981 lines
19 KiB
C
981 lines
19 KiB
C
/*
|
|
* Copyright (C) 1984-2022 Mark Nudelman
|
|
*
|
|
* You may distribute under the terms of either the GNU General Public
|
|
* License or the Less License, as specified in the README file.
|
|
*
|
|
* For more information, see the README file.
|
|
*/
|
|
|
|
|
|
/*
|
|
* Low level character input from the input file.
|
|
* We use these special purpose routines which optimize moving
|
|
* both forward and backward from the current read pointer.
|
|
*/
|
|
|
|
#include "less.h"
|
|
#if MSDOS_COMPILER==WIN32C
|
|
#include <errno.h>
|
|
#include <windows.h>
|
|
#endif
|
|
|
|
#if HAVE_STAT_INO
|
|
#include <sys/stat.h>
|
|
extern dev_t curr_dev;
|
|
extern ino_t curr_ino;
|
|
#endif
|
|
|
|
#if HAVE_PROCFS
|
|
#include <sys/statfs.h>
|
|
#endif
|
|
|
|
typedef POSITION BLOCKNUM;
|
|
|
|
public int ignore_eoi;
|
|
|
|
/*
|
|
* Pool of buffers holding the most recently used blocks of the input file.
|
|
* The buffer pool is kept as a doubly-linked circular list,
|
|
* in order from most- to least-recently used.
|
|
* The circular list is anchored by the file state "thisfile".
|
|
*/
|
|
struct bufnode {
|
|
struct bufnode *next, *prev;
|
|
struct bufnode *hnext, *hprev;
|
|
};
|
|
|
|
#define LBUFSIZE 8192
|
|
struct buf {
|
|
struct bufnode node;
|
|
BLOCKNUM block;
|
|
unsigned int datasize;
|
|
unsigned char data[LBUFSIZE];
|
|
};
|
|
#define bufnode_buf(bn) ((struct buf *) bn)
|
|
|
|
/*
|
|
* The file state is maintained in a filestate structure.
|
|
* A pointer to the filestate is kept in the ifile structure.
|
|
*/
|
|
#define BUFHASH_SIZE 1024
|
|
struct filestate {
|
|
struct bufnode buflist;
|
|
struct bufnode hashtbl[BUFHASH_SIZE];
|
|
int file;
|
|
int flags;
|
|
POSITION fpos;
|
|
int nbufs;
|
|
BLOCKNUM block;
|
|
unsigned int offset;
|
|
POSITION fsize;
|
|
};
|
|
|
|
#define ch_bufhead thisfile->buflist.next
|
|
#define ch_buftail thisfile->buflist.prev
|
|
#define ch_nbufs thisfile->nbufs
|
|
#define ch_block thisfile->block
|
|
#define ch_offset thisfile->offset
|
|
#define ch_fpos thisfile->fpos
|
|
#define ch_fsize thisfile->fsize
|
|
#define ch_flags thisfile->flags
|
|
#define ch_file thisfile->file
|
|
|
|
#define END_OF_CHAIN (&thisfile->buflist)
|
|
#define END_OF_HCHAIN(h) (&thisfile->hashtbl[h])
|
|
#define BUFHASH(blk) ((blk) & (BUFHASH_SIZE-1))
|
|
|
|
/*
|
|
* Macros to manipulate the list of buffers in thisfile->buflist.
|
|
*/
|
|
#define FOR_BUFS(bn) \
|
|
for (bn = ch_bufhead; bn != END_OF_CHAIN; bn = bn->next)
|
|
|
|
#define BUF_RM(bn) \
|
|
(bn)->next->prev = (bn)->prev; \
|
|
(bn)->prev->next = (bn)->next;
|
|
|
|
#define BUF_INS_HEAD(bn) \
|
|
(bn)->next = ch_bufhead; \
|
|
(bn)->prev = END_OF_CHAIN; \
|
|
ch_bufhead->prev = (bn); \
|
|
ch_bufhead = (bn);
|
|
|
|
#define BUF_INS_TAIL(bn) \
|
|
(bn)->next = END_OF_CHAIN; \
|
|
(bn)->prev = ch_buftail; \
|
|
ch_buftail->next = (bn); \
|
|
ch_buftail = (bn);
|
|
|
|
/*
|
|
* Macros to manipulate the list of buffers in thisfile->hashtbl[n].
|
|
*/
|
|
#define FOR_BUFS_IN_CHAIN(h,bn) \
|
|
for (bn = thisfile->hashtbl[h].hnext; \
|
|
bn != END_OF_HCHAIN(h); bn = bn->hnext)
|
|
|
|
#define BUF_HASH_RM(bn) \
|
|
(bn)->hnext->hprev = (bn)->hprev; \
|
|
(bn)->hprev->hnext = (bn)->hnext;
|
|
|
|
#define BUF_HASH_INS(bn,h) \
|
|
(bn)->hnext = thisfile->hashtbl[h].hnext; \
|
|
(bn)->hprev = END_OF_HCHAIN(h); \
|
|
thisfile->hashtbl[h].hnext->hprev = (bn); \
|
|
thisfile->hashtbl[h].hnext = (bn);
|
|
|
|
static struct filestate *thisfile;
|
|
static int ch_ungotchar = -1;
|
|
static int maxbufs = -1;
|
|
|
|
extern int autobuf;
|
|
extern int sigs;
|
|
extern int secure;
|
|
extern int screen_trashed;
|
|
extern int follow_mode;
|
|
extern constant char helpdata[];
|
|
extern constant int size_helpdata;
|
|
extern IFILE curr_ifile;
|
|
#if LOGFILE
|
|
extern int logfile;
|
|
extern char *namelogfile;
|
|
#endif
|
|
|
|
static int ch_addbuf();
|
|
|
|
|
|
/*
|
|
* Get the character pointed to by the read pointer.
|
|
*/
|
|
int
|
|
ch_get(VOID_PARAM)
|
|
{
|
|
struct buf *bp;
|
|
struct bufnode *bn;
|
|
int n;
|
|
int slept;
|
|
int h;
|
|
POSITION pos;
|
|
POSITION len;
|
|
|
|
if (thisfile == NULL)
|
|
return (EOI);
|
|
|
|
/*
|
|
* Quick check for the common case where
|
|
* the desired char is in the head buffer.
|
|
*/
|
|
if (ch_bufhead != END_OF_CHAIN)
|
|
{
|
|
bp = bufnode_buf(ch_bufhead);
|
|
if (ch_block == bp->block && ch_offset < bp->datasize)
|
|
return bp->data[ch_offset];
|
|
}
|
|
|
|
slept = FALSE;
|
|
|
|
/*
|
|
* Look for a buffer holding the desired block.
|
|
*/
|
|
h = BUFHASH(ch_block);
|
|
FOR_BUFS_IN_CHAIN(h, bn)
|
|
{
|
|
bp = bufnode_buf(bn);
|
|
if (bp->block == ch_block)
|
|
{
|
|
if (ch_offset >= bp->datasize)
|
|
/*
|
|
* Need more data in this buffer.
|
|
*/
|
|
break;
|
|
goto found;
|
|
}
|
|
}
|
|
if (bn == END_OF_HCHAIN(h))
|
|
{
|
|
/*
|
|
* Block is not in a buffer.
|
|
* Take the least recently used buffer
|
|
* and read the desired block into it.
|
|
* If the LRU buffer has data in it,
|
|
* then maybe allocate a new buffer.
|
|
*/
|
|
if (ch_buftail == END_OF_CHAIN ||
|
|
bufnode_buf(ch_buftail)->block != -1)
|
|
{
|
|
/*
|
|
* There is no empty buffer to use.
|
|
* Allocate a new buffer if:
|
|
* 1. We can't seek on this file and -b is not in effect; or
|
|
* 2. We haven't allocated the max buffers for this file yet.
|
|
*/
|
|
if ((autobuf && !(ch_flags & CH_CANSEEK)) ||
|
|
(maxbufs < 0 || ch_nbufs < maxbufs))
|
|
if (ch_addbuf())
|
|
/*
|
|
* Allocation failed: turn off autobuf.
|
|
*/
|
|
autobuf = OPT_OFF;
|
|
}
|
|
bn = ch_buftail;
|
|
bp = bufnode_buf(bn);
|
|
BUF_HASH_RM(bn); /* Remove from old hash chain. */
|
|
bp->block = ch_block;
|
|
bp->datasize = 0;
|
|
BUF_HASH_INS(bn, h); /* Insert into new hash chain. */
|
|
}
|
|
|
|
read_more:
|
|
pos = (ch_block * LBUFSIZE) + bp->datasize;
|
|
if ((len = ch_length()) != NULL_POSITION && pos >= len)
|
|
/*
|
|
* At end of file.
|
|
*/
|
|
return (EOI);
|
|
|
|
if (pos != ch_fpos)
|
|
{
|
|
/*
|
|
* Not at the correct position: must seek.
|
|
* If input is a pipe, we're in trouble (can't seek on a pipe).
|
|
* Some data has been lost: just return "?".
|
|
*/
|
|
if (!(ch_flags & CH_CANSEEK))
|
|
return ('?');
|
|
if (lseek(ch_file, (off_t)pos, SEEK_SET) == BAD_LSEEK)
|
|
{
|
|
error("seek error", NULL_PARG);
|
|
clear_eol();
|
|
return (EOI);
|
|
}
|
|
ch_fpos = pos;
|
|
}
|
|
|
|
/*
|
|
* Read the block.
|
|
* If we read less than a full block, that's ok.
|
|
* We use partial block and pick up the rest next time.
|
|
*/
|
|
if (ch_ungotchar != -1)
|
|
{
|
|
bp->data[bp->datasize] = ch_ungotchar;
|
|
n = 1;
|
|
ch_ungotchar = -1;
|
|
} else if (ch_flags & CH_HELPFILE)
|
|
{
|
|
bp->data[bp->datasize] = helpdata[ch_fpos];
|
|
n = 1;
|
|
} else
|
|
{
|
|
n = iread(ch_file, &bp->data[bp->datasize],
|
|
(unsigned int)(LBUFSIZE - bp->datasize));
|
|
}
|
|
|
|
if (n == READ_INTR)
|
|
return (EOI);
|
|
if (n < 0)
|
|
{
|
|
#if MSDOS_COMPILER==WIN32C
|
|
if (errno != EPIPE)
|
|
#endif
|
|
{
|
|
error("read error", NULL_PARG);
|
|
clear_eol();
|
|
}
|
|
n = 0;
|
|
}
|
|
|
|
#if LOGFILE
|
|
/*
|
|
* If we have a log file, write the new data to it.
|
|
*/
|
|
if (!secure && logfile >= 0 && n > 0)
|
|
write(logfile, (char *) &bp->data[bp->datasize], n);
|
|
#endif
|
|
|
|
ch_fpos += n;
|
|
bp->datasize += n;
|
|
|
|
/*
|
|
* If we have read to end of file, set ch_fsize to indicate
|
|
* the position of the end of file.
|
|
*/
|
|
if (n == 0)
|
|
{
|
|
ch_fsize = pos;
|
|
if (ignore_eoi)
|
|
{
|
|
/*
|
|
* We are ignoring EOF.
|
|
* Wait a while, then try again.
|
|
*/
|
|
if (!slept)
|
|
{
|
|
PARG parg;
|
|
parg.p_string = wait_message();
|
|
ierror("%s", &parg);
|
|
}
|
|
sleep_ms(2); /* Reduce system load */
|
|
slept = TRUE;
|
|
|
|
#if HAVE_STAT_INO
|
|
if (follow_mode == FOLLOW_NAME)
|
|
{
|
|
/* See whether the file's i-number has changed,
|
|
* or the file has shrunk.
|
|
* If so, force the file to be closed and
|
|
* reopened. */
|
|
struct stat st;
|
|
POSITION curr_pos = ch_tell();
|
|
int r = stat(get_filename(curr_ifile), &st);
|
|
if (r == 0 && (st.st_ino != curr_ino ||
|
|
st.st_dev != curr_dev ||
|
|
(curr_pos != NULL_POSITION && st.st_size < curr_pos)))
|
|
{
|
|
/* screen_trashed=2 causes
|
|
* make_display to reopen the file. */
|
|
screen_trashed = 2;
|
|
return (EOI);
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
if (sigs)
|
|
return (EOI);
|
|
}
|
|
|
|
found:
|
|
if (ch_bufhead != bn)
|
|
{
|
|
/*
|
|
* Move the buffer to the head of the buffer chain.
|
|
* This orders the buffer chain, most- to least-recently used.
|
|
*/
|
|
BUF_RM(bn);
|
|
BUF_INS_HEAD(bn);
|
|
|
|
/*
|
|
* Move to head of hash chain too.
|
|
*/
|
|
BUF_HASH_RM(bn);
|
|
BUF_HASH_INS(bn, h);
|
|
}
|
|
|
|
if (ch_offset >= bp->datasize)
|
|
/*
|
|
* After all that, we still don't have enough data.
|
|
* Go back and try again.
|
|
*/
|
|
goto read_more;
|
|
|
|
return (bp->data[ch_offset]);
|
|
}
|
|
|
|
/*
|
|
* ch_ungetchar is a rather kludgy and limited way to push
|
|
* a single char onto an input file descriptor.
|
|
*/
|
|
public void
|
|
ch_ungetchar(c)
|
|
int c;
|
|
{
|
|
if (c != -1 && ch_ungotchar != -1)
|
|
error("ch_ungetchar overrun", NULL_PARG);
|
|
ch_ungotchar = c;
|
|
}
|
|
|
|
#if LOGFILE
|
|
/*
|
|
* Close the logfile.
|
|
* If we haven't read all of standard input into it, do that now.
|
|
*/
|
|
public void
|
|
end_logfile(VOID_PARAM)
|
|
{
|
|
static int tried = FALSE;
|
|
|
|
if (logfile < 0)
|
|
return;
|
|
if (!tried && ch_fsize == NULL_POSITION)
|
|
{
|
|
tried = TRUE;
|
|
ierror("Finishing logfile", NULL_PARG);
|
|
while (ch_forw_get() != EOI)
|
|
if (ABORT_SIGS())
|
|
break;
|
|
}
|
|
close(logfile);
|
|
logfile = -1;
|
|
free(namelogfile);
|
|
namelogfile = NULL;
|
|
}
|
|
|
|
/*
|
|
* Start a log file AFTER less has already been running.
|
|
* Invoked from the - command; see toggle_option().
|
|
* Write all the existing buffered data to the log file.
|
|
*/
|
|
public void
|
|
sync_logfile(VOID_PARAM)
|
|
{
|
|
struct buf *bp;
|
|
struct bufnode *bn;
|
|
int warned = FALSE;
|
|
BLOCKNUM block;
|
|
BLOCKNUM nblocks;
|
|
|
|
nblocks = (ch_fpos + LBUFSIZE - 1) / LBUFSIZE;
|
|
for (block = 0; block < nblocks; block++)
|
|
{
|
|
int wrote = FALSE;
|
|
FOR_BUFS(bn)
|
|
{
|
|
bp = bufnode_buf(bn);
|
|
if (bp->block == block)
|
|
{
|
|
write(logfile, (char *) bp->data, bp->datasize);
|
|
wrote = TRUE;
|
|
break;
|
|
}
|
|
}
|
|
if (!wrote && !warned)
|
|
{
|
|
error("Warning: log file is incomplete",
|
|
NULL_PARG);
|
|
warned = TRUE;
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif
|
|
|
|
/*
|
|
* Determine if a specific block is currently in one of the buffers.
|
|
*/
|
|
static int
|
|
buffered(block)
|
|
BLOCKNUM block;
|
|
{
|
|
struct buf *bp;
|
|
struct bufnode *bn;
|
|
int h;
|
|
|
|
h = BUFHASH(block);
|
|
FOR_BUFS_IN_CHAIN(h, bn)
|
|
{
|
|
bp = bufnode_buf(bn);
|
|
if (bp->block == block)
|
|
return (TRUE);
|
|
}
|
|
return (FALSE);
|
|
}
|
|
|
|
/*
|
|
* Seek to a specified position in the file.
|
|
* Return 0 if successful, non-zero if can't seek there.
|
|
*/
|
|
public int
|
|
ch_seek(pos)
|
|
POSITION pos;
|
|
{
|
|
BLOCKNUM new_block;
|
|
POSITION len;
|
|
|
|
if (thisfile == NULL)
|
|
return (0);
|
|
|
|
len = ch_length();
|
|
if (pos < ch_zero() || (len != NULL_POSITION && pos > len))
|
|
return (1);
|
|
|
|
new_block = pos / LBUFSIZE;
|
|
if (!(ch_flags & CH_CANSEEK) && pos != ch_fpos && !buffered(new_block))
|
|
{
|
|
if (ch_fpos > pos)
|
|
return (1);
|
|
while (ch_fpos < pos)
|
|
{
|
|
if (ch_forw_get() == EOI)
|
|
return (1);
|
|
if (ABORT_SIGS())
|
|
return (1);
|
|
}
|
|
return (0);
|
|
}
|
|
/*
|
|
* Set read pointer.
|
|
*/
|
|
ch_block = new_block;
|
|
ch_offset = pos % LBUFSIZE;
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Seek to the end of the file.
|
|
*/
|
|
public int
|
|
ch_end_seek(VOID_PARAM)
|
|
{
|
|
POSITION len;
|
|
|
|
if (thisfile == NULL)
|
|
return (0);
|
|
|
|
if (ch_flags & CH_CANSEEK)
|
|
ch_fsize = filesize(ch_file);
|
|
|
|
len = ch_length();
|
|
if (len != NULL_POSITION)
|
|
return (ch_seek(len));
|
|
|
|
/*
|
|
* Do it the slow way: read till end of data.
|
|
*/
|
|
while (ch_forw_get() != EOI)
|
|
if (ABORT_SIGS())
|
|
return (1);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Seek to the last position in the file that is currently buffered.
|
|
*/
|
|
public int
|
|
ch_end_buffer_seek(VOID_PARAM)
|
|
{
|
|
struct buf *bp;
|
|
struct bufnode *bn;
|
|
POSITION buf_pos;
|
|
POSITION end_pos;
|
|
|
|
if (thisfile == NULL || (ch_flags & CH_CANSEEK))
|
|
return (ch_end_seek());
|
|
|
|
end_pos = 0;
|
|
FOR_BUFS(bn)
|
|
{
|
|
bp = bufnode_buf(bn);
|
|
buf_pos = (bp->block * LBUFSIZE) + bp->datasize;
|
|
if (buf_pos > end_pos)
|
|
end_pos = buf_pos;
|
|
}
|
|
|
|
return (ch_seek(end_pos));
|
|
}
|
|
|
|
/*
|
|
* Seek to the beginning of the file, or as close to it as we can get.
|
|
* We may not be able to seek there if input is a pipe and the
|
|
* beginning of the pipe is no longer buffered.
|
|
*/
|
|
public int
|
|
ch_beg_seek(VOID_PARAM)
|
|
{
|
|
struct bufnode *bn;
|
|
struct bufnode *firstbn;
|
|
|
|
/*
|
|
* Try a plain ch_seek first.
|
|
*/
|
|
if (ch_seek(ch_zero()) == 0)
|
|
return (0);
|
|
|
|
/*
|
|
* Can't get to position 0.
|
|
* Look thru the buffers for the one closest to position 0.
|
|
*/
|
|
firstbn = ch_bufhead;
|
|
if (firstbn == END_OF_CHAIN)
|
|
return (1);
|
|
FOR_BUFS(bn)
|
|
{
|
|
if (bufnode_buf(bn)->block < bufnode_buf(firstbn)->block)
|
|
firstbn = bn;
|
|
}
|
|
ch_block = bufnode_buf(firstbn)->block;
|
|
ch_offset = 0;
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Return the length of the file, if known.
|
|
*/
|
|
public POSITION
|
|
ch_length(VOID_PARAM)
|
|
{
|
|
if (thisfile == NULL)
|
|
return (NULL_POSITION);
|
|
if (ignore_eoi)
|
|
return (NULL_POSITION);
|
|
if (ch_flags & CH_HELPFILE)
|
|
return (size_helpdata);
|
|
if (ch_flags & CH_NODATA)
|
|
return (0);
|
|
return (ch_fsize);
|
|
}
|
|
|
|
/*
|
|
* Return the current position in the file.
|
|
*/
|
|
public POSITION
|
|
ch_tell(VOID_PARAM)
|
|
{
|
|
if (thisfile == NULL)
|
|
return (NULL_POSITION);
|
|
return (ch_block * LBUFSIZE) + ch_offset;
|
|
}
|
|
|
|
/*
|
|
* Get the current char and post-increment the read pointer.
|
|
*/
|
|
public int
|
|
ch_forw_get(VOID_PARAM)
|
|
{
|
|
int c;
|
|
|
|
if (thisfile == NULL)
|
|
return (EOI);
|
|
c = ch_get();
|
|
if (c == EOI)
|
|
return (EOI);
|
|
if (ch_offset < LBUFSIZE-1)
|
|
ch_offset++;
|
|
else
|
|
{
|
|
ch_block ++;
|
|
ch_offset = 0;
|
|
}
|
|
return (c);
|
|
}
|
|
|
|
/*
|
|
* Pre-decrement the read pointer and get the new current char.
|
|
*/
|
|
public int
|
|
ch_back_get(VOID_PARAM)
|
|
{
|
|
if (thisfile == NULL)
|
|
return (EOI);
|
|
if (ch_offset > 0)
|
|
ch_offset --;
|
|
else
|
|
{
|
|
if (ch_block <= 0)
|
|
return (EOI);
|
|
if (!(ch_flags & CH_CANSEEK) && !buffered(ch_block-1))
|
|
return (EOI);
|
|
ch_block--;
|
|
ch_offset = LBUFSIZE-1;
|
|
}
|
|
return (ch_get());
|
|
}
|
|
|
|
/*
|
|
* Set max amount of buffer space.
|
|
* bufspace is in units of 1024 bytes. -1 mean no limit.
|
|
*/
|
|
public void
|
|
ch_setbufspace(bufspace)
|
|
int bufspace;
|
|
{
|
|
if (bufspace < 0)
|
|
maxbufs = -1;
|
|
else
|
|
{
|
|
maxbufs = ((bufspace * 1024) + LBUFSIZE-1) / LBUFSIZE;
|
|
if (maxbufs < 1)
|
|
maxbufs = 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Flush (discard) any saved file state, including buffer contents.
|
|
*/
|
|
public void
|
|
ch_flush(VOID_PARAM)
|
|
{
|
|
struct bufnode *bn;
|
|
|
|
if (thisfile == NULL)
|
|
return;
|
|
|
|
if (!(ch_flags & CH_CANSEEK))
|
|
{
|
|
/*
|
|
* If input is a pipe, we don't flush buffer contents,
|
|
* since the contents can't be recovered.
|
|
*/
|
|
ch_fsize = NULL_POSITION;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Initialize all the buffers.
|
|
*/
|
|
FOR_BUFS(bn)
|
|
{
|
|
bufnode_buf(bn)->block = -1;
|
|
}
|
|
|
|
/*
|
|
* Figure out the size of the file, if we can.
|
|
*/
|
|
ch_fsize = filesize(ch_file);
|
|
|
|
/*
|
|
* Seek to a known position: the beginning of the file.
|
|
*/
|
|
ch_fpos = 0;
|
|
ch_block = 0; /* ch_fpos / LBUFSIZE; */
|
|
ch_offset = 0; /* ch_fpos % LBUFSIZE; */
|
|
|
|
#if HAVE_PROCFS
|
|
/*
|
|
* This is a kludge to workaround a Linux kernel bug: files in
|
|
* /proc have a size of 0 according to fstat() but have readable
|
|
* data. They are sometimes, but not always, seekable.
|
|
* Force them to be non-seekable here.
|
|
*/
|
|
if (ch_fsize == 0)
|
|
{
|
|
struct statfs st;
|
|
if (fstatfs(ch_file, &st) == 0)
|
|
{
|
|
if (st.f_type == PROC_SUPER_MAGIC)
|
|
{
|
|
ch_fsize = NULL_POSITION;
|
|
ch_flags &= ~CH_CANSEEK;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
if (lseek(ch_file, (off_t)0, SEEK_SET) == BAD_LSEEK)
|
|
{
|
|
/*
|
|
* Warning only; even if the seek fails for some reason,
|
|
* there's a good chance we're at the beginning anyway.
|
|
* {{ I think this is bogus reasoning. }}
|
|
*/
|
|
error("seek error to 0", NULL_PARG);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Allocate a new buffer.
|
|
* The buffer is added to the tail of the buffer chain.
|
|
*/
|
|
static int
|
|
ch_addbuf(VOID_PARAM)
|
|
{
|
|
struct buf *bp;
|
|
struct bufnode *bn;
|
|
|
|
/*
|
|
* Allocate and initialize a new buffer and link it
|
|
* onto the tail of the buffer list.
|
|
*/
|
|
bp = (struct buf *) calloc(1, sizeof(struct buf));
|
|
if (bp == NULL)
|
|
return (1);
|
|
ch_nbufs++;
|
|
bp->block = -1;
|
|
bn = &bp->node;
|
|
|
|
BUF_INS_TAIL(bn);
|
|
BUF_HASH_INS(bn, 0);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
*
|
|
*/
|
|
static void
|
|
init_hashtbl(VOID_PARAM)
|
|
{
|
|
int h;
|
|
|
|
for (h = 0; h < BUFHASH_SIZE; h++)
|
|
{
|
|
thisfile->hashtbl[h].hnext = END_OF_HCHAIN(h);
|
|
thisfile->hashtbl[h].hprev = END_OF_HCHAIN(h);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Delete all buffers for this file.
|
|
*/
|
|
static void
|
|
ch_delbufs(VOID_PARAM)
|
|
{
|
|
struct bufnode *bn;
|
|
|
|
while (ch_bufhead != END_OF_CHAIN)
|
|
{
|
|
bn = ch_bufhead;
|
|
BUF_RM(bn);
|
|
free(bufnode_buf(bn));
|
|
}
|
|
ch_nbufs = 0;
|
|
init_hashtbl();
|
|
}
|
|
|
|
/*
|
|
* Is it possible to seek on a file descriptor?
|
|
*/
|
|
public int
|
|
seekable(f)
|
|
int f;
|
|
{
|
|
#if MSDOS_COMPILER
|
|
extern int fd0;
|
|
if (f == fd0 && !isatty(fd0))
|
|
{
|
|
/*
|
|
* In MS-DOS, pipes are seekable. Check for
|
|
* standard input, and pretend it is not seekable.
|
|
*/
|
|
return (0);
|
|
}
|
|
#endif
|
|
return (lseek(f, (off_t)1, SEEK_SET) != BAD_LSEEK);
|
|
}
|
|
|
|
/*
|
|
* Force EOF to be at the current read position.
|
|
* This is used after an ignore_eof read, during which the EOF may change.
|
|
*/
|
|
public void
|
|
ch_set_eof(VOID_PARAM)
|
|
{
|
|
if (ch_fsize != NULL_POSITION && ch_fsize < ch_fpos)
|
|
ch_fsize = ch_fpos;
|
|
}
|
|
|
|
|
|
/*
|
|
* Initialize file state for a new file.
|
|
*/
|
|
public void
|
|
ch_init(f, flags)
|
|
int f;
|
|
int flags;
|
|
{
|
|
/*
|
|
* See if we already have a filestate for this file.
|
|
*/
|
|
thisfile = (struct filestate *) get_filestate(curr_ifile);
|
|
if (thisfile == NULL)
|
|
{
|
|
/*
|
|
* Allocate and initialize a new filestate.
|
|
*/
|
|
thisfile = (struct filestate *)
|
|
ecalloc(1, sizeof(struct filestate));
|
|
thisfile->buflist.next = thisfile->buflist.prev = END_OF_CHAIN;
|
|
thisfile->nbufs = 0;
|
|
thisfile->flags = flags;
|
|
thisfile->fpos = 0;
|
|
thisfile->block = 0;
|
|
thisfile->offset = 0;
|
|
thisfile->file = -1;
|
|
thisfile->fsize = NULL_POSITION;
|
|
init_hashtbl();
|
|
/*
|
|
* Try to seek; set CH_CANSEEK if it works.
|
|
*/
|
|
if ((flags & CH_CANSEEK) && !seekable(f))
|
|
ch_flags &= ~CH_CANSEEK;
|
|
set_filestate(curr_ifile, (void *) thisfile);
|
|
}
|
|
if (thisfile->file == -1)
|
|
thisfile->file = f;
|
|
ch_flush();
|
|
}
|
|
|
|
/*
|
|
* Close a filestate.
|
|
*/
|
|
public void
|
|
ch_close(VOID_PARAM)
|
|
{
|
|
int keepstate = FALSE;
|
|
|
|
if (thisfile == NULL)
|
|
return;
|
|
|
|
if ((ch_flags & (CH_CANSEEK|CH_POPENED|CH_HELPFILE)) && !(ch_flags & CH_KEEPOPEN))
|
|
{
|
|
/*
|
|
* We can seek or re-open, so we don't need to keep buffers.
|
|
*/
|
|
ch_delbufs();
|
|
} else
|
|
keepstate = TRUE;
|
|
if (!(ch_flags & CH_KEEPOPEN))
|
|
{
|
|
/*
|
|
* We don't need to keep the file descriptor open
|
|
* (because we can re-open it.)
|
|
* But don't really close it if it was opened via popen(),
|
|
* because pclose() wants to close it.
|
|
*/
|
|
if (!(ch_flags & (CH_POPENED|CH_HELPFILE)))
|
|
close(ch_file);
|
|
ch_file = -1;
|
|
} else
|
|
keepstate = TRUE;
|
|
if (!keepstate)
|
|
{
|
|
/*
|
|
* We don't even need to keep the filestate structure.
|
|
*/
|
|
free(thisfile);
|
|
thisfile = NULL;
|
|
set_filestate(curr_ifile, (void *) NULL);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Return ch_flags for the current file.
|
|
*/
|
|
public int
|
|
ch_getflags(VOID_PARAM)
|
|
{
|
|
if (thisfile == NULL)
|
|
return (0);
|
|
return (ch_flags);
|
|
}
|
|
|
|
#if 0
|
|
public void
|
|
ch_dump(struct filestate *fs)
|
|
{
|
|
struct buf *bp;
|
|
struct bufnode *bn;
|
|
unsigned char *s;
|
|
|
|
if (fs == NULL)
|
|
{
|
|
printf(" --no filestate\n");
|
|
return;
|
|
}
|
|
printf(" file %d, flags %x, fpos %x, fsize %x, blk/off %x/%x\n",
|
|
fs->file, fs->flags, fs->fpos,
|
|
fs->fsize, fs->block, fs->offset);
|
|
printf(" %d bufs:\n", fs->nbufs);
|
|
for (bn = fs->next; bn != &fs->buflist; bn = bn->next)
|
|
{
|
|
bp = bufnode_buf(bn);
|
|
printf("%x: blk %x, size %x \"",
|
|
bp, bp->block, bp->datasize);
|
|
for (s = bp->data; s < bp->data + 30; s++)
|
|
if (*s >= ' ' && *s < 0x7F)
|
|
printf("%c", *s);
|
|
else
|
|
printf(".");
|
|
printf("\"\n");
|
|
}
|
|
}
|
|
#endif
|