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.

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().

{
 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);
}

__big_insert()

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

Definition at line 88 of file hash_bigkey.c.

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().

{
 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);
}

__big_keydata()

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

Definition at line 507 of file hash_bigkey.c.

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

Referenced by __big_split(), and hash_seq().

{
 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);
}

__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.

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

Referenced by collect_key(), and hash_access().

{
 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);
}

__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.

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().

{
 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);
}

__find_bigpair()

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

Definition at line 267 of file hash_bigkey.c.

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

Referenced by hash_access().

{
 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);
}

__find_last_page()

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

Definition at line 319 of file hash_bigkey.c.

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

Referenced by __big_split(), and hash_access().

{
 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);
}

__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.

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

Referenced by __big_return().

{
 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);
}

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.

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

Referenced by __big_keydata().

{
 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);
}