109 lines
3.1 KiB
TypeScript
109 lines
3.1 KiB
TypeScript
/**
|
|
* Copyright 2019 Google LLC
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* https://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations under
|
|
* the License.
|
|
*/
|
|
|
|
/**
|
|
* Save Float32Array in arbitrarily sized chunks.
|
|
* Load Float32Array in arbitrarily sized chunks.
|
|
* Determine if there's enough data to grab a certain amount.
|
|
*/
|
|
export class CircularAudioBuffer {
|
|
buffer: Float32Array;
|
|
// The index that we are currently full up to. New data is written from
|
|
// [currentIndex + 1, maxLength]. Data can be read from [0, currentIndex].
|
|
currentIndex: number;
|
|
|
|
constructor(maxLength: number) {
|
|
this.buffer = new Float32Array(maxLength);
|
|
this.currentIndex = 0;
|
|
}
|
|
|
|
/**
|
|
* Add a new buffer of data. Called when we get new audio input samples.
|
|
*/
|
|
addBuffer(newBuffer: Float32Array) {
|
|
// Do we have enough data in this buffer?
|
|
const remaining = this.buffer.length - this.currentIndex;
|
|
if (this.currentIndex + newBuffer.length > this.buffer.length) {
|
|
console.error(
|
|
`Not enough space to write ${newBuffer.length}` +
|
|
` to this circular buffer with ${remaining} left.`);
|
|
return;
|
|
}
|
|
this.buffer.set(newBuffer, this.currentIndex);
|
|
this.currentIndex += newBuffer.length;
|
|
}
|
|
|
|
/**
|
|
* How many samples are stored currently?
|
|
*/
|
|
getLength() {
|
|
return this.currentIndex;
|
|
}
|
|
|
|
/**
|
|
* How much space remains?
|
|
*/
|
|
getRemainingLength() {
|
|
return this.buffer.length - this.currentIndex;
|
|
}
|
|
|
|
/**
|
|
* Return the first N samples of the buffer, and remove them. Called when we
|
|
* want to get a buffer of audio data of a fixed size.
|
|
*/
|
|
popBuffer(length: number) {
|
|
// Do we have enough data to read back?
|
|
if (this.currentIndex < length) {
|
|
console.error(
|
|
`This circular buffer doesn't have ${length} entries in it.`);
|
|
return undefined;
|
|
}
|
|
if (length === 0) {
|
|
console.warn(`Calling popBuffer(0) does nothing.`);
|
|
return undefined;
|
|
}
|
|
const popped = this.buffer.slice(0, length);
|
|
const remaining = this.buffer.slice(length, this.buffer.length);
|
|
// Remove the popped entries from the buffer.
|
|
this.buffer.fill(0);
|
|
this.buffer.set(remaining, 0);
|
|
// Send the currentIndex back.
|
|
this.currentIndex -= length;
|
|
return popped;
|
|
}
|
|
|
|
/**
|
|
* Get the the first part of the buffer without mutating it.
|
|
*/
|
|
getBuffer(length?: number) {
|
|
if (!length) {
|
|
length = this.getLength();
|
|
}
|
|
// Do we have enough data to read back?
|
|
if (this.currentIndex < length) {
|
|
console.error(
|
|
`This circular buffer doesn't have ${length} entries in it.`);
|
|
return undefined;
|
|
}
|
|
return this.buffer.slice(0, length);
|
|
}
|
|
|
|
clear() {
|
|
this.currentIndex = 0;
|
|
this.buffer.fill(0);
|
|
}
|
|
}
|