* An IFILE represents an input file.
* It is actually a pointer to an ifile structure,
* but is opaque outside this module.
* Ifile structures are kept in a linked list in the order they
* appear on the command line.
* Any new file which does not already appear in the list is
* inserted after the current file.
struct ifile
*h_next
; /* Links for command line list */
int h_index
; /* Index within command line list */
char *h_filename
; /* Name of the file */
struct scrpos h_scrpos
; /* Saved position within the file */
* Convert an IFILE (external representation)
* to a struct file (internal representation), and vice versa.
#define int_ifile(h) ((struct ifile *)(h))
#define ext_ifile(h) ((IFILE)(h))
* Anchor for linked list.
static struct ifile anchor
= { &anchor
, &anchor
, 0 };
* Allocate a new ifile structure and stick a filename in it.
* It should go after "prev" in the list
* (or at the beginning of the list if "prev" is NULL).
* Return a pointer to the new ifile structure.
new_ifile(filename
, prev
)
register struct ifile
*p
;
register struct ifile
*np
;
* Allocate and initialize structure.
p
= (struct ifile
*) ecalloc(1, sizeof(struct ifile
));
p
->h_filename
= filename
;
p
->h_scrpos
.pos
= NULL_POSITION
;
p
->h_next
= prev
->h_next
;
prev
->h_next
->h_prev
= p
;
* Calculate index for the new one,
* and adjust the indexes for subsequent ifiles in the list.
p
->h_index
= prev
->h_index
+ 1;
for (np
= p
->h_next
; np
!= &anchor
; np
= np
->h_next
)
* Get the ifile after a given one in the list.
register struct ifile
*p
;
p
= (h
== NULL_IFILE
) ? &anchor
: int_ifile(h
);
if (p
->h_next
== &anchor
)
return (ext_ifile(p
->h_next
));
* Get the ifile before a given one in the list.
register struct ifile
*p
;
p
= (h
== NULL_IFILE
) ? &anchor
: int_ifile(h
);
if (p
->h_prev
== &anchor
)
return (ext_ifile(p
->h_prev
));
* Return the number of ifiles.
* Find an ifile structure, given a filename.
register struct ifile
*p
;
for (p
= anchor
.h_next
; p
!= &anchor
; p
= p
->h_next
)
if (strcmp(filename
, p
->h_filename
) == 0)
* Get the ifile associated with a filename.
* If the filename has not been seen before,
* insert the new ifile after "prev" in the list.
get_ifile(filename
, prev
)
register struct ifile
*p
;
if ((p
= find_ifile(filename
)) == NULL
)
p
= new_ifile(save(filename
), int_ifile(prev
));
* Get the filename associated with a ifile.
return (int_ifile(ifile
)->h_filename
);
* Get the index of the file associated with a ifile.
return (int_ifile(ifile
)->h_index
);
* Save the file position to be associated with a given file.
int_ifile(ifile
)->h_scrpos
= *scrpos
;
* Recall the file position associated with a file.
* If no position has been associated with the file, return NULL_POSITION.
*scrpos
= int_ifile(ifile
)->h_scrpos
;