   */
     37 
     38 #include "SigProc_FIX.h"
     39 
     40 void silk_insertion_sort_increasing(
     41     opus_int32           *a,             /* I/O   Unsorted / Sorted vector               */
     42     opus_int             *idx,           /* O     Index vector for the sorted elements   */
     43     const opus_int       L,              /* I     Vector length                          */
     44     const opus_int       K               /* I     Number of correctly sorted positions   */
     45 )
     46 {
     47     opus_int32    value;
     48     opus_int        i, j;
     49 
     50     /* Safety checks */
     51     silk_assert( K >  0 );
     52     silk_assert( L >  0 );
     53     silk_assert( L >= K );
     54 
     55     /* Write start indices in index vector */
     56     for( i = 0; i < K; i++ ) {
     57         idx[ i ] = i;
     58     }
     59 
     60     /* Sort vector elements by value, increasing order */
     61     for( i = 1; i < K; i++ ) {
     62         value = a[ i ];
     63         for( j = i - 1; ( j >= 0 ) && ( value < a[ j ] ); j-- ) {
     64             a[ j + 1 ]   = a[ j ];       /* Shift value */
     65             idx[ j + 1 ] = idx[ j ];     /* Shift index */
     66         }
     67         a[ j + 1 ]   = value;   /* Write value */
     68         idx[ j + 1 ] = i;       /* Write index */
     69     }
     70 
     71     /* If less than L values are asked for, check the remaining values, */
     72     /* but only spend CPU to ensure that the K first values are correct */
     73     for( i = K; i < L; i++ ) {
     74         value = a[ i ];
     75         if( value < a[ K - 1 ] ) {
     76             for( j = K - 2; ( j >= 0 ) && ( value < a[ j ] ); j-- ) {
     77                 a[ j + 1 ]   = a[ j ];       /* Shift value */
     78                 idx[ j + 1 ] = idx[ j ];     /* Shift index */
     79             }
     80             a[ j + 1 ]   = value;   /* Write value */
     81             idx[ j + 1 ] = i;       /* Write index */
     82         }
     83     }
     84 }
     85 
     86 #ifdef FIXED_POINT
     87 /* This function is only used by the fixed-point build */
     88 void silk_insertion_sort_decreasing_int16(
     89     opus_int16                  *a,                 /* I/O   Unsorted / Sorted vector                                   */
     90     opus_int                    *idx,               /* O     Index vector for the sorted elements                       */
     91     const opus_int              L,                  /* I     Vector length                                              */
     92     const opus_int              K                   /* I     Number of correctly sorted positions                       */
     93 )
     94 {
     95     opus_int i, j;
     96     opus_int value;
     97 
     98     /* Safety checks */
     99     silk_assert( K >  0 );
    100     silk_assert( L >  0 );
    101     silk_assert( L >= K );
    102 
    103     /* Write start indices in index vector */
    104     for( i = 0; i < K; i++ ) {
    105         idx[ i ] = i;
    106     }
    107 
    108     /* Sort vector elements by value, decreasing order */
    109     for( i = 1; i < K; i++ ) {
    110         value = a[ i ];
    111         for( j = i - 1; ( j >= 0 ) && ( value > a[ j ] ); j-- ) {
    112             a[ j + 1 ]   = a[ j ];     /* Shift value */
    113             idx[ j + 1 ] = idx[ j ];   /* Shift index */
    114         }
    115         a[ j + 1 ]   = value;   /* Write value */
    116         idx[ j + 1 ] = i;       /* Write index */
    117     }
    118 
    119     /* If less than L values are asked for, check the remaining values, */
    120     /* but only spend CPU to ensure that the K first values are correct */
    121     for( i = K; i < L; i++ ) {
    122         value = a[ i ];
    123         if( value > a[ K - 1 ] ) {
    124             for( j = K - 2; ( j >= 0 ) && ( value > a[ j ] ); j-- ) {
    125                 a[ j + 1 ]   = a[ j ];     /* Shift value */
    126                 idx[ j + 1 ] = idx[ j ];   /* Shift index */
    127             }
    128             a[ j + 1 ]   = value;   /* Write value */
    129             idx[ j + 1 ] = i;       /* Write index */
    130         }
    131     }
    132 }
    133 #endif
    134 
    135 void silk_insertion_sort_increasing_all_values_int16(
    136      opus_int16                 *a,                 /* I/O   Unsorted / Sorted vector                                   */
    137      const opus_int             L                   /* I     Vector length                                              */
    138 )
    139 {
    140     opus_int    value;
    141     opus_int    i, j;
    142 
    143     /* Safety checks */
    144     silk_assert( L >  0 );
    145 
    146     /* Sort vector elements by value, increasing order */
    147     for( i = 1; i < L; i++ ) {
    148         value = a[ i ];
    149         for( j = i - 1; ( j >= 0 ) && ( value < a[ j ] ); j-- ) {
    150             a[ j + 1 ] = a[ j ]; /* Shift value */
    151         }
    152         a[ j + 1 ] = value; /* Write value */
    153     }
    154 }
    155