diff options
Diffstat (limited to 'db/hash/hash_bigkey.c')
| -rw-r--r-- | db/hash/hash_bigkey.c | 667 |
1 files changed, 667 insertions, 0 deletions
diff --git a/db/hash/hash_bigkey.c b/db/hash/hash_bigkey.c new file mode 100644 index 0000000000..578314a645 --- /dev/null +++ b/db/hash/hash_bigkey.c @@ -0,0 +1,667 @@ +/*- + * 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 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 + */ + +#include <sys/param.h> + +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#ifdef DEBUG +#include <assert.h> +#endif + +#include <db.h> +#include "hash.h" +#include "page.h" +#include "extern.h" + +static int collect_key __P((HTAB *, BUFHEAD *, int, DBT *, int)); +static int collect_data __P((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 +__big_insert(hashp, bufp, key, val) + HTAB *hashp; + BUFHEAD *bufp; + const DBT *key, *val; +{ + 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 (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 = __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); +} + +/* + * 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 +__big_delete(hashp, bufp) + HTAB *hashp; + BUFHEAD *bufp; +{ + 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 != rbufp) + __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 +__find_bigpair(hashp, bufp, ndx, key, size) + HTAB *hashp; + BUFHEAD *bufp; + int ndx; + char *key; + int size; +{ + 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); +} + +/* + * 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 u_int16_t +__find_last_page(hashp, bpp) + HTAB *hashp; + BUFHEAD **bpp; +{ + 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); +} + +/* + * Return the data for the key/data pair that begins on this page at this + * index (index should always be 1). + */ +extern int +__big_return(hashp, bufp, ndx, val, set_current) + HTAB *hashp; + BUFHEAD *bufp; + int ndx; + DBT *val; + int set_current; +{ + 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 == -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); +} +/* + * Count how big the total datasize is by recursing through the pages. Then + * allocate a buffer and copy the data as you recurse up. + */ +static int +collect_data(hashp, bufp, len, set) + HTAB *hashp; + BUFHEAD *bufp; + int len, set; +{ + 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); +} + +/* + * Fill in the key and data for this big pair. + */ +extern int +__big_keydata(hashp, bufp, key, val, set) + HTAB *hashp; + BUFHEAD *bufp; + DBT *key, *val; + int set; +{ + key->size = collect_key(hashp, bufp, 0, val, set); + if (key->size == -1) + return (-1); + key->data = (u_char *)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(hashp, bufp, len, val, set) + HTAB *hashp; + BUFHEAD *bufp; + int len; + DBT *val; + int set; +{ + 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); +} + +/* + * Returns: + * 0 => OK + * -1 => error + */ +extern int +__big_split(hashp, op, np, big_keyp, addr, obucket, ret) + 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; + int addr; /* Address of big_keyp */ + u_int32_t obucket;/* Old Bucket */ + SPLIT_RETURN *ret; +{ + 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); +} |