1 /*
2 * Copyright (C) 2018 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <array>
18 #include <climits>
19 #include <math.h>
20
21 #include <audio_utils/sample.h>
22 #include <gtest/gtest.h>
23
24 static_assert(sizeof(sample_minifloat_t) == sizeof(uint16_t),
25 "sizeof(sample_minifloat_t != sizeof(uint16_t");
26
signum(float f)27 static constexpr int signum(float f)
28 {
29 return (f > 0) - (f < 0);
30 }
31
TEST(audio_utils_sample,Convert)32 TEST(audio_utils_sample, Convert)
33 {
34 std::vector<float> fvec;
35 // verify minifloat <-> float is a bijection, and monotonic as float
36 for (int i = 0; i <= 0xFFFF; i++) {
37 // construct floats in order
38 const int val = i < 0x8000 ? 0xFFFF - i : i ^ 0x8000;
39 // TODO shouldn't depend on representation in order to skip negative zero
40 if (val == 0x8000) {
41 // This is an undefined value and so we won't test its behavior
42 continue;
43 }
44 // TODO reinterpret_cast<sample_minifloat_t>(val) fails
45 const sample_minifloat_t in = (sample_minifloat_t) val;
46 const float f = float_from_sample(in);
47 const sample_minifloat_t out = sample_from_float(f);
48 ASSERT_EQ(in, out);
49 fvec.push_back(f);
50 }
51 // no longer needed since we construct floats in order
52 // #include <algorithm>
53 // std::sort(fvec.begin(), fvec.end());
54 float prev = -2.0f;
55 for (auto curr : fvec) {
56 // LT instead of LE because no negative zero
57 ASSERT_LT(prev, curr);
58 int signum_prev = signum(prev);
59 int signum_curr = signum(curr);
60 ASSERT_LE(signum_prev, signum_curr);
61 if (signum_prev == signum_curr) {
62 // confirm ratio between adjacent values (3:45 of "Will it float?" video)
63 float ratio = curr / prev;
64 float lower, upper;
65 // normal
66 if (fabsf(curr) >= 0.001f) {
67 upper = 1.005f;
68 lower = 0.995f;
69 // denormal
70 } else {
71 upper = 2.0f;
72 lower = 0.5f;
73 }
74 ASSERT_GE(ratio, lower) << "prev " << prev << " curr " << curr;
75 ASSERT_LE(ratio, upper) << "prev " << prev << " curr " << curr;
76 }
77 prev = curr;
78 }
79 ASSERT_LT(prev, 2.0f);
80 }
81