| /*- |
| * Copyright (c) 1990, 1993, 1994 |
| * The Regents of the University of California. All rights reserved. |
| * |
| * This code is derived from software contributed to Berkeley by |
| * Margo Seltzer. |
| * |
| * 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. ***REMOVED*** - see |
| * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change |
| * 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[] = "@(#)hash_bigkey.c 8.3 (Berkeley) 5/31/94"; |
| #endif /* LIBC_SCCS and not lint */ |
| |
| /* |
| * PACKAGE: hash |
| * DESCRIPTION: |
| * Big key/data handling for the hashing package. |
| * |
| * ROUTINES: |
| * External |
| * __big_keydata |
| * __big_split |
| * __big_insert |
| * __big_return |
| * __big_delete |
| * __find_last_page |
| * Internal |
| * collect_key |
| * collect_data |
| */ |
| |
| #if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh) |
| #include <sys/param.h> |
| #endif |
| |
| #include <errno.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #ifdef DEBUG |
| #include <assert.h> |
| #endif |
| |
| #include "mcom_db.h" |
| #include "hash.h" |
| #include "page.h" |
| /* #include "extern.h" */ |
| |
| static int collect_key(HTAB *, BUFHEAD *, int, DBT *, int); |
| static int collect_data(HTAB *, BUFHEAD *, int, int); |
| |
| /* |
| * Big_insert |
| * |
| * You need to do an insert and the key/data pair is too big |
| * |
| * Returns: |
| * 0 ==> OK |
| *-1 ==> ERROR |
| */ |
| extern int |
| dbm_big_insert(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val) |
| { |
| register uint16 *p; |
| uint key_size, n, val_size; |
| uint16 space, move_bytes, off; |
| char *cp, *key_data, *val_data; |
| |
| cp = bufp->page; /* Character pointer of p. */ |
| p = (uint16 *)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 = PR_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 = dbm_add_ovflpage(hashp, bufp); |
| if (!bufp) |
| return (-1); |
| n = p[0]; |
| if (!key_size) { |
| if (FREESPACE(p)) { |
| move_bytes = PR_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 = (uint16 *)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 = PR_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 (space == val_size && 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 = dbm_add_ovflpage(hashp, bufp); |
| if (!bufp) |
| return (-1); |
| cp = bufp->page; |
| p = (uint16 *)cp; |
| } else |
| p[n] = FULL_KEY_DATA; |
| bufp->flags |= BUF_MOD; |
| } |
| return (0); |
| } |
| |
| /* |
| * Called when bufp's page contains a partial key (index should be 1) |
| * |
| * All pages in the big key/data pair except bufp are freed. We cannot |
| * free bufp because the page pointing to it is lost and we can't get rid |
| * of its pointer. |
| * |
| * Returns: |
| * 0 => OK |
| *-1 => ERROR |
| */ |
| extern int |
| dbm_big_delete(HTAB *hashp, BUFHEAD *bufp) |
| { |
| register BUFHEAD *last_bfp, *rbufp; |
| uint16 *bp, pageno; |
| int key_done, n; |
| |
| rbufp = bufp; |
| last_bfp = NULL; |
| bp = (uint16 *)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 = dbm_get_buf(hashp, pageno, rbufp, 0); |
| if (last_bfp) |
| dbm_free_ovflpage(hashp, last_bfp); |
| last_bfp = rbufp; |
| if (!rbufp) |
| return (-1); /* Error. */ |
| bp = (uint16 *)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 = (uint16 *)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) |
| dbm_free_ovflpage(hashp, rbufp); |
| if (last_bfp != rbufp) |
| dbm_free_ovflpage(hashp, last_bfp); |
| |
| hashp->NKEYS--; |
| return (0); |
| } |
| /* |
| * Returns: |
| * 0 = key not found |
| * -1 = get next overflow page |
| * -2 means key not found and this is big key/data |
| * -3 error |
| */ |
| extern int |
| dbm_find_bigpair(HTAB *hashp, BUFHEAD *bufp, int ndx, char *key, int size) |
| { |
| register uint16 *bp; |
| register char *p; |
| int ksize; |
| uint16 bytes; |
| char *kkey; |
| |
| bp = (uint16 *)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 = dbm_get_buf(hashp, bp[ndx + 2], bufp, 0); |
| if (!bufp) |
| return (-3); |
| p = bufp->page; |
| bp = (uint16 *)p; |
| ndx = 1; |
| } |
| |
| if (bytes != ksize || memcmp(p + bp[ndx], kkey, bytes)) { |
| #ifdef HASH_STATISTICS |
| ++hash_collisions; |
| #endif |
| return (-2); |
| } else |
| return (ndx); |
| } |
| |
| /* |
| * Given the buffer pointer of the first overflow page of a big pair, |
| * find the end of the big pair |
| * |
| * This will set bpp to the buffer header of the last page of the big pair. |
| * It will return the pageno of the overflow page following the last page |
| * of the pair; 0 if there isn't any (i.e. big pair is the last key in the |
| * bucket) |
| */ |
| extern uint16 |
| dbm_find_last_page(HTAB *hashp, BUFHEAD **bpp) |
| { |
| BUFHEAD *bufp; |
| uint16 *bp, pageno; |
| uint n; |
| |
| bufp = *bpp; |
| bp = (uint16 *)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; |
| |
| /* LJM bound the size of n to reasonable limits |
| */ |
| if (n > hashp->BSIZE / sizeof(uint16)) |
| return (0); |
| |
| pageno = bp[n - 1]; |
| bufp = dbm_get_buf(hashp, pageno, bufp, 0); |
| if (!bufp) |
| return (0); /* Need to indicate an error! */ |
| bp = (uint16 *)bufp->page; |
| } |
| |
| *bpp = bufp; |
| if (bp[0] > 2) |
| return (bp[3]); |
| else |
| return (0); |
| } |
| |
| /* |
| * Return the data for the key/data pair that begins on this page at this |
| * index (index should always be 1). |
| */ |
| extern int |
| dbm_big_return( |
| HTAB *hashp, |
| BUFHEAD *bufp, |
| int ndx, |
| DBT *val, |
| int set_current) |
| { |
| BUFHEAD *save_p; |
| uint16 *bp, len, off, save_addr; |
| char *tp; |
| int save_flags; |
| |
| bp = (uint16 *)bufp->page; |
| while (bp[ndx + 1] == PARTIAL_KEY) { |
| bufp = dbm_get_buf(hashp, bp[bp[0] - 1], bufp, 0); |
| if (!bufp) |
| return (-1); |
| bp = (uint16 *)bufp->page; |
| ndx = 1; |
| } |
| |
| if (bp[ndx + 1] == FULL_KEY) { |
| bufp = dbm_get_buf(hashp, bp[bp[0] - 1], bufp, 0); |
| if (!bufp) |
| return (-1); |
| bp = (uint16 *)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 = dbm_get_buf(hashp, bp[bp[0] - 1], bufp, 0); |
| if (!bufp) |
| return (-1); |
| bp = (uint16 *)bufp->page; |
| } else { |
| /* The data is all on one page. */ |
| tp = (char *)bp; |
| off = bp[bp[0]]; |
| val->data = (uint8 *)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 = dbm_get_buf(hashp, |
| bp[bp[0] - 1], bufp, 0); |
| if (!hashp->cpage) |
| return (-1); |
| hashp->cndx = 1; |
| if (!((uint16 *) |
| hashp->cpage->page)[0]) { |
| hashp->cbucket++; |
| hashp->cpage = NULL; |
| } |
| } |
| } |
| return (0); |
| } |
| |
| /* pin our saved buf so that we don't lose if |
| * we run out of buffers */ |
| save_flags = save_p->flags; |
| save_p->flags |= BUF_PIN; |
| val->size = collect_data(hashp, bufp, (int)len, set_current); |
| save_p->flags = save_flags; |
| 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 = (uint8 *)hashp->tmp_buf; |
| return (0); |
| } |
| |
| /* |
| * Count how big the total datasize is by looping through the pages. Then |
| * allocate a buffer and copy the data in the second loop. NOTE: Our caller |
| * may already have a bp which it is holding onto. The caller is |
| * responsible for copying that bp into our temp buffer. 'len' is how much |
| * space to reserve for that buffer. |
| */ |
| static int |
| collect_data( |
| HTAB *hashp, |
| BUFHEAD *bufp, |
| int len, int set) |
| { |
| register uint16 *bp; |
| BUFHEAD *save_bufp; |
| int save_flags; |
| int mylen, totlen; |
| |
| /* |
| * save the input buf head because we need to walk the list twice. |
| * pin it to make sure it doesn't leave the buffer pool. |
| * This has the effect of growing the buffer pool if necessary. |
| */ |
| save_bufp = bufp; |
| save_flags = save_bufp->flags; |
| save_bufp->flags |= BUF_PIN; |
| |
| /* read the length of the buffer */ |
| for (totlen = len; bufp; bufp = dbm_get_buf(hashp, bp[bp[0] - 1], bufp, 0)) { |
| bp = (uint16 *)bufp->page; |
| mylen = hashp->BSIZE - bp[1]; |
| |
| /* if mylen ever goes negative it means that the |
| * page is screwed up. |
| */ |
| if (mylen < 0) { |
| save_bufp->flags = save_flags; |
| return (-1); |
| } |
| totlen += mylen; |
| if (bp[2] == FULL_KEY_DATA) { /* End of Data */ |
| break; |
| } |
| } |
| |
| if (!bufp) { |
| save_bufp->flags = save_flags; |
| return (-1); |
| } |
| |
| /* allocate a temp buf */ |
| if (hashp->tmp_buf) |
| free(hashp->tmp_buf); |
| if ((hashp->tmp_buf = (char *)malloc((size_t)totlen)) == NULL) { |
| save_bufp->flags = save_flags; |
| return (-1); |
| } |
| |
| /* copy the buffers back into temp buf */ |
| for (bufp = save_bufp; bufp; |
| bufp = dbm_get_buf(hashp, bp[bp[0] - 1], bufp, 0)) { |
| bp = (uint16 *)bufp->page; |
| mylen = hashp->BSIZE - bp[1]; |
| memmove(&hashp->tmp_buf[len], (bufp->page) + bp[1], (size_t)mylen); |
| len += mylen; |
| if (bp[2] == FULL_KEY_DATA) { |
| break; |
| } |
| } |
| |
| /* 'clear' the pin flags */ |
| save_bufp->flags = save_flags; |
| |
| /* update the database cursor */ |
| if (set) { |
| hashp->cndx = 1; |
| if (bp[0] == 2) { /* No more buckets in chain */ |
| hashp->cpage = NULL; |
| hashp->cbucket++; |
| } else { |
| hashp->cpage = dbm_get_buf(hashp, bp[bp[0] - 1], bufp, 0); |
| if (!hashp->cpage) |
| return (-1); |
| else if (!((uint16 *)hashp->cpage->page)[0]) { |
| hashp->cbucket++; |
| hashp->cpage = NULL; |
| } |
| } |
| } |
| return (totlen); |
| } |
| |
| /* |
| * Fill in the key and data for this big pair. |
| */ |
| extern int |
| dbm_big_keydata( |
| HTAB *hashp, |
| BUFHEAD *bufp, |
| DBT *key, DBT *val, |
| int set) |
| { |
| key->size = collect_key(hashp, bufp, 0, val, set); |
| if (key->size == (size_t)-1) |
| return (-1); |
| key->data = (uint8 *)hashp->tmp_key; |
| return (0); |
| } |
| |
| /* |
| * Count how big the total key size is by recursing through the pages. Then |
| * collect the data, allocate a buffer and copy the key as you recurse up. |
| */ |
| static int |
| collect_key( |
| HTAB *hashp, |
| BUFHEAD *bufp, |
| int len, |
| DBT *val, |
| int set) |
| { |
| BUFHEAD *xbp; |
| char *p; |
| int mylen, totlen; |
| uint16 *bp, save_addr; |
| |
| p = bufp->page; |
| bp = (uint16 *)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((size_t)totlen)) == NULL) |
| return (-1); |
| if (dbm_big_return(hashp, bufp, 1, val, set)) |
| return (-1); |
| } else { |
| xbp = dbm_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], (size_t)mylen); |
| return (totlen); |
| } |
| |
| /* |
| * Returns: |
| * 0 => OK |
| * -1 => error |
| */ |
| extern int |
| dbm_big_split( |
| HTAB *hashp, |
| BUFHEAD *op, /* Pointer to where to put keys that go in old bucket */ |
| BUFHEAD *np, /* Pointer to new bucket page */ |
| /* Pointer to first page containing the big key/data */ |
| BUFHEAD *big_keyp, |
| uint32 addr, /* Address of big_keyp */ |
| uint32 obucket, /* Old Bucket */ |
| SPLIT_RETURN *ret) |
| { |
| register BUFHEAD *tmpp; |
| register uint16 *tp; |
| BUFHEAD *bp; |
| DBT key, val; |
| uint32 change; |
| uint16 free_space, n, off; |
| |
| bp = big_keyp; |
| |
| /* Now figure out where the big key/data goes */ |
| if (dbm_big_keydata(hashp, big_keyp, &key, &val, 0)) |
| return (-1); |
| change = (dbm_call_hash(hashp, (char *)key.data, key.size) != obucket); |
| |
| if ((ret->next_addr = dbm_find_last_page(hashp, &big_keyp))) { |
| if (!(ret->nextp = |
| dbm_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 = (uint16 *)tmpp->page; |
| |
| #if 0 /* this get's tripped on database corrupted error */ |
| assert(FREESPACE(tp) >= OVFLSIZE); |
| #endif |
| if (FREESPACE(tp) < OVFLSIZE) |
| return (DATABASE_CORRUPTED_ERROR); |
| |
| n = tp[0]; |
| off = OFFSET(tp); |
| free_space = FREESPACE(tp); |
| tp[++n] = (uint16)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 = (uint16 *)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 = dbm_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); |
| } |
