rec_get.c

Go to the documentation of this file.

/*-
 * Copyright (c) 1990, 1993, 1994
 * The Regents of the University of California.  All rights reserved.
 *
 * 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[] = "@(#)rec_get.c  8.9 (Berkeley) 8/18/94";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>

#include <errno.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "../include/db.h"
#include "recno.h"

/*
 * __REC_GET -- Get a record from the btree.
 *
 * Parameters:
 * dbp:  pointer to access method
 * key:  key to find
 * data: data to return
 * flag: currently unused
 *
 * Returns:
 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
 */
int
__rec_get(dbp, key, data, flags)
   const DB *dbp;
   const DBT *key;
   DBT *data;
   u_int flags;
{
   BTREE *t;
   EPG *e;
   recno_t nrec;
   int status;

   t = dbp->internal;

   /* Toss any page pinned across calls. */
   if (t->bt_pinned != NULL) {
      mpool_put(t->bt_mp, t->bt_pinned, 0);
      t->bt_pinned = NULL;
   }

   /* Get currently doesn't take any flags, and keys of 0 are illegal. */
   if (flags || (nrec = *(recno_t *)key->data) == 0) {
      errno = EINVAL;
      return (RET_ERROR);
   }

   /*
    * If we haven't seen this record yet, try to find it in the
    * original file.
    */
   if (nrec > t->bt_nrecs) {
      if (F_ISSET(t, R_EOF | R_INMEM))
         return (RET_SPECIAL);
      if ((status = t->bt_irec(t, nrec)) != RET_SUCCESS)
         return (status);
   }

   --nrec;
   if ((e = __rec_search(t, nrec, SEARCH)) == NULL)
      return (RET_ERROR);

   status = __rec_ret(t, e, 0, NULL, data);
   if (F_ISSET(t, B_DB_LOCK))
      mpool_put(t->bt_mp, e->page, 0);
   else
      t->bt_pinned = e->page;
   return (status);
}

/*
 * __REC_FPIPE -- Get fixed length records from a pipe.
 *
 * Parameters:
 * t: tree
 * cnt:  records to read
 *
 * Returns:
 * RET_ERROR, RET_SUCCESS
 */
int
__rec_fpipe(t, top)
   BTREE *t;
   recno_t top;
{
   DBT data;
   recno_t nrec;
   size_t len;
   int ch;
   u_char *p;

   if (t->bt_rdata.size < t->bt_reclen) {
      t->bt_rdata.data = t->bt_rdata.data == NULL ?
          malloc(t->bt_reclen) :
          realloc(t->bt_rdata.data, t->bt_reclen);
      if (t->bt_rdata.data == NULL)
         return (RET_ERROR);
      t->bt_rdata.size = t->bt_reclen;
   }
   data.data = t->bt_rdata.data;
   data.size = t->bt_reclen;

   for (nrec = t->bt_nrecs; nrec < top;) {
      len = t->bt_reclen;
      for (p = t->bt_rdata.data;; *p++ = ch)
         if ((ch = getc(t->bt_rfp)) == EOF || !--len) {
            if (ch != EOF)
               *p = ch;
            if (len != 0)
               memset(p, t->bt_bval, len);
            if (__rec_iput(t,
                nrec, &data, 0) != RET_SUCCESS)
               return (RET_ERROR);
            ++nrec;
            break;
         }
      if (ch == EOF)
         break;
   }
   if (nrec < top) {
      F_SET(t, R_EOF);
      return (RET_SPECIAL);
   }
   return (RET_SUCCESS);
}

/*
 * __REC_VPIPE -- Get variable length records from a pipe.
 *
 * Parameters:
 * t: tree
 * cnt:  records to read
 *
 * Returns:
 * RET_ERROR, RET_SUCCESS
 */
int
__rec_vpipe(t, top)
   BTREE *t;
   recno_t top;
{
   DBT data;
   recno_t nrec;
   indx_t len;
   size_t sz;
   int bval, ch;
   u_char *p;

   bval = t->bt_bval;
   for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
      for (p = t->bt_rdata.data,
          sz = t->bt_rdata.size;; *p++ = ch, --sz) {
         if ((ch = getc(t->bt_rfp)) == EOF || ch == bval) {
            data.data = t->bt_rdata.data;
            data.size = p - (u_char *)t->bt_rdata.data;
            if (ch == EOF && data.size == 0)
               break;
            if (__rec_iput(t, nrec, &data, 0)
                != RET_SUCCESS)
               return (RET_ERROR);
            break;
         }
         if (sz == 0) {
            len = p - (u_char *)t->bt_rdata.data;
            t->bt_rdata.size += (sz = 256);
            t->bt_rdata.data = t->bt_rdata.data == NULL ?
                malloc(t->bt_rdata.size) :
                realloc(t->bt_rdata.data, t->bt_rdata.size);
            if (t->bt_rdata.data == NULL)
               return (RET_ERROR);
            p = (u_char *)t->bt_rdata.data + len;
         }
      }
      if (ch == EOF)
         break;
   }
   if (nrec < top) {
      F_SET(t, R_EOF);
      return (RET_SPECIAL);
   }
   return (RET_SUCCESS);
}

/*
 * __REC_FMAP -- Get fixed length records from a file.
 *
 * Parameters:
 * t: tree
 * cnt:  records to read
 *
 * Returns:
 * RET_ERROR, RET_SUCCESS
 */
int
__rec_fmap(t, top)
   BTREE *t;
   recno_t top;
{
   DBT data;
   recno_t nrec;
   u_char *sp, *ep, *p;
   size_t len;

   if (t->bt_rdata.size < t->bt_reclen) {
      t->bt_rdata.data = t->bt_rdata.data == NULL ?
          malloc(t->bt_reclen) :
          realloc(t->bt_rdata.data, t->bt_reclen);
      if (t->bt_rdata.data == NULL)
         return (RET_ERROR);
      t->bt_rdata.size = t->bt_reclen;
   }
   data.data = t->bt_rdata.data;
   data.size = t->bt_reclen;

   sp = (u_char *)t->bt_cmap;
   ep = (u_char *)t->bt_emap;
   for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
      if (sp >= ep) {
         F_SET(t, R_EOF);
         return (RET_SPECIAL);
      }
      len = t->bt_reclen;
      for (p = t->bt_rdata.data;
          sp < ep && len > 0; *p++ = *sp++, --len);
      if (len != 0)
         memset(p, t->bt_bval, len);
      if (__rec_iput(t, nrec, &data, 0) != RET_SUCCESS)
         return (RET_ERROR);
   }
   t->bt_cmap = (caddr_t)sp;
   return (RET_SUCCESS);
}

/*
 * __REC_VMAP -- Get variable length records from a file.
 *
 * Parameters:
 * t: tree
 * cnt:  records to read
 *
 * Returns:
 * RET_ERROR, RET_SUCCESS
 */
int
__rec_vmap(t, top)
   BTREE *t;
   recno_t top;
{
   DBT data;
   u_char *sp, *ep;
   recno_t nrec;
   int bval;

   sp = (u_char *)t->bt_cmap;
   ep = (u_char *)t->bt_emap;
   bval = t->bt_bval;

   for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
      if (sp >= ep) {
         F_SET(t, R_EOF);
         return (RET_SPECIAL);
      }
      for (data.data = sp; sp < ep && *sp != bval; ++sp);
      data.size = sp - (u_char *)data.data;
      if (__rec_iput(t, nrec, &data, 0) != RET_SUCCESS)
         return (RET_ERROR);
      ++sp;
   }
   t->bt_cmap = (caddr_t)sp;
   return (RET_SUCCESS);
}