Reached the PE optional header

icon-changer.lua

@@ -12,7 +12,7 @@ local bor,band,lshift,rshift = bit.bor,bit.band,bit.lshift,bit.rshift
 
 --==Internal Functions==--
 
-local function readNumber(str,bigEndian)
+local function decodeNumber(str,bigEndian)
   local num = 0
   
   if bigEndian then str = str:reverse() end
@@ -36,6 +36,26 @@ function icapi.extractIcon(exeFile)
   --DOS Header
   if exeFile:read(2) ~= "MZ" then return error("This is not an executable file !") end
   
+  exeFile:read(58) --Skip 58 bytes
+  
+  local PEHeaderOffset = decodeNumber(exeFile:read(4),true) --Offset to the 'PE\0\0' signature relative to the beginning of the file
+  
+  exeFile:seek(PEHeaderOffset) --Seek into the PE Header
+  
+  --PE Header
+  if exeFile:read(4) ~= "PE\0\0" then return error("Corrupted executable file !") end
+  
+  --COFF Header
+  exeFile:read(2) --Skip Machine.
+  
+  local NumberOfSections = decodeNumber(exeFile:read(2))
+  
+  exeFile:read(12) --Skip 3 long values (12 bytes).
+  
+  local SizeOfOptionalHeader = decodeNumber(exeFile:read(2))
+  
+  exeFile:read(2) --Skip a short value (2 bytes) (Characteristics).
+  
   
 end