hash_bigkey.c File Reference

#include <sys/param.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "../include/db.h"
#include "hash.h"
#include "page.h"
#include "extern.h"

Include dependency graph for hash_bigkey.c:

Go to the source code of this file.

Functions
int	__big_delete (HTAB *hashp, BUFHEAD *bufp)
int	__big_insert (HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val)
int	__big_keydata (HTAB *hashp, BUFHEAD *bufp, DBT *key, DBT *val, int set)
int	__big_return (HTAB *hashp, BUFHEAD *bufp, int ndx, DBT *val, int set_current)
int	__big_split (HTAB *hashp, BUFHEAD *op, BUFHEAD *np, BUFHEAD *big_keyp, int addr, u_int32_t obucket, SPLIT_RETURN *ret)
int	__find_bigpair (HTAB *hashp, BUFHEAD *bufp, int ndx, char *key, int size)
u_int16_t	__find_last_page (HTAB *hashp, BUFHEAD **bpp)
static int collect_key	__P ((HTAB *, BUFHEAD *, int, DBT *, int))
static int collect_data	__P ((HTAB *, BUFHEAD *, int, int))
static int	collect_data (HTAB *hashp, BUFHEAD *bufp, int len, int set)
static int	collect_key (HTAB *hashp, BUFHEAD *bufp, int len, DBT *val, int set)

Function Documentation

__big_delete()

int __big_delete	(	HTAB *	hashp,
		BUFHEAD *	bufp
	)

Definition at line 188 of file hash_bigkey.c.

{
    register BUFHEAD *last_bfp, *rbufp;
    u_int16_t *bp, pageno;
    int key_done, n;
 
    rbufp = bufp;
    last_bfp = NULL;
    bp = (u_int16_t *)bufp->page;
    pageno = 0;
    key_done = 0;
 
    while (!key_done || (bp[2] != FULL_KEY_DATA)) {
        if (bp[2] == FULL_KEY || bp[2] == FULL_KEY_DATA)
            key_done = 1;
 
        /*
         * If there is freespace left on a FULL_KEY_DATA page, then
         * the data is short and fits entirely on this page, and this
         * is the last page.
         */
        if (bp[2] == FULL_KEY_DATA && FREESPACE(bp))
            break;
        pageno = bp[bp[0] - 1];
        rbufp->flags |= BUF_MOD;
        rbufp = __get_buf(hashp, pageno, rbufp, 0);
        if (last_bfp)
            __free_ovflpage(hashp, last_bfp);
        last_bfp = rbufp;
        if (!rbufp)
            return (-1);        /* Error. */
        bp = (u_int16_t *)rbufp->page;
    }
 
    /*
     * If we get here then rbufp points to the last page of the big
     * key/data pair.  Bufp points to the first one -- it should now be
     * empty pointing to the next page after this pair.  Can't free it
     * because we don't have the page pointing to it.
     */
 
    /* This is information from the last page of the pair. */
    n = bp[0];
    pageno = bp[n - 1];
 
    /* Now, bp is the first page of the pair. */
    bp = (u_int16_t *)bufp->page;
    if (n > 2) {
        /* There is an overflow page. */
        bp[1] = pageno;
        bp[2] = OVFLPAGE;
        bufp->ovfl = rbufp->ovfl;
    } else
        /* This is the last page. */
        bufp->ovfl = NULL;
    n -= 2;
    bp[0] = n;
    FREESPACE(bp) = hashp->BSIZE - PAGE_META(n);
    OFFSET(bp) = hashp->BSIZE - 1;
 
    bufp->flags |= BUF_MOD;
    if (rbufp)
        __free_ovflpage(hashp, rbufp);
    if (last_bfp && last_bfp != rbufp)
        __free_ovflpage(hashp, last_bfp);
 
    hashp->NKEYS--;
    return (0);
}

References __free_ovflpage(), __get_buf(), BUF_MOD, _bufhead::flags, FREESPACE, FULL_KEY, FULL_KEY_DATA, if(), NULL, OFFSET, _bufhead::ovfl, OVFLPAGE, _bufhead::page, PAGE_META, and while().

Referenced by __delpair().

__big_insert()

int __big_insert	(	HTAB *	hashp,
		BUFHEAD *	bufp,
		const DBT *	key,
		const DBT *	val
	)

Definition at line 88 of file hash_bigkey.c.

{
    register u_int16_t *p;
    int key_size, n, val_size;
    u_int16_t space, move_bytes, off;
    char *cp, *key_data, *val_data;
 
    cp = bufp->page;        /* Character pointer of p. */
    p = (u_int16_t *)cp;
 
    key_data = (char *)key->data;
    key_size = key->size;
    val_data = (char *)val->data;
    val_size = val->size;
 
    /* First move the Key */
    for (space = FREESPACE(p) - BIGOVERHEAD; key_size;
        space = FREESPACE(p) - BIGOVERHEAD) {
        move_bytes = MIN(space, key_size);
        off = OFFSET(p) - move_bytes;
        memmove(cp + off, key_data, move_bytes);
        key_size -= move_bytes;
        key_data += move_bytes;
        n = p[0];
        p[++n] = off;
        p[0] = ++n;
        FREESPACE(p) = off - PAGE_META(n);
        OFFSET(p) = off;
        p[n] = PARTIAL_KEY;
        bufp = __add_ovflpage(hashp, bufp);
        if (!bufp)
            return (-1);
        n = p[0];
        if (!key_size) {
            if (FREESPACE(p)) {
                move_bytes = MIN(FREESPACE(p), val_size);
                off = OFFSET(p) - move_bytes;
                p[n] = off;
                memmove(cp + off, val_data, move_bytes);
                val_data += move_bytes;
                val_size -= move_bytes;
                p[n - 2] = FULL_KEY_DATA;
                FREESPACE(p) = FREESPACE(p) - move_bytes;
                OFFSET(p) = off;
            } else
                p[n - 2] = FULL_KEY;
        }
        p = (u_int16_t *)bufp->page;
        cp = bufp->page;
        bufp->flags |= BUF_MOD;
    }
 
    /* Now move the data */
    for (space = FREESPACE(p) - BIGOVERHEAD; val_size;
        space = FREESPACE(p) - BIGOVERHEAD) {
        move_bytes = MIN(space, val_size);
        /*
         * Here's the hack to make sure that if the data ends on the
         * same page as the key ends, FREESPACE is at least one.
         */
        if ((int) space == val_size && (size_t) val_size == val->size)
            move_bytes--;
        off = OFFSET(p) - move_bytes;
        memmove(cp + off, val_data, move_bytes);
        val_size -= move_bytes;
        val_data += move_bytes;
        n = p[0];
        p[++n] = off;
        p[0] = ++n;
        FREESPACE(p) = off - PAGE_META(n);
        OFFSET(p) = off;
        if (val_size) {
            p[n] = FULL_KEY;
            bufp = __add_ovflpage(hashp, bufp);
            if (!bufp)
                return (-1);
            cp = bufp->page;
            p = (u_int16_t *)cp;
        } else
            p[n] = FULL_KEY_DATA;
        bufp->flags |= BUF_MOD;
    }
    return (0);
}

References __add_ovflpage(), BIGOVERHEAD, BUF_MOD, DBT::data, _bufhead::flags, FREESPACE, FULL_KEY, FULL_KEY_DATA, MIN, OFFSET, _bufhead::page, PAGE_META, PARTIAL_KEY, and DBT::size.

Referenced by __addel().

__big_keydata()

int __big_keydata	(	HTAB *	hashp,
		BUFHEAD *	bufp,
		DBT *	key,
		DBT *	val,
		int	set
	)

Definition at line 507 of file hash_bigkey.c.

{
    key->size = collect_key(hashp, bufp, 0, val, set);
    if (key->size == (size_t) -1)
        return (-1);
    key->data = (u_char *)hashp->tmp_key;
    return (0);
}

References collect_key(), DBT::data, set(), DBT::size, and htab::tmp_key.

Referenced by __big_split(), and hash_seq().

__big_return()

int __big_return	(	HTAB *	hashp,
		BUFHEAD *	bufp,
		int	ndx,
		DBT *	val,
		int	set_current
	)

Definition at line 360 of file hash_bigkey.c.

{
    BUFHEAD *save_p;
    u_int16_t *bp, len, off, save_addr;
    char *tp;
 
    bp = (u_int16_t *)bufp->page;
    while (bp[ndx + 1] == PARTIAL_KEY) {
        bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
        if (!bufp)
            return (-1);
        bp = (u_int16_t *)bufp->page;
        ndx = 1;
    }
 
    if (bp[ndx + 1] == FULL_KEY) {
        bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
        if (!bufp)
            return (-1);
        bp = (u_int16_t *)bufp->page;
        save_p = bufp;
        save_addr = save_p->addr;
        off = bp[1];
        len = 0;
    } else
        if (!FREESPACE(bp)) {
            /*
             * This is a hack.  We can't distinguish between
             * FULL_KEY_DATA that contains complete data or
             * incomplete data, so we require that if the data
             * is complete, there is at least 1 byte of free
             * space left.
             */
            off = bp[bp[0]];
            len = bp[1] - off;
            save_p = bufp;
            save_addr = bufp->addr;
            bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
            if (!bufp)
                return (-1);
            bp = (u_int16_t *)bufp->page;
        } else {
            /* The data is all on one page. */
            tp = (char *)bp;
            off = bp[bp[0]];
            val->data = (u_char *)tp + off;
            val->size = bp[1] - off;
            if (set_current) {
                if (bp[0] == 2) {   /* No more buckets in
                             * chain */
                    hashp->cpage = NULL;
                    hashp->cbucket++;
                    hashp->cndx = 1;
                } else {
                    hashp->cpage = __get_buf(hashp,
                        bp[bp[0] - 1], bufp, 0);
                    if (!hashp->cpage)
                        return (-1);
                    hashp->cndx = 1;
                    if (!((u_int16_t *)
                        hashp->cpage->page)[0]) {
                        hashp->cbucket++;
                        hashp->cpage = NULL;
                    }
                }
            }
            return (0);
        }
 
    val->size = collect_data(hashp, bufp, (int)len, set_current);
    if (val->size == (size_t) -1)
        return (-1);
    if (save_p->addr != save_addr) {
        /* We are pretty short on buffers. */
        errno = EINVAL;         /* OUT OF BUFFERS */
        return (-1);
    }
    memmove(hashp->tmp_buf, (save_p->page) + off, len);
    val->data = (u_char *)hashp->tmp_buf;
    return (0);
}

References __get_buf(), _bufhead::addr, htab::cbucket, htab::cndx, collect_data(), htab::cpage, errno, FREESPACE, FULL_KEY, len(), NULL, _bufhead::page, PARTIAL_KEY, htab::tmp_buf, and while().

Referenced by collect_key(), and hash_access().

__big_split()

int __big_split	(	HTAB *	hashp,
		BUFHEAD *	op,
		BUFHEAD *	np,
		BUFHEAD *	big_keyp,
		int	addr,
		u_int32_t	obucket,
		SPLIT_RETURN *	ret
	)

Definition at line 570 of file hash_bigkey.c.

{
    register BUFHEAD *tmpp;
    register u_int16_t *tp;
    BUFHEAD *bp;
    DBT key, val;
    u_int32_t change;
    u_int16_t free_space, n, off;
 
    bp = big_keyp;
 
    /* Now figure out where the big key/data goes */
    if (__big_keydata(hashp, big_keyp, &key, &val, 0))
        return (-1);
    change = (__call_hash(hashp, key.data, key.size) != obucket);
 
    if ((ret->next_addr = __find_last_page(hashp, &big_keyp))) {
        if (!(ret->nextp =
            __get_buf(hashp, ret->next_addr, big_keyp, 0)))
            return (-1);;
    } else
        ret->nextp = NULL;
 
    /* Now make one of np/op point to the big key/data pair */
#ifdef DEBUG
    assert(np->ovfl == NULL);
#endif
    if (change)
        tmpp = np;
    else
        tmpp = op;
 
    tmpp->flags |= BUF_MOD;
#ifdef DEBUG1
    (void)fprintf(stderr,
        "BIG_SPLIT: %d->ovfl was %d is now %d\n", tmpp->addr,
        (tmpp->ovfl ? tmpp->ovfl->addr : 0), (bp ? bp->addr : 0));
#endif
    tmpp->ovfl = bp;    /* one of op/np point to big_keyp */
    tp = (u_int16_t *)tmpp->page;
#ifdef DEBUG
    assert(FREESPACE(tp) >= OVFLSIZE);
#endif
    n = tp[0];
    off = OFFSET(tp);
    free_space = FREESPACE(tp);
    tp[++n] = (u_int16_t)addr;
    tp[++n] = OVFLPAGE;
    tp[0] = n;
    OFFSET(tp) = off;
    FREESPACE(tp) = free_space - OVFLSIZE;
 
    /*
     * Finally, set the new and old return values. BIG_KEYP contains a
     * pointer to the last page of the big key_data pair. Make sure that
     * big_keyp has no following page (2 elements) or create an empty
     * following page.
     */
 
    ret->newp = np;
    ret->oldp = op;
 
    tp = (u_int16_t *)big_keyp->page;
    big_keyp->flags |= BUF_MOD;
    if (tp[0] > 2) {
        /*
         * There may be either one or two offsets on this page.  If
         * there is one, then the overflow page is linked on normally
         * and tp[4] is OVFLPAGE.  If there are two, tp[4] contains
         * the second offset and needs to get stuffed in after the
         * next overflow page is added.
         */
        n = tp[4];
        free_space = FREESPACE(tp);
        off = OFFSET(tp);
        tp[0] -= 2;
        FREESPACE(tp) = free_space + OVFLSIZE;
        OFFSET(tp) = off;
        tmpp = __add_ovflpage(hashp, big_keyp);
        if (!tmpp)
            return (-1);
        tp[4] = n;
    } else
        tmpp = big_keyp;
 
    if (change)
        ret->newp = tmpp;
    else
        ret->oldp = tmpp;
    return (0);
}

References __add_ovflpage(), __big_keydata(), __call_hash(), __find_last_page(), __get_buf(), _bufhead::addr, BUF_MOD, DBT::data, DEBUG, _bufhead::flags, FREESPACE, if(), SPLIT_RETURN::newp, SPLIT_RETURN::next_addr, SPLIT_RETURN::nextp, NULL, OFFSET, SPLIT_RETURN::oldp, _bufhead::ovfl, OVFLPAGE, OVFLSIZE, _bufhead::page, and DBT::size.

Referenced by ugly_split().

__find_bigpair()

int __find_bigpair	(	HTAB *	hashp,
		BUFHEAD *	bufp,
		int	ndx,
		char *	key,
		int	size
	)

Definition at line 267 of file hash_bigkey.c.

{
    register u_int16_t *bp;
    register char *p;
    int ksize;
    u_int16_t bytes;
    char *kkey;
 
    bp = (u_int16_t *)bufp->page;
    p = bufp->page;
    ksize = size;
    kkey = key;
 
    for (bytes = hashp->BSIZE - bp[ndx];
        bytes <= size && bp[ndx + 1] == PARTIAL_KEY;
        bytes = hashp->BSIZE - bp[ndx]) {
        if (memcmp(p + bp[ndx], kkey, bytes))
            return (-2);
        kkey += bytes;
        ksize -= bytes;
        bufp = __get_buf(hashp, bp[ndx + 2], bufp, 0);
        if (!bufp)
            return (-3);
        p = bufp->page;
        bp = (u_int16_t *)p;
        ndx = 1;
    }
 
    if (bytes != ksize || memcmp(p + bp[ndx], kkey, bytes)) {
#ifdef HASH_STATISTICS
        ++hash_collisions;
#endif
        return (-2);
    } else
        return (ndx);
}

References __get_buf(), _bufhead::page, and PARTIAL_KEY.

Referenced by hash_access().

__find_last_page()

u_int16_t __find_last_page	(	HTAB *	hashp,
		BUFHEAD **	bpp
	)

Definition at line 319 of file hash_bigkey.c.

{
    BUFHEAD *bufp;
    u_int16_t *bp, pageno;
    int n;
 
    bufp = *bpp;
    bp = (u_int16_t *)bufp->page;
    for (;;) {
        n = bp[0];
 
        /*
         * This is the last page if: the tag is FULL_KEY_DATA and
         * either only 2 entries OVFLPAGE marker is explicit there
         * is freespace on the page.
         */
        if (bp[2] == FULL_KEY_DATA &&
            ((n == 2) || (bp[n] == OVFLPAGE) || (FREESPACE(bp))))
            break;
 
        pageno = bp[n - 1];
        bufp = __get_buf(hashp, pageno, bufp, 0);
        if (!bufp)
            return (0); /* Need to indicate an error! */
        bp = (u_int16_t *)bufp->page;
    }
 
    *bpp = bufp;
    if (bp[0] > 2)
        return (bp[3]);
    else
        return (0);
}

References __get_buf(), FREESPACE, FULL_KEY_DATA, OVFLPAGE, and _bufhead::page.

Referenced by __big_split(), and hash_access().

__P() [1/2]

static int collect_key __P ( (HTAB *, BUFHEAD *, int, DBT *, int)  )

static

__P() [2/2]

static int collect_data __P ( (HTAB *, BUFHEAD *, int, int)  )

static

collect_data()

static int collect_data ( HTAB *  hashp, BUFHEAD *  bufp, int  len, int  set  )

static

Definition at line 451 of file hash_bigkey.c.

{
    register u_int16_t *bp;
    register char *p;
    BUFHEAD *xbp;
    u_int16_t save_addr;
    int mylen, totlen;
 
    p = bufp->page;
    bp = (u_int16_t *)p;
    mylen = hashp->BSIZE - bp[1];
    save_addr = bufp->addr;
 
    if (bp[2] == FULL_KEY_DATA) {       /* End of Data */
        totlen = len + mylen;
        if (hashp->tmp_buf)
            free(hashp->tmp_buf);
        if ((hashp->tmp_buf = (char *)malloc(totlen)) == NULL)
            return (-1);
        if (set) {
            hashp->cndx = 1;
            if (bp[0] == 2) {   /* No more buckets in chain */
                hashp->cpage = NULL;
                hashp->cbucket++;
            } else {
                hashp->cpage =
                    __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
                if (!hashp->cpage)
                    return (-1);
                else if (!((u_int16_t *)hashp->cpage->page)[0]) {
                    hashp->cbucket++;
                    hashp->cpage = NULL;
                }
            }
        }
    } else {
        xbp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
        if (!xbp || ((totlen =
            collect_data(hashp, xbp, len + mylen, set)) < 1))
            return (-1);
    }
    if (bufp->addr != save_addr) {
        errno = EINVAL;         /* Out of buffers. */
        return (-1);
    }
    memmove(&hashp->tmp_buf[len], (bufp->page) + bp[1], mylen);
    return (totlen);
}

References __get_buf(), _bufhead::addr, htab::cbucket, htab::cndx, collect_data(), htab::cpage, errno, free(), FULL_KEY_DATA, len(), malloc(), NULL, _bufhead::page, set(), and htab::tmp_buf.

Referenced by __big_return(), and collect_data().

collect_key()

static int collect_key ( HTAB *  hashp, BUFHEAD *  bufp, int  len, DBT *  val, int  set  )

static

Definition at line 525 of file hash_bigkey.c.

{
    BUFHEAD *xbp;
    char *p;
    int mylen, totlen;
    u_int16_t *bp, save_addr;
 
    p = bufp->page;
    bp = (u_int16_t *)p;
    mylen = hashp->BSIZE - bp[1];
 
    save_addr = bufp->addr;
    totlen = len + mylen;
    if (bp[2] == FULL_KEY || bp[2] == FULL_KEY_DATA) {    /* End of Key. */
        if (hashp->tmp_key != NULL)
            free(hashp->tmp_key);
        if ((hashp->tmp_key = (char *)malloc(totlen)) == NULL)
            return (-1);
        if (__big_return(hashp, bufp, 1, val, set))
            return (-1);
    } else {
        xbp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
        if (!xbp || ((totlen =
            collect_key(hashp, xbp, totlen, val, set)) < 1))
            return (-1);
    }
    if (bufp->addr != save_addr) {
        errno = EINVAL;     /* MIS -- OUT OF BUFFERS */
        return (-1);
    }
    memmove(&hashp->tmp_key[len], (bufp->page) + bp[1], mylen);
    return (totlen);
}

References __big_return(), __get_buf(), _bufhead::addr, collect_key(), errno, free(), FULL_KEY, FULL_KEY_DATA, len(), malloc(), NULL, _bufhead::page, set(), and htab::tmp_key.

Referenced by __big_keydata(), and collect_key().