a few questions about pro

/*
Filepacker script based on the super simple filepacker by Thomas Oppl
Usage:
	Create resource file:
	FILE* <file pointer> = fopen("<file name>", "wb");
	
	Add a file:
	addfile(<resource file pointer>,"<name of file to be added>");
	
	Don't forget to use fclose(<file pointer>) after adding all files!
	
	Load a resource into the engine buffer:
	loadresources("<resource file name>");
	
*/

#include <acknex.h>
#include <stdio.h>

int compress(byte *dest, long *destlen, const byte *source, long sourcelen);
API(compress, zlib1)

int compress2(byte *dest, long *destlen, const byte *source, long sourcelen, int level);
API(compress2, zlib1)

int uncompress(byte *dest, long *destlen, const byte *source, long sourcelen);
API(uncompress, zlib1)

void encipher(unsigned int num_rounds, unsigned long *v, unsigned long *k) // 64-bit block feistel network with a 128-bit key
{
	unsigned long v0 = v[0], v1 = v[1], i;
	unsigned long sum = 0, delta = 0x9E3779B9;
	for(i = 0; i < num_rounds; i++)
	{
		v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
		sum += delta;
		v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum >> 11) & 3]);
	}
	v[0] = v0; v[1] = v1;
}

void decipher(unsigned int num_rounds, unsigned long* v, unsigned long* k) // 64-bit block feistel network with a 128-bit key
{
    unsigned long v0 = v[0], v1 = v[1], i;
    unsigned long delta = 0x9E3779B9, sum = delta * num_rounds;
    for(i = 0; i < num_rounds; i++)
    {
        v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum >> 11) & 3]);
        sum -= delta;
        v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
    }
    
    v[0] = v0; v[1] = v1;
}

void encipherbuffer(char *buffer, long Size)
{
	unsigned long key[4] = {15671, 176, 807912, 235807};
	long offset = 0;
	while(offset < Size - 8)
	{
		encipher(64, (unsigned long*)(buffer + offset), key);
		offset += 8;
	}
}

void decipherbuffer(char *buffer, long Size)
{
	unsigned long key[4] = {15671, 176, 807912, 235807};
	long offset = 0;
	while(offset < Size - 8)
	{
		decipher(64, (unsigned long*)(buffer + offset), key);
		offset += 8;
	}	
}

void addfile(FILE *fp, char *filename)
{
	long Size;
	char *buffer = file_load(filename, NULL, &Size);
	
	long compressedsize = (Size + 12) * 1.1; // must be a bit bigger than the source buffer
	char *compressedbuffer = (char*)sys_malloc(sizeof(char) * compressedsize);
	
	compress2(compressedbuffer, &compressedsize, buffer,Size,9);
	printf("\nname: %s | size: %d | compressedsize: %d", filename,Size, compressedsize);
	
	encipherbuffer(compressedbuffer, compressedsize);
	
	long length = str_len(filename);
	
	fwrite(&length, sizeof(long), 1, fp);
	fwrite(filename, sizeof(char) * length, 1, fp);
	fwrite(&Size, sizeof(long), 1, fp);
	fwrite(&compressedsize, sizeof(long), 1, fp);
	fwrite(compressedbuffer, sizeof(char) * compressedsize, 1, fp);
	
	sys_free(buffer);
	sys_free(compressedbuffer);
}

void loadresources(char *filename)
{
	FILE *fp = fopen(filename, "rb");
	if(!fp) {error("couldn't open file!"); return;}

	long length;
	while(fread(&length, sizeof(long), 1, fp)) // while not eof
	{	
		char *name = (char*)sys_malloc(sizeof(char) * (length + 1));
		fread(name, sizeof(char) * length, 1, fp);
		name[length] = 0; // termination
		
		long Size;
		fread(&Size, sizeof(long), 1, fp);
		long compressedsize;
		fread(&compressedsize, sizeof(long), 1, fp);
		
		char *compressedbuffer = (char*)sys_malloc(sizeof(char) * compressedsize);
		fread(compressedbuffer, sizeof(char) * compressedsize, 1, fp);
		
		//printf("name: %s | size: %d | compressedsize: %d", name, Size, compressedsize);
		
		decipherbuffer(compressedbuffer, compressedsize);
		
		char *buffer = (char*)sys_malloc(sizeof(char) * Size);
		uncompress(buffer, Size, compressedbuffer, compressedsize);
		add_buffer(name, buffer, Size);
		
		sys_free(name);
		sys_free(compressedbuffer);
	}

	fclose(fp);
}

void loadresources_file(char *resourcename, char* filename)
{
	FILE *fp = fopen(resourcename, "rb");
	if(!fp) {error("couldn't open file!"); return;}

	long length;
	while(fread(&length, sizeof(long), 1, fp)) // while not eof
	{	
		char *name = (char*)sys_malloc(sizeof(char) * (length + 1));
		fread(name, sizeof(char) * length, 1, fp);
		name[length] = 0; // termination
		
		if(!str_cmpi(filename,name))
		{
		   sys_free(name);
		   continue;
		}
		
		long Size;
		fread(&Size, sizeof(long), 1, fp);
		long compressedsize;
		fread(&compressedsize, sizeof(long), 1, fp);
		
		char *compressedbuffer = (char*)sys_malloc(sizeof(char) * compressedsize);
		fread(compressedbuffer, sizeof(char) * compressedsize, 1, fp);
		
		//printf("name: %s | size: %d | compressedsize: %d", name, Size, compressedsize);
		
		decipherbuffer(compressedbuffer, compressedsize);
		
		char *buffer = (char*)sys_malloc(sizeof(char) * Size);
		uncompress(buffer, Size, compressedbuffer, compressedsize);
		add_buffer(name, buffer, Size);
		
		sys_free(name);
		sys_free(compressedbuffer);
		fclose(fp);
		return;
	}

	fclose(fp);
}