rec_get.c

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/*-
 * 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);
}