///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// -> Creator: Christian
// -> Version: 4
// -> CT/TechID: 72
// -> Description: Change a GM exe's icon with one from a file. Please read the
//    warnings below carefully.
// -> Table of contents: General info, usage info, precautions, error codes, credits, licence agreement.
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// -> Usage:
// argument0 - [STRING] Exe path
// argument1 - [STRING] Ico path
// argument2 - [BOOL] true=Slower/full error detect
//    false=Fast/no error detect
// returns - [REAL] 1 = success or negative number = fail
//          check below for error codes
// -> Example: exe_ch_ico("myapp.exe","myicon.ico",true)
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// -> Precautions:
// The icon file must contain one 32*32 icon. [if not, when argument2 is false, it is detected]
// The script may handle true color icons.
// WARNING MAY NOT WORK WITH EXE's NOT MADE WITH GAMEMAKER6
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// -> ERROR CODES
// Errors are detectable by reading the resulting number given by this script. Errors always
// return a negative number while when the script is successfull it returns 1.
// The error code consists of two digits, the first telling were the error occured and the second
// why it occured. Example -10 means it has something to do with the icon (1) and the file wasn't
// found (0). When the first digit is 1 it is about the icon, 2 about the executable and 3 generic error.
// Full error code List:
// -10 icon file not found
// -11 invalid ico file
// -12 more then one icon or none
// -13 icon is smaller then 32*32
// -14 icon is larger then 32*32
// -15 unknown cause
// -20 exe file not found
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// -> Special thanks to:
// TGMG - Gave the exact exe co-ords (even though i found them before him but
//                he confirmed them)
// Sindarin - Some generic help with GM executables and icons
// cdm319 - Offered help by looking/finding resources
// Vladimir - Original c/c++ code for changing the icons using UpdateResource
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// -> Usage Licence Agreement
// This agreement gives you the permition to use this script in any way you want.
// Christian Sciberras or Covac Software are not to be held responsible for
// malfunctions and/or data loses of this script.
// Credit to the creator (or Covac Software) is not to be ommited.
// In the case that this script is to be redistributed, it is necessary that this agreement
// is distributed with it.
// Termination
// If you disagree with any of these terms please remove and do not use this or
// copies of this script.
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
var ff1,ff2,buf,nm,sig;
if file_exists(argument0)=false then return -20
if file_exists(argument1)=false then return -10
ff2=file_bin_open(argument0,2)
ff1=file_bin_open(argument1,0)
if argument2=true
{
sig=''
repeat(8){sig+=string(file_bin_read_byte(ff1))}
file_bin_seek(ff1,0)
if !(sig='0010103232')
{
 if string_copy(sig,0,4)!='0010' {return -11}
 if string_copy(sig,5,2)!='10' {return -12}
 if real(string_copy(sig,7,2))+real(string_copy(sig,9,2))<=63 {return -13}
 if real(string_copy(sig,7,2))+real(string_copy(sig,9,2))>=65 {return -14}
 return -15
}
}
buf=''
file_bin_seek(ff1,22)
do
{
file_bin_seek(ff1,file_bin_position(ff1))
buf+=chr(file_bin_read_byte(ff1))
}
until (file_bin_position(ff1)=file_bin_size(ff1))
nm=1
do { if string_length(buf)>=4265 then buf=string_copy(buf,0,4264)
if string_length(buf)<=4263 then buf+=chr(255) } until (string_length(buf)=4264)
file_bin_seek(ff2,486668)
repeat (string_length(buf))
{file_bin_write_byte(ff2,ord(string_char_at(buf,nm))) file_bin_seek(ff2,file_bin_position(ff2)) nm+=1}
return 1