source: trunk/minix/commands/elvis/cut.c@ 21

/* 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 NANONS 9       /* number of anonymous 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     tmpnum; /* ID number of the temp file */
        char    lnmode; /* boolean: line-mode cut? (as opposed to char-mode) */
}
        named[27],      /* cut buffers "a through "z and ". */
        anon[NANONS];   /* anonymous cut buffers */

static char     cbname; /* name chosen for next cut/paste operation */
static char     dotcb;  /* cut buffer to use if "doingdot" is set */


#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->tmpnum != tmpnum)
                        continue;

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

        /* then the anonymous buffers */
        for (cb = anon; cb < &anon[NANONS]; cb++)
        {
                if (cb->tmpnum != tmpnum)
                        continue;

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

        /* return the length of the list */
        return n;
}
#endif

static void maybezap(num)
        int     num;    /* the tmpnum of the temporary file to [maybe] delete */
{
        char    cutfname[80];
        int     i;

        /* if this is the current tmp file, then we'd better keep it! */
        if (tmpfd >= 0 && num == tmpnum)
        {
                return;
        }

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

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

/* This function frees a cut buffer.  If it was the last cut buffer that
 * refered to an old temp file, then it will delete the temp file. */
static void cutfree(buf)
        struct cutbuf   *buf;
{
        int     num;

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

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

        /* maybe delete the temp file */
        maybezap(num);
}

/* This function is called when we are about to abort a tmp file.
 *
 * To minimize the number of extra files lying around, only named cut buffers
 * are preserved in a file switch; the anonymous buffers just go away.
 */
void cutswitch()
{
        int     i;

        /* mark the current temp file as being "obsolete", and close it.  */
        storename((char *)0);
        close(tmpfd);
        tmpfd = -1;

        /* discard all anonymous cut buffers */
        for (i = 0; i < NANONS; i++)
        {
                cutfree(&anon[i]);
        }

        /* delete the temp file, if we don't really need it */
        maybezap(tmpnum);
}

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

        /* free the anonymous buffers, if they aren't already free */
        cutswitch();

        /* 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]);
        }

        /* delete the temp file */
        maybezap(tmpnum);
}


/* 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;
        REG long        l;
        REG int         i;
        REG 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;

        /* handle the "doingdot" quirks */
        if (doingdot)
        {
                if (!cbname)
                {
                        cbname = dotcb;
                }
        }
        else if (cbname != '.')
        {
                dotcb = cbname;
        }

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

                /* shift the anonymous cut buffers */
                for (i = NANONS - 1; i > 0; i--)
                {
                        anon[i] = anon[i - 1];
                }

                /* use the first anonymous cut buffer */
                cb = anon;
                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);
                dotcb = cbname = '\0';
                return;
        }
        cbname = '\0';
        cb->tmpnum = tmpnum;

        /* 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)
        struct cutbuf   *cb;
        int             blkno;
{
        char            cutfname[50];/* name of an old temp file */
        int             fd;     /* either tmpfd or the result of open() */
#if MSDOS || TOS
        int             i;
#endif

        /* decide which fd to use */
        if (cb->tmpnum == tmpnum)
        {
                fd = tmpfd;
        }
        else
        {
#if MSDOS || TOS
                strcpy(cutfname, o_directory);
                if ((i = strlen(cutfname)) && !strchr(":/\\", cutfname[i-1]))
                        cutfname[i++]=SLASH;
                sprintf(cutfname+i, TMPNAME+3, getpid(), cb->tmpnum);
#else
                sprintf(cutfname, TMPNAME, o_directory, getpid(), cb->tmpnum);
#endif
                fd = open(cutfname, O_RDONLY);
        }

        /* 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!");
        }

        /* close the fd, if it isn't tmpfd */
        if (fd != tmpfd)
        {
                close(fd);
        }
}


/* 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;
        REG int                 i;

        /* handle the "doingdot" quirks */
        if (doingdot)
        {
                if (!cbname)
                {
                        if (dotcb >= '1' && dotcb < '1' + NANONS - 1)
                        {
                                dotcb++;
                        }
                        cbname = dotcb;
                }
        }
        else if (cbname != '.')
        {
                dotcb = cbname;
        }

        /* 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 = &anon[cbname - '1'];
        }
        else if (cbname == '.')
        {
                cb = &named[26];
        }
        else if (!cbname)
        {
                cb = anon;
        }
        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