#include <stdio.h>

unsigned char sram[0x8000];

void generate_new_sav();
int read_file(char * filename);
void write_file(char * filename);

main(int argc, char *argv[]) {
	if(argc!=3) {
		printf("use this program to patch LSDj v2 (32 kB) .sav files into LSDJ v3 (128 kB) .sav files\n\n");
		printf("usage: lsdmerge source destination\n");
		return 0;
	}
	read_file(argv[1]);
	write_file(argv[2]);
	return 1;
}

void write_file(char * filename) {
	FILE *out;

	out=fopen(filename, "rb+");
	if(out==NULL) {
		unsigned int i;
		unsigned char zero=0;
		printf("couldn't open destination file '%s'\n",filename);
		printf("creating new file...\n");
		out=fopen(filename, "wb");
		for(i=0; i<131072; i++) {
			fwrite(&zero,1,1,out);
		}
		fclose(out);
		out=fopen(filename, "rb+");
	}
	if(ferror(out)) {
		printf("file error %d",ferror(out));
		exit(1);
	}
	fseek(out,0,SEEK_END);
	if(ftell(out)!=131072) {
		printf("error: destination file '%s' has wrong file length (should be 128 kB)", filename);
		exit(1);
	}
	fseek(out,0,SEEK_SET);
	fwrite(sram, 32768, 1, out);
	if(ferror(out)) {
		printf("file error %d when writing to '%s'",ferror(out),filename);
		exit(1);
	}
	fclose(out);
	printf("wrote file '%s' successfully",filename);
}

int read_file(char *filename) {
	FILE *in;
	int read;

	in=fopen(filename,"rb");
	if(in==NULL) {
		printf("error: can't open file '%s'", filename);
		exit(1);
	}
	fseek(in,0,SEEK_END);
	if(ftell(in)!=32768) {
		printf("error: source file '%s' has wrong file length (should be 32 kB)", filename);
		exit(1);
	}
	fseek(in,0,SEEK_SET);

	read=fread(sram,1,32768,in);
	
	if(ferror(in)) {
		printf("file error %d when reading from '%s'",ferror(in),filename);
		exit(1);
	}

	fclose(in);

	return 1;
}