id3-helpers.js
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import { toUint8, bytesMatch } from './byte-helpers.js';
var ID3 = toUint8([0x49, 0x44, 0x33]);
export var getId3Size = function getId3Size(bytes, offset) {
if (offset === void 0) {
offset = 0;
}
bytes = toUint8(bytes);
var flags = bytes[offset + 5];
var returnSize = bytes[offset + 6] << 21 | bytes[offset + 7] << 14 | bytes[offset + 8] << 7 | bytes[offset + 9];
var footerPresent = (flags & 16) >> 4;
if (footerPresent) {
return returnSize + 20;
}
return returnSize + 10;
};
export var getId3Offset = function getId3Offset(bytes, offset) {
if (offset === void 0) {
offset = 0;
}
bytes = toUint8(bytes);
if (bytes.length - offset < 10 || !bytesMatch(bytes, ID3, {
offset: offset
})) {
return offset;
}
offset += getId3Size(bytes, offset); // recursive check for id3 tags as some files
// have multiple ID3 tag sections even though
// they should not.
return getId3Offset(bytes, offset);
};