[Core] Simplify audio_duration_to_ms() and audio_ms_to_duration(), reduce firmware size by a few bytes. (#21427)

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Pascal Getreuer 2023-07-07 08:47:16 -06:00 committed by GitHub
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6 changed files with 220 additions and 13 deletions

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// Copyright 2023 Google LLC
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#pragma once

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// Copyright 2023 Google LLC
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include "audio.h"
void audio_driver_initialize(void) {}
void audio_driver_start() {}
void audio_driver_stop() {}

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@ -547,20 +547,39 @@ void audio_decrease_tempo(uint8_t tempo_change) {
note_tempo -= tempo_change;
}
// TODO in the int-math version are some bugs; songs sometimes abruptly end - maybe an issue with the timer/system-tick wrapping around?
/**
* Converts from units of 1/64ths of a beat to milliseconds.
*
* Round-off error is at most 1 millisecond.
*
* Conversion will never overflow for duration_bpm <= 699, provided that
* note_tempo is at least 10. This is quite a long duration, over ten beats.
*
* Beware that for duration_bpm > 699, the result may overflow uint16_t range
* when duration_bpm is large compared to note_tempo:
*
* duration_bpm * 60 * 1000 / (64 * note_tempo) > UINT16_MAX
*
* duration_bpm > (2 * 65535 / 1875) * note_tempo
* = 69.904 * note_tempo.
*/
uint16_t audio_duration_to_ms(uint16_t duration_bpm) {
#if defined(__AVR__)
// doing int-math saves us some bytes in the overall firmware size, but the intermediate result is less accurate before being cast to/returned as uint
return ((uint32_t)duration_bpm * 60 * 1000) / (64 * note_tempo);
// NOTE: beware of uint16_t overflows when note_tempo is low and/or the duration is long
#else
return ((float)duration_bpm * 60) / (64 * note_tempo) * 1000;
#endif
return ((uint32_t)duration_bpm * 1875) / ((uint_fast16_t)note_tempo * 2);
}
/**
* Converts from units of milliseconds to 1/64ths of a beat.
*
* Round-off error is at most 1/64th of a beat.
*
* This conversion never overflows: since duration_ms <= UINT16_MAX = 65535
* and note_tempo <= 255, the result is always in uint16_t range:
*
* duration_ms * 64 * note_tempo / 60 / 1000
* <= 65535 * 2 * 255 / 1875
* = 17825.52
* <= UINT16_MAX.
*/
uint16_t audio_ms_to_duration(uint16_t duration_ms) {
#if defined(__AVR__)
return ((uint32_t)duration_ms * 64 * note_tempo) / 60 / 1000;
#else
return ((float)duration_ms * 64 * note_tempo) / 60 / 1000;
#endif
return ((uint32_t)duration_ms * 2 * note_tempo) / 1875;
}

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tests/audio/config.h Normal file
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// Copyright 2023 Google LLC
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#pragma once
#include "test_common.h"

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tests/audio/test.mk Normal file
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# Copyright 2023 Google LLC
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
AUDIO_ENABLE = yes

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tests/audio/test_audio.cpp Normal file
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// Copyright 2023 Google LLC
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include <cmath>
#include <random>
#include "gtest/gtest.h"
#include "keyboard_report_util.hpp"
#include "test_common.hpp"
namespace {
class AudioTest : public TestFixture {
public:
uint16_t infer_tempo() {
return audio_ms_to_duration(1875) / 2;
}
};
TEST_F(AudioTest, OnOffToggle) {
audio_on();
EXPECT_TRUE(audio_is_on());
audio_off();
EXPECT_FALSE(audio_is_on());
audio_toggle();
EXPECT_TRUE(audio_is_on());
audio_toggle();
EXPECT_FALSE(audio_is_on());
}
TEST_F(AudioTest, ChangeTempo) {
for (int tempo = 50; tempo <= 250; tempo += 50) {
audio_set_tempo(tempo);
EXPECT_EQ(infer_tempo(), tempo);
}
audio_set_tempo(10);
audio_increase_tempo(25);
EXPECT_EQ(infer_tempo(), 35);
audio_decrease_tempo(4);
EXPECT_EQ(infer_tempo(), 31);
audio_increase_tempo(250);
EXPECT_EQ(infer_tempo(), 255);
audio_set_tempo(9);
EXPECT_EQ(infer_tempo(), 10);
audio_decrease_tempo(100);
EXPECT_EQ(infer_tempo(), 10);
}
TEST_F(AudioTest, BpmConversion) {
const int tol = 1;
audio_set_tempo(120);
// At 120 bpm, there are 2 beats per second, and a whole note is 500 ms.
EXPECT_NEAR(audio_duration_to_ms(64 /* whole note */), 500, tol);
EXPECT_NEAR(audio_ms_to_duration(500), 64, tol);
EXPECT_EQ(audio_duration_to_ms(0), 0);
EXPECT_EQ(audio_ms_to_duration(0), 0);
audio_set_tempo(10);
// At 10 bpm, UINT16_MAX ms corresponds to 699/64 beats and is the longest
// duration that can be converted without overflow.
EXPECT_NEAR(audio_ms_to_duration(UINT16_MAX), 699, tol);
EXPECT_NEAR(audio_duration_to_ms(699), 65531, tol);
audio_set_tempo(255);
// At 255 bpm, UINT16_MAX ms corresponds to 17825/64 beats and is the longest
// duration that can be converted without overflow.
EXPECT_NEAR(audio_ms_to_duration(UINT16_MAX), 17825, tol);
EXPECT_NEAR(audio_duration_to_ms(17825), 65533, tol);
std::mt19937 rng(0 /*seed*/);
std::uniform_int_distribution<int> dist_tempo(10, 255);
std::uniform_int_distribution<int> dist_ms(0, UINT16_MAX);
// Test bpm <-> ms conversions for random tempos and durations.
for (int trial = 0; trial < 50; ++trial) {
const int tempo = dist_tempo(rng);
const int duration_ms = dist_ms(rng);
SCOPED_TRACE("tempo " + testing::PrintToString(tempo) + ", duration " + testing::PrintToString(duration_ms) + " ms");
audio_set_tempo(tempo);
int duration_bpm = std::round((64.0f / (60.0f * 1000.0f)) * duration_ms * tempo);
ASSERT_NEAR(audio_ms_to_duration(duration_ms), duration_bpm, tol);
int roundtrip_ms = std::round((60.0f * 1000.0f / 64.0f) * duration_bpm / tempo);
// Because of round-off error, duration_ms and roundtrip_ms may differ by
// about (60 * 1000 / 64) / tempo.
int roundtrip_tol = tol * (60.0f * 1000.0f / 64.0f) / tempo;
ASSERT_NEAR(roundtrip_ms, duration_ms, roundtrip_tol);
// Only test converting back to ms if the result would be in uint16_t range.
if (roundtrip_ms <= UINT16_MAX) {
ASSERT_NEAR(audio_duration_to_ms(duration_bpm), roundtrip_ms, tol);
}
}
}
} // namespace