db/recno/rec_get.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1990, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice, this list of conditions and the following disclaimer.
  31  * 2. Redistributions in binary form must reproduce the above copyright
  32  *    notice, this list of conditions and the following disclaimer in the
  33  *    documentation and/or other materials provided with the distribution.
  34  * 3. All advertising materials mentioning features or use of this software
  35  *    must display the following acknowledgement:
  36  *      This product includes software developed by the University of
  37  *      California, Berkeley and its contributors.
  38  * 4. Neither the name of the University nor the names of its contributors
  39  *    may be used to endorse or promote products derived from this software
  40  *    without specific prior written permission.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  45  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  52  * SUCH DAMAGE.
  53  */
  54
  55
  56 #include <sys/types.h>
  57
  58 #include <errno.h>
  59 #include <stddef.h>
  60 #include <stdio.h>
  61 #include <stdlib.h>
  62 #include <string.h>
  63 #include <unistd.h>
  64
  65 #include <db.h>
  66 #include "recno.h"
  67
  68 /*
  69  * __REC_GET -- Get a record from the btree.
  70  *
  71  * Parameters:
  72  *      dbp:    pointer to access method
  73  *      key:    key to find
  74  *      data:   data to return
  75  *      flag:   currently unused
  76  *
  77  * Returns:
  78  *      RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
  79  */
  80 int
  81 __rec_get(dbp, key, data, flags)
  82         const DB *dbp;
  83         const DBT *key;
  84         DBT *data;
  85         u_int flags;
  86 {
  87         BTREE *t;
  88         EPG *e;
  89         recno_t nrec;
  90         int status;
  91
  92         t = dbp->internal;
  93
  94         /* Toss any page pinned across calls. */
  95         if (t->bt_pinned != NULL) {
  96                 mpool_put(t->bt_mp, t->bt_pinned, 0);
  97                 t->bt_pinned = NULL;
  98         }
  99
 100         /* Get currently doesn't take any flags, and keys of 0 are illegal. */
 101         if (flags || (nrec = *(recno_t *)key->data) == 0) {
 102                 errno = EINVAL;
 103                 return (RET_ERROR);
 104         }
 105
 106         /*
 107          * If we haven't seen this record yet, try to find it in the
 108          * original file.
 109          */
 110         if (nrec > t->bt_nrecs) {
 111                 if (ISSET(t, R_EOF | R_INMEM))
 112                         return (RET_SPECIAL);
 113                 if ((status = t->bt_irec(t, nrec)) != RET_SUCCESS)
 114                         return (status);
 115         }
 116
 117         --nrec;
 118         if ((e = __rec_search(t, nrec, SEARCH)) == NULL)
 119                 return (RET_ERROR);
 120
 121         status = __rec_ret(t, e, 0, NULL, data);
 122         if (ISSET(t, B_DB_LOCK))
 123                 mpool_put(t->bt_mp, e->page, 0);
 124         else
 125                 t->bt_pinned = e->page;
 126         return (status);
 127 }
 128
 129 /*
 130  * __REC_FPIPE -- Get fixed length records from a pipe.
 131  *
 132  * Parameters:
 133  *      t:      tree
 134  *      cnt:    records to read
 135  *
 136  * Returns:
 137  *      RET_ERROR, RET_SUCCESS
 138  */
 139 int
 140 __rec_fpipe(t, top)
 141         BTREE *t;
 142         recno_t top;
 143 {
 144         DBT data;
 145         recno_t nrec;
 146         size_t len;
 147         int ch;
 148         char *p;
 149
 150         if (t->bt_dbufsz < t->bt_reclen) {
 151                 if ((t->bt_dbuf =
 152                     (char *)realloc(t->bt_dbuf, t->bt_reclen)) == NULL)
 153                         return (RET_ERROR);
 154                 t->bt_dbufsz = t->bt_reclen;
 155         }
 156         data.data = t->bt_dbuf;
 157         data.size = t->bt_reclen;
 158
 159         for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
 160                 len = t->bt_reclen;
 161                 for (p = t->bt_dbuf;; *p++ = ch)
 162                         if ((ch = getc(t->bt_rfp)) == EOF || !len--) {
 163                                 if (__rec_iput(t, nrec, &data, 0)
 164                                     != RET_SUCCESS)
 165                                         return (RET_ERROR);
 166                                 break;
 167                         }
 168                 if (ch == EOF)
 169                         break;
 170         }
 171         if (nrec < top) {
 172                 SET(t, R_EOF);
 173                 return (RET_SPECIAL);
 174         }
 175         return (RET_SUCCESS);
 176 }
 177
 178 /*
 179  * __REC_VPIPE -- Get variable length records from a pipe.
 180  *
 181  * Parameters:
 182  *      t:      tree
 183  *      cnt:    records to read
 184  *
 185  * Returns:
 186  *      RET_ERROR, RET_SUCCESS
 187  */
 188 int
 189 __rec_vpipe(t, top)
 190         BTREE *t;
 191         recno_t top;
 192 {
 193         DBT data;
 194         recno_t nrec;
 195         indx_t len;
 196         size_t sz;
 197         int bval, ch;
 198         char *p;
 199
 200         bval = t->bt_bval;
 201         for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
 202                 for (p = t->bt_dbuf, sz = t->bt_dbufsz;; *p++ = ch, --sz) {
 203                         if ((ch = getc(t->bt_rfp)) == EOF || ch == bval) {
 204                                 data.data = t->bt_dbuf;
 205                                 data.size = p - t->bt_dbuf;
 206                                 if (ch == EOF && data.size == 0)
 207                                         break;
 208                                 if (__rec_iput(t, nrec, &data, 0)
 209                                     != RET_SUCCESS)
 210                                         return (RET_ERROR);
 211                                 break;
 212                         }
 213                         if (sz == 0) {
 214                                 len = p - t->bt_dbuf;
 215                                 t->bt_dbufsz += (sz = 256);
 216                                 if ((t->bt_dbuf = (char *)realloc(t->bt_dbuf,
 217                                     t->bt_dbufsz)) == NULL)
 218                                         return (RET_ERROR);
 219                                 p = t->bt_dbuf + len;
 220                         }
 221                 }
 222                 if (ch == EOF)
 223                         break;
 224         }
 225         if (nrec < top) {
 226                 SET(t, R_EOF);
 227                 return (RET_SPECIAL);
 228         }
 229         return (RET_SUCCESS);
 230 }
 231
 232 /*
 233  * __REC_FMAP -- Get fixed length records from a file.
 234  *
 235  * Parameters:
 236  *      t:      tree
 237  *      cnt:    records to read
 238  *
 239  * Returns:
 240  *      RET_ERROR, RET_SUCCESS
 241  */
 242 int
 243 __rec_fmap(t, top)
 244         BTREE *t;
 245         recno_t top;
 246 {
 247         DBT data;
 248         recno_t nrec;
 249         caddr_t sp, ep;
 250         size_t len;
 251         char *p;
 252
 253         if (t->bt_dbufsz < t->bt_reclen) {
 254                 if ((t->bt_dbuf =
 255                     (char *)realloc(t->bt_dbuf, t->bt_reclen)) == NULL)
 256                         return (RET_ERROR);
 257                 t->bt_dbufsz = t->bt_reclen;
 258         }
 259         data.data = t->bt_dbuf;
 260         data.size = t->bt_reclen;
 261
 262         sp = t->bt_cmap;
 263         ep = t->bt_emap;
 264         for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
 265                 if (sp >= ep) {
 266                         SET(t, R_EOF);
 267                         return (RET_SPECIAL);
 268                 }
 269                 len = t->bt_reclen;
 270                 for (p = t->bt_dbuf; sp < ep && len--; *p++ = *sp++);
 271                 memset(p, t->bt_bval, len);
 272                 if (__rec_iput(t, nrec, &data, 0) != RET_SUCCESS)
 273                         return (RET_ERROR);
 274         }
 275         t->bt_cmap = sp;
 276         return (RET_SUCCESS);
 277 }
 278
 279 /*
 280  * __REC_VMAP -- Get variable length records from a file.
 281  *
 282  * Parameters:
 283  *      t:      tree
 284  *      cnt:    records to read
 285  *
 286  * Returns:
 287  *      RET_ERROR, RET_SUCCESS
 288  */
 289 int
 290 __rec_vmap(t, top)
 291         BTREE *t;
 292         recno_t top;
 293 {
 294         DBT data;
 295         caddr_t sp, ep;
 296         recno_t nrec;
 297         int bval;
 298
 299         sp = t->bt_cmap;
 300         ep = t->bt_emap;
 301         bval = t->bt_bval;
 302
 303         for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
 304                 if (sp >= ep) {
 305                         SET(t, R_EOF);
 306                         return (RET_SPECIAL);
 307                 }
 308                 for (data.data = sp; sp < ep && *sp != bval; ++sp);
 309                 data.size = sp - (caddr_t)data.data;
 310                 if (__rec_iput(t, nrec, &data, 0) != RET_SUCCESS)
 311                         return (RET_ERROR);
 312                 ++sp;
 313         }
 314         t->bt_cmap = sp;
 315         return (RET_SUCCESS);
 316 }