diff options
Diffstat (limited to 'src/plugins/kdb/db2/libdb2/hash/hash.c')
| -rw-r--r-- | src/plugins/kdb/db2/libdb2/hash/hash.c | 1067 |
1 files changed, 1067 insertions, 0 deletions
diff --git a/src/plugins/kdb/db2/libdb2/hash/hash.c b/src/plugins/kdb/db2/libdb2/hash/hash.c new file mode 100644 index 000000000000..76f5d470932e --- /dev/null +++ b/src/plugins/kdb/db2/libdb2/hash/hash.c @@ -0,0 +1,1067 @@ +/*- + * 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.c 8.12 (Berkeley) 11/7/95"; +#endif /* LIBC_SCCS and not lint */ + +#include <sys/param.h> +#include <sys/stat.h> + +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#ifdef DEBUG +#include <assert.h> +#endif + +#include "db-int.h" +#include "hash.h" +#include "page.h" +#include "extern.h" + +static int32_t flush_meta __P((HTAB *)); +static int32_t hash_access __P((HTAB *, ACTION, const DBT *, DBT *)); +static int32_t hash_close __P((DB *)); +static int32_t hash_delete __P((const DB *, const DBT *, u_int32_t)); +static int32_t hash_fd __P((const DB *)); +static int32_t hash_get __P((const DB *, const DBT *, DBT *, u_int32_t)); +static int32_t hash_put __P((const DB *, DBT *, const DBT *, u_int32_t)); +static int32_t hash_seq __P((const DB *, DBT *, DBT *, u_int32_t)); +static int32_t hash_sync __P((const DB *, u_int32_t)); +static int32_t hdestroy __P((HTAB *)); +static int32_t cursor_get __P((const DB *, CURSOR *, DBT *, DBT *, \ + u_int32_t)); +static int32_t cursor_delete __P((const DB *, CURSOR *, u_int32_t)); +static HTAB *init_hash __P((HTAB *, const char *, const HASHINFO *)); +static int32_t init_htab __P((HTAB *, int32_t)); +#if DB_BYTE_ORDER == DB_LITTLE_ENDIAN +static void swap_header __P((HTAB *)); +static void swap_header_copy __P((HASHHDR *, HASHHDR *)); +#endif +static u_int32_t hget_header __P((HTAB *, u_int32_t)); +static void hput_header __P((HTAB *)); + +#define RETURN_ERROR(ERR, LOC) { save_errno = ERR; goto LOC; } + +/* Return values */ +#define SUCCESS (0) +#define ERROR (-1) +#define ABNORMAL (1) + +#ifdef HASH_STATISTICS +u_int32_t hash_accesses, hash_collisions, hash_expansions, hash_overflows, + hash_bigpages; +#endif + +/************************** INTERFACE ROUTINES ***************************/ +/* OPEN/CLOSE */ + +extern DB * +__kdb2_hash_open(file, flags, mode, info, dflags) + const char *file; + int flags, mode, dflags; + const HASHINFO *info; /* Special directives for create */ +{ + struct stat statbuf; + DB *dbp; + DBT mpool_key; + HTAB *hashp; + int32_t bpages, csize, new_table, save_errno, specified_file; + + if ((flags & O_ACCMODE) == O_WRONLY) { + errno = EINVAL; + return (NULL); + } + if (!(hashp = (HTAB *)calloc(1, sizeof(HTAB)))) + return (NULL); + hashp->fp = -1; + + /* set this now, before file goes away... */ + specified_file = (file != NULL); + if (!file) { + file = tmpnam(NULL); + /* store the file name so that we can unlink it later */ + hashp->fname = file; +#ifdef DEBUG + fprintf(stderr, "Using file name %s.\n", file); +#endif + } + /* + * Even if user wants write only, we need to be able to read + * the actual file, so we need to open it read/write. But, the + * field in the hashp structure needs to be accurate so that + * we can check accesses. + */ + hashp->flags = flags; + hashp->save_file = specified_file && (hashp->flags & O_RDWR); + + new_table = 0; + if (!file || (flags & O_TRUNC) || + (stat(file, &statbuf) && (errno == ENOENT))) { + if (errno == ENOENT) + errno = 0; /* In case someone looks at errno. */ + new_table = 1; + } + if (file) { + if ((hashp->fp = open(file, flags|O_BINARY, mode)) == -1) + RETURN_ERROR(errno, error0); + (void)fcntl(hashp->fp, F_SETFD, 1); + } + + /* Process arguments to set up hash table header. */ + if (new_table) { + if (!(hashp = init_hash(hashp, file, info))) + RETURN_ERROR(errno, error1); + } else { + /* Table already exists */ + if (info && info->hash) + hashp->hash = info->hash; + else + hashp->hash = __default_hash; + + /* copy metadata from page into header */ + if (hget_header(hashp, + (info && info->bsize ? info->bsize : DEF_BUCKET_SIZE)) != + sizeof(HASHHDR)) + RETURN_ERROR(EFTYPE, error1); + + /* Verify file type, versions and hash function */ + if (hashp->hdr.magic != HASHMAGIC) + RETURN_ERROR(EFTYPE, error1); +#define OLDHASHVERSION 1 + if (hashp->hdr.version != HASHVERSION && + hashp->hdr.version != OLDHASHVERSION) + RETURN_ERROR(EFTYPE, error1); + if (hashp->hash(CHARKEY, sizeof(CHARKEY)) + != hashp->hdr.h_charkey) + RETURN_ERROR(EFTYPE, error1); + /* + * Figure out how many segments we need. Max_Bucket is the + * maximum bucket number, so the number of buckets is + * max_bucket + 1. + */ + + /* Read in bitmaps */ + bpages = (hashp->hdr.spares[hashp->hdr.ovfl_point] + + (hashp->hdr.bsize << BYTE_SHIFT) - 1) >> + (hashp->hdr.bshift + BYTE_SHIFT); + + hashp->nmaps = bpages; + (void)memset(&hashp->mapp[0], 0, bpages * sizeof(u_int32_t *)); + } + + /* start up mpool */ + mpool_key.data = (u_int8_t *)file; + mpool_key.size = strlen(file); + + if (info && info->cachesize) + csize = info->cachesize / hashp->hdr.bsize; + else + csize = DEF_CACHESIZE / hashp->hdr.bsize; + hashp->mp = mpool_open(&mpool_key, hashp->fp, hashp->hdr.bsize, csize); + + if (!hashp->mp) + RETURN_ERROR(errno, error1); + mpool_filter(hashp->mp, __pgin_routine, __pgout_routine, hashp); + + /* + * For a new table, set up the bitmaps. + */ + if (new_table && + init_htab(hashp, info && info->nelem ? info->nelem : 1)) + goto error2; + + /* initialize the cursor queue */ + TAILQ_INIT(&hashp->curs_queue); + hashp->seq_cursor = NULL; + + + /* get a chunk of memory for our split buffer */ + hashp->split_buf = (PAGE16 *)malloc(hashp->hdr.bsize); + if (!hashp->split_buf) + goto error2; + + hashp->new_file = new_table; + + if (!(dbp = (DB *)malloc(sizeof(DB)))) + goto error2; + + dbp->internal = hashp; + dbp->close = hash_close; + dbp->del = hash_delete; + dbp->fd = hash_fd; + dbp->get = hash_get; + dbp->put = hash_put; + dbp->seq = hash_seq; + dbp->sync = hash_sync; + dbp->type = DB_HASH; + +#ifdef DEBUG + (void)fprintf(stderr, + "%s\n%s%lx\n%s%d\n%s%d\n%s%d\n%s%d\n%s%d\n%s%x\n%s%x\n%s%d\n%s%d\n", + "init_htab:", + "TABLE POINTER ", (void *)hashp, + "BUCKET SIZE ", hashp->hdr.bsize, + "BUCKET SHIFT ", hashp->hdr.bshift, + "FILL FACTOR ", hashp->hdr.ffactor, + "MAX BUCKET ", hashp->hdr.max_bucket, + "OVFL POINT ", hashp->hdr.ovfl_point, + "LAST FREED ", hashp->hdr.last_freed, + "HIGH MASK ", hashp->hdr.high_mask, + "LOW MASK ", hashp->hdr.low_mask, + "NKEYS ", hashp->hdr.nkeys); +#endif +#ifdef HASH_STATISTICS + hash_overflows = hash_accesses = hash_collisions = hash_expansions = 0; + hash_bigpages = 0; +#endif + return (dbp); + +error2: + save_errno = errno; + hdestroy(hashp); + errno = save_errno; + return (NULL); + +error1: + if (hashp != NULL) + (void)close(hashp->fp); + +error0: + free(hashp); + errno = save_errno; + return (NULL); +} + +static int32_t +hash_close(dbp) + DB *dbp; +{ + HTAB *hashp; + int32_t retval; + + if (!dbp) + return (ERROR); + + hashp = (HTAB *)dbp->internal; + retval = hdestroy(hashp); + free(dbp); + return (retval); +} + +static int32_t +hash_fd(dbp) + const DB *dbp; +{ + HTAB *hashp; + + if (!dbp) + return (ERROR); + + hashp = (HTAB *)dbp->internal; + if (hashp->fp == -1) { + errno = ENOENT; + return (-1); + } + return (hashp->fp); +} + +/************************** LOCAL CREATION ROUTINES **********************/ +static HTAB * +init_hash(hashp, file, info) + HTAB *hashp; + const char *file; + const HASHINFO *info; +{ + struct stat statbuf; + + hashp->hdr.nkeys = 0; + hashp->hdr.lorder = DB_BYTE_ORDER; + hashp->hdr.bsize = DEF_BUCKET_SIZE; + hashp->hdr.bshift = DEF_BUCKET_SHIFT; + hashp->hdr.ffactor = DEF_FFACTOR; + hashp->hash = __default_hash; + memset(hashp->hdr.spares, 0, sizeof(hashp->hdr.spares)); + memset(hashp->hdr.bitmaps, 0, sizeof(hashp->hdr.bitmaps)); + + /* Fix bucket size to be optimal for file system */ + if (file != NULL) { + if (stat(file, &statbuf)) + return (NULL); + hashp->hdr.bsize = statbuf.st_blksize; + if (hashp->hdr.bsize > MAX_BSIZE) + hashp->hdr.bsize = MAX_BSIZE; + hashp->hdr.bshift = __log2(hashp->hdr.bsize); + } + if (info) { + if (info->bsize) { + /* Round pagesize up to power of 2 */ + hashp->hdr.bshift = __log2(info->bsize); + hashp->hdr.bsize = 1 << hashp->hdr.bshift; + if (hashp->hdr.bsize > MAX_BSIZE) { + errno = EINVAL; + return (NULL); + } + } + if (info->ffactor) + hashp->hdr.ffactor = info->ffactor; + if (info->hash) + hashp->hash = info->hash; + if (info->lorder) { + if ((info->lorder != DB_BIG_ENDIAN) && + (info->lorder != DB_LITTLE_ENDIAN)) { + errno = EINVAL; + return (NULL); + } + hashp->hdr.lorder = info->lorder; + } + } + return (hashp); +} + +/* + * Returns 0 on No Error + */ +static int32_t +init_htab(hashp, nelem) + HTAB *hashp; + int32_t nelem; +{ + int32_t l2, nbuckets; + + /* + * Divide number of elements by the fill factor and determine a + * desired number of buckets. Allocate space for the next greater + * power of two number of buckets. + */ + nelem = (nelem - 1) / hashp->hdr.ffactor + 1; + + l2 = __log2(MAX(nelem, 2)); + nbuckets = 1 << l2; + + hashp->hdr.spares[l2] = l2 + 1; + hashp->hdr.spares[l2 + 1] = l2 + 1; + hashp->hdr.ovfl_point = l2; + hashp->hdr.last_freed = 2; + + hashp->hdr.max_bucket = hashp->hdr.low_mask = nbuckets - 1; + hashp->hdr.high_mask = (nbuckets << 1) - 1; + + /* + * The number of header pages is the size of the header divided by + * the amount of freespace on header pages (the page size - the + * size of 1 integer where the length of the header info on that + * page is stored) plus another page if it didn't divide evenly. + */ + hashp->hdr.hdrpages = + (sizeof(HASHHDR) / (hashp->hdr.bsize - HEADER_OVERHEAD)) + + (((sizeof(HASHHDR) % (hashp->hdr.bsize - HEADER_OVERHEAD)) == 0) + ? 0 : 1); + + /* Create pages for these buckets */ + /* + for (i = 0; i <= hashp->hdr.max_bucket; i++) { + if (__new_page(hashp, (u_int32_t)i, A_BUCKET) != 0) + return (-1); + } + */ + + /* First bitmap page is at: splitpoint l2 page offset 1 */ + if (__ibitmap(hashp, OADDR_OF(l2, 1), l2 + 1, 0)) + return (-1); + + return (0); +} + +/* + * Functions to get/put hash header. We access the file directly. + */ +static u_int32_t +hget_header(hashp, page_size) + HTAB *hashp; + u_int32_t page_size; +{ + u_int32_t num_copied; + u_int8_t *hdr_dest; + + num_copied = 0; + + hdr_dest = (u_int8_t *)&hashp->hdr; + + /* + * XXX + * This should not be printing to stderr on a "normal" error case. + */ + lseek(hashp->fp, 0, SEEK_SET); + num_copied = read(hashp->fp, hdr_dest, sizeof(HASHHDR)); + if (num_copied != sizeof(HASHHDR)) { + fprintf(stderr, "hash: could not retrieve header"); + return (0); + } +#if DB_BYTE_ORDER == DB_LITTLE_ENDIAN + swap_header(hashp); +#endif + return (num_copied); +} + +static void +hput_header(hashp) + HTAB *hashp; +{ + HASHHDR *whdrp; +#if DB_BYTE_ORDER == DB_LITTLE_ENDIAN + HASHHDR whdr; +#endif + u_int32_t num_copied; + + num_copied = 0; + + whdrp = &hashp->hdr; +#if DB_BYTE_ORDER == DB_LITTLE_ENDIAN + whdrp = &whdr; + swap_header_copy(&hashp->hdr, whdrp); +#endif + + lseek(hashp->fp, 0, SEEK_SET); + num_copied = write(hashp->fp, whdrp, sizeof(HASHHDR)); + if (num_copied != sizeof(HASHHDR)) + (void)fprintf(stderr, "hash: could not write hash header"); + return; +} + +/********************** DESTROY/CLOSE ROUTINES ************************/ + +/* + * Flushes any changes to the file if necessary and destroys the hashp + * structure, freeing all allocated space. + */ +static int32_t +hdestroy(hashp) + HTAB *hashp; +{ + int32_t save_errno; + + save_errno = 0; + +#ifdef HASH_STATISTICS + { int i; + (void)fprintf(stderr, "hdestroy: accesses %ld collisions %ld\n", + hash_accesses, hash_collisions); + (void)fprintf(stderr, + "hdestroy: expansions %ld\n", hash_expansions); + (void)fprintf(stderr, + "hdestroy: overflows %ld\n", hash_overflows); + (void)fprintf(stderr, + "hdestroy: big key/data pages %ld\n", hash_bigpages); + (void)fprintf(stderr, + "keys %ld maxp %d\n", hashp->hdr.nkeys, hashp->hdr.max_bucket); + + for (i = 0; i < NCACHED; i++) + (void)fprintf(stderr, + "spares[%d] = %d\n", i, hashp->hdr.spares[i]); + } +#endif + + if (flush_meta(hashp) && !save_errno) + save_errno = errno; + + /* Free the split page */ + if (hashp->split_buf) + free(hashp->split_buf); + + /* Free the big key and big data returns */ + if (hashp->bigkey_buf) + free(hashp->bigkey_buf); + if (hashp->bigdata_buf) + free(hashp->bigdata_buf); + + /* XXX This should really iterate over the cursor queue, but + it's not clear how to do that, and the only cursor a hash + table ever creates is the one used by hash_seq(). Passing + NULL as the first arg is also a kludge, but I know that + it's never used, so I do it. The intent is to plug the + memory leak. Correctness can come later. */ + + if (hashp->seq_cursor) + hashp->seq_cursor->delete(NULL, hashp->seq_cursor, 0); + + /* shut down mpool */ + mpool_sync(hashp->mp); + mpool_close(hashp->mp); + + if (hashp->fp != -1) + (void)close(hashp->fp); + + /* + * *** This may cause problems if hashp->fname is set in any case + * other than the case that we are generating a temporary file name. + * Note that the new version of mpool should support temporary + * files within mpool itself. + */ + if (hashp->fname && !hashp->save_file) { +#ifdef DEBUG + fprintf(stderr, "Unlinking file %s.\n", hashp->fname); +#endif + /* we need to chmod the file to allow it to be deleted... */ + chmod(hashp->fname, 0700); + unlink(hashp->fname); + /* destroy the temporary name */ + tmpnam(NULL); + } + free(hashp); + + if (save_errno) { + errno = save_errno; + return (ERROR); + } + return (SUCCESS); +} + +/* + * Write modified pages to disk + * + * Returns: + * 0 == OK + * -1 ERROR + */ +static int32_t +hash_sync(dbp, flags) + const DB *dbp; + u_int32_t flags; +{ + HTAB *hashp; + + hashp = (HTAB *)dbp->internal; + + /* + * XXX + * Check success/failure conditions. + */ + return (flush_meta(hashp) || mpool_sync(hashp->mp)); +} + +/* + * Returns: + * 0 == OK + * -1 indicates that errno should be set + */ +static int32_t +flush_meta(hashp) + HTAB *hashp; +{ + int32_t i; + + if (!hashp->save_file) + return (0); + hashp->hdr.magic = HASHMAGIC; + hashp->hdr.version = HASHVERSION; + hashp->hdr.h_charkey = hashp->hash(CHARKEY, sizeof(CHARKEY)); + + /* write out metadata */ + hput_header(hashp); + + for (i = 0; i < NCACHED; i++) + if (hashp->mapp[i]) { + if (__put_page(hashp, + (PAGE16 *)hashp->mapp[i], A_BITMAP, 1)) + return (-1); + hashp->mapp[i] = NULL; + } + return (0); +} + +/*******************************SEARCH ROUTINES *****************************/ +/* + * All the access routines return + * + * Returns: + * 0 on SUCCESS + * 1 to indicate an external ERROR (i.e. key not found, etc) + * -1 to indicate an internal ERROR (i.e. out of memory, etc) + */ + +/* *** make sure this is true! */ + +static int32_t +hash_get(dbp, key, data, flag) + const DB *dbp; + const DBT *key; + DBT *data; + u_int32_t flag; +{ + HTAB *hashp; + + hashp = (HTAB *)dbp->internal; + if (flag) { + hashp->local_errno = errno = EINVAL; + return (ERROR); + } + return (hash_access(hashp, HASH_GET, key, data)); +} + +static int32_t +hash_put(dbp, key, data, flag) + const DB *dbp; + DBT *key; + const DBT *data; + u_int32_t flag; +{ + HTAB *hashp; + + hashp = (HTAB *)dbp->internal; + if (flag && flag != R_NOOVERWRITE) { + hashp->local_errno = errno = EINVAL; + return (ERROR); + } + if ((hashp->flags & O_ACCMODE) == O_RDONLY) { + hashp->local_errno = errno = EPERM; + return (ERROR); + } + return (hash_access(hashp, flag == R_NOOVERWRITE ? + HASH_PUTNEW : HASH_PUT, key, (DBT *)data)); +} + +static int32_t +hash_delete(dbp, key, flag) + const DB *dbp; + const DBT *key; + u_int32_t flag; /* Ignored */ +{ + HTAB *hashp; + + hashp = (HTAB *)dbp->internal; + if (flag) { + hashp->local_errno = errno = EINVAL; + return (ERROR); + } + if ((hashp->flags & O_ACCMODE) == O_RDONLY) { + hashp->local_errno = errno = EPERM; + return (ERROR); + } + + return (hash_access(hashp, HASH_DELETE, key, NULL)); +} + +/* + * Assume that hashp has been set in wrapper routine. + */ +static int32_t +hash_access(hashp, action, key, val) + HTAB *hashp; + ACTION action; + const DBT *key; + DBT *val; +{ + DBT page_key, page_val; + CURSOR cursor; + ITEM_INFO item_info; + u_int32_t bucket; + u_int32_t num_items; + +#ifdef HASH_STATISTICS + hash_accesses++; +#endif + + num_items = 0; + + /* + * Set up item_info so that we're looking for space to add an item + * as we cycle through the pages looking for the key. + */ + if (action == HASH_PUT || action == HASH_PUTNEW) { + if (ISBIG(key->size + val->size, hashp)) + item_info.seek_size = PAIR_OVERHEAD; + else + item_info.seek_size = key->size + val->size; + } else + item_info.seek_size = 0; + item_info.seek_found_page = 0; + + bucket = __call_hash(hashp, (int8_t *)key->data, key->size); + + cursor.pagep = NULL; + __get_item_reset(hashp, &cursor); + + cursor.bucket = bucket; + while (1) { + __get_item_next(hashp, &cursor, &page_key, &page_val, &item_info); + if (item_info.status == ITEM_ERROR) + return (ABNORMAL); + if (item_info.status == ITEM_NO_MORE) + break; + num_items++; + if (item_info.key_off == BIGPAIR) { + /* + * !!! + * 0 is a valid index. + */ + if (__find_bigpair(hashp, &cursor, (int8_t *)key->data, + key->size) > 0) + goto found; + } else if (key->size == page_key.size && + !memcmp(key->data, page_key.data, key->size)) + goto found; + } +#ifdef HASH_STATISTICS + hash_collisions++; +#endif + __get_item_done(hashp, &cursor); + + /* + * At this point, item_info will list either the last page in + * the chain, or the last page in the chain plus a pgno for where + * to find the first page in the chain with space for the + * item we wish to add. + */ + + /* Not found */ + switch (action) { + case HASH_PUT: + case HASH_PUTNEW: + if (__addel(hashp, &item_info, key, val, num_items, 0)) + return (ERROR); + break; + case HASH_GET: + case HASH_DELETE: + default: + return (ABNORMAL); + } + + if (item_info.caused_expand) + __expand_table(hashp); + return (SUCCESS); + +found: __get_item_done(hashp, &cursor); + + switch (action) { + case HASH_PUTNEW: + /* mpool_put(hashp->mp, pagep, 0); */ + return (ABNORMAL); + case HASH_GET: + if (item_info.key_off == BIGPAIR) { + if (__big_return(hashp, &item_info, val, 0)) + return (ERROR); + } else { + val->data = page_val.data; + val->size = page_val.size; + } + /* *** data may not be available! */ + break; + case HASH_PUT: + if (__delpair(hashp, &cursor, &item_info) || + __addel(hashp, &item_info, key, val, UNKNOWN, 0)) + return (ERROR); + __get_item_done(hashp, &cursor); + if (item_info.caused_expand) + __expand_table(hashp); + break; + case HASH_DELETE: + if (__delpair(hashp, &cursor, &item_info)) + return (ERROR); + break; + default: + abort(); + } + return (SUCCESS); +} + +/* ****************** CURSORS ********************************** */ +CURSOR * +__cursor_creat(dbp) + const DB *dbp; +{ + CURSOR *new_curs; + HTAB *hashp; + + new_curs = (CURSOR *)malloc(sizeof(struct cursor_t)); + if (!new_curs) + return NULL; + new_curs->internal = + (struct item_info *)malloc(sizeof(struct item_info)); + if (!new_curs->internal) { + free(new_curs); + return NULL; + } + new_curs->get = cursor_get; + new_curs->delete = cursor_delete; + + new_curs->bucket = 0; + new_curs->pgno = INVALID_PGNO; + new_curs->ndx = 0; + new_curs->pgndx = 0; + new_curs->pagep = NULL; + + /* place onto queue of cursors */ + hashp = (HTAB *)dbp->internal; + TAILQ_INSERT_TAIL(&hashp->curs_queue, new_curs, queue); + + return new_curs; +} + +static int32_t +cursor_get(dbp, cursorp, key, val, flags) + const DB *dbp; + CURSOR *cursorp; + DBT *key, *val; + u_int32_t flags; +{ + HTAB *hashp; + ITEM_INFO item_info; + + hashp = (HTAB *)dbp->internal; + + if (flags && flags != R_FIRST && flags != R_NEXT) { + hashp->local_errno = errno = EINVAL; + return (ERROR); + } +#ifdef HASH_STATISTICS + hash_accesses++; +#endif + + item_info.seek_size = 0; + + if (flags == R_FIRST) + __get_item_first(hashp, cursorp, key, val, &item_info); + else + __get_item_next(hashp, cursorp, key, val, &item_info); + + /* + * This needs to be changed around. As is, get_item_next advances + * the pointers on the page but this function actually advances + * bucket pointers. This works, since the only other place we + * use get_item_next is in hash_access which only deals with one + * bucket at a time. However, there is the problem that certain other + * functions (such as find_bigpair and delpair) depend on the + * pgndx member of the cursor. Right now, they are using pngdx - 1 + * since indices refer to the __next__ item that is to be fetched + * from the page. This is ugly, as you may have noticed, whoever + * you are. The best solution would be to depend on item_infos to + * deal with _current_ information, and have the cursors only + * deal with _next_ information. In that scheme, get_item_next + * would also advance buckets. Version 3... + */ + + + /* + * Must always enter this loop to do error handling and + * check for big key/data pair. + */ + while (1) { + if (item_info.status == ITEM_OK) { + if (item_info.key_off == BIGPAIR && + __big_keydata(hashp, cursorp->pagep, key, val, + item_info.pgndx)) + return (ABNORMAL); + + break; + } else if (item_info.status != ITEM_NO_MORE) + return (ABNORMAL); + + __put_page(hashp, cursorp->pagep, A_RAW, 0); + cursorp->ndx = cursorp->pgndx = 0; + cursorp->bucket++; + cursorp->pgno = INVALID_PGNO; + cursorp->pagep = NULL; + if (cursorp->bucket > hashp->hdr.max_bucket) + return (ABNORMAL); + __get_item_next(hashp, cursorp, key, val, &item_info); + } + + __get_item_done(hashp, cursorp); + return (0); +} + +static int32_t +cursor_delete(dbp, cursor, flags) + const DB *dbp; + CURSOR *cursor; + u_int32_t flags; +{ + /* XXX this is empirically determined, so it might not be completely + correct, but it seems to work. At the very least it fixes + a memory leak */ + + free(cursor->internal); + free(cursor); + + return (0); +} + +static int32_t +hash_seq(dbp, key, val, flag) + const DB *dbp; + DBT *key, *val; + u_int32_t flag; +{ + HTAB *hashp; + + /* + * Seq just uses the default cursor to go sequecing through the + * database. Note that the default cursor is the first in the list. + */ + + hashp = (HTAB *)dbp->internal; + if (!hashp->seq_cursor) + hashp->seq_cursor = __cursor_creat(dbp); + + return (hashp->seq_cursor->get(dbp, hashp->seq_cursor, key, val, flag)); +} + +/********************************* UTILITIES ************************/ + +/* + * Returns: + * 0 ==> OK + * -1 ==> Error + */ +int32_t +__expand_table(hashp) + HTAB *hashp; +{ + u_int32_t old_bucket, new_bucket; + int32_t spare_ndx; + +#ifdef HASH_STATISTICS + hash_expansions++; +#endif + new_bucket = ++hashp->hdr.max_bucket; + old_bucket = (hashp->hdr.max_bucket & hashp->hdr.low_mask); + + /* Get a page for this new bucket */ + if (__new_page(hashp, new_bucket, A_BUCKET) != 0) + return (-1); + + /* + * If the split point is increasing (hdr.max_bucket's log base 2 + * increases), we need to copy the current contents of the spare + * split bucket to the next bucket. + */ + spare_ndx = __log2(hashp->hdr.max_bucket + 1); + if (spare_ndx > hashp->hdr.ovfl_point) { + hashp->hdr.spares[spare_ndx] = hashp->hdr.spares[hashp->hdr.ovfl_point]; + hashp->hdr.ovfl_point = spare_ndx; + } + if (new_bucket > hashp->hdr.high_mask) { + /* Starting a new doubling */ + hashp->hdr.low_mask = hashp->hdr.high_mask; + hashp->hdr.high_mask = new_bucket | hashp->hdr.low_mask; + } + if (BUCKET_TO_PAGE(new_bucket) > MAX_PAGES(hashp)) { + fprintf(stderr, "hash: Cannot allocate new bucket. Pages exhausted.\n"); + return (-1); + } + /* Relocate records to the new bucket */ + return (__split_page(hashp, old_bucket, new_bucket)); +} + +u_int32_t +__call_hash(hashp, k, len) + HTAB *hashp; + int8_t *k; + int32_t len; +{ + u_int32_t n, bucket; + + n = hashp->hash(k, len); + bucket = n & hashp->hdr.high_mask; + if (bucket > hashp->hdr.max_bucket) + bucket = bucket & hashp->hdr.low_mask; + return (bucket); +} + +#if DB_BYTE_ORDER == DB_LITTLE_ENDIAN +/* + * Hashp->hdr needs to be byteswapped. + */ +static void +swap_header_copy(srcp, destp) + HASHHDR *srcp, *destp; +{ + int32_t i; + + P_32_COPY(srcp->magic, destp->magic); + P_32_COPY(srcp->version, destp->version); + P_32_COPY(srcp->lorder, destp->lorder); + P_32_COPY(srcp->bsize, destp->bsize); + P_32_COPY(srcp->bshift, destp->bshift); + P_32_COPY(srcp->ovfl_point, destp->ovfl_point); + P_32_COPY(srcp->last_freed, destp->last_freed); + P_32_COPY(srcp->max_bucket, destp->max_bucket); + P_32_COPY(srcp->high_mask, destp->high_mask); + P_32_COPY(srcp->low_mask, destp->low_mask); + P_32_COPY(srcp->ffactor, destp->ffactor); + P_32_COPY(srcp->nkeys, destp->nkeys); + P_32_COPY(srcp->hdrpages, destp->hdrpages); + P_32_COPY(srcp->h_charkey, destp->h_charkey); + for (i = 0; i < NCACHED; i++) { + P_32_COPY(srcp->spares[i], destp->spares[i]); + P_16_COPY(srcp->bitmaps[i], destp->bitmaps[i]); + } +} + +static void +swap_header(hashp) + HTAB *hashp; +{ + HASHHDR *hdrp; + int32_t i; + + hdrp = &hashp->hdr; + + M_32_SWAP(hdrp->magic); + M_32_SWAP(hdrp->version); + M_32_SWAP(hdrp->lorder); + M_32_SWAP(hdrp->bsize); + M_32_SWAP(hdrp->bshift); + M_32_SWAP(hdrp->ovfl_point); + M_32_SWAP(hdrp->last_freed); + M_32_SWAP(hdrp->max_bucket); + M_32_SWAP(hdrp->high_mask); + M_32_SWAP(hdrp->low_mask); + M_32_SWAP(hdrp->ffactor); + M_32_SWAP(hdrp->nkeys); + M_32_SWAP(hdrp->hdrpages); + M_32_SWAP(hdrp->h_charkey); + for (i = 0; i < NCACHED; i++) { + M_32_SWAP(hdrp->spares[i]); + M_16_SWAP(hdrp->bitmaps[i]); + } +} +#endif /* DB_BYTE_ORDER == DB_LITTLE_ENDIAN */ |