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);
}