readHeader

1 files changed, 69 insertions, 16 deletions

diff --git a/src/lundump.js b/src/lundump.js
index 69445d4..1d1a959 100644
--- a/src/lundump.js
+++ b/src/lundump.js
@@ -3,8 +3,11 @@
 
 const DataView  = require('buffer-dataview');
 const fs        = require('fs');
+const assert    = require('assert');
+
 const lua_State = require('./lstate.js').lua_State;
 const LClosure  = require('./lobject.js').LClosure;
+const Proto     = require('./lfunc.js').Proto;
 
 /**
  * Parse Lua 5.3 bytecode
@@ -15,9 +18,17 @@ class BytecodeParser {
     /**
      * Initilialize bytecode parser
      * @constructor
+     * @param {lua_State} Lua state object
      * @param {DataView} dataView Contains the binary data
      */
-    constructor(dataView) {
+    constructor(L, dataView) {
+        this.intSize = 4;
+        this.size_tSize = 8;
+        this.instructionSize = 4;
+        this.integerSize = 8;
+        this.numberSize = 8;
+
+        this.L = L;
         this.dataView = dataView;
         this.offset = 0;
     }
@@ -32,36 +43,78 @@ class BytecodeParser {
         return byte;
     }
 
-    peekWord() {
-        return this.dataView.getUint32(this.offset, true);
+    peekInteger() {
+        return this.dataView.getInt32(this.offset, true);
+    }
+
+    readInteger() {
+        let integer = this.peekInteger();
+        this.offset += this.integerSize;
+
+        return integer;
+    }
+
+    peekNumber() {
+        return this.dataView.getFloat64(this.offset, true);
+    }
+
+    readNumber() {
+        let number = this.peekNumber();
+        this.offset += this.numberSize;
+
+        return number;
     }
 
-    readWord() {
-        let word = this.peekWord();
-        this.offset += 4;
+    readString(n) {
+        let string = "";
 
-        return word;
+        for (let i = 0; i < n; i++)
+            string += String.fromCharCode(this.readByte());
+
+        return string;
     }
 
     checkHeader() {
-        if (this.readByte() !== 0x1b
-            || this.readByte() !== 0x4c
-            || this.readByte() !== 0x75
-            || this.readByte() !== 0x61)
-            throw new Error("Bad LUA_SIGNATURE, expected [1b 4c 75 61]");
+        if (this.readString(4) !== "\x1bLua")
+            throw new Error("bad LUA_SIGNATURE, expected '<esc>Lua'");
 
         if (this.readByte() !== 0x53)
-            throw new Error("Bad Lua version, expected 5.3");
+            throw new Error("bad Lua version, expected 5.3");
 
         if (this.readByte() !== 0)
-            throw new Error("Supports only official PUC-Rio implementation")
+            throw new Error("supports only official PUC-Rio implementation");
+
+        if (this.readString(6) !== "\x19\x93\r\n\x1a\n")
+            throw new Error("bytecode corrupted");
+
+        this.intSize         = this.readByte();
+        this.size_tSize      = this.readByte();
+        this.instructionSize = this.readByte();
+        this.integerSize     = this.readByte();
+        this.numberSize      = this.readByte();
+
+        if (this.readInteger() !== 0x5678)
+            throw new Error("endianness mismatch");
+
+        if (this.readNumber() !== 370.5)
+            throw new Error("float format mismatch in");
+
     }
 
     luaU_undump() {
         checkHeader();
-        let cl = new LClosure(L, this.readByte());
+
+        let cl = new LClosure(this.L, this.readByte());
+        L.top++;
+        cl.p = new Proto(this.L);
+
+        loadFunction(cl.p);
+
+        assert(cl.nupvalues === cl.p.upvalues.length);
 
         return cl;
     }
 
-}
\ No newline at end of file
+}
+
+module.exports = BytecodeParser;
\ No newline at end of file