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/*
* Copyright (c) 2018, Alliance for Open Media. All rights reserved.
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/
#ifndef AOM_AOM_DSP_RECENTER_H_
#define AOM_AOM_DSP_RECENTER_H_
#include "config/aom_config.h"
#include "aom/aom_integer.h"
// Inverse recenters a non-negative literal v around a reference r
static inline uint16_t inv_recenter_nonneg(uint16_t r, uint16_t v) {
if (v > (r << 1))
return v;
else if ((v & 1) == 0)
return (v >> 1) + r;
else
return r - ((v + 1) >> 1);
}
// Inverse recenters a non-negative literal v in [0, n-1] around a
// reference r also in [0, n-1]
static inline uint16_t inv_recenter_finite_nonneg(uint16_t n, uint16_t r,
uint16_t v) {
if ((r << 1) <= n) {
return inv_recenter_nonneg(r, v);
} else {
return n - 1 - inv_recenter_nonneg(n - 1 - r, v);
}
}
// Recenters a non-negative literal v around a reference r
static inline uint16_t recenter_nonneg(uint16_t r, uint16_t v) {
if (v > (r << 1))
return v;
else if (v >= r)
return ((v - r) << 1);
else
return ((r - v) << 1) - 1;
}
// Recenters a non-negative literal v in [0, n-1] around a
// reference r also in [0, n-1]
static inline uint16_t recenter_finite_nonneg(uint16_t n, uint16_t r,
uint16_t v) {
if ((r << 1) <= n) {
return recenter_nonneg(r, v);
} else {
return recenter_nonneg(n - 1 - r, n - 1 - v);
}
}
#endif // AOM_AOM_DSP_RECENTER_H_