ref: 9edde42690a11afea6681275411d2c5f16484ea4
dir: /silk/float/SKP_Silk_sort_FLP.c/
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/* 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 */
#include "SKP_Silk_typedef.h"
#include "SKP_Silk_SigProc_FLP.h"
void SKP_Silk_insertion_sort_decreasing_FLP(
SKP_float *a, /* I/O: Unsorted / Sorted vector */
SKP_int *index, /* O: Index vector for the sorted elements */
const SKP_int L, /* I: Vector length */
const SKP_int K /* I: Number of correctly sorted positions */
)
{
SKP_float value;
SKP_int i, j;
/* Safety checks */
SKP_assert( K > 0 );
SKP_assert( L > 0 );
SKP_assert( L >= K );
/* Write start indices in index vector */
for( i = 0; i < K; i++ ) {
index[ 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 */
index[ j + 1 ] = index[ j ]; /* Shift index */
}
a[ j + 1 ] = value; /* Write value */
index[ j + 1 ] = i; /* Write index */
}
/* If less than L values are asked 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 */
index[ j + 1 ] = index[ j ]; /* Shift index */
}
a[ j + 1 ] = value; /* Write value */
index[ j + 1 ] = i; /* Write index */
}
}
}