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/*
* Copyright (c) 2021, Alliance for Open Media. All rights reserved
*
* This source code is subject to the terms of the BSD 3-Clause Clear License
* and the Alliance for Open Media Patent License 1.0. If the BSD 3-Clause Clear
* License was not distributed with this source code in the LICENSE file, you
* can obtain it at aomedia.org/license/software-license/bsd-3-c-c/. 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
* aomedia.org/license/patent-license/.
*/
#include "aom_dsp/binary_codes_reader.h"
#include "aom_dsp/recenter.h"
#include "av1/common/common.h"
uint16_t aom_read_primitive_quniform_(aom_reader *r,
uint16_t n ACCT_STR_PARAM) {
if (n <= 1) return 0;
const int l = get_msb(n) + 1;
const int m = (1 << l) - n;
const int v = aom_read_literal(r, l - 1, ACCT_STR_NAME);
return v < m ? v : (v << 1) - m + aom_read_bit(r, ACCT_STR_NAME);
}
// Decode finite subexponential code that for a symbol v in [0, n-1] with
// parameter k
uint16_t aom_read_primitive_subexpfin_(aom_reader *r, uint16_t n,
uint16_t k ACCT_STR_PARAM) {
int i = 0;
int mk = 0;
while (1) {
int b = (i ? k + i - 1 : k);
int a = (1 << b);
if (n <= mk + 3 * a) {
return aom_read_primitive_quniform(r, n - mk, ACCT_STR_NAME) + mk;
}
if (!aom_read_bit(r, ACCT_STR_NAME)) {
return aom_read_literal(r, b, ACCT_STR_NAME) + mk;
}
i = i + 1;
mk += a;
}
assert(0);
return 0;
}
uint16_t aom_read_primitive_refsubexpfin_(aom_reader *r, uint16_t n, uint16_t k,
uint16_t ref ACCT_STR_PARAM) {
return inv_recenter_finite_nonneg(
n, ref, aom_read_primitive_subexpfin(r, n, k, ACCT_STR_NAME));
}