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import * as ID3Util from "./ID3Util" |
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import { isString } from "./util" |
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import { TextEncoding } from "./definitions/Encoding" |
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5
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type Value = Buffer | number | string |
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7
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export class FrameBuilder { |
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private identifier: string |
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private buffer = Buffer.alloc(0) |
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constructor(identifier: string) { |
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this.identifier = identifier |
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} |
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15
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appendValue( |
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value: Value, |
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size?: number | null, |
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encoding: TextEncoding = TextEncoding.ISO_8859_1 |
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) { |
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const convertedValue = convertValue(value, encoding) |
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this.appendBuffer(staticValueToBuffer(convertedValue, size)) |
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return this |
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} |
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appendNumber(value: number, size: number) { |
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if (!Number.isInteger(value)) { |
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throw new RangeError("An integer value is expected") |
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} |
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let hexValue = value.toString(16) |
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if (hexValue.length % 2 !== 0) { |
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hexValue = "0" + hexValue |
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} |
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this.appendBuffer( |
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staticValueToBuffer(Buffer.from(hexValue, 'hex'), size) |
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) |
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return this |
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} |
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appendNullTerminatedValue( |
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value = '', |
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encoding: TextEncoding = TextEncoding.ISO_8859_1 |
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) { |
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this.appendBuffer( |
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convertValue(value, encoding), |
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getTerminatingMarker(encoding) |
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) |
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return this |
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} |
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getBuffer() { |
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return this.buffer |
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} |
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getBufferWithPartialHeader() { |
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const header = Buffer.alloc(10) |
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header.write(this.identifier, 0) |
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header.writeUInt32BE(this.buffer.length, 4) |
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return Buffer.concat([header, this.buffer]) |
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} |
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private appendBuffer(...buffers: Buffer[]) { |
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this.buffer = Buffer.concat([this.buffer, ...buffers]) |
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} |
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} |
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function convertValue( |
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value: Value, |
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encoding: TextEncoding = TextEncoding.ISO_8859_1 |
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) { |
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if (value instanceof Buffer) { |
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return value |
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} |
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if (Number.isInteger(value) || isString(value)) { |
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return ID3Util.stringToEncodedBuffer(value.toString(), encoding) |
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} |
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return Buffer.alloc(0) |
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} |
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function staticValueToBuffer(buffer: Buffer, size?: number | null) { |
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if (size && buffer.length < size) { |
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return Buffer.concat([Buffer.alloc(size - buffer.length, 0x00), buffer]) |
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} |
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return buffer |
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} |
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86
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function getTerminatingMarker(encoding: TextEncoding) { |
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if (encoding === TextEncoding.UTF_16_WITH_BOM || |
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encoding === TextEncoding.UTF_16_BE |
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) { |
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return Buffer.alloc(2, 0x00) |
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} |
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return Buffer.alloc(1, 0x00) |
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} |
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95
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Zazama /
node-id3
