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1 /***********************************************************************
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2 Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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3 Redistribution and use in source and binary forms, with or without
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4 modification, are permitted provided that the following conditions
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5 are met:
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6 - Redistributions of source code must retain the above copyright notice,
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7 this list of conditions and the following disclaimer.
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8 - Redistributions in binary form must reproduce the above copyright
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9 notice, this list of conditions and the following disclaimer in the
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10 documentation and/or other materials provided with the distribution.
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11 - Neither the name of Internet Society, IETF or IETF Trust, nor the
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12 names of specific contributors, may be used to endorse or promote
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13 products derived from this software without specific prior written
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14 permission.
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15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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25 POSSIBILITY OF SUCH DAMAGE.
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26 ***********************************************************************/
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27
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28 #ifdef HAVE_CONFIG_H
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29 #include "config.h"
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30 #endif
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31
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32 /* Insertion sort (fast for already almost sorted arrays): */
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33 /* Best case: O(n) for an already sorted array */
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34 /* Worst case: O(n^2) for an inversely sorted array */
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35
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36 #include "typedef.h"
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37 #include "SigProc_FLP.h"
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38
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39 void silk_insertion_sort_decreasing_FLP(
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40 silk_float *a, /* I/O Unsorted / Sorted vector */
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41 opus_int *idx, /* O Index vector for the sorted elements */
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42 const opus_int L, /* I Vector length */
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43 const opus_int K /* I Number of correctly sorted positions */
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44 )
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45 {
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46 silk_float value;
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47 opus_int i, j;
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48
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49 /* Safety checks */
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50 celt_assert( K > 0 );
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51 celt_assert( L > 0 );
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52 celt_assert( L >= K );
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53
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54 /* Write start indices in index vector */
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55 for( i = 0; i < K; i++ ) {
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56 idx[ i ] = i;
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57 }
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58
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59 /* Sort vector elements by value, decreasing order */
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60 for( i = 1; i < K; i++ ) {
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61 value = a[ i ];
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62 for( j = i - 1; ( j >= 0 ) && ( value > a[ j ] ); j-- ) {
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63 a[ j + 1 ] = a[ j ]; /* Shift value */
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64 idx[ j + 1 ] = idx[ j ]; /* Shift index */
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65 }
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66 a[ j + 1 ] = value; /* Write value */
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67 idx[ j + 1 ] = i; /* Write index */
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68 }
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69
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70 /* If less than L values are asked check the remaining values, */
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71 /* but only spend CPU to ensure that the K first values are correct */
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72 for( i = K; i < L; i++ ) {
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73 value = a[ i ];
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74 if( value > a[ K - 1 ] ) {
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75 for( j = K - 2; ( j >= 0 ) && ( value > a[ j ] ); j-- ) {
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76 a[ j + 1 ] = a[ j ]; /* Shift value */
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77 idx[ j + 1 ] = idx[ j ]; /* Shift index */
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78 }
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79 a[ j + 1 ] = value; /* Write value */
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80 idx[ j + 1 ] = i; /* Write index */
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81 }
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82 }
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83 }
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