/*
  Copyright (C) 1991, Andrew Molitor. All rights reserved.
  */
/*
  #define DEBUG
  */
/*
  This a a dbm emulation module for VMS, using indexed files to do
  the database thang. It emulates new dbm.

  */

#include "autoconf.h"
#include "copyright.h"
#ifndef	lint
static char *RCSid = "$Id: vms_dbm.c,v 1.7 1995/03/21 00:01:39 ambar Exp $";
USE(RCSid);
#endif

#include	<ssdef.h>
#include	<rms.h>

#include	"vms_dbm.h"

static char dbmbuff[MAX_RECORD];


DBM *
dbm_open(filename, flags, mode)
    char *filename;
    int flags;			/* Ignored. */
    int mode;			/* Ignored. */
{
    DBM *newdb;
    char *name;
    int status;

    /* Make a new DBM struct */
#ifdef DEBUG
    printf("Opening DB file %s\n", filename);
#endif
    newdb = (DBM *) malloc(sizeof(struct rmsblocks));

    if (newdb == (DBM *) 0) {
	return ((DBM *) 0);
    }
    name = (char *) malloc(strlen(filename) + 1);
    if (name == (char *) 0) {
	free((char *) newdb);
	return ((DBM *) 0);
    }
    strcpy(name, filename);

    /* Fill it in with stuff */

    /* FAB */

    newdb->fab = cc$rms_fab;
    (newdb->fab).fab$l_fna = name;
    (newdb->fab).fab$l_xab = &(newdb->xab);
    (newdb->fab).fab$b_fns = strlen(name);
    (newdb->fab).fab$b_bks = BUCKET_SIZE;
    (newdb->fab).fab$b_org = FAB$C_IDX;
    (newdb->fab).fab$w_mrs = MAX_RECORD;
    (newdb->fab).fab$b_rfm = FAB$C_VAR;
    (newdb->fab).fab$l_fop = FAB$M_CIF;
    (newdb->fab).fab$b_fac = FAB$M_PUT | FAB$M_GET | FAB$M_UPD | FAB$M_DEL;

    /* RAB */

    newdb->rab = cc$rms_rab;
    (newdb->rab).rab$l_fab = &(newdb->fab);
    (newdb->rab).rab$b_rac = RAB$C_KEY;
    (newdb->rab).rab$l_rop = RAB$V_UIF | RAB$V_LIM;
    (newdb->rab).rab$l_ubf = dbmbuff;
    (newdb->rab).rab$w_usz = MAX_RECORD;

    /* XAB */

    newdb->xab = cc$rms_xabkey;
    (newdb->xab).xab$b_dtp = XAB$C_STG;
    (newdb->xab).xab$w_pos = 0;
    (newdb->xab).xab$b_siz = KEY_SIZE;
    (newdb->xab).xab$b_ref = 0;

    /* Try to open it */

    status = sys$create(&(newdb->fab));
    if ((status & 1) == 0) {	/* Failed open, try to create it */
#ifdef DEBUG
	printf("$open failed, status %d.\n", status);
#endif
	goto bag;
    }
    /* We're poppin'. Connect the rab up. */

    status = sys$connect(&(newdb->rab));
    if ((status & 1) == 0) {
#ifdef DEBUG
	printf("$connect failed, status %d\n", status);
#endif
	goto bag;
    }
    /* Ready to go, we hope */
#ifdef DEBUG
    printf("Succeeded.\n");
#endif
    return (newdb);
  bag:
    free((char *) newdb);
    free((char *) name);
    return ((DBM *) 0);
}

dbm_close(db)
    DBM *db;
{
    sys$close(&(db->fab));
    free((db->fab).fab$l_fna);
    free((char *) db);
}

datum
dbm_fetch(db, key)
    DBM *db;
    datum key;
{
    int status;
    int i;
    datum answer;
    char keybuff[KEY_SIZE];
    char *p, *s;

    /* Fill in the key part of the rab */

    p = keybuff;
    s = key.dptr;
    for (i = 0; i < KEY_SIZE && i < key.dsize; i++)
	*p++ = *s++;

    while (i++ < KEY_SIZE)
	*p++ = '\0';

    (db->rab).rab$l_kbf = keybuff;
    (db->rab).rab$b_ksz = KEY_SIZE;

    /* Now go get it */

    status = sys$get(&(db->rab));
    if ((status & 1) == 0) {
#ifdef DEBUG
	printf("$get failed, status %d\n", status);
#endif
	goto bag;
    }
    answer.dsize = (db->rab).rab$w_rsz - KEY_SIZE;
    answer.dptr = malloc(answer.dsize);
    if (answer.dptr == (char *) 0) {
	goto bag;
    }
    bcopy((db->rab).rab$l_rbf + KEY_SIZE, answer.dptr, answer.dsize);
    return (answer);
  bag:
    answer.dptr = (char *) 0;
    answer.dsize = 0;
    return (answer);
}

dbm_store(db, key, content, flags)
    DBM *db;
    datum key;
    datum content;
    int flags;			/* Ignored */
{
    int status;
    int i;
    char *p, *s;

    /* Build the record */
#ifdef DEBUG
    printf("dbm_store: data size = %d\n", content.dsize);
#endif
    /* Fill in KEY_SIZE bytes of key */

    p = dbmbuff;
    s = key.dptr;
    for (i = 0; i < key.dsize && i < KEY_SIZE; i++)
	*p++ = *s++;
    while (i++ < KEY_SIZE)
	*p++ = '\0';

    bcopy(content.dptr, dbmbuff + KEY_SIZE, content.dsize);
    (db->rab).rab$l_rbf = dbmbuff;
    (db->rab).rab$w_rsz = content.dsize + KEY_SIZE;

    (db->rab).rab$l_kbf = dbmbuff;
    (db->rab).rab$b_ksz = KEY_SIZE;
#ifdef DEBUG
    printf("Searching for record %s, size = %d\n",
	   dbmbuff, (db->rab).rab$w_rsz);
#endif
    status = sys$find(&(db->rab));
    if (status == RMS$_NORMAL) {
	status = sys$update(&(db->rab));
    } else if (status == RMS$_RNF) {
#ifdef DEBUG
	printf("Record not found. Trying $put %d\n", status);
#endif
	status = sys$put(&(db->rab));
    }
    if ((status & 1) == 0) {
#ifdef DEBUG
	printf("$update/$put failed. status code %d\n", status);
#endif
	return (1);
    }
    return (0);
}

dbm_delete(db, key)
    DBM *db;
    datum key;
{
    int status;
    int i;
    datum answer;
    char keybuff[KEY_SIZE];
    char *p, *s;

    /* Fill in the key part of the rab */

    p = keybuff;
    s = key.dptr;
    for (i = 0; i < KEY_SIZE && i < key.dsize; i++)
	*p++ = *s++;

    while (i++ < KEY_SIZE)
	*p++ = '\0';

    (db->rab).rab$l_kbf = keybuff;
    (db->rab).rab$b_ksz = KEY_SIZE;

    /* Now go KILL it */

    status = sys$find(&(db->rab));
    if ((status & 1) == 0) {
#ifdef DEBUG
	printf("$find in delete() failed, status %d\n", status);
#endif
	return (1);
    }
    status = sys$delete(&(db->rab));
    if ((status & 1) == 0) {
#ifdef DEBUG
	printf("$delete failed, status %d\n", status);
#endif
	return (1);
    }
    return (0);
}

datum
dbm_firstkey(db)
    DBM *db;
{
    int status;
    datum answer;

    status = sys$rewind(&(db->rab));
    if ((status & 1) == 0) {
#ifdef DEBUG
	printf("$rewind failed, status == %d\n", status);
#endif
	goto bag;
    }
    /* Set the file to sequential access */

    (db->rab).rab$b_rac = RAB$C_SEQ;
    status = sys$get(&(db->rab));
    if ((status & 1) == 0) {
#ifdef DEBUG
	printf("$get in firstkey() failed. status = %d\n", status);
#endif
	goto bag;
    }
    /* Save the key away */
    bcopy((db->rab).rab$l_rbf, db->currkey, KEY_SIZE);

    /* Put the file back to random access. */

    (db->rab).rab$b_rac = RAB$C_KEY;

    answer.dptr = db->currkey;
    answer.dsize = strlen(db->currkey);
    return (answer);
  bag:
    (db->rab).rab$b_rac = RAB$C_KEY;
    answer.dptr = (char *) 0;
    answer.dsize = 0;
    return (answer);
}

datum
dbm_nextkey(db)
    DBM *db;
{
    int status;
    datum answer;

    (db->rab).rab$l_kbf = db->currkey;
    (db->rab).rab$b_ksz = KEY_SIZE;

    /* Seek over to the current record */

    status = sys$find(&(db->rab));
    if ((status & 1) == 0) {
#ifdef DEBUG
	printf("$find in nextkey() failed. Status = %d\n", status);
#endif
	goto bag;
    }
    /* set file sequential */
    (db->rab).rab$b_rac = RAB$C_SEQ;

    /* Skip one */
    status = sys$find(&(db->rab));
    if (status == RMS$_EOF) {	/* We're done! */
#ifdef DEBUG
	printf("EOF detected in nextkey.\n");
#endif
	status = sys$rewind(&(db->rab));
#ifdef DEBUG
	if ((status & 1) == 0) {
	    printf("$rewind at EOF, in nextkey(), failed. status = %d\n", status);
	}
#endif
	goto bag;
    }
    status = sys$get(&(db->rab));
    if ((status & 1) == 0) {
#ifdef DEBUG
	printf("$get in nextkey() failed. status = %d\n", status);
#endif
	goto bag;
    }
    /* Save the key away */
    bcopy((db->rab).rab$l_rbf, db->currkey, KEY_SIZE);

    /* Put the file back to random access. */
    (db->rab).rab$b_rac = RAB$C_KEY;

    answer.dptr = db->currkey;
    answer.dsize = strlen(db->currkey);
    return (answer);
  bag:
    answer.dptr = (char *) 0;
    answer.dsize = 0;
    /* Put the file back to random access. */
    (db->rab).rab$b_rac = RAB$C_KEY;
    return (answer);
}