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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
40void 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 */
88void 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
135void 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