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);
}