Add copy of .ttf font with .eot extension for testing

[wine-gecko.git] / dbm / src / h_page.c

/*-
 * 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(unix)
#define MY_LSEEK lseek
#else
#define MY_LSEEK new_lseek
extern long new_lseek(int fd, long pos, int start);
#endif

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)hash_page.c 8.7 (Berkeley) 8/16/94";
#endif /* LIBC_SCCS and not lint */

#include "watcomfx.h"

/*
 * PACKAGE:  hashing
 *
 * DESCRIPTION:
 *      Page manipulation for hashing package.
 *
 * ROUTINES:
 *
 * External
 *      __get_page
 *      __add_ovflpage
 * Internal
 *      overflow_page
 *      open_temp
 */
#ifndef macintosh
#include <sys/types.h>
#endif

#if defined(macintosh)
#include <unistd.h>
#endif

#include <errno.h>
#include <fcntl.h>
#if defined(_WIN32) || defined(_WINDOWS) 
#include <io.h>
#endif
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh) && !defined(XP_OS2_VACPP)
#include <unistd.h>
#endif

#include <assert.h>

#include "mcom_db.h"
#include "hash.h"
#include "page.h"
/* #include "extern.h" */

extern int mkstempflags(char *path, int extraFlags);

static uint32   *fetch_bitmap __P((HTAB *, uint32));
static uint32    first_free __P((uint32));
static int       open_temp __P((HTAB *));
static uint16    overflow_page __P((HTAB *));
static void      squeeze_key __P((uint16 *, const DBT *, const DBT *));
static int       ugly_split
                    __P((HTAB *, uint32, BUFHEAD *, BUFHEAD *, int, int));

#define PAGE_INIT(P) { \
        ((uint16 *)(P))[0] = 0; \
        ((uint16 *)(P))[1] = hashp->BSIZE - 3 * sizeof(uint16); \
        ((uint16 *)(P))[2] = hashp->BSIZE; \
}

/* implement a new lseek using lseek that
 * writes zero's when extending a file
 * beyond the end.
 */
long new_lseek(int fd, long offset, int origin)
{
        long cur_pos=0;
        long end_pos=0;
        long seek_pos=0;

        if(origin == SEEK_CUR)
      { 
        if(offset < 1)                                                    
                return(lseek(fd, offset, SEEK_CUR));

                cur_pos = lseek(fd, 0, SEEK_CUR);

                if(cur_pos < 0)
                        return(cur_pos);
          }
                                                                                 
        end_pos = lseek(fd, 0, SEEK_END);
        if(end_pos < 0)
                return(end_pos);

        if(origin == SEEK_SET)
                seek_pos = offset;
        else if(origin == SEEK_CUR)
                seek_pos = cur_pos + offset;
        else if(origin == SEEK_END)
                seek_pos = end_pos + offset;
        else
          {
                assert(0);
                return(-1);
          }

        /* the seek position desired is before the
         * end of the file.  We don't need
         * to do anything special except the seek.
         */
        if(seek_pos <= end_pos)
                return(lseek(fd, seek_pos, SEEK_SET));
                
          /* the seek position is beyond the end of the
           * file.  Write zero's to the end.
           *
           * we are already at the end of the file so
           * we just need to "write()" zeros for the
           * difference between seek_pos-end_pos and
           * then seek to the position to finish
           * the call
           */
          { 
                char buffer[1024];
                long len = seek_pos-end_pos;
                memset(&buffer, 0, 1024);
                while(len > 0)
              {
                write(fd, (char*)&buffer, (size_t)(1024 > len ? len : 1024));
                    len -= 1024;
                  }
                return(lseek(fd, seek_pos, SEEK_SET));
          }             

}

/*
 * This is called AFTER we have verified that there is room on the page for
 * the pair (PAIRFITS has returned true) so we go right ahead and start moving
 * stuff on.
 */
static void
putpair(char *p, const DBT *key, DBT * val)
{
        register uint16 *bp, n, off;

        bp = (uint16 *)p;

        /* Enter the key first. */
        n = bp[0];

        off = OFFSET(bp) - key->size;
        memmove(p + off, key->data, key->size);
        bp[++n] = off;

        /* Now the data. */
        off -= val->size;
        memmove(p + off, val->data, val->size);
        bp[++n] = off;

        /* Adjust page info. */
        bp[0] = n;
        bp[n + 1] = off - ((n + 3) * sizeof(uint16));
        bp[n + 2] = off;
}

/*
 * Returns:
 *       0 OK
 *      -1 error
 */
extern int
__delpair(HTAB *hashp, BUFHEAD *bufp, int ndx)
{
        register uint16 *bp, newoff;
        register int n;
        uint16 pairlen;

        bp = (uint16 *)bufp->page;
        n = bp[0];

        if (bp[ndx + 1] < REAL_KEY)
                return (__big_delete(hashp, bufp));
        if (ndx != 1)
                newoff = bp[ndx - 1];
        else
                newoff = hashp->BSIZE;
        pairlen = newoff - bp[ndx + 1];

        if (ndx != (n - 1)) {
                /* Hard Case -- need to shuffle keys */
                register int i;
                register char *src = bufp->page + (int)OFFSET(bp);
                uint32 dst_offset = (uint32)OFFSET(bp) + (uint32)pairlen;
                register char *dst = bufp->page + dst_offset;
                uint32 length = bp[ndx + 1] - OFFSET(bp);

                /*
                 * +-----------+XXX+---------+XXX+---------+---------> +infinity
                 * |           |             |             |
                 * 0           src_offset    dst_offset    BSIZE
                 *
                 * Dst_offset is > src_offset, so if src_offset were bad, dst_offset
                 * would be too, therefore we check only dst_offset.
                 *
                 * If dst_offset is >= BSIZE, either OFFSET(bp), or pairlen, or both
                 * is corrupted.
                 *
                 * Once we know dst_offset is < BSIZE, we can subtract it from BSIZE
                 * to get an upper bound on length.
                 */
                if(dst_offset > (uint32)hashp->BSIZE)
                        return(DATABASE_CORRUPTED_ERROR);

                if(length > (uint32)(hashp->BSIZE - dst_offset))
                        return(DATABASE_CORRUPTED_ERROR);

                memmove(dst, src, length);

                /* Now adjust the pointers */
                for (i = ndx + 2; i <= n; i += 2) {
                        if (bp[i + 1] == OVFLPAGE) {
                                bp[i - 2] = bp[i];
                                bp[i - 1] = bp[i + 1];
                        } else {
                                bp[i - 2] = bp[i] + pairlen;
                                bp[i - 1] = bp[i + 1] + pairlen;
                        }
                }
        }
        /* Finally adjust the page data */
        bp[n] = OFFSET(bp) + pairlen;
        bp[n - 1] = bp[n + 1] + pairlen + 2 * sizeof(uint16);
        bp[0] = n - 2;
        hashp->NKEYS--;

        bufp->flags |= BUF_MOD;
        return (0);
}
/*
 * Returns:
 *       0 ==> OK
 *      -1 ==> Error
 */
extern int
__split_page(HTAB *hashp, uint32 obucket, uint32 nbucket)
{
        register BUFHEAD *new_bufp, *old_bufp;
        register uint16 *ino;
        register uint16 *tmp_uint16_array;
        register char *np;
        DBT key, val;
    uint16 n, ndx;
        int retval;
        uint16 copyto, diff, moved;
        size_t off;
        char *op;

        copyto = (uint16)hashp->BSIZE;
        off = (uint16)hashp->BSIZE;
        old_bufp = __get_buf(hashp, obucket, NULL, 0);
        if (old_bufp == NULL)
                return (-1);
        new_bufp = __get_buf(hashp, nbucket, NULL, 0);
        if (new_bufp == NULL)
                return (-1);

        old_bufp->flags |= (BUF_MOD | BUF_PIN);
        new_bufp->flags |= (BUF_MOD | BUF_PIN);

        ino = (uint16 *)(op = old_bufp->page);
        np = new_bufp->page;

        moved = 0;

        for (n = 1, ndx = 1; n < ino[0]; n += 2) {
                if (ino[n + 1] < REAL_KEY) {
                        retval = ugly_split(hashp, obucket, old_bufp, new_bufp,
                            (int)copyto, (int)moved);
                        old_bufp->flags &= ~BUF_PIN;
                        new_bufp->flags &= ~BUF_PIN;
                        return (retval);

                }
                key.data = (uint8 *)op + ino[n];

                /* check here for ino[n] being greater than
                 * off.  If it is then the database has
                 * been corrupted.
                 */
                if(ino[n] > off)
                        return(DATABASE_CORRUPTED_ERROR);

                key.size = off - ino[n];

#ifdef DEBUG
                /* make sure the size is positive */
                assert(((int)key.size) > -1);
#endif

                if (__call_hash(hashp, (char *)key.data, key.size) == obucket) {
                        /* Don't switch page */
                        diff = copyto - off;
                        if (diff) {
                                copyto = ino[n + 1] + diff;
                                memmove(op + copyto, op + ino[n + 1],
                                    off - ino[n + 1]);
                                ino[ndx] = copyto + ino[n] - ino[n + 1];
                                ino[ndx + 1] = copyto;
                        } else
                                copyto = ino[n + 1];
                        ndx += 2;
                } else {
                        /* Switch page */
                        val.data = (uint8 *)op + ino[n + 1];
                        val.size = ino[n] - ino[n + 1];

                        /* if the pair doesn't fit something is horribly
                         * wrong.  LJM
                         */
                        tmp_uint16_array = (uint16*)np;
                        if(!PAIRFITS(tmp_uint16_array, &key, &val))
                                return(DATABASE_CORRUPTED_ERROR);

                        putpair(np, &key, &val);
                        moved += 2;
                }

                off = ino[n + 1];
        }

        /* Now clean up the page */
        ino[0] -= moved;
        FREESPACE(ino) = copyto - sizeof(uint16) * (ino[0] + 3);
        OFFSET(ino) = copyto;

#ifdef DEBUG3
        (void)fprintf(stderr, "split %d/%d\n",
            ((uint16 *)np)[0] / 2,
            ((uint16 *)op)[0] / 2);
#endif
        /* unpin both pages */
        old_bufp->flags &= ~BUF_PIN;
        new_bufp->flags &= ~BUF_PIN;
        return (0);
}

/*
 * Called when we encounter an overflow or big key/data page during split
 * handling.  This is special cased since we have to begin checking whether
 * the key/data pairs fit on their respective pages and because we may need
 * overflow pages for both the old and new pages.
 *
 * The first page might be a page with regular key/data pairs in which case
 * we have a regular overflow condition and just need to go on to the next
 * page or it might be a big key/data pair in which case we need to fix the
 * big key/data pair.
 *
 * Returns:
 *       0 ==> success
 *      -1 ==> failure
 */

/* the maximum number of loops we will allow UGLY split to chew
 * on before we assume the database is corrupted and throw it
 * away.
 */
#define MAX_UGLY_SPLIT_LOOPS 10000

static int
ugly_split(HTAB *hashp, uint32 obucket, BUFHEAD *old_bufp,
 BUFHEAD *new_bufp,/* Same as __split_page. */ int copyto, int moved)
        /* int copyto;   First byte on page which contains key/data values. */
        /* int moved;    Number of pairs moved to new page. */
{
        register BUFHEAD *bufp; /* Buffer header for ino */
        register uint16 *ino;   /* Page keys come off of */
        register uint16 *np;    /* New page */
        register uint16 *op;    /* Page keys go on to if they aren't moving */
    uint32 loop_detection=0;

        BUFHEAD *last_bfp;      /* Last buf header OVFL needing to be freed */
        DBT key, val;
        SPLIT_RETURN ret;
        uint16 n, off, ov_addr, scopyto;
        char *cino;             /* Character value of ino */
        int status;

        bufp = old_bufp;
        ino = (uint16 *)old_bufp->page;
        np = (uint16 *)new_bufp->page;
        op = (uint16 *)old_bufp->page;
        last_bfp = NULL;
        scopyto = (uint16)copyto;       /* ANSI */

        n = ino[0] - 1;
        while (n < ino[0]) {


        /* this function goes nuts sometimes and never returns. 
         * I havent found the problem yet but I need a solution
         * so if we loop too often we assume a database curruption error
         * :LJM
         */
        loop_detection++;

        if(loop_detection > MAX_UGLY_SPLIT_LOOPS)
            return DATABASE_CORRUPTED_ERROR;

                if (ino[2] < REAL_KEY && ino[2] != OVFLPAGE) {
                        if ((status = __big_split(hashp, old_bufp,
                            new_bufp, bufp, bufp->addr, obucket, &ret)))
                                return (status);
                        old_bufp = ret.oldp;
                        if (!old_bufp)
                                return (-1);
                        op = (uint16 *)old_bufp->page;
                        new_bufp = ret.newp;
                        if (!new_bufp)
                                return (-1);
                        np = (uint16 *)new_bufp->page;
                        bufp = ret.nextp;
                        if (!bufp)
                                return (0);
                        cino = (char *)bufp->page;
                        ino = (uint16 *)cino;
                        last_bfp = ret.nextp;
                } else if (ino[n + 1] == OVFLPAGE) {
                        ov_addr = ino[n];
                        /*
                         * Fix up the old page -- the extra 2 are the fields
                         * which contained the overflow information.
                         */
                        ino[0] -= (moved + 2);
                        FREESPACE(ino) =
                            scopyto - sizeof(uint16) * (ino[0] + 3);
                        OFFSET(ino) = scopyto;

                        bufp = __get_buf(hashp, ov_addr, bufp, 0);
                        if (!bufp)
                                return (-1);

                        ino = (uint16 *)bufp->page;
                        n = 1;
                        scopyto = hashp->BSIZE;
                        moved = 0;

                        if (last_bfp)
                                __free_ovflpage(hashp, last_bfp);
                        last_bfp = bufp;
                }
                /* Move regular sized pairs of there are any */
                off = hashp->BSIZE;
                for (n = 1; (n < ino[0]) && (ino[n + 1] >= REAL_KEY); n += 2) {
                        cino = (char *)ino;
                        key.data = (uint8 *)cino + ino[n];
                        key.size = off - ino[n];
                        val.data = (uint8 *)cino + ino[n + 1];
                        val.size = ino[n] - ino[n + 1];
                        off = ino[n + 1];

                        if (__call_hash(hashp, (char*)key.data, key.size) == obucket) {
                                /* Keep on old page */
                                if (PAIRFITS(op, (&key), (&val)))
                                        putpair((char *)op, &key, &val);
                                else {
                                        old_bufp =
                                            __add_ovflpage(hashp, old_bufp);
                                        if (!old_bufp)
                                                return (-1);
                                        op = (uint16 *)old_bufp->page;
                                        putpair((char *)op, &key, &val);
                                }
                                old_bufp->flags |= BUF_MOD;
                        } else {
                                /* Move to new page */
                                if (PAIRFITS(np, (&key), (&val)))
                                        putpair((char *)np, &key, &val);
                                else {
                                        new_bufp =
                                            __add_ovflpage(hashp, new_bufp);
                                        if (!new_bufp)
                                                return (-1);
                                        np = (uint16 *)new_bufp->page;
                                        putpair((char *)np, &key, &val);
                                }
                                new_bufp->flags |= BUF_MOD;
                        }
                }
        }
        if (last_bfp)
                __free_ovflpage(hashp, last_bfp);
        return (0);
}

/*
 * Add the given pair to the page
 *
 * Returns:
 *      0 ==> OK
 *      1 ==> failure
 */
extern int
__addel(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT * val)
{
        register uint16 *bp, *sop;
        int do_expand;

        bp = (uint16 *)bufp->page;
        do_expand = 0;
        while (bp[0] && (bp[2] < REAL_KEY || bp[bp[0]] < REAL_KEY))
                /* Exception case */
                if (bp[2] == FULL_KEY_DATA && bp[0] == 2)
                        /* This is the last page of a big key/data pair
                           and we need to add another page */
                        break;
                else if (bp[2] < REAL_KEY && bp[bp[0]] != OVFLPAGE) {
                        bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
                        if (!bufp)
                          {
#ifdef DEBUG
                                assert(0);
#endif
                                return (-1);
                          }
                        bp = (uint16 *)bufp->page;
                } else
                        /* Try to squeeze key on this page */
                        if (FREESPACE(bp) > PAIRSIZE(key, val)) {
                          {
                                squeeze_key(bp, key, val);

                                /* LJM: I added this because I think it was
                                 * left out on accident.
                                 * if this isn't incremented nkeys will not
                                 * be the actual number of keys in the db.
                                 */
                                hashp->NKEYS++;
                                return (0);
                          }
                        } else {
                                bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
                                if (!bufp)
                              {
#ifdef DEBUG
                                    assert(0);
#endif
                                        return (-1);
                                  }
                                bp = (uint16 *)bufp->page;
                        }

        if (PAIRFITS(bp, key, val))
                putpair(bufp->page, key, (DBT *)val);
        else {
                do_expand = 1;
                bufp = __add_ovflpage(hashp, bufp);
                if (!bufp)
              {
#ifdef DEBUG
                    assert(0);
#endif
                        return (-1);
                  }
                sop = (uint16 *)bufp->page;

                if (PAIRFITS(sop, key, val))
                        putpair((char *)sop, key, (DBT *)val);
                else
                        if (__big_insert(hashp, bufp, key, val))
                  {
#ifdef DEBUG
                        assert(0);
#endif
                            return (-1);
                      }
        }
        bufp->flags |= BUF_MOD;
        /*
         * If the average number of keys per bucket exceeds the fill factor,
         * expand the table.
         */
        hashp->NKEYS++;
        if (do_expand ||
            (hashp->NKEYS / (hashp->MAX_BUCKET + 1) > hashp->FFACTOR))
                return (__expand_table(hashp));
        return (0);
}

/*
 *
 * Returns:
 *      pointer on success
 *      NULL on error
 */
extern BUFHEAD *
__add_ovflpage(HTAB *hashp, BUFHEAD *bufp)
{
        register uint16 *sp;
        uint16 ndx, ovfl_num;
#ifdef DEBUG1
        int tmp1, tmp2;
#endif
        sp = (uint16 *)bufp->page;

        /* Check if we are dynamically determining the fill factor */
        if (hashp->FFACTOR == DEF_FFACTOR) {
                hashp->FFACTOR = sp[0] >> 1;
                if (hashp->FFACTOR < MIN_FFACTOR)
                        hashp->FFACTOR = MIN_FFACTOR;
        }
        bufp->flags |= BUF_MOD;
        ovfl_num = overflow_page(hashp);
#ifdef DEBUG1
        tmp1 = bufp->addr;
        tmp2 = bufp->ovfl ? bufp->ovfl->addr : 0;
#endif
        if (!ovfl_num || !(bufp->ovfl = __get_buf(hashp, ovfl_num, bufp, 1)))
                return (NULL);
        bufp->ovfl->flags |= BUF_MOD;
#ifdef DEBUG1
        (void)fprintf(stderr, "ADDOVFLPAGE: %d->ovfl was %d is now %d\n",
            tmp1, tmp2, bufp->ovfl->addr);
#endif
        ndx = sp[0];
        /*
         * Since a pair is allocated on a page only if there's room to add
         * an overflow page, we know that the OVFL information will fit on
         * the page.
         */
        sp[ndx + 4] = OFFSET(sp);
        sp[ndx + 3] = FREESPACE(sp) - OVFLSIZE;
        sp[ndx + 1] = ovfl_num;
        sp[ndx + 2] = OVFLPAGE;
        sp[0] = ndx + 2;
#ifdef HASH_STATISTICS
        hash_overflows++;
#endif
        return (bufp->ovfl);
}

/*
 * Returns:
 *       0 indicates SUCCESS
 *      -1 indicates FAILURE
 */
extern int
__get_page(HTAB *hashp,
        char * p,
        uint32 bucket, 
        int is_bucket, 
        int is_disk, 
        int is_bitmap)
{
        register int fd, page;
        size_t size;
        int rsize;
        uint16 *bp;

        fd = hashp->fp;
        size = hashp->BSIZE;

        if ((fd == -1) || !is_disk) {
                PAGE_INIT(p);
                return (0);
        }
        if (is_bucket)
                page = BUCKET_TO_PAGE(bucket);
        else
                page = OADDR_TO_PAGE(bucket);
        if ((MY_LSEEK(fd, (off_t)page << hashp->BSHIFT, SEEK_SET) == -1) ||
            ((rsize = read(fd, p, size)) == -1))
                return (-1);

        bp = (uint16 *)p;
        if (!rsize)
                bp[0] = 0;      /* We hit the EOF, so initialize a new page */
        else
                if ((unsigned)rsize != size) {
                        errno = EFTYPE;
                        return (-1);
                }

        if (!is_bitmap && !bp[0]) {
                PAGE_INIT(p);
        } else {

#ifdef DEBUG
                if(BYTE_ORDER == LITTLE_ENDIAN)
                  {
                        int is_little_endian;
                        is_little_endian = BYTE_ORDER;
                  }
                else if(BYTE_ORDER == BIG_ENDIAN)
                  {
                        int is_big_endian;
                        is_big_endian = BYTE_ORDER;
                  }
                else
                  {
                        assert(0);
                  }
#endif

                if (hashp->LORDER != BYTE_ORDER) {
                        register int i, max;

                        if (is_bitmap) {
                                max = hashp->BSIZE >> 2; /* divide by 4 */
                                for (i = 0; i < max; i++)
                                        M_32_SWAP(((int *)p)[i]);
                        } else {
                                M_16_SWAP(bp[0]);
                                max = bp[0] + 2;

                        /* bound the size of max by
                         * the maximum number of entries
                         * in the array
                         */
                                if((unsigned)max > (size / sizeof(uint16)))
                                        return(DATABASE_CORRUPTED_ERROR);

                                /* do the byte order swap
                                 */
                                for (i = 1; i <= max; i++)
                                        M_16_SWAP(bp[i]);
                        }
                }

                /* check the validity of the page here
                 * (after doing byte order swaping if necessary)
                 */
                if(!is_bitmap && bp[0] != 0)
                  {
                        uint16 num_keys = bp[0];
                        uint16 offset;
                        uint16 i;

                        /* bp[0] is supposed to be the number of
                         * entries currently in the page.  If
                         * bp[0] is too large (larger than the whole
                         * page) then the page is corrupted
                         */
                        if(bp[0] > (size / sizeof(uint16)))
                                return(DATABASE_CORRUPTED_ERROR);
                        
                        /* bound free space */
                        if(FREESPACE(bp) > size)
                                return(DATABASE_CORRUPTED_ERROR);
                
                        /* check each key and data offset to make
                         * sure they are all within bounds they
                         * should all be less than the previous
                         * offset as well.
                         */
                        offset = size;
                        for(i=1 ; i <= num_keys; i+=2)
                          {
                                /* ignore overflow pages etc. */
                                if(bp[i+1] >= REAL_KEY)
                                  {
                                                
                                        if(bp[i] > offset || bp[i+1] > bp[i])                   
                                                return(DATABASE_CORRUPTED_ERROR);
                        
                                        offset = bp[i+1];
                                  }
                                else
                                  {
                                        /* there are no other valid keys after
                                         * seeing a non REAL_KEY
                                         */
                                        break;
                                  }
                          }
                }
        }
        return (0);
}

/*
 * Write page p to disk
 *
 * Returns:
 *       0 ==> OK
 *      -1 ==>failure
 */
extern int
__put_page(HTAB *hashp, char *p, uint32 bucket, int is_bucket, int is_bitmap)
{
        register int fd, page;
        size_t size;
        int wsize;
        off_t offset;

        size = hashp->BSIZE;
        if ((hashp->fp == -1) && open_temp(hashp))
                return (-1);
        fd = hashp->fp;

        if (hashp->LORDER != BYTE_ORDER) {
                register int i;
                register int max;

                if (is_bitmap) {
                        max = hashp->BSIZE >> 2;        /* divide by 4 */
                        for (i = 0; i < max; i++)
                                M_32_SWAP(((int *)p)[i]);
                } else {
                        max = ((uint16 *)p)[0] + 2;

            /* bound the size of max by
             * the maximum number of entries
             * in the array
             */
            if((unsigned)max > (size / sizeof(uint16)))
                return(DATABASE_CORRUPTED_ERROR);

                        for (i = 0; i <= max; i++)
                                M_16_SWAP(((uint16 *)p)[i]);

                }
        }

        if (is_bucket)
                page = BUCKET_TO_PAGE(bucket);
        else
                page = OADDR_TO_PAGE(bucket);
        offset = (off_t)page << hashp->BSHIFT;
        if ((MY_LSEEK(fd, offset, SEEK_SET) == -1) ||
            ((wsize = write(fd, p, size)) == -1))
                /* Errno is set */
                return (-1);
        if ((unsigned)wsize != size) {
                errno = EFTYPE;
                return (-1);
        }
#if defined(_WIN32) || defined(_WINDOWS) 
        if (offset + size > hashp->file_size) {
                hashp->updateEOF = 1;
        }
#endif
        /* put the page back the way it was so that it isn't byteswapped
         * if it remains in memory - LJM
         */
        if (hashp->LORDER != BYTE_ORDER) {
                register int i;
                register int max;

                if (is_bitmap) {
                        max = hashp->BSIZE >> 2;        /* divide by 4 */
                        for (i = 0; i < max; i++)
                                M_32_SWAP(((int *)p)[i]);
                } else {
                uint16 *bp = (uint16 *)p;

                        M_16_SWAP(bp[0]);
                        max = bp[0] + 2;

                        /* no need to bound the size if max again
                         * since it was done already above
                         */

                        /* do the byte order re-swap
                         */
                        for (i = 1; i <= max; i++)
                                M_16_SWAP(bp[i]);
                }
        }

        return (0);
}

#define BYTE_MASK       ((1 << INT_BYTE_SHIFT) -1)
/*
 * Initialize a new bitmap page.  Bitmap pages are left in memory
 * once they are read in.
 */
extern int
__ibitmap(HTAB *hashp, int pnum, int nbits, int ndx)
{
        uint32 *ip;
        size_t clearbytes, clearints;

        if ((ip = (uint32 *)malloc((size_t)hashp->BSIZE)) == NULL)
                return (1);
        hashp->nmaps++;
        clearints = ((nbits - 1) >> INT_BYTE_SHIFT) + 1;
        clearbytes = clearints << INT_TO_BYTE;
        (void)memset((char *)ip, 0, clearbytes);
        (void)memset(((char *)ip) + clearbytes, 0xFF,
            hashp->BSIZE - clearbytes);
        ip[clearints - 1] = ALL_SET << (nbits & BYTE_MASK);
        SETBIT(ip, 0);
        hashp->BITMAPS[ndx] = (uint16)pnum;
        hashp->mapp[ndx] = ip;
        return (0);
}

static uint32
first_free(uint32 map)
{
        register uint32 i, mask;

        mask = 0x1;
        for (i = 0; i < BITS_PER_MAP; i++) {
                if (!(mask & map))
                        return (i);
                mask = mask << 1;
        }
        return (i);
}

static uint16
overflow_page(HTAB *hashp)
{
        register uint32 *freep=NULL;
        register int max_free, offset, splitnum;
        uint16 addr;
        uint32 i;
        int bit, first_page, free_bit, free_page, in_use_bits, j;
#ifdef DEBUG2
        int tmp1, tmp2;
#endif
        splitnum = hashp->OVFL_POINT;
        max_free = hashp->SPARES[splitnum];

        free_page = (max_free - 1) >> (hashp->BSHIFT + BYTE_SHIFT);
        free_bit = (max_free - 1) & ((hashp->BSIZE << BYTE_SHIFT) - 1);

        /* Look through all the free maps to find the first free block */
        first_page = hashp->LAST_FREED >>(hashp->BSHIFT + BYTE_SHIFT);
        for ( i = first_page; i <= (unsigned)free_page; i++ ) {
                if (!(freep = (uint32 *)hashp->mapp[i]) &&
                    !(freep = fetch_bitmap(hashp, i)))
                        return (0);
                if (i == (unsigned)free_page)
                        in_use_bits = free_bit;
                else
                        in_use_bits = (hashp->BSIZE << BYTE_SHIFT) - 1;
                
                if (i == (unsigned)first_page) {
                        bit = hashp->LAST_FREED &
                            ((hashp->BSIZE << BYTE_SHIFT) - 1);
                        j = bit / BITS_PER_MAP;
                        bit = bit & ~(BITS_PER_MAP - 1);
                } else {
                        bit = 0;
                        j = 0;
                }
                for (; bit <= in_use_bits; j++, bit += BITS_PER_MAP)
                        if (freep[j] != ALL_SET)
                                goto found;
        }

        /* No Free Page Found */
        hashp->LAST_FREED = hashp->SPARES[splitnum];
        hashp->SPARES[splitnum]++;
        offset = hashp->SPARES[splitnum] -
            (splitnum ? hashp->SPARES[splitnum - 1] : 0);

#define OVMSG   "HASH: Out of overflow pages.  Increase page size\n"
        if (offset > SPLITMASK) {
                if (++splitnum >= NCACHED) {
#ifndef macintosh
                        (void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1);
#endif
                        return (0);
                }
                hashp->OVFL_POINT = splitnum;
                hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1];
                hashp->SPARES[splitnum-1]--;
                offset = 1;
        }

        /* Check if we need to allocate a new bitmap page */
        if (free_bit == (hashp->BSIZE << BYTE_SHIFT) - 1) {
                free_page++;
                if (free_page >= NCACHED) {
#ifndef macintosh
                        (void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1);
#endif
                        return (0);
                }
                /*
                 * This is tricky.  The 1 indicates that you want the new page
                 * allocated with 1 clear bit.  Actually, you are going to
                 * allocate 2 pages from this map.  The first is going to be
                 * the map page, the second is the overflow page we were
                 * looking for.  The init_bitmap routine automatically, sets
                 * the first bit of itself to indicate that the bitmap itself
                 * is in use.  We would explicitly set the second bit, but
                 * don't have to if we tell init_bitmap not to leave it clear
                 * in the first place.
                 */
                if (__ibitmap(hashp,
                    (int)OADDR_OF(splitnum, offset), 1, free_page))
                        return (0);
                hashp->SPARES[splitnum]++;
#ifdef DEBUG2
                free_bit = 2;
#endif
                offset++;
                if (offset > SPLITMASK) {
                        if (++splitnum >= NCACHED) {
#ifndef macintosh
                                (void)write(STDERR_FILENO, OVMSG,
                                    sizeof(OVMSG) - 1);
#endif
                                return (0);
                        }
                        hashp->OVFL_POINT = splitnum;
                        hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1];
                        hashp->SPARES[splitnum-1]--;
                        offset = 0;
                }
        } else {
                /*
                 * Free_bit addresses the last used bit.  Bump it to address
                 * the first available bit.
                 */
                free_bit++;
                SETBIT(freep, free_bit);
        }

        /* Calculate address of the new overflow page */
        addr = OADDR_OF(splitnum, offset);
#ifdef DEBUG2
        (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n",
            addr, free_bit, free_page);
#endif
        return (addr);

found:
        bit = bit + first_free(freep[j]);
        SETBIT(freep, bit);
#ifdef DEBUG2
        tmp1 = bit;
        tmp2 = i;
#endif
        /*
         * Bits are addressed starting with 0, but overflow pages are addressed
         * beginning at 1. Bit is a bit addressnumber, so we need to increment
         * it to convert it to a page number.
         */
        bit = 1 + bit + (i * (hashp->BSIZE << BYTE_SHIFT));
        if (bit >= hashp->LAST_FREED)
                hashp->LAST_FREED = bit - 1;

        /* Calculate the split number for this page */
        for (i = 0; (i < (unsigned)splitnum) && (bit > hashp->SPARES[i]); i++) {}
        offset = (i ? bit - hashp->SPARES[i - 1] : bit);
        if (offset >= SPLITMASK)
                return (0);     /* Out of overflow pages */
        addr = OADDR_OF(i, offset);
#ifdef DEBUG2
        (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n",
            addr, tmp1, tmp2);
#endif

        /* Allocate and return the overflow page */
        return (addr);
}

/*
 * Mark this overflow page as free.
 */
extern void
__free_ovflpage(HTAB *hashp, BUFHEAD *obufp)
{
        uint16 addr;
        uint32 *freep;
        uint32 bit_address, free_page, free_bit;
        uint16 ndx;

        if(!obufp || !obufp->addr)
            return;

        addr = obufp->addr;
#ifdef DEBUG1
        (void)fprintf(stderr, "Freeing %d\n", addr);
#endif
        ndx = (((uint16)addr) >> SPLITSHIFT);
        bit_address =
            (ndx ? hashp->SPARES[ndx - 1] : 0) + (addr & SPLITMASK) - 1;
        if (bit_address < (uint32)hashp->LAST_FREED)
                hashp->LAST_FREED = bit_address;
        free_page = (bit_address >> (hashp->BSHIFT + BYTE_SHIFT));
        free_bit = bit_address & ((hashp->BSIZE << BYTE_SHIFT) - 1);

        if (!(freep = hashp->mapp[free_page])) 
                freep = fetch_bitmap(hashp, free_page);

#ifdef DEBUG
        /*
         * This had better never happen.  It means we tried to read a bitmap
         * that has already had overflow pages allocated off it, and we
         * failed to read it from the file.
         */
        if (!freep)
          {
                assert(0);
                return;
          }
#endif
        CLRBIT(freep, free_bit);
#ifdef DEBUG2
        (void)fprintf(stderr, "FREE_OVFLPAGE: ADDR: %d BIT: %d PAGE %d\n",
            obufp->addr, free_bit, free_page);
#endif
        __reclaim_buf(hashp, obufp);
}

/*
 * Returns:
 *       0 success
 *      -1 failure
 */
static int
open_temp(HTAB *hashp)
{
#ifdef XP_OS2
        hashp->fp = mkstemp(NULL);
#else
#if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh)
        sigset_t set, oset;
#endif
#if !defined(macintosh)
        char * tmpdir;
        size_t len;
        char last;
#endif
        static const char namestr[] = "/_hashXXXXXX";
        char filename[1024];

#if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh)
        /* Block signals; make sure file goes away at process exit. */
        (void)sigfillset(&set);
        (void)sigprocmask(SIG_BLOCK, &set, &oset);
#endif

        filename[0] = 0;
#if defined(macintosh)
        strcat(filename, namestr + 1);
#else
        tmpdir = getenv("TMP");
        if (!tmpdir)
                tmpdir = getenv("TMPDIR");
        if (!tmpdir)
                tmpdir = getenv("TEMP");
        if (!tmpdir)
                tmpdir = ".";
        len = strlen(tmpdir);
        if (len && len < (sizeof filename - sizeof namestr)) {
                strcpy(filename, tmpdir);
        }
        len = strlen(filename);
        last = tmpdir[len - 1];
        strcat(filename, (last == '/' || last == '\\') ? namestr + 1 : namestr);
#endif

#if defined(_WIN32) || defined(_WINDOWS)
        if ((hashp->fp = mkstempflags(filename, _O_BINARY|_O_TEMPORARY)) != -1) {
                if (hashp->filename) {
                        free(hashp->filename);
                }
                hashp->filename = strdup(filename);
                hashp->is_temp = 1;
        }
#else
        if ((hashp->fp = mkstemp(filename)) != -1) {
                (void)unlink(filename);
#if !defined(macintosh)
                (void)fcntl(hashp->fp, F_SETFD, 1);
#endif                                                                    
        }
#endif

#if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh)
        (void)sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL);
#endif
#endif  /* !OS2 */
        return (hashp->fp != -1 ? 0 : -1);
}

/*
 * We have to know that the key will fit, but the last entry on the page is
 * an overflow pair, so we need to shift things.
 */
static void
squeeze_key(uint16 *sp, const DBT * key, const DBT * val)
{
        register char *p;
        uint16 free_space, n, off, pageno;

        p = (char *)sp;
        n = sp[0];
        free_space = FREESPACE(sp);
        off = OFFSET(sp);

        pageno = sp[n - 1];
        off -= key->size;
        sp[n - 1] = off;
        memmove(p + off, key->data, key->size);
        off -= val->size;
        sp[n] = off;
        memmove(p + off, val->data, val->size);
        sp[0] = n + 2;
        sp[n + 1] = pageno;
        sp[n + 2] = OVFLPAGE;
        FREESPACE(sp) = free_space - PAIRSIZE(key, val);
        OFFSET(sp) = off;
}

static uint32 *
fetch_bitmap(HTAB *hashp, uint32 ndx)
{
        if (ndx >= (unsigned)hashp->nmaps)
                return (NULL);
        if ((hashp->mapp[ndx] = (uint32 *)malloc((size_t)hashp->BSIZE)) == NULL)
                return (NULL);
        if (__get_page(hashp,
            (char *)hashp->mapp[ndx], hashp->BITMAPS[ndx], 0, 1, 1)) {
                free(hashp->mapp[ndx]);
                hashp->mapp[ndx] = NULL; /* NEW: 9-11-95 */
                return (NULL);
        }                 
        return (hashp->mapp[ndx]);
}

#ifdef DEBUG4
int
print_chain(int addr)
{
        BUFHEAD *bufp;
        short *bp, oaddr;

        (void)fprintf(stderr, "%d ", addr);
        bufp = __get_buf(hashp, addr, NULL, 0);
        bp = (short *)bufp->page;
        while (bp[0] && ((bp[bp[0]] == OVFLPAGE) ||
                ((bp[0] > 2) && bp[2] < REAL_KEY))) {
                oaddr = bp[bp[0] - 1];
                (void)fprintf(stderr, "%d ", (int)oaddr);
                bufp = __get_buf(hashp, (int)oaddr, bufp, 0);
                bp = (short *)bufp->page;
        }
        (void)fprintf(stderr, "\n");
}
#endif