/* cut.c */

/* Author:
 *	Steve Kirkendall
 *	14407 SW Teal Blvd. #C
 *	Beaverton, OR 97005
 *	kirkenda@cs.pdx.edu
 */


/* This file contains function which manipulate the cut buffers. */

#include "config.h"
#include "vi.h"
#if TURBOC
#include <process.h>		/* needed for getpid */
#endif
#if TOS
#include <osbind.h>
#define	rename(a,b)	Frename(0,a,b)
#endif

# define NANNONS	9	/* number of annonymous buffers */

static struct cutbuf
{
	short	*phys;	/* pointer to an array of #s of BLKs containing text */
	int	nblks;	/* number of blocks in phys[] array */
	int	start;	/* offset into first block of start of cut */
	int	end;	/* offset into last block of end of cut */
	int	fd;	/* fd of tmp file, or -1 to use tmpfd */
	char	lnmode;	/* boolean: line-mode cut? (as opposed to char-mode) */
}
	named[27],	/* cut buffers "a through "z and ". */
	annon[NANNONS];	/* annonymous cut buffers */

static char	cbname;	/* name chosen for next cut/paste operation */


#ifndef NO_RECYCLE
/* This function builds a list of all blocks needed in the current tmp file
 * for the contents of cut buffers.
 * !!! WARNING: if you have more than ~450000 bytes of text in all of the
 * cut buffers, then this will fail disastrously, because buffer overflow
 * is *not* allowed for.
 */
int cutneeds(need)
	BLK		*need;	/* this is where we deposit the list */
{
	struct cutbuf	*cb;	/* used to count through cut buffers */
	int		i;	/* used to count through blocks of a cut buffer */
	int		n;	/* total number of blocks in list */

	n = 0;

	/* first the named buffers... */
	for (cb = named; cb < &named[27]; cb++)
	{
		if (cb->fd > 0)
			continue;

		for (i = cb->nblks; i-- > 0; )
		{
			need->n[n++] = cb->phys[i];
		}
	}

	/* then the anonymous buffers */
	for (cb = annon; cb < &annon[NANNONS]; cb++)
	{
		if (cb->fd > 0)
			continue;

		for (i = cb->nblks; i-- > 0; )
		{
			need->n[n++] = cb->phys[i];
		}
	}

	return n;
}
#endif

/* This function frees a cut buffer */
static void cutfree(buf)
	REG struct cutbuf	*buf;
{
	char	cutfname[50];
	int	i;

	/* return immediately if the buffer is already empty */
	if (buf->nblks <= 0)
	{
		return;
	}

	/* else free up stuff */
	buf->nblks = 0;
#ifdef DEBUG
	if (!buf->phys)
		msg("cutfree() tried to free an NULL buf->phys pointer.");
#endif
	free((char *)buf->phys);

	/* see if anybody else needs this tmp file */
	if (buf->fd >= 0)
	{
		for (i = 0; i < 27; i++)
		{
			if (named[i].nblks > 0 && named[i].fd == buf->fd)
			{
				break;
			}
		}
	}

	/* if nobody else needs it, then discard the tmp file */
	if (buf->fd >= 0 && i == 27)
	{
		close(buf->fd);
#if MSDOS || TOS
		strcpy(cutfname, o_directory);
		if ((i = strlen(cutfname)) && !strchr(":/\\", cutfname[i-1]))
			cutfname[i++]=SLASH;
		sprintf(cutfname+i, CUTNAME+3, getpid(), buf->fd);
#else
		sprintf(cutfname, CUTNAME, o_directory, getpid(), buf->fd);
#endif
		unlink(cutfname);
	}
}

/* This function is called when we are about to abort a tmp file.  If any
 * cut buffers still need the file, then a copy of the file should be
 * created for use by the cut buffers.
 *
 * To minimize the number of extra files lying around, only named cut buffers
 * are preserved in a file switch; the annonymous buffers just go away.
 */
void cutswitch(tmpname)
	char	*tmpname; /* name of the tmp file */
{
	char	cutfname[50];	/* used to build a new name for the tmp file */
	int	fd;		/* a new fd for the current tmp file */
	int	i;
#if MSDOS || TOS
	int	j;
#endif

	/* discard all annonymous cut buffers */
	for (i = 0; i < NANNONS; i++)
	{
		cutfree(&annon[i]);
	}

	/* find the first named buffer that uses this tmp file */
	for (i = 0; i < 27; i++)
	{
		if (named[i].nblks > 0 && named[i].fd < 0)
		{
			break;
		}
	}

	/* if none of them use this tmp file, then we're done */
	if (i == 27)
	{
		return;
	}

	/* else we'll need this file and an fd a little longer */
#if MSDOS || TOS
	strcpy(cutfname, o_directory);
	if ((j = strlen(cutfname)) && !strchr(":/\\", cutfname[j-1]))
		cutfname[j++]=SLASH;
	close(tmpfd);
	fd = open(tmpname, O_RDONLY|O_BINARY);
	close(fd);
	sprintf(cutfname+j, CUTNAME+3, getpid(), fd);
	rename(tmpname, cutfname);
	fd = open(cutfname, O_RDONLY|O_BINARY);
	tmpfd = -1; /* we'll try to close this in tmp.c, but who cares? */
#else
	fd = dup(tmpfd);
# if OSK
	sprintf(cutfname, CUTNAME, "", getpid(), fd);
	if (!link(tmpname, &cutfname[1])) /* skip slash */
		unlink(tmpname);
# else	
	sprintf(cutfname, CUTNAME, o_directory, getpid(), fd);
	link(tmpname, cutfname) || unlink(tmpname);
# endif
#endif

	/* have all cut buffers use the new fd instead */
	for (; i < 27; i++)
	{
		if (named[i].nblks > 0 && named[i].fd < 0)
		{
			named[i].fd = fd;
		}
	}
}

/* This function should be called just before termination of vi */
void cutend()
{
	int	i;

	/* free all named cut buffers, since they might be forcing an older
	 * tmp file to be retained.
	 */
	for (i = 0; i < 27; i++)
	{
		cutfree(&named[i]);
	}
}


/* This function is used to select the cut buffer to be used next */
void cutname(name)
	int	name;	/* a single character */
{
	cbname = name;
}




/* This function copies a selected segment of text to a cut buffer */
void cut(from, to)
	MARK	from;		/* start of text to cut */
	MARK	to;		/* end of text to cut */
{
	int		first;	/* logical number of first block in cut */
	int		last;	/* logical number of last block used in cut */
	long		line;	/* a line number */
	int		lnmode;	/* boolean: will this be a line-mode cut? */
	MARK		delthru;/* end of text temporarily inserted for apnd */
	REG struct cutbuf *cb;
	long	l;
	int		i;
	char	*scan;
	char		*blkc;

	/* detect whether this must be a line-mode cut or char-mode cut */
	if (markidx(from) == 0 && markidx(to) == 0)
		lnmode = TRUE;
	else
		lnmode = FALSE;

	/* by default, we don't "delthru" anything */
	delthru = MARK_UNSET;

	/* decide which cut buffer to use */
	if (!cbname)
	{
		/* free up the last annonymous cut buffer */
		cutfree(&annon[NANNONS - 1]);

		/* shift the annonymous cut buffers */
		for (i = NANNONS - 1; i > 0; i--)
		{
			annon[i] = annon[i - 1];
		}

		/* use the first annonymous cut buffer */
		cb = annon;
		cb->nblks = 0;
	}
	else if (cbname >= 'a' && cbname <= 'z')
	{
		cb = &named[cbname - 'a'];
		cutfree(cb);
	}
#ifndef CRUNCH
	else if (cbname >= 'A' && cbname <= 'Z')
	{
		cb = &named[cbname - 'A'];
		if (cb->nblks > 0)
		{
			/* resolve linemode/charmode differences */
			if (!lnmode && cb->lnmode)
			{
				from &= ~(BLKSIZE - 1);
				if (markidx(to) != 0 || to == from)
				{
					to = to + BLKSIZE - markidx(to);
				}
				lnmode = TRUE;
			}

			/* insert the old cut-buffer before the new text */
			mark[28] = to;
			delthru = paste(from, FALSE, TRUE);
			if (delthru == MARK_UNSET)
			{
				return;
			}
			delthru++;
			to = mark[28];
		}
		cutfree(cb);
	}
#endif /* not CRUNCH */
	else if (cbname == '.')
	{
		cb = &named[26];
		cutfree(cb);
	}
	else
	{
		msg("Invalid cut buffer name: \"%c", cbname);
		cbname = '\0';
		return;
	}
	cbname = '\0';
	cb->fd = -1;

	/* detect whether we're doing a line mode cut */
	cb->lnmode = lnmode;

	/* ---------- */

	/* Reporting... */	
	if (markidx(from) == 0 && markidx(to) == 0)
	{
		rptlines = markline(to) - markline(from);
		rptlabel = "yanked";
	}

	/* ---------- */

	/* make sure each block has a physical disk address */
	blksync();

	/* find the first block in the cut */
	line = markline(from);
	for (first = 1; line > lnum[first]; first++)
	{
	}

	/* fetch text of the block containing that line */
	blkc = scan = blkget(first)->c;

	/* find the mark in the block */
	for (l = lnum[first - 1]; ++l < line; )
	{
		while (*scan++ != '\n')
		{
		}
	}
	scan += markidx(from);

	/* remember the offset of the start */
	cb->start = scan - blkc;

	/* ---------- */

	/* find the last block in the cut */
	line = markline(to);
	for (last = first; line > lnum[last]; last++)
	{
	}

	/* fetch text of the block containing that line */
	if (last != first)
	{
		blkc = scan = blkget(last)->c;
	}
	else
	{
		scan = blkc;
	}

	/* find the mark in the block */
	for (l = lnum[last - 1]; ++l < line; )
	{
		while (*scan++ != '\n')
		{
		}
	}
	if (markline(to) <= nlines)
	{
		scan += markidx(to);
	}

	/* remember the offset of the end */
	cb->end = scan - blkc;

	/* ------- */

	/* remember the physical block numbers of all included blocks */
	cb->nblks = last - first;
	if (cb->end > 0)
	{
		cb->nblks++;
	}
#ifdef lint
	cb->phys = (short *)0;
#else
	cb->phys = (short *)malloc((unsigned)(cb->nblks * sizeof(short)));
#endif
	for (i = 0; i < cb->nblks; i++)
	{
		cb->phys[i] = hdr.n[first++];
	}

#ifndef CRUNCH
	/* if we temporarily inserted text for appending, then delete that
	 * text now -- before the user sees it.
	 */
	if (delthru)
	{
		line = rptlines;
		delete(from, delthru);
		rptlines = line;
		rptlabel = "yanked";
	}
#endif /* not CRUNCH */
}


static void readcutblk(cb, blkno)
	REG struct cutbuf	*cb;
	int		blkno;
{
	int		fd;	/* either tmpfd or cb->fd */

	/* decide which fd to use */
	if (cb->fd >= 0)
	{
		fd = cb->fd;
	}
	else
	{
		fd = tmpfd;
	}

	/* get the block */
	lseek(fd, (long)cb->phys[blkno] * (long)BLKSIZE, 0);
	if (read(fd, tmpblk.c, (unsigned)BLKSIZE) != BLKSIZE)
	{
		msg("Error reading back from tmp file for pasting!");
	}
}


/* This function inserts text from a cut buffer, and returns the MARK where
 * insertion ended.  Return MARK_UNSET on errors.
 */
MARK paste(at, after, retend)
	MARK	at;	/* where to insert the text */
	int	after;	/* boolean: insert after mark? (rather than before) */
	int	retend;	/* boolean: return end of text? (rather than start) */
{
	REG struct cutbuf	*cb;
	int			i;

	/* decide which cut buffer to use */
	if (cbname >= 'A' && cbname <= 'Z')
	{
		cb = &named[cbname - 'A'];
	}
	else if (cbname >= 'a' && cbname <= 'z')
	{
		cb = &named[cbname - 'a'];
	}
	else if (cbname >= '1' && cbname <= '9')
	{
		cb = &annon[cbname - '1'];
	}
	else if (cbname == '.')
	{
		cb = &named[26];
	}
	else if (!cbname)
	{
		cb = annon;
	}
	else
	{
		msg("Invalid cut buffer name: \"%c", cbname);
		cbname = '\0';
		return MARK_UNSET;
	}

	/* make sure it isn't empty */
	if (cb->nblks == 0)
	{
		if (cbname)
			msg("Cut buffer \"%c is empty", cbname);
		else
			msg("Cut buffer is empty");
		cbname = '\0';
		return MARK_UNSET;
	}
	cbname = '\0';

	/* adjust the insertion MARK for "after" and line-mode cuts */
	if (cb->lnmode)
	{
		at &= ~(BLKSIZE - 1);
		if (after)
		{
			at += BLKSIZE;
		}
	}
	else if (after)
	{
		/* careful! if markidx(at) == 0 we might be pasting into an
		 * empty line -- so we can't blindly increment "at".
		 */
		if (markidx(at) == 0)
		{
			pfetch(markline(at));
			if (plen != 0)
			{
				at++;
			}
		}
		else
		{
			at++;
		}
	}

	/* put a copy of the "at" mark in the mark[] array, so it stays in
	 * sync with changes made via add().
	 */
	mark[27] = at;

	/* simple one-block paste? */
	if (cb->nblks == 1)
	{
		/* get the block */
		readcutblk(cb, 0);

		/* isolate the text we need within it */
		if (cb->end)
		{
			tmpblk.c[cb->end] = '\0';
		}

		/* insert it */
		ChangeText
		{
			add(at, &tmpblk.c[cb->start]);
		}
	}
	else
	{
		/* multi-block paste */

		ChangeText
		{
			i = cb->nblks - 1;

			/* add text from the last block first */
			if (cb->end > 0)
			{
				readcutblk(cb, i);
				tmpblk.c[cb->end] = '\0';
				add(at, tmpblk.c);
				i--;
			}

			/* add intervening blocks */
			while (i > 0)
			{
				readcutblk(cb, i);
				add(at, tmpblk.c);
				i--;
			}

			/* add text from the first cut block */
			readcutblk(cb, 0);
			add(at, &tmpblk.c[cb->start]);
		}
	}

	/* Reporting... */
	rptlines = markline(mark[27]) - markline(at);
	rptlabel = "pasted";

	/* return the mark at the beginning/end of inserted text */
	if (retend)
	{
		return mark[27] - 1L;
	}
	return at;
}




#ifndef NO_AT

/* This function copies characters from a cut buffer into a string.
 * It returns the number of characters in the cut buffer.  If the cut
 * buffer is too large to fit in the string (i.e. if cb2str() returns
 * a number >= size) then the characters will not have been copied.
 * It returns 0 if the cut buffer is empty, and -1 for invalid cut buffers.
 */
int cb2str(name, buf, size)
	int	name;	/* the name of a cut-buffer to get: a-z only! */
	char	*buf;	/* where to put the string */
	unsigned size;	/* size of buf */
{
	REG struct cutbuf	*cb;
	REG char		*src;
	REG char		*dest;

	/* decide which cut buffer to use */
	if (name >= 'a' && name <= 'z')
	{
		cb = &named[name - 'a'];
	}
	else
	{
		return -1;
	}

	/* if the buffer is empty, return 0 */
	if (cb->nblks == 0)
	{
		return 0;
	}

	/* !!! if not a single-block cut, then fail */
	if (cb->nblks != 1)
	{
		return size;
	}

	/* if too big, return the size now, without doing anything */
	if (cb->end - cb->start >= size)
	{
		return cb->end - cb->start;
	}

	/* get the block */
	readcutblk(cb, 0);

	/* isolate the string within that blk */
	if (cb->start == 0)
	{
		tmpblk.c[cb->end] = '\0';
	}
	else
	{
		for (dest = tmpblk.c, src = dest + cb->start; src < tmpblk.c + cb->end; )
		{
			*dest++ = *src++;
		}
		*dest = '\0';
	}

	/* copy the string into the buffer */
	if (buf != tmpblk.c)
	{
		strcpy(buf, tmpblk.c);
	}

	/* return the length */
	return cb->end - cb->start;
}
#endif
