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rec_get.c

/*-
 * 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 <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);
}

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