30 lines
957 B
TypeScript
30 lines
957 B
TypeScript
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export function extractData(buffer, dataLength = 2000): string {
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let binaryData: string = "";
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const pngHeader = [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a]; // Header PNG
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const headerEndIndex: number = buffer.findIndex((_, i) =>
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pngHeader.every((byte, j) => buffer[i + j] === byte)
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) + pngHeader.length;
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for (let i = headerEndIndex; i < buffer.length; i++) {
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if (binaryData.length < dataLength * 8) {
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const binaryByte: string = buffer[i].toString(2).padStart(8, "0");
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binaryData += binaryByte.slice(-1);
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} else {
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break;
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}
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}
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let result: string = "";
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for (let i = 0; i < binaryData.length; i += 8) {
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const byte: string = binaryData.slice(i, i + 8);
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result += String.fromCharCode(parseInt(byte, 2));
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}
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if (result.includes("0end")) {
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result = result.split("0end")[0];
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return result;
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}
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return null;
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}
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