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//! NLSF stabilizer:
//!
//! - Moves NLSFs further apart if they are too close
//! - Moves NLSFs away from borders if they are too close
//! - High effort to achieve a modification with minimum
//! Euclidean distance to input vector
//! - Output are sorted NLSF coefficients
//!
use crate::silk::sort::silk_insertion_sort_increasing_all_values_int16;
use crate::silk::SigProc_FIX::{silk_max_int, silk_min_int};
pub mod typedef_h {
pub const silk_int16_MIN: i32 = i16::MIN as i32;
pub const silk_int16_MAX: i32 = i16::MAX as i32;
}
pub use self::typedef_h::{silk_int16_MAX, silk_int16_MIN};
pub const MAX_LOOPS: i32 = 20;
/// NLSF stabilizer, for a single input data vector
pub fn silk_NLSF_stabilize(NLSF_Q15: &mut [i16], NDeltaMin_Q15: &[i16]) {
let mut i: usize = 0;
let mut I: usize = 0;
let mut k: usize = 0;
let mut loops: i32 = 0;
let mut center_freq_Q15: i16 = 0;
let mut diff_Q15: i32 = 0;
let mut min_diff_Q15: i32 = 0;
let mut min_center_Q15: i32 = 0;
let mut max_center_Q15: i32 = 0;
let L = NLSF_Q15.len();
/* This is necessary to ensure an output within range of a opus_int16 */
assert!(NDeltaMin_Q15[L] >= 1);
loops = 0;
while loops < MAX_LOOPS {
/**************************/
/* Find smallest distance */
/**************************/
/* First element */
min_diff_Q15 = NLSF_Q15[0] as i32 - NDeltaMin_Q15[0] as i32;
I = 0;
/* Middle elements */
i = 1;
while i < L {
diff_Q15 = NLSF_Q15[i] as i32 - (NLSF_Q15[i - 1] as i32 + NDeltaMin_Q15[i] as i32);
if diff_Q15 < min_diff_Q15 {
min_diff_Q15 = diff_Q15;
I = i;
}
i += 1;
}
/* Last element */
diff_Q15 = ((1) << 15) - (NLSF_Q15[L - 1] as i32 + NDeltaMin_Q15[L] as i32);
if diff_Q15 < min_diff_Q15 {
min_diff_Q15 = diff_Q15;
I = L;
}
/***************************************************/
/* Now check if the smallest distance non-negative */
/***************************************************/
if min_diff_Q15 >= 0 {
return;
}
if I == 0 {
/* Move away from lower limit */
NLSF_Q15[0] = NDeltaMin_Q15[0];
} else if I == L {
/* Move away from higher limit */
NLSF_Q15[L - 1] = (((1) << 15) - NDeltaMin_Q15[L] as i32) as i16;
} else {
/* Find the lower extreme for the location of the current center frequency */
min_center_Q15 = 0;
k = 0;
while k < I {
min_center_Q15 += NDeltaMin_Q15[k] as i32;
k += 1;
}
min_center_Q15 += NDeltaMin_Q15[I] as i32 >> 1;
/* Find the upper extreme for the location of the current center frequency */
max_center_Q15 = (1) << 15;
k = L;
while k > I {
max_center_Q15 -= NDeltaMin_Q15[k] as i32;
k -= 1;
}
max_center_Q15 -= NDeltaMin_Q15[I] as i32 >> 1;
/* Move apart, sorted by value, keeping the same center frequency */
center_freq_Q15 = (if min_center_Q15 > max_center_Q15 {
if (if 1 == 1 {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1)
+ (NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 & 1)
} else {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1 - 1) + 1 >> 1
}) > min_center_Q15
{
min_center_Q15
} else if (if 1 == 1 {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1)
+ (NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 & 1)
} else {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1 - 1) + 1 >> 1
}) < max_center_Q15
{
max_center_Q15
} else if 1 == 1 {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1)
+ (NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 & 1)
} else {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1 - 1) + 1 >> 1
}
} else if (if 1 == 1 {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1)
+ (NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 & 1)
} else {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1 - 1) + 1 >> 1
}) > max_center_Q15
{
max_center_Q15
} else if (if 1 == 1 {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1)
+ (NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 & 1)
} else {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1 - 1) + 1 >> 1
}) < min_center_Q15
{
min_center_Q15
} else if 1 == 1 {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1)
+ (NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 & 1)
} else {
(NLSF_Q15[I - 1] as i32 + NLSF_Q15[I] as i32 >> 1 - 1) + 1 >> 1
}) as i16;
NLSF_Q15[I - 1] = (center_freq_Q15 as i32 - (NDeltaMin_Q15[I] as i32 >> 1)) as i16;
NLSF_Q15[I] = (NLSF_Q15[I - 1] as i32 + NDeltaMin_Q15[I] as i32) as i16;
}
loops += 1;
}
/* Safe and simple fall back method, which is less ideal than the above */
if loops == MAX_LOOPS {
/* 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 */
silk_insertion_sort_increasing_all_values_int16(NLSF_Q15);
/* First NLSF should be no less than NDeltaMin[0] */
NLSF_Q15[0] = silk_max_int(NLSF_Q15[0] as i32, NDeltaMin_Q15[0 as usize] as i32) as i16;
/* Keep delta_min distance between the NLSFs */
i = 1;
while i < L {
NLSF_Q15[i] = silk_max_int(
NLSF_Q15[i] as i32,
(if NLSF_Q15[i - 1] as i32 + NDeltaMin_Q15[i] as i32 > silk_int16_MAX {
silk_int16_MAX
} else if (NLSF_Q15[i - 1] as i32 + NDeltaMin_Q15[i] as i32) < silk_int16_MIN {
silk_int16_MIN
} else {
NLSF_Q15[i - 1] as i32 + NDeltaMin_Q15[i] as i32
}) as i16 as i32,
) as i16;
i += 1;
}
/* Last NLSF should be no higher than 1 - NDeltaMin[L] */
NLSF_Q15[L - 1] = silk_min_int(
NLSF_Q15[L - 1] as i32,
((1) << 15) - NDeltaMin_Q15[L] as i32,
) as i16;
/* Keep NDeltaMin distance between the NLSFs */
for i in (0..=L - 2).rev() {
NLSF_Q15[i] = silk_min_int(
NLSF_Q15[i] as i32,
NLSF_Q15[i + 1] as i32 - NDeltaMin_Q15[i + 1] as i32,
) as i16;
}
}
}