bas.c: warn and return from walk_code() if the program ends in the middle of a line.

1 files changed, 4 insertions, 0 deletions

diff --git a/bas.c b/bas.c
index ddc424f..94ba310 100644
--- a/bas.c
+++ b/bas.c
@@ -316,6 +316,10 @@ void walk_code(unsigned int startlineno, unsigned int endlineno) {
 		lineno = tmpno;
 		offset = program[linepos + 2];
 		nextpos = linepos + offset;
+		if(nextpos > filelen) {
+			fprintf(stderr, "Warning: program truncated in the middle of line %d.\n", lineno);
+			return;
+		}
 
 		end = nextpos;
 		pos = linepos;