Created
June 6, 2019 10:28
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Читаем заголовок WAV файла на Node.js из STDIN
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| const inputStream = process.stdin; | |
| function readHeader(stream) { | |
| let buffer = stream.read(44); | |
| const chunkId = buffer.slice(0, 4).toString(); | |
| const chunkSize = buffer.readUInt32LE(4); | |
| const format = buffer.slice(8, 12).toString(); | |
| const subchunk1Id = buffer.slice(12, 16).toString(); | |
| const subchunk1Size = buffer.readUInt32LE(16); | |
| const audioFormat = buffer.readUInt16LE(20); | |
| const numChannels = buffer.readUInt16LE(22); | |
| const sampleRate = buffer.readUInt32LE(24); | |
| const byteRate = buffer.readUInt32LE(28); | |
| const blockAlign = buffer.readUInt16LE(32); | |
| const bitsPerSample = buffer.readUInt16LE(34); | |
| // Skip unknown chunks | |
| let dataSubchunkId = buffer.slice(36, 40).toString(); | |
| let dataSubchunkSize = buffer.readUInt32LE(40); | |
| while (dataSubchunkId !== 'data') { | |
| console.log('Skipping unknown subchunk', dataSubchunkId); | |
| buffer = stream.read(dataSubchunkSize + 8); | |
| dataSubchunkId = buffer.slice(dataSubchunkSize, dataSubchunkSize + 4).toString(); | |
| dataSubchunkSize = buffer.readUInt32LE(dataSubchunkSize + 4); | |
| } | |
| return { | |
| chunkId, | |
| chunkSize, | |
| format, | |
| subchunk1Id, | |
| subchunk1Size, | |
| audioFormat, | |
| numChannels, | |
| sampleRate, | |
| byteRate, | |
| blockAlign, | |
| bitsPerSample, | |
| dataSubchunkId, | |
| dataSubchunkSize, | |
| }; | |
| } | |
| function validateHeader(header) { | |
| if (header.chunkId !== 'RIFF') { | |
| throw new Error('Unsupported format: Chunk ID must be "RIFF"'); | |
| } | |
| if (header.format !== 'WAVE') { | |
| throw new Error('Unsupported format: Format must be "WAVE"'); | |
| } | |
| if (header.subchunk1Id !== 'fmt ') { | |
| throw new Error('Unsupported format: First subchunk ID must be "fmt "'); | |
| } | |
| if (header.dataSubchunkId !== 'data') { | |
| throw new Error('Unsupported format: Subchunk with ID "data" not found'); | |
| } | |
| } | |
| inputStream.on('readable', () => { | |
| const header = readHeader(inputStream); | |
| console.log('Header', header); | |
| try { | |
| validateHeader(header); | |
| } catch (error) { | |
| console.error(error); | |
| process.exit(1); | |
| } | |
| }); |
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