1*05767d91SRobert Wu /*
2*05767d91SRobert Wu * Copyright 2019 The Android Open Source Project
3*05767d91SRobert Wu *
4*05767d91SRobert Wu * Licensed under the Apache License, Version 2.0 (the "License");
5*05767d91SRobert Wu * you may not use this file except in compliance with the License.
6*05767d91SRobert Wu * You may obtain a copy of the License at
7*05767d91SRobert Wu *
8*05767d91SRobert Wu * http://www.apache.org/licenses/LICENSE-2.0
9*05767d91SRobert Wu *
10*05767d91SRobert Wu * Unless required by applicable law or agreed to in writing, software
11*05767d91SRobert Wu * distributed under the License is distributed on an "AS IS" BASIS,
12*05767d91SRobert Wu * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13*05767d91SRobert Wu * See the License for the specific language governing permissions and
14*05767d91SRobert Wu * limitations under the License.
15*05767d91SRobert Wu */
16*05767d91SRobert Wu
17*05767d91SRobert Wu #include "IntegerRatio.h"
18*05767d91SRobert Wu
19*05767d91SRobert Wu using namespace RESAMPLER_OUTER_NAMESPACE::resampler;
20*05767d91SRobert Wu
21*05767d91SRobert Wu // Enough primes to cover the common sample rates.
22*05767d91SRobert Wu static const int kPrimes[] = {
23*05767d91SRobert Wu 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41,
24*05767d91SRobert Wu 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97,
25*05767d91SRobert Wu 101, 103, 107, 109, 113, 127, 131, 137, 139, 149,
26*05767d91SRobert Wu 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199};
27*05767d91SRobert Wu
reduce()28*05767d91SRobert Wu void IntegerRatio::reduce() {
29*05767d91SRobert Wu for (int prime : kPrimes) {
30*05767d91SRobert Wu if (mNumerator < prime || mDenominator < prime) {
31*05767d91SRobert Wu break;
32*05767d91SRobert Wu }
33*05767d91SRobert Wu
34*05767d91SRobert Wu // Find biggest prime factor for numerator.
35*05767d91SRobert Wu while (true) {
36*05767d91SRobert Wu int top = mNumerator / prime;
37*05767d91SRobert Wu int bottom = mDenominator / prime;
38*05767d91SRobert Wu if ((top >= 1)
39*05767d91SRobert Wu && (bottom >= 1)
40*05767d91SRobert Wu && (top * prime == mNumerator) // divided evenly?
41*05767d91SRobert Wu && (bottom * prime == mDenominator)) {
42*05767d91SRobert Wu mNumerator = top;
43*05767d91SRobert Wu mDenominator = bottom;
44*05767d91SRobert Wu } else {
45*05767d91SRobert Wu break;
46*05767d91SRobert Wu }
47*05767d91SRobert Wu }
48*05767d91SRobert Wu
49*05767d91SRobert Wu }
50*05767d91SRobert Wu }
51