adding GNU dc ("desk calculator")

[unix-history] / lib / libc / db / btree / insert.c

/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Mike Olson.
*
* 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, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by the University of
*      California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)insert.c    5.3 (Berkeley) 2/22/91";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <db.h>
#include <stdlib.h>
#include <string.h>
#include "btree.h"

/*
*  _BT_INSERT -- Insert a new user datum in the btree.
*
*      This routine is called by bt_put, the public interface, once the
*      location for the new item is known.  We do the work here, and
*      handle splits if necessary.
*
*      Parameters:
*              t -- btree in which to do the insertion.
*              item -- BTITEM describing location of new datum
*              key -- key to insert
*              data -- data associated with key
*              flag -- magic cookie passed recursively to bt_put if we
*                      have to do a split
*
*      Returns:
*              RET_SUCCESS, RET_ERROR.
*/

int
_bt_insert(t, item, key, data, flag)
       BTREE_P t;
       BTITEM *item;
       DBT *key;
       DBT *data;
       int flag;
{
       index_t index;
       BTHEADER *h;
       DATUM *d;
       int nbytes;
       int status;
       pgno_t pgno;
       int keysize, datasize;
       int bigkey, bigdata;

       if (_bt_getpage(t, item->bti_pgno) == RET_ERROR)
               return (RET_ERROR);
       h = t->bt_curpage;

       if (TOOBIG(t, data->size)) {
               bigdata = TRUE;
               datasize = sizeof(pgno_t);
       } else {
               bigdata = FALSE;
               datasize = data->size;
       }

       if (TOOBIG(t, key->size)) {
               bigkey = TRUE;
               keysize = sizeof(pgno_t);
       } else {
               bigkey = FALSE;
               keysize = key->size;
       }

       nbytes = keysize + datasize + (sizeof(DATUM) - sizeof(char));
       nbytes = LONGALIGN(nbytes) + sizeof(index_t);

       /* if there's not enough room here, split the page */
       if ((h->h_upper - h->h_lower) < nbytes) {
               if (_bt_split(t) == RET_ERROR)
                       return (RET_ERROR);

               /* okay, try again (empty the stack first, though) */
               while (_bt_pop((BTREE) t) != P_NONE)
                       continue;

               return (bt_put((BTREE) t, key, data, flag));
       }

       /* put together a leaf page datum from the key/data pair */
       index = item->bti_index;
       nbytes = keysize + datasize + (sizeof(DATUM) - sizeof(char));

       if ((d = (DATUM *) malloc((unsigned) nbytes)) == (DATUM *) NULL)
               return (RET_ERROR);

       d->d_ksize = keysize;
       d->d_dsize = datasize;
       d->d_flags = 0;

       if (bigkey) {
               if (_bt_indirect(t, key, &pgno) == RET_ERROR)
                       return (RET_ERROR);
               (void) bcopy((char *) &pgno, &(d->d_bytes[0]), sizeof(pgno));
               d->d_flags |= D_BIGKEY;
               if (_bt_getpage(t, item->bti_pgno) == RET_ERROR)
                       return (RET_ERROR);
       } else {
               if (d->d_ksize > 0) {
                       (void) bcopy((char *) key->data,
                                     (char *) &(d->d_bytes[0]),
                                     (int) d->d_ksize);
               }
       }

       if (bigdata) {
               if (_bt_indirect(t, data, &pgno) == RET_ERROR)
                       return (RET_ERROR);
               (void) bcopy((char *) &pgno,
                            &(d->d_bytes[keysize]),
                            sizeof(pgno));
               d->d_flags |= D_BIGDATA;
               if (_bt_getpage(t, item->bti_pgno) == RET_ERROR)
                       return (RET_ERROR);
       } else {
               if (d->d_dsize > 0) {
                       (void) bcopy((char *) data->data,
                                     (char *) &(d->d_bytes[keysize]),
                                     (int) d->d_dsize);
               }
       }

       /* do the insertion */
       status = _bt_insertat(t, (char *) d, index);

       (void) free((char *) d);

       return (status);
}

/*
*  _BT_INSERTI -- Insert IDATUM on current page in the btree.
*
*      This routine handles insertions to internal pages after splits
*      lower in the tree.  On entry, t->bt_curpage is the page to get
*      the new IDATUM.  We are also given pgno, the page number of the
*      IDATUM that is immediately left of the new IDATUM's position.
*      This guarantees that the IDATUM for the right half of the page
*      after a split goes next to the IDATUM for its left half.
*
*      Parameters:
*              t -- tree in which to do insertion.
*              id -- new IDATUM to insert
*              pgno -- page number of IDATUM left of id's position
*
*      Returns:
*              RET_SUCCESS, RET_ERROR.
*/

int
_bt_inserti(t, id, pgno)
       BTREE_P t;
       IDATUM *id;
       pgno_t pgno;
{
       BTHEADER *h = t->bt_curpage;
       index_t next, i;
       IDATUM *idx;
       char *key;
       pgno_t chain;
       int free_key;
       int ignore;

       if (id->i_flags & D_BIGKEY) {
               free_key = TRUE;
               bcopy(&(id->i_bytes[0]), (char *) &chain, sizeof(chain));
               if (_bt_getbig(t, chain, &key, &ignore) == RET_ERROR)
                       return (RET_ERROR);
       } else {
               free_key = FALSE;
               key = &(id->i_bytes[0]);
       }
       i = _bt_binsrch(t, key);

       next = NEXTINDEX(h);
       while (i < next && _bt_cmp(t, key, i) >= 0)
               i++;

       if (free_key)
               (void) free(key);

       /* okay, now we're close; find adjacent IDATUM */
       for (;;) {
               idx = (IDATUM *) GETDATUM(h,i);
               if (idx->i_pgno == pgno) {
                       i++;
                       break;
               }
               --i;
       }

       /* correctly positioned, do the insertion */
       return (_bt_insertat(t, (char *) id, i));
}

/*
*  _BT_INSERTAT -- Insert a datum at a given location on the current page.
*
*      This routine does insertions on both leaf and internal pages.
*
*      Parameters:
*              t -- tree in which to do insertion.
*              p -- DATUM or IDATUM to insert.
*              index -- index in line pointer array to put this item.
*
*      Returns:
*              RET_SUCCESS, RET_ERROR.
*
*      Side Effects:
*              Will rearrange line pointers to make space for the new
*              entry.  This means that any scans currently active are
*              invalid after this.
*
*      Warnings:
*              There must be sufficient room for the new item on the page.
*/

int
_bt_insertat(t, p, index)
       BTREE_P t;
       char *p;
       index_t index;
{
       IDATUM *id = (IDATUM *) p;
       DATUM *d = (DATUM *) p;
       BTHEADER *h;
       CURSOR *c;
       index_t nxtindex;
       char *src, *dest;
       int nbytes;

       /* insertion may confuse an active scan.  fix it. */
       c = &(t->bt_cursor);
       if (t->bt_flags & BTF_SEQINIT && t->bt_curpage->h_pgno == c->c_pgno)
               if (_bt_fixscan(t, index, d, INSERT) == RET_ERROR)
                       return (RET_ERROR);

       h = t->bt_curpage;
       nxtindex = (index_t) NEXTINDEX(h);

       /*
        *  If we're inserting at the middle of the line pointer array,
        *  copy pointers that will follow the new one up on the page.
        */

       if (index < nxtindex) {
               src = (char *) &(h->h_linp[index]);
               dest = (char *) &(h->h_linp[index + 1]);
               nbytes = (h->h_lower - (src - ((char *) h)))
                        + sizeof(h->h_linp[0]);
               (void) bcopy(src, dest, nbytes);
       }

       /* compute size and copy data to page */
       if (h->h_flags & F_LEAF) {
               nbytes = d->d_ksize + d->d_dsize
                        + (sizeof(DATUM) - sizeof(char));
       } else {
               nbytes = id->i_size + (sizeof(IDATUM) - sizeof(char));
       }
       dest = (((char *) h) + h->h_upper) - LONGALIGN(nbytes);
       (void) bcopy((char *) p, dest, nbytes);

       /* update statistics */
       dest -= (int) h;
       h->h_linp[index] = (index_t) dest;
       h->h_upper = (index_t) dest;
       h->h_lower += sizeof(index_t);

       /* we're done */
       h->h_flags |= F_DIRTY;

       return (RET_SUCCESS);
}