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ifile.c
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1998-03-03
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/*
* Copyright (c) 1984,1985,1989,1994,1995,1996 Mark Nudelman
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice in the documentation and/or other materials provided with
* the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* 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.
*/
#include "less.h"
extern IFILE curr_ifile;
struct ifile {
struct ifile *h_next; /* Links for command line list */
struct ifile *h_prev;
char *h_filename; /* Name of the file */
void *h_filestate; /* File state (used in ch.c) */
int h_index; /* Index within command line list */
int h_hold; /* Hold count */
char h_opened; /* Has this ifile been opened? */
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 };
static int ifiles = 0;
static void
incr_index(p, incr)
register struct ifile *p;
int incr;
{
for (; p != &anchor; p = p->h_next)
p->h_index += incr;
}
static void
link_ifile(p, prev)
struct ifile *p;
struct ifile *prev;
{
/*
* Link into list.
*/
if (prev == NULL)
prev = &anchor;
p->h_next = prev->h_next;
p->h_prev = prev;
prev->h_next->h_prev = p;
prev->h_next = p;
/*
* Calculate index for the new one,
* and adjust the indexes for subsequent ifiles in the list.
*/
p->h_index = prev->h_index + 1;
incr_index(p->h_next, 1);
ifiles++;
}
static void
unlink_ifile(p)
struct ifile *p;
{
p->h_next->h_prev = p->h_prev;
p->h_prev->h_next = p->h_next;
incr_index(p->h_next, -1);
ifiles--;
}
/*
* 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.
*/
static struct ifile *
new_ifile(filename, prev)
char *filename;
struct ifile *prev;
{
register struct ifile *p;
/*
* Allocate and initialize structure.
*/
p = (struct ifile *) ecalloc(1, sizeof(struct ifile));
p->h_filename = save(filename);
p->h_scrpos.pos = NULL_POSITION;
p->h_opened = 0;
p->h_hold = 0;
p->h_filestate = NULL;
link_ifile(p, prev);
return (p);
}
/*
* Delete an existing ifile structure.
*/
public void
del_ifile(h)
IFILE h;
{
register struct ifile *p;
if (h == NULL_IFILE)
return;
/*
* If the ifile we're deleting is the currently open ifile,
* move off it.
*/
if (h == curr_ifile)
curr_ifile = getoff_ifile(curr_ifile);
p = int_ifile(h);
unlink_ifile(p);
free(p->h_filename);
free(p);
}
/*
* Get the ifile after a given one in the list.
*/
public IFILE
next_ifile(h)
IFILE h;
{
register struct ifile *p;
p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
if (p->h_next == &anchor)
return (NULL_IFILE);
return (ext_ifile(p->h_next));
}
/*
* Get the ifile before a given one in the list.
*/
public IFILE
prev_ifile(h)
IFILE h;
{
register struct ifile *p;
p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
if (p->h_prev == &anchor)
return (NULL_IFILE);
return (ext_ifile(p->h_prev));
}
/*
* Return a different ifile from the given one.
*/
public IFILE
getoff_ifile(ifile)
IFILE ifile;
{
IFILE newifile;
if ((newifile = prev_ifile(ifile)) != NULL_IFILE)
return (newifile);
if ((newifile = next_ifile(ifile)) != NULL_IFILE)
return (newifile);
return (NULL_IFILE);
}
/*
* Return the number of ifiles.
*/
public int
nifile()
{
return (ifiles);
}
/*
* Find an ifile structure, given a filename.
*/
static struct ifile *
find_ifile(filename)
char *filename;
{
register struct ifile *p;
for (p = anchor.h_next; p != &anchor; p = p->h_next)
if (strcmp(filename, p->h_filename) == 0)
return (p);
return (NULL);
}
/*
* Get the ifile associated with a filename.
* If the filename has not been seen before,
* insert the new ifile after "prev" in the list.
*/
public IFILE
get_ifile(filename, prev)
char *filename;
IFILE prev;
{
register struct ifile *p;
if ((p = find_ifile(filename)) == NULL)
p = new_ifile(filename, int_ifile(prev));
return (ext_ifile(p));
}
/*
* Get the filename associated with a ifile.
*/
public char *
get_filename(ifile)
IFILE ifile;
{
if (ifile == NULL)
return (NULL);
return (int_ifile(ifile)->h_filename);
}
/*
* Get the index of the file associated with a ifile.
*/
public int
get_index(ifile)
IFILE ifile;
{
return (int_ifile(ifile)->h_index);
}
/*
* Save the file position to be associated with a given file.
*/
public void
store_pos(ifile, scrpos)
IFILE ifile;
struct scrpos *scrpos;
{
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.
*/
public void
get_pos(ifile, scrpos)
IFILE ifile;
struct scrpos *scrpos;
{
*scrpos = int_ifile(ifile)->h_scrpos;
}
/*
* Mark the ifile as "opened".
*/
public void
set_open(ifile)
IFILE ifile;
{
int_ifile(ifile)->h_opened = 1;
}
/*
* Return whether the ifile has been opened previously.
*/
public int
opened(ifile)
IFILE ifile;
{
return (int_ifile(ifile)->h_opened);
}
public void
hold_ifile(ifile, incr)
IFILE ifile;
int incr;
{
int_ifile(ifile)->h_hold += incr;
}
public int
held_ifile(ifile)
IFILE ifile;
{
return (int_ifile(ifile)->h_hold);
}
public void *
get_filestate(ifile)
IFILE ifile;
{
return (int_ifile(ifile)->h_filestate);
}
public void
set_filestate(ifile, filestate)
IFILE ifile;
void *filestate;
{
int_ifile(ifile)->h_filestate = filestate;
}
#if 0
public void
if_dump()
{
register struct ifile *p;
for (p = anchor.h_next; p != &anchor; p = p->h_next)
{
printf("%x: %d. <%s> pos %d,%x\n",
p, p->h_index, p->h_filename,
p->h_scrpos.ln, p->h_scrpos.pos);
ch_dump(p->h_filestate);
}
}
#endif