Str8 str8_read_entire_file(Arena *arena, Str8 filename)
{
	/* TODO(pryazha): Make it crossplatform already */
	Assert(filename.ptr);
	Assert(filename.length);

	Str8 result = {0};
	Arena *tmp = arena_alloc(0);

	char *cfilename = str8_to_cstr(tmp, filename);

	FILE *f = fopen(cfilename, "rb");
	if (!f)
		return result;

	fseek(f, 0, SEEK_END);
	U64 size = ftell(f);
	rewind(f);

	U8 *mem = arena_push(arena, size+1);
	fread(mem, size, 1, f);
	fclose(f);

	mem[size] = 0;

	result = str8(mem, size);

	arena_release(tmp);

	return result;
}