mkjs/code/formats/narc.js

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2017-09-08 09:24:16 -07:00
//
// narc.js
//--------------------
// Reads narc archives and provides access to files by directory structure.
// by RHY3756547
//
window.narc = function(input) {
this.load = load;
this.getFile = getFile;
var arc = this;
var handlers = [];
window.onmousemove = function(evt) {
mouseX = evt.pageX;
mouseY = evt.pageY;
}
this.scopeEval = function(code) {return eval(code)} //for debug purposes
function load(buffer) {
arc.buffer = buffer; //we will use this data in the future.
var view = new DataView(buffer);
arc.stamp = readChar(view, 0x0)+readChar(view, 0x1)+readChar(view, 0x2)+readChar(view, 0x3);
if (arc.stamp != "NARC") throw "File provided is not a NARC archive! Expected NARC, found "+arc.stamp+".";
arc.byteOrder = view.getUint16(0x4, true); //todo: check byte order and flip to little endian when necessary
arc.version = view.getUint16(0x6, true);
arc.size = view.getUint32(0x8, true);
arc.headSize = view.getUint16(0xC, true);
arc.numBlocks = view.getUint16(0xE, true);
var off = arc.headSize;
arc.sections = {};
for (var i=0; i<arc.numBlocks; i++) {
var section = readSection(view, off);
arc.sections[section.type] = section;
off = 4*Math.ceil(section.nextOff/4);
}
}
function readSection(view, off) {
var obj = {};
obj.type = readChar(view, off+0x0)+readChar(view, off+0x1)+readChar(view, off+0x2)+readChar(view, off+0x3);
obj.size = view.getUint32(off+0x4, true);
if (handlers[obj.type] == null) throw "Unknown NARC section "+obj.type+"!";
handlers[obj.type](view, off+0x8, obj);
obj.nextOff = off+obj.size;
return obj;
}
function getFile(name) {
var path = name.split("/");
var start = (path[0] == "")?1:0; //fix dirs relative to root (eg "/hi/test.bin")
var table = arc.sections["BTNF"].directories;
var curDir = table[0].entries; //root
for (var i=start; i<path.length; i++) {
var found = false;
for (var j=0; j<curDir.length; j++) {
if (curDir[j].name == path[i]) {
if (curDir[j].dir) {
found = true;
curDir = table[curDir[j].id-0xF000].entries;
break;
} else {
return readFileWithID(curDir[j].id);
}
}
}
if (!found) {
console.error("File not found: "+name+", could not find "+path[i]);
return null;
}
}
console.error("Path is not a file: "+name);
return null; //incomplete path; we ended on a directory, not a file!
}
function readFileWithID(id) {
var table = arc.sections["BTAF"].files;
var file = table[id];
var off = arc.sections["GMIF"].baseOff;
if (file == null) {
console.error("File ID invalid: "+id);
return null;
}
return arc.buffer.slice(file.start+off, file.end+off);
}
var handlers = {};
handlers["BTAF"] = function(view, off, obj) {
obj.numFiles = view.getUint16(off, true);
obj.reserved = view.getUint16(off+0x2, true);
obj.files = [];
off += 4;
for (var i=0; i<obj.numFiles; i++) {
var fl = {}
fl.start = view.getUint32(off, true);
fl.end = view.getUint32(off+4, true);
obj.files.push(fl);
off += 8;
}
}
handlers["BTNF"] = function(view, off, obj) { //filename table - includes directories and filenames.
var soff = off;
obj.directories = [];
//read root dir, then we know number of directories to read.
var root = {};
var dirOff = soff+view.getUint32(off, true);
root.firstFile = view.getUint16(off+4, true);
populateDir(view, dirOff, root);
root.numDir = view.getUint16(off+6, true);
off += 8;
obj.directories.push(root);
var n = root.numDir-1;
for (var i=0; i<n; i++) {
var dir = {};
var dirOff = soff+view.getUint32(off, true);
dir.firstFile = view.getUint16(off+4, true);
populateDir(view, dirOff, dir);
dir.parent = view.getUint16(off+6, true);
off += 8;
obj.directories.push(dir);
}
}
handlers["GMIF"] = function(view, off, obj) {
obj.baseOff = off;
}
function populateDir(view, off, dir) {
curFile = dir.firstFile;
dir.entries = [];
while (true) {
var flag = view.getUint8(off++);
var len = flag&127;
if (! (flag&128)) { //file or end of dir
if (len == 0) return;
else {
dir.entries.push({
dir: false,
id: curFile++,
name: readString(view, off, len)
})
off += len;
}
} else {
var dirID = view.getUint16(off+len, true);
dir.entries.push({
dir: true,
id: dirID,
name: readString(view, off, len)
});
off += len+2;
}
}
}
function readString(view, off, length) {
var str = "";
for (var i=0; i<length; i++) {
str += readChar(view, off++);
}
return str;
}
function readChar(view, offset) {
return String.fromCharCode(view.getUint8(offset));
}
if (input != null) {
if (typeof input == "string") {
var xml = new XMLHttpRequest();
xml.responseType = "arraybuffer";
xml.open("GET", input, true);
xml.onload = function() {
load(xml.response);
}
xml.send();
} else {
load(input);
}
}
}