ref: b816d1da6844396092bc9c2d2969bef35ae32d8f
dir: /silk/sort.c/
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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
/* Insertion sort (fast for already almost sorted arrays): */
/* Best case: O(n) for an already sorted array */
/* Worst case: O(n^2) for an inversely sorted array */
/* */
/* Shell short: https://en.wikipedia.org/wiki/Shell_sort */
#include "SigProc_FIX.h"
void silk_insertion_sort_increasing(
opus_int32 *a, /* I/O Unsorted / Sorted vector */
opus_int *idx, /* O Index vector for the sorted elements */
const opus_int L, /* I Vector length */
const opus_int K /* I Number of correctly sorted positions */
)
{
opus_int32 value;
opus_int i, j;
/* Safety checks */
celt_assert( K > 0 );
celt_assert( L > 0 );
celt_assert( L >= K );
/* Write start indices in index vector */
for( i = 0; i < K; i++ ) {
idx[ i ] = i;
}
/* Sort vector elements by value, increasing order */
for( i = 1; i < K; i++ ) {
value = a[ i ];
for( j = i - 1; ( j >= 0 ) && ( value < a[ j ] ); j-- ) {
a[ j + 1 ] = a[ j ]; /* Shift value */
idx[ j + 1 ] = idx[ j ]; /* Shift index */
}
a[ j + 1 ] = value; /* Write value */
idx[ j + 1 ] = i; /* Write index */
}
/* If less than L values are asked for, check the remaining values, */
/* but only spend CPU to ensure that the K first values are correct */
for( i = K; i < L; i++ ) {
value = a[ i ];
if( value < a[ K - 1 ] ) {
for( j = K - 2; ( j >= 0 ) && ( value < a[ j ] ); j-- ) {
a[ j + 1 ] = a[ j ]; /* Shift value */
idx[ j + 1 ] = idx[ j ]; /* Shift index */
}
a[ j + 1 ] = value; /* Write value */
idx[ j + 1 ] = i; /* Write index */
}
}
}
#ifdef FIXED_POINT
/* This function is only used by the fixed-point build */
void silk_insertion_sort_decreasing_int16(
opus_int16 *a, /* I/O Unsorted / Sorted vector */
opus_int *idx, /* O Index vector for the sorted elements */
const opus_int L, /* I Vector length */
const opus_int K /* I Number of correctly sorted positions */
)
{
opus_int i, j;
opus_int value;
/* Safety checks */
celt_assert( K > 0 );
celt_assert( L > 0 );
celt_assert( L >= K );
/* Write start indices in index vector */
for( i = 0; i < K; i++ ) {
idx[ i ] = i;
}
/* Sort vector elements by value, decreasing order */
for( i = 1; i < K; i++ ) {
value = a[ i ];
for( j = i - 1; ( j >= 0 ) && ( value > a[ j ] ); j-- ) {
a[ j + 1 ] = a[ j ]; /* Shift value */
idx[ j + 1 ] = idx[ j ]; /* Shift index */
}
a[ j + 1 ] = value; /* Write value */
idx[ j + 1 ] = i; /* Write index */
}
/* If less than L values are asked for, check the remaining values, */
/* but only spend CPU to ensure that the K first values are correct */
for( i = K; i < L; i++ ) {
value = a[ i ];
if( value > a[ K - 1 ] ) {
for( j = K - 2; ( j >= 0 ) && ( value > a[ j ] ); j-- ) {
a[ j + 1 ] = a[ j ]; /* Shift value */
idx[ j + 1 ] = idx[ j ]; /* Shift index */
}
a[ j + 1 ] = value; /* Write value */
idx[ j + 1 ] = i; /* Write index */
}
}
}
#endif
void silk_insertion_sort_increasing_all_values_int16(
opus_int16 *a, /* I/O Unsorted / Sorted vector */
const opus_int L /* I Vector length */
)
{
opus_int value;
opus_int i, j;
/* Safety checks */
celt_assert( L > 0 );
/* Sort vector elements by value, increasing order */
for( i = 1; i < L; i++ ) {
value = a[ i ];
for( j = i - 1; ( j >= 0 ) && ( value < a[ j ] ); j-- ) {
a[ j + 1 ] = a[ j ]; /* Shift value */
}
a[ j + 1 ] = value; /* Write value */
}
}