hi!
using info on this forum, stunpack and bit of hacking, heres source code to a quick&dirty program that combines mcga.hdr, the uncompressed ega.cmn, mcga.cod and mcga.dif into a new game.exe. this new exe replaces load.exe/*.hdr/*.cmn/*.cod/*.dif.
made with msvc. some tweaks may be needed. enjoy!
#include <fstream>
void next_offset(unsigned short* arg0, unsigned short* arg2, unsigned long arg4) {
unsigned short var2;
arg4 += *arg0;
var2 = arg4 / 0x10;
*arg2 += var2;
*arg0 = arg4 - (var2 << 4);
}
bool apply_dif(const char* filename, char* bytes) {
std::ifstream fs;
fs.open(filename, std::ios::in | std::ios::binary);
if (!fs) return false;
unsigned short var8;
unsigned char val1;
unsigned short output_ofs = 0x0000;
unsigned short output_seg = 0x0000;//0x01A7;
if (output_ofs == 0)
output_seg -= 0x1000;
output_ofs--;
next_offset(&output_ofs, &output_seg, 0);
while (true) {
fs.read((char*)&var8, sizeof(unsigned short));
if (var8 == 0) break; // eof
next_offset(&output_ofs, &output_seg, var8 & 0x7fff);
int pos = output_seg << 4 | output_ofs;
char* buffer = &bytes[pos];
fs.read((char*)buffer, sizeof(unsigned char));
fs.read((char*)&buffer[1], sizeof(unsigned char));
if ((var8 & 0x8000) != 0) {
fs.read((char*)&buffer[2], sizeof(unsigned char));
fs.read((char*)&buffer[3], sizeof(unsigned char));
}
}
fs.close();
return true;
}
size_t copy_binary(const char* filename, char* exeimage) {
std::ifstream fs;
fs.open(filename, std::ios::in | std::ios::binary);
if (!fs) return 0;
fs.seekg(0, SEEK_END);
size_t size = fs.tellg();
fs.seekg(0, SEEK_SET);
fs.read(exeimage, size);
fs.close();
return size;
}
void save_binary(std::string filename, char* image, int size) {
std::ofstream fs;
fs.open(filename.c_str(), std::ios::out | std::ios::binary);
fs.write(image, size);
fs.close();
}
int main() {
char exehdr[30];
copy_binary("assets\\mcga.hdr", exehdr);
unsigned short bytes_in_last_page = *(unsigned short*)((char*)&exehdr[2]);
unsigned short pages_in_executable = *(unsigned short*)((char*)&exehdr[4]);
unsigned short relocation_offset = *(unsigned short*)((char*)&exehdr[24]);
unsigned short paragraphs_in_header = *(unsigned short*)((char*)&exehdr[8]);
int executable_size = (pages_in_executable * 512);
if (bytes_in_last_page > 0)
executable_size += -512 + bytes_in_last_page;
int header_size = paragraphs_in_header * 16;
char* exeimage = new char[executable_size];
memcpy(exeimage, exehdr, 30);
int size = copy_binary("assets\\ega.cmn", &exeimage[header_size]);
apply_dif("assets\\mcga.dif", &exeimage[header_size]);
copy_binary("assets\\mcga.cod", &exeimage[header_size + size]);
save_binary("game.exe", exeimage, executable_size);
return 0;
}
