Detect some files that don't meet Applesoft file format constraints

This commit is contained in:
Eric Fischer 2017-11-03 12:36:21 -07:00
parent a053bc2c72
commit 351b2a2d48

38
fp.c
View File

@ -129,6 +129,8 @@ token (int c)
void
process (FILE *f, char *name)
{
int oldptr = 0;
while (1) {
int a, b;
int c;
@ -136,16 +138,37 @@ process (FILE *f, char *name)
a = getc (f); /* useless (to us) pointer to next line */
b = getc (f); /* high half of pointer */
if (a == EOF || b == EOF)
return;
if (a == 0 && b == 0)
if (a == EOF || b == EOF) {
fprintf(stderr, "Unexpected EOF\n");
exit(EXIT_FAILURE);
}
if (a == 0 && b == 0) {
int c = getc(f);
if (c != EOF) {
fprintf(stderr, "More data follows 0/0 EOF tag\n");
exit(EXIT_FAILURE);
}
return;
}
int ptr = a + 256 * b;
if (ptr < 2048) {
fprintf(stderr, "Impossible pointer %d\n", ptr);
exit(EXIT_FAILURE);
}
if (ptr < oldptr) {
fprintf(stderr, "Pointer %d < old %d\n", ptr, oldptr);
exit(EXIT_FAILURE);
}
oldptr = ptr;
a = getc (f); /* line number */
b = getc (f); /* high half of line number */
if (a == EOF || b == EOF)
return;
if (a == EOF || b == EOF) {
fprintf(stderr, "Unexpected EOF\n");
exit(EXIT_FAILURE);
}
printf ("%d ", a + 256 * b);
@ -159,6 +182,11 @@ process (FILE *f, char *name)
printf ("%c", c);
}
if (c == EOF) {
fprintf(stderr, "Unexpected EOF\n");
exit(EXIT_FAILURE);
}
printf ("\n");
}
}