js-cfb/bits/82_zparse.js

104 lines
3.1 KiB
JavaScript

function warn_or_throw(wrn, msg) {
if(wrn) { if(typeof console !== 'undefined') console.error(msg); }
else throw new Error(msg);
}
function parse_zip(file/*:RawBytes*/, options/*:CFBReadOpts*/)/*:CFBContainer*/ {
var blob/*:CFBlob*/ = /*::(*/file/*:: :any)*/;
prep_blob(blob, 0);
var FileIndex/*:CFBFileIndex*/ = [], FullPaths/*:Array<string>*/ = [];
var o = {
FileIndex: FileIndex,
FullPaths: FullPaths
};
init_cfb(o, { root: options.root });
/* find end of central directory, start just after signature */
var i = blob.length - 4;
while((blob[i] != 0x50 || blob[i+1] != 0x4b || blob[i+2] != 0x05 || blob[i+3] != 0x06) && i >= 0) --i;
blob.l = i + 4;
/* parse end of central directory */
blob.l += 4;
var fcnt = blob.read_shift(2);
blob.l += 6;
var start_cd = blob.read_shift(4);
/* parse central directory */
blob.l = start_cd;
for(i = 0; i < fcnt; ++i) {
/* trust local file header instead of CD entry */
blob.l += 20;
var csz = blob.read_shift(4);
var usz = blob.read_shift(4);
var namelen = blob.read_shift(2);
var efsz = blob.read_shift(2);
var fcsz = blob.read_shift(2);
blob.l += 8;
var offset = blob.read_shift(4);
var EF = parse_extra_field(/*::(*/blob.slice(blob.l+namelen, blob.l+namelen+efsz)/*:: :any)*/);
blob.l += namelen + efsz + fcsz;
var L = blob.l;
blob.l = offset + 4;
parse_local_file(blob, csz, usz, o, EF);
blob.l = L;
}
return o;
}
/* head starts just after local file header signature */
function parse_local_file(blob/*:CFBlob*/, csz/*:number*/, usz/*:number*/, o/*:CFBContainer*/, EF) {
/* [local file header] */
blob.l += 2;
var flags = blob.read_shift(2);
var meth = blob.read_shift(2);
var date = parse_dos_date(blob);
if(flags & 0x2041) throw new Error("Unsupported ZIP encryption");
var crc32 = blob.read_shift(4);
var _csz = blob.read_shift(4);
var _usz = blob.read_shift(4);
var namelen = blob.read_shift(2);
var efsz = blob.read_shift(2);
// TODO: flags & (1<<11) // UTF8
var name = ""; for(var i = 0; i < namelen; ++i) name += String.fromCharCode(blob[blob.l++]);
if(efsz) {
var ef = parse_extra_field(/*::(*/blob.slice(blob.l, blob.l + efsz)/*:: :any)*/);
if((ef[0x5455]||{}).mt) date = ef[0x5455].mt;
if(((EF||{})[0x5455]||{}).mt) date = EF[0x5455].mt;
}
blob.l += efsz;
/* [encryption header] */
/* [file data] */
var data = blob.slice(blob.l, blob.l + _csz);
switch(meth) {
case 8: data = _inflateRawSync(blob, _usz); break;
case 0: break; // TODO: scan for magic number
default: throw new Error("Unsupported ZIP Compression method " + meth);
}
/* [data descriptor] */
var wrn = false;
if(flags & 8) {
crc32 = blob.read_shift(4);
if(crc32 == 0x08074b50) { crc32 = blob.read_shift(4); wrn = true; }
_csz = blob.read_shift(4);
_usz = blob.read_shift(4);
}
if(_csz != csz) warn_or_throw(wrn, "Bad compressed size: " + csz + " != " + _csz);
if(_usz != usz) warn_or_throw(wrn, "Bad uncompressed size: " + usz + " != " + _usz);
var _crc32 = CRC32.buf(data, 0);
if((crc32>>0) != (_crc32>>0)) warn_or_throw(wrn, "Bad CRC32 checksum: " + crc32 + " != " + _crc32);
cfb_add(o, name, data, {unsafe: true, mt: date});
}