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rec_get.c revision 1.10.14.1 
      1 /*	$NetBSD: rec_get.c,v 1.10.14.1 2001/10/08 20:18:38 nathanw Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990, 1993, 1994
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)rec_get.c	8.9 (Berkeley) 8/18/94";
     40 #else
     41 __RCSID("$NetBSD: rec_get.c,v 1.10.14.1 2001/10/08 20:18:38 nathanw Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include "namespace.h"
     46 #include <sys/types.h>
     47 
     48 #include <errno.h>
     49 #include <stddef.h>
     50 #include <stdio.h>
     51 #include <stdlib.h>
     52 #include <string.h>
     53 #include <unistd.h>
     54 
     55 #include <db.h>
     56 #include "recno.h"
     57 
     58 /*
     59  * __REC_GET -- Get a record from the btree.
     60  *
     61  * Parameters:
     62  *	dbp:	pointer to access method
     63  *	key:	key to find
     64  *	data:	data to return
     65  *	flag:	currently unused
     66  *
     67  * Returns:
     68  *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
     69  */
     70 int
     71 __rec_get(dbp, key, data, flags)
     72 	const DB *dbp;
     73 	const DBT *key;
     74 	DBT *data;
     75 	u_int flags;
     76 {
     77 	BTREE *t;
     78 	EPG *e;
     79 	recno_t nrec;
     80 	int status;
     81 
     82 	t = dbp->internal;
     83 
     84 	/* Toss any page pinned across calls. */
     85 	if (t->bt_pinned != NULL) {
     86 		mpool_put(t->bt_mp, t->bt_pinned, 0);
     87 		t->bt_pinned = NULL;
     88 	}
     89 
     90 	/* Get currently doesn't take any flags, and keys of 0 are illegal. */
     91 	if (flags || (nrec = *(recno_t *)key->data) == 0) {
     92 		errno = EINVAL;
     93 		return (RET_ERROR);
     94 	}
     95 
     96 	/*
     97 	 * If we haven't seen this record yet, try to find it in the
     98 	 * original file.
     99 	 */
    100 	if (nrec > t->bt_nrecs) {
    101 		if (F_ISSET(t, R_EOF | R_INMEM))
    102 			return (RET_SPECIAL);
    103 		if ((status = t->bt_irec(t, nrec)) != RET_SUCCESS)
    104 			return (status);
    105 	}
    106 
    107 	--nrec;
    108 	if ((e = __rec_search(t, nrec, SEARCH)) == NULL)
    109 		return (RET_ERROR);
    110 
    111 	status = __rec_ret(t, e, 0, NULL, data);
    112 	if (F_ISSET(t, B_DB_LOCK))
    113 		mpool_put(t->bt_mp, e->page, 0);
    114 	else
    115 		t->bt_pinned = e->page;
    116 	return (status);
    117 }
    118 
    119 /*
    120  * __REC_FPIPE -- Get fixed length records from a pipe.
    121  *
    122  * Parameters:
    123  *	t:	tree
    124  *	cnt:	records to read
    125  *
    126  * Returns:
    127  *	RET_ERROR, RET_SUCCESS
    128  */
    129 int
    130 __rec_fpipe(t, top)
    131 	BTREE *t;
    132 	recno_t top;
    133 {
    134 	DBT data;
    135 	recno_t nrec;
    136 	size_t len;
    137 	int ch;
    138 	u_char *p;
    139 
    140 	if (t->bt_rdata.size < t->bt_reclen) {
    141 		t->bt_rdata.data = t->bt_rdata.data == NULL ?
    142 		    malloc(t->bt_reclen) :
    143 		    realloc(t->bt_rdata.data, t->bt_reclen);
    144 		if (t->bt_rdata.data == NULL)
    145 			return (RET_ERROR);
    146 		t->bt_rdata.size = t->bt_reclen;
    147 	}
    148 	data.data = t->bt_rdata.data;
    149 	data.size = t->bt_reclen;
    150 
    151 	for (nrec = t->bt_nrecs; nrec < top;) {
    152 		len = t->bt_reclen;
    153 		for (p = t->bt_rdata.data;; *p++ = ch)
    154 			if ((ch = getc(t->bt_rfp)) == EOF || !--len) {
    155 				if (ch != EOF)
    156 					*p = ch;
    157 				if (len != 0)
    158 					memset(p, t->bt_bval, len);
    159 				if (__rec_iput(t,
    160 				    nrec, &data, 0) != RET_SUCCESS)
    161 					return (RET_ERROR);
    162 				++nrec;
    163 				break;
    164 			}
    165 		if (ch == EOF)
    166 			break;
    167 	}
    168 	if (nrec < top) {
    169 		F_SET(t, R_EOF);
    170 		return (RET_SPECIAL);
    171 	}
    172 	return (RET_SUCCESS);
    173 }
    174 
    175 /*
    176  * __REC_VPIPE -- Get variable length records from a pipe.
    177  *
    178  * Parameters:
    179  *	t:	tree
    180  *	cnt:	records to read
    181  *
    182  * Returns:
    183  *	RET_ERROR, RET_SUCCESS
    184  */
    185 int
    186 __rec_vpipe(t, top)
    187 	BTREE *t;
    188 	recno_t top;
    189 {
    190 	DBT data;
    191 	recno_t nrec;
    192 	ptrdiff_t len;
    193 	size_t sz;
    194 	int bval, ch;
    195 	u_char *p;
    196 
    197 	bval = t->bt_bval;
    198 	for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
    199 		for (p = t->bt_rdata.data,
    200 		    sz = t->bt_rdata.size;; *p++ = ch, --sz) {
    201 			if ((ch = getc(t->bt_rfp)) == EOF || ch == bval) {
    202 				data.data = t->bt_rdata.data;
    203 				data.size = p - (u_char *)t->bt_rdata.data;
    204 				if (ch == EOF && data.size == 0)
    205 					break;
    206 				if (__rec_iput(t, nrec, &data, 0)
    207 				    != RET_SUCCESS)
    208 					return (RET_ERROR);
    209 				break;
    210 			}
    211 			if (sz == 0) {
    212 				len = p - (u_char *)t->bt_rdata.data;
    213 				t->bt_rdata.size += (sz = 256);
    214 				t->bt_rdata.data = t->bt_rdata.data == NULL ?
    215 				    malloc(t->bt_rdata.size) :
    216 				    realloc(t->bt_rdata.data, t->bt_rdata.size);
    217 				if (t->bt_rdata.data == NULL)
    218 					return (RET_ERROR);
    219 				p = (u_char *)t->bt_rdata.data + len;
    220 			}
    221 		}
    222 		if (ch == EOF)
    223 			break;
    224 	}
    225 	if (nrec < top) {
    226 		F_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 	u_char *sp, *ep, *p;
    250 	size_t len;
    251 
    252 	if (t->bt_rdata.size < t->bt_reclen) {
    253 		t->bt_rdata.data = t->bt_rdata.data == NULL ?
    254 		    malloc(t->bt_reclen) :
    255 		    realloc(t->bt_rdata.data, t->bt_reclen);
    256 		if (t->bt_rdata.data == NULL)
    257 			return (RET_ERROR);
    258 		t->bt_rdata.size = t->bt_reclen;
    259 	}
    260 	data.data = t->bt_rdata.data;
    261 	data.size = t->bt_reclen;
    262 
    263 	sp = (u_char *)t->bt_cmap;
    264 	ep = (u_char *)t->bt_emap;
    265 	for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
    266 		if (sp >= ep) {
    267 			F_SET(t, R_EOF);
    268 			return (RET_SPECIAL);
    269 		}
    270 		len = t->bt_reclen;
    271 		for (p = t->bt_rdata.data;
    272 		    sp < ep && len > 0; *p++ = *sp++, --len);
    273 		if (len != 0)
    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 = (caddr_t)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 	u_char *sp, *ep;
    299 	recno_t nrec;
    300 	int bval;
    301 
    302 	sp = (u_char *)t->bt_cmap;
    303 	ep = (u_char *)t->bt_emap;
    304 	bval = t->bt_bval;
    305 
    306 	for (nrec = t->bt_nrecs; nrec < top; ++nrec) {
    307 		if (sp >= ep) {
    308 			F_SET(t, R_EOF);
    309 			return (RET_SPECIAL);
    310 		}
    311 		for (data.data = sp; sp < ep && *sp != bval; ++sp);
    312 		data.size = sp - (u_char *)data.data;
    313 		if (__rec_iput(t, nrec, &data, 0) != RET_SUCCESS)
    314 			return (RET_ERROR);
    315 		++sp;
    316 	}
    317 	t->bt_cmap = (caddr_t)sp;
    318 	return (RET_SUCCESS);
    319 }
    320