Add basic error checking

huffman.c

@@ -51,7 +51,10 @@ int encode_file(FILE *in, FILE *out)
 	long size = get_file_size(in);
 
 	fseek(in, 0, SEEK_SET);
+
 	tree = create_tree(in);
+	if (!tree)
+		return -1;
 
 	encode_header(&bitbuf, tree);
 
@@ -84,6 +87,7 @@ int decode_file(FILE *in, FILE *out)
 
 int main(int argc, char *argv[])
 {
+	int ret;
 	const char *infile, *outfile;
 	bool decompress = false;
 
@@ -118,11 +122,11 @@ int main(int argc, char *argv[])
 	}
 
 	if (decompress)
-		decode_file(input, output);
+		ret = decode_file(input, output);
 	else
-		encode_file(input, output);
+		ret = encode_file(input, output);
 
 	fclose(input);
 	fclose(output);
-	return 0;
+	return ret;
 }