347 lines
6.3 KiB
C
347 lines
6.3 KiB
C
/*
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* Copyright (C) 1984-2002 Mark Nudelman
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*
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* You may distribute under the terms of either the GNU General Public
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* License or the Less License, as specified in the README file.
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*
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* For more information about less, or for information on how to
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* contact the author, see the README file.
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*/
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/*
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* An IFILE represents an input file.
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*
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* It is actually a pointer to an ifile structure,
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* but is opaque outside this module.
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* Ifile structures are kept in a linked list in the order they
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* appear on the command line.
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* Any new file which does not already appear in the list is
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* inserted after the current file.
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*/
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#include "less.h"
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extern IFILE curr_ifile;
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struct ifile {
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struct ifile *h_next; /* Links for command line list */
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struct ifile *h_prev;
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char *h_filename; /* Name of the file */
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void *h_filestate; /* File state (used in ch.c) */
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int h_index; /* Index within command line list */
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int h_hold; /* Hold count */
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char h_opened; /* Has this ifile been opened? */
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struct scrpos h_scrpos; /* Saved position within the file */
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};
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/*
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* Convert an IFILE (external representation)
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* to a struct file (internal representation), and vice versa.
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*/
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#define int_ifile(h) ((struct ifile *)(h))
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#define ext_ifile(h) ((IFILE)(h))
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/*
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* Anchor for linked list.
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*/
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static struct ifile anchor = { &anchor, &anchor, NULL, NULL, 0, 0, '\0',
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{ NULL_POSITION, 0 } };
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static int ifiles = 0;
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static void
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incr_index(p, incr)
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register struct ifile *p;
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int incr;
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{
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for (; p != &anchor; p = p->h_next)
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p->h_index += incr;
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}
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/*
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* Link an ifile into the ifile list.
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*/
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static void
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link_ifile(p, prev)
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struct ifile *p;
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struct ifile *prev;
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{
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/*
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* Link into list.
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*/
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if (prev == NULL)
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prev = &anchor;
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p->h_next = prev->h_next;
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p->h_prev = prev;
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prev->h_next->h_prev = p;
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prev->h_next = p;
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/*
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* Calculate index for the new one,
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* and adjust the indexes for subsequent ifiles in the list.
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*/
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p->h_index = prev->h_index + 1;
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incr_index(p->h_next, 1);
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ifiles++;
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}
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/*
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* Unlink an ifile from the ifile list.
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*/
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static void
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unlink_ifile(p)
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struct ifile *p;
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{
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p->h_next->h_prev = p->h_prev;
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p->h_prev->h_next = p->h_next;
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incr_index(p->h_next, -1);
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ifiles--;
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}
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/*
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* Allocate a new ifile structure and stick a filename in it.
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* It should go after "prev" in the list
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* (or at the beginning of the list if "prev" is NULL).
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* Return a pointer to the new ifile structure.
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*/
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static struct ifile *
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new_ifile(filename, prev)
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char *filename;
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struct ifile *prev;
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{
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register struct ifile *p;
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/*
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* Allocate and initialize structure.
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*/
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p = (struct ifile *) ecalloc(1, sizeof(struct ifile));
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p->h_filename = save(filename);
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p->h_scrpos.pos = NULL_POSITION;
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p->h_opened = 0;
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p->h_hold = 0;
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p->h_filestate = NULL;
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link_ifile(p, prev);
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return (p);
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}
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/*
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* Delete an existing ifile structure.
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*/
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public void
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del_ifile(h)
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IFILE h;
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{
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register struct ifile *p;
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if (h == NULL_IFILE)
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return;
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/*
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* If the ifile we're deleting is the currently open ifile,
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* move off it.
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*/
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unmark(h);
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if (h == curr_ifile)
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curr_ifile = getoff_ifile(curr_ifile);
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p = int_ifile(h);
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unlink_ifile(p);
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free(p->h_filename);
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free(p);
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}
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/*
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* Get the ifile after a given one in the list.
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*/
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public IFILE
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next_ifile(h)
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IFILE h;
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{
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register struct ifile *p;
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p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
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if (p->h_next == &anchor)
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return (NULL_IFILE);
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return (ext_ifile(p->h_next));
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}
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/*
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* Get the ifile before a given one in the list.
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*/
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public IFILE
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prev_ifile(h)
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IFILE h;
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{
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register struct ifile *p;
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p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
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if (p->h_prev == &anchor)
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return (NULL_IFILE);
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return (ext_ifile(p->h_prev));
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}
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/*
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* Return a different ifile from the given one.
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*/
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public IFILE
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getoff_ifile(ifile)
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IFILE ifile;
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{
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IFILE newifile;
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if ((newifile = prev_ifile(ifile)) != NULL_IFILE)
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return (newifile);
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if ((newifile = next_ifile(ifile)) != NULL_IFILE)
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return (newifile);
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return (NULL_IFILE);
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}
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/*
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* Return the number of ifiles.
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*/
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public int
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nifile()
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{
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return (ifiles);
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}
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/*
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* Find an ifile structure, given a filename.
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*/
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static struct ifile *
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find_ifile(filename)
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char *filename;
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{
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register struct ifile *p;
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for (p = anchor.h_next; p != &anchor; p = p->h_next)
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if (strcmp(filename, p->h_filename) == 0)
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return (p);
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return (NULL);
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}
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/*
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* Get the ifile associated with a filename.
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* If the filename has not been seen before,
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* insert the new ifile after "prev" in the list.
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*/
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public IFILE
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get_ifile(filename, prev)
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char *filename;
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IFILE prev;
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{
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register struct ifile *p;
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if ((p = find_ifile(filename)) == NULL)
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p = new_ifile(filename, int_ifile(prev));
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return (ext_ifile(p));
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}
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/*
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* Get the filename associated with a ifile.
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*/
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public char *
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get_filename(ifile)
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IFILE ifile;
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{
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if (ifile == NULL)
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return (NULL);
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return (int_ifile(ifile)->h_filename);
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}
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/*
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* Get the index of the file associated with a ifile.
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*/
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public int
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get_index(ifile)
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IFILE ifile;
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{
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return (int_ifile(ifile)->h_index);
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}
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/*
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* Save the file position to be associated with a given file.
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*/
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public void
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store_pos(ifile, scrpos)
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IFILE ifile;
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struct scrpos *scrpos;
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{
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int_ifile(ifile)->h_scrpos = *scrpos;
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}
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/*
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* Recall the file position associated with a file.
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* If no position has been associated with the file, return NULL_POSITION.
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*/
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public void
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get_pos(ifile, scrpos)
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IFILE ifile;
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struct scrpos *scrpos;
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{
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*scrpos = int_ifile(ifile)->h_scrpos;
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}
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/*
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* Mark the ifile as "opened".
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*/
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public void
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set_open(ifile)
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IFILE ifile;
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{
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int_ifile(ifile)->h_opened = 1;
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}
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/*
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* Return whether the ifile has been opened previously.
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*/
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public int
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opened(ifile)
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IFILE ifile;
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{
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return (int_ifile(ifile)->h_opened);
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}
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public void
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hold_ifile(ifile, incr)
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IFILE ifile;
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int incr;
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{
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int_ifile(ifile)->h_hold += incr;
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}
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public int
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held_ifile(ifile)
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IFILE ifile;
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{
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return (int_ifile(ifile)->h_hold);
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}
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public void *
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get_filestate(ifile)
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IFILE ifile;
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{
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return (int_ifile(ifile)->h_filestate);
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}
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public void
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set_filestate(ifile, filestate)
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IFILE ifile;
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void *filestate;
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{
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int_ifile(ifile)->h_filestate = filestate;
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}
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#if 0
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public void
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if_dump()
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{
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register struct ifile *p;
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for (p = anchor.h_next; p != &anchor; p = p->h_next)
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{
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printf("%x: %d. <%s> pos %d,%x\n",
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p, p->h_index, p->h_filename,
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p->h_scrpos.ln, p->h_scrpos.pos);
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ch_dump(p->h_filestate);
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}
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}
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#endif
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