/*      $OpenBSD: delete.c,v 1.12 2017/11/26 09:59:41 mestre Exp $      */

/*-
 * Copyright (c) 1992, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1992, 1993, 1994, 1995, 1996
 *      Keith Bostic.  All rights reserved.
 *
 * See the LICENSE file for redistribution information.
 */

#include "config.h"

#include <sys/types.h>
#include <sys/queue.h>

#include <bitstring.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "common.h"

/*
 * del --
 *      Delete a range of text.
 *
 * PUBLIC: int del(SCR *, MARK *, MARK *, int);
 */
int
del(SCR *sp, MARK *fm, MARK *tm, int lmode)
{
        recno_t lno;
        size_t blen, len, nlen, tlen;
        char *bp, *p;
        int eof, rval;

        bp = NULL;

        /* Case 1 -- delete in line mode. */
        if (lmode) {
                for (lno = tm->lno; lno >= fm->lno; --lno) {
                        if (db_delete(sp, lno))
                                return (1);
                        ++sp->rptlines[L_DELETED];
                        if (lno % INTERRUPT_CHECK == 0 && INTERRUPTED(sp))
                                break;
                }
                goto done;
        }

        /*
         * Case 2 -- delete to EOF.  This is a special case because it's
         * easier to pick it off than try and find it in the other cases.
         */
        if (db_last(sp, &lno))
                return (1);
        if (tm->lno >= lno) {
                if (tm->lno == lno) {
                        if (db_get(sp, lno, DBG_FATAL, &p, &len))
                                return (1);
                        eof = tm->cno != -1 && tm->cno >= len ? 1 : 0;
                } else
                        eof = 1;
                if (eof) {
                        for (lno = tm->lno; lno > fm->lno; --lno) {
                                if (db_delete(sp, lno))
                                        return (1);
                                ++sp->rptlines[L_DELETED];
                                if (lno %
                                    INTERRUPT_CHECK == 0 && INTERRUPTED(sp))
                                        break;
                        }
                        if (db_get(sp, fm->lno, DBG_FATAL, &p, &len))
                                return (1);
                        GET_SPACE_RET(sp, bp, blen, fm->cno);
                        memcpy(bp, p, fm->cno);
                        if (db_set(sp, fm->lno, bp, fm->cno))
                                return (1);
                        goto done;
                }
        }

        /* Case 3 -- delete within a single line. */
        if (tm->lno == fm->lno) {
                if (db_get(sp, fm->lno, DBG_FATAL, &p, &len))
                        return (1);
                if (len != 0) {
                        GET_SPACE_RET(sp, bp, blen, len);
                        if (fm->cno != 0)
                                memcpy(bp, p, fm->cno);
                        memcpy(bp + fm->cno, p + (tm->cno + 1), len - (tm->cno + 1));
                        if (db_set(sp, fm->lno,
                            bp, len - ((tm->cno - fm->cno) + 1)))
                                goto err;
                        goto done;
                }
        }

        /*
         * Case 4 -- delete over multiple lines.
         *
         * Copy the start partial line into place.
         */
        if ((tlen = fm->cno) != 0) {
                if (db_get(sp, fm->lno, DBG_FATAL, &p, NULL))
                        return (1);
                GET_SPACE_RET(sp, bp, blen, tlen + 256);
                memcpy(bp, p, tlen);
        }

        /* Copy the end partial line into place. */
        if (db_get(sp, tm->lno, DBG_FATAL, &p, &len))
                goto err;
        if (len != 0 && tm->cno != len - 1) {
                if (len < tm->cno + 1 || len - (tm->cno + 1) > SIZE_MAX - tlen) {
                        msgq(sp, M_ERR, "Line length overflow");
                        goto err;
                }
                nlen = (len - (tm->cno + 1)) + tlen;
                if (tlen == 0) {
                        GET_SPACE_RET(sp, bp, blen, nlen);
                } else
                        ADD_SPACE_RET(sp, bp, blen, nlen);

                memcpy(bp + tlen, p + (tm->cno + 1), len - (tm->cno + 1));
                tlen += len - (tm->cno + 1);
        }

        /* Set the current line. */
        if (db_set(sp, fm->lno, bp, tlen))
                goto err;

        /* Delete the last and intermediate lines. */
        for (lno = tm->lno; lno > fm->lno; --lno) {
                if (db_delete(sp, lno))
                        goto err;
                ++sp->rptlines[L_DELETED];
                if (lno % INTERRUPT_CHECK == 0 && INTERRUPTED(sp))
                        break;
        }

done:   rval = 0;
        if (0)
err:            rval = 1;
        if (bp != NULL)
                FREE_SPACE(sp, bp, blen);
        return (rval);
}