js-cfb/bits/41_mver.js

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/* [MS-CFB] 2.2 Compound File Header -- read up to major version */
function check_get_mver(blob/*:CFBlob*/)/*:[number, number]*/ {
2018-09-04 07:14:20 +00:00
if(blob[blob.l] == 0x50 && blob[blob.l + 1] == 0x4b) return [0, 0];
// header signature 8
blob.chk(HEADER_SIGNATURE, 'Header Signature: ');
// clsid 16
//blob.chk(HEADER_CLSID, 'CLSID: ');
blob.l += 16;
// minor version 2
var mver/*:number*/ = blob.read_shift(2, 'u');
return [blob.read_shift(2,'u'), mver];
}
function check_shifts(blob/*:CFBlob*/, mver/*:number*/)/*:void*/ {
var shift = 0x09;
// Byte Order
//blob.chk('feff', 'Byte Order: '); // note: some writers put 0xffff
blob.l += 2;
// Sector Shift
switch((shift = blob.read_shift(2))) {
case 0x09: if(mver != 3) throw new Error('Sector Shift: Expected 9 saw ' + shift); break;
case 0x0c: if(mver != 4) throw new Error('Sector Shift: Expected 12 saw ' + shift); break;
default: throw new Error('Sector Shift: Expected 9 or 12 saw ' + shift);
}
// Mini Sector Shift
blob.chk('0600', 'Mini Sector Shift: ');
// Reserved
blob.chk('000000000000', 'Reserved: ');
}