61 lines
1.8 KiB
Plaintext
61 lines
1.8 KiB
Plaintext
import {StringType} from 'token-types';
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export function stringToBytes(string, encoding) {
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if (encoding === 'utf-16le') {
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const bytes = [];
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for (let index = 0; index < string.length; index++) {
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const code = string.charCodeAt(index); // eslint-disable-line unicorn/prefer-code-point
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bytes.push(code & 0xFF, (code >> 8) & 0xFF); // High byte
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}
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return bytes;
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}
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if (encoding === 'utf-16be') {
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const bytes = [];
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for (let index = 0; index < string.length; index++) {
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const code = string.charCodeAt(index); // eslint-disable-line unicorn/prefer-code-point
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bytes.push((code >> 8) & 0xFF, code & 0xFF); // Low byte
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}
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return bytes;
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}
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return [...string].map(character => character.charCodeAt(0)); // eslint-disable-line unicorn/prefer-code-point
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}
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/**
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Checks whether the TAR checksum is valid.
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@param {Uint8Array} arrayBuffer - The TAR header `[offset ... offset + 512]`.
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@param {number} offset - TAR header offset.
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@returns {boolean} `true` if the TAR checksum is valid, otherwise `false`.
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*/
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export function tarHeaderChecksumMatches(arrayBuffer, offset = 0) {
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const readSum = Number.parseInt(new StringType(6).get(arrayBuffer, 148).replace(/\0.*$/, '').trim(), 8); // Read sum in header
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if (Number.isNaN(readSum)) {
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return false;
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}
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let sum = 8 * 0x20; // Initialize signed bit sum
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for (let index = offset; index < offset + 148; index++) {
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sum += arrayBuffer[index];
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}
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for (let index = offset + 156; index < offset + 512; index++) {
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sum += arrayBuffer[index];
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}
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return readSum === sum;
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}
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/**
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ID3 UINT32 sync-safe tokenizer token.
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28 bits (representing up to 256MB) integer, the msb is 0 to avoid "false syncsignals".
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*/
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export const uint32SyncSafeToken = {
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get: (buffer, offset) => (buffer[offset + 3] & 0x7F) | ((buffer[offset + 2]) << 7) | ((buffer[offset + 1]) << 14) | ((buffer[offset]) << 21),
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len: 4,
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};
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