rec_search.c File Reference

#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include "../include/db.h"
#include "recno.h"

Include dependency graph for rec_search.c:

Go to the source code of this file.

Functions
EPG *	__rec_search (BTREE *t, recno_t recno, enum SRCHOP op)

Function Documentation

__rec_search()

EPG * __rec_search	(	BTREE *	t,
		recno_t	recno,
		enum SRCHOP	op
	)

Definition at line 64 of file rec_search.c.

{
    register indx_t index;
    register PAGE *h;
    EPGNO *parent;
    RINTERNAL *r;
    pgno_t pg;
    indx_t top;
    recno_t total;
    int sverrno;
 
    BT_CLR(t);
    for (pg = P_ROOT, total = 0;;) {
        if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
            goto err;
        if (h->flags & P_RLEAF) {
            t->bt_cur.page = h;
            t->bt_cur.index = recno - total;
            return (&t->bt_cur);
        }
        for (index = 0, top = NEXTINDEX(h);;) {
            r = GETRINTERNAL(h, index);
            if (++index == top || total + r->nrecs > recno)
                break;
            total += r->nrecs;
        }
 
        BT_PUSH(t, pg, index - 1);
 
        pg = r->pgno;
        switch (op) {
        case SDELETE:
            --GETRINTERNAL(h, (index - 1))->nrecs;
            mpool_put(t->bt_mp, h, MPOOL_DIRTY);
            break;
        case SINSERT:
            ++GETRINTERNAL(h, (index - 1))->nrecs;
            mpool_put(t->bt_mp, h, MPOOL_DIRTY);
            break;
        case SEARCH:
            mpool_put(t->bt_mp, h, 0);
            break;
        }
 
    }
    /* Try and recover the tree. */
err:    sverrno = errno;
    if (op != SEARCH)
        while  ((parent = BT_POP(t)) != NULL) {
            if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
                break;
            if (op == SINSERT)
                --GETRINTERNAL(h, parent->index)->nrecs;
            else
                ++GETRINTERNAL(h, parent->index)->nrecs;
                        mpool_put(t->bt_mp, h, MPOOL_DIRTY);
                }
    errno = sverrno;
    return (NULL);
}

References BT_CLR, _btree::bt_cur, _btree::bt_mp, BT_POP, BT_PUSH, errno, _page::flags, GETRINTERNAL, _epgno::index, _epg::index, MPOOL_DIRTY, mpool_get(), mpool_put(), NEXTINDEX, _rinternal::nrecs, NULL, P_RLEAF, P_ROOT, _epg::page, _rinternal::pgno, _epgno::pgno, SDELETE, SEARCH, SINSERT, and total.

Referenced by __rec_get(), __rec_iput(), __rec_seq(), and rec_rdelete().