db/recno/rec_get.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1990, 1993
  27  *      The Regents of the University of California.  All rights reserved.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 #include <sys/types.h>
  60
  61 #include <errno.h>
  62 #include <stddef.h>
  63 #include <stdio.h>
  64 #include <stdlib.h>
  65 #include <string.h>
  66 #include <unistd.h>
  67
  68 #include <db.h>
  69 #include "recno.h"
  70
  71 /*
  72  * __REC_GET -- Get a record from the btree.
  73  *
  74  * Parameters:
  75  *      dbp:    pointer to access method
  76  *      key:    key to find
  77  *      data:   data to return
  78  *      flag:   currently unused
  79  *
  80  * Returns:
  81  *      RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
  82  */
  83 int
  84 __rec_get(dbp, key, data, flags)
  85         const DB *dbp;
  86         const DBT *key;
  87         DBT *data;
  88         u_int flags;
  89 {
  90         BTREE *t;
  91         EPG *e;
  92         recno_t nrec;
  93         int status;
  94
  95         t = dbp->internal;
  96
  97         /* Toss any page pinned across calls. */
  98         if (t->bt_pinned != NULL) {
  99                 mpool_put(t->bt_mp, t->bt_pinned, 0);
 100                 t->bt_pinned = NULL;
 101         }
 102
 103         /* Get currently doesn't take any flags, and keys of 0 are illegal. */
 104         if (flags || (nrec = *(recno_t *)key->data) == 0) {
 105                 errno = EINVAL;
 106                 return (RET_ERROR);
 107         }
 108
 109         /*
 110          * If we haven't seen this record yet, try to find it in the
 111          * original file.
 112          */
 113         if (nrec > t->bt_nrecs) {
 114                 if (ISSET(t, R_EOF | R_INMEM))
 115                         return (RET_SPECIAL);
 116                 if ((status = t->bt_irec(t, nrec)) != RET_SUCCESS)
 117                         return (status);
 118         }
 119
 120         --nrec;
 121         if ((e = __rec_search(t, nrec, SEARCH)) == NULL)
 122                 return (RET_ERROR);
 123
 124         status = __rec_ret(t, e, 0, NULL, data);
 125         if (ISSET(t, B_DB_LOCK))
 126                 mpool_put(t->bt_mp, e->page, 0);
 127         else
 128                 t->bt_pinned = e->page;
 129         return (status);
 130 }
 131
 132 /*
 133  * __REC_FPIPE -- Get fixed length records from a pipe.
 134  *
 135  * Parameters:
 136  *      t:      tree
 137  *      cnt:    records to read
 138  *
 139  * Returns:
 140  *      RET_ERROR, RET_SUCCESS
 141  */
 142 int
 143 __rec_fpipe(t, top)
 144         BTREE *t;
 145         recno_t top;
 146 {
 147         DBT data;
 148         recno_t nrec;
 149         size_t len;
 150         int ch;
 151         char *p;
 152
 153         if (t->bt_dbufsz < t->bt_reclen) {
 154                 if ((t->bt_dbuf =
 155                     (char *)realloc(t->bt_dbuf, t->bt_reclen)) == NULL)
 156                         return (RET_ERROR);
 157                 t->bt_dbufsz = t->bt_reclen;
 158         }
 159         data.data = t->bt_dbuf;
 160         data.size = t->bt_reclen;
 161
 162         for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
 163                 len = t->bt_reclen;
 164                 for (p = t->bt_dbuf;; *p++ = ch)
 165                         if ((ch = getc(t->bt_rfp)) == EOF || !len--) {
 166                                 if (__rec_iput(t, nrec, &data, 0)
 167                                     != RET_SUCCESS)
 168                                         return (RET_ERROR);
 169                                 break;
 170                         }
 171                 if (ch == EOF)
 172                         break;
 173         }
 174         if (nrec < top) {
 175                 SET(t, R_EOF);
 176                 return (RET_SPECIAL);
 177         }
 178         return (RET_SUCCESS);
 179 }
 180
 181 /*
 182  * __REC_VPIPE -- Get variable length records from a pipe.
 183  *
 184  * Parameters:
 185  *      t:      tree
 186  *      cnt:    records to read
 187  *
 188  * Returns:
 189  *      RET_ERROR, RET_SUCCESS
 190  */
 191 int
 192 __rec_vpipe(t, top)
 193         BTREE *t;
 194         recno_t top;
 195 {
 196         DBT data;
 197         recno_t nrec;
 198         indx_t len;
 199         size_t sz;
 200         int bval, ch;
 201         char *p;
 202
 203         bval = t->bt_bval;
 204         for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
 205                 for (p = t->bt_dbuf, sz = t->bt_dbufsz;; *p++ = ch, --sz) {
 206                         if ((ch = getc(t->bt_rfp)) == EOF || ch == bval) {
 207                                 data.data = t->bt_dbuf;
 208                                 data.size = p - t->bt_dbuf;
 209                                 if (ch == EOF && data.size == 0)
 210                                         break;
 211                                 if (__rec_iput(t, nrec, &data, 0)
 212                                     != RET_SUCCESS)
 213                                         return (RET_ERROR);
 214                                 break;
 215                         }
 216                         if (sz == 0) {
 217                                 len = p - t->bt_dbuf;
 218                                 t->bt_dbufsz += (sz = 256);
 219                                 if ((t->bt_dbuf = (char *)realloc(t->bt_dbuf,
 220                                     t->bt_dbufsz)) == NULL)
 221                                         return (RET_ERROR);
 222                                 p = t->bt_dbuf + len;
 223                         }
 224                 }
 225                 if (ch == EOF)
 226                         break;
 227         }
 228         if (nrec < top) {
 229                 SET(t, R_EOF);
 230                 return (RET_SPECIAL);
 231         }
 232         return (RET_SUCCESS);
 233 }
 234
 235 /*
 236  * __REC_FMAP -- Get fixed length records from a file.
 237  *
 238  * Parameters:
 239  *      t:      tree
 240  *      cnt:    records to read
 241  *
 242  * Returns:
 243  *      RET_ERROR, RET_SUCCESS
 244  */
 245 int
 246 __rec_fmap(t, top)
 247         BTREE *t;
 248         recno_t top;
 249 {
 250         DBT data;
 251         recno_t nrec;
 252         caddr_t sp, ep;
 253         size_t len;
 254         char *p;
 255
 256         if (t->bt_dbufsz < t->bt_reclen) {
 257                 if ((t->bt_dbuf =
 258                     (char *)realloc(t->bt_dbuf, t->bt_reclen)) == NULL)
 259                         return (RET_ERROR);
 260                 t->bt_dbufsz = t->bt_reclen;
 261         }
 262         data.data = t->bt_dbuf;
 263         data.size = t->bt_reclen;
 264
 265         sp = t->bt_cmap;
 266         ep = t->bt_emap;
 267         for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
 268                 if (sp >= ep) {
 269                         SET(t, R_EOF);
 270                         return (RET_SPECIAL);
 271                 }
 272                 len = t->bt_reclen;
 273                 for (p = t->bt_dbuf; sp < ep && len--; *p++ = *sp++);
 274                 memset(p, t->bt_bval, len);
 275                 if (__rec_iput(t, nrec, &data, 0) != RET_SUCCESS)
 276                         return (RET_ERROR);
 277         }
 278         t->bt_cmap = sp;
 279         return (RET_SUCCESS);
 280 }
 281
 282 /*
 283  * __REC_VMAP -- Get variable length records from a file.
 284  *
 285  * Parameters:
 286  *      t:      tree
 287  *      cnt:    records to read
 288  *
 289  * Returns:
 290  *      RET_ERROR, RET_SUCCESS
 291  */
 292 int
 293 __rec_vmap(t, top)
 294         BTREE *t;
 295         recno_t top;
 296 {
 297         DBT data;
 298         caddr_t sp, ep;
 299         recno_t nrec;
 300         int bval;
 301
 302         sp = t->bt_cmap;
 303         ep = t->bt_emap;
 304         bval = t->bt_bval;
 305
 306         for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
 307                 if (sp >= ep) {
 308                         SET(t, R_EOF);
 309                         return (RET_SPECIAL);
 310                 }
 311                 for (data.data = sp; sp < ep && *sp != bval; ++sp);
 312                 data.size = sp - (caddr_t)data.data;
 313                 if (__rec_iput(t, nrec, &data, 0) != RET_SUCCESS)
 314                         return (RET_ERROR);
 315                 ++sp;
 316         }
 317         t->bt_cmap = sp;
 318         return (RET_SUCCESS);
 319 }