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/*
* Copyright (c) 1993 Brad Eacker,
* (Music, Intuition, Software, and Computers)
* All Rights Reserved
*/
#include <stdio.h>
#include <fcntl.h>
#include "dbf.h"
int get_piece(dbhead_t *dbh, long offset, char *cp, int len);
int put_piece(dbhead_t *dbh, long offset, char *cp, int len);
/*
* get a record off the database
*/
char *get_dbf_record(dbhead_t *dbh, long rec_num)
{
long offset;
char *cp;
if (rec_num > dbh->db_records) {
return NULL;
}
if ((cp = (char *)malloc(dbh->db_rlen)) == NULL) {
return NULL;
}
/* go to the correct spot on the file */
offset = dbh->db_hlen + (rec_num - 1) * dbh->db_rlen;
if (get_piece(dbh, offset, cp, dbh->db_rlen) != dbh->db_rlen) {
free(cp);
cp = NULL;
}
if (cp)
dbh->db_cur_rec = rec_num;
return cp;
}
int
get_piece(dbhead_t *dbh, long offset, char *cp, int len)
{
/* go to the correct spot on the file */
if ( lseek(dbh->db_fd, offset, 0) < 0 ) {
return -1;
}
/* read the record into the allocated space */
return read(dbh->db_fd, cp, len);
}
/*
* put a record to the database
*/
long put_dbf_record(dbhead_t *dbh, long rec_num, char *cp)
{
long offset;
if (rec_num == 0) {
rec_num = dbh->db_records;
}
if (rec_num > dbh->db_records) {
return 0L;
}
/* go to the correct spot on the file */
offset = dbh->db_hlen + (rec_num - 1) * dbh->db_rlen;
if (put_piece(dbh, offset, cp, dbh->db_rlen) != dbh->db_rlen) {
rec_num = -1;
}
return rec_num;
}
int put_piece(dbhead_t *dbh, long offset, char *cp, int len)
{
/* go to the correct spot on the file */
if ( lseek(dbh->db_fd, offset, 0) < 0 ) {
return -1;
}
/* write the record into the file */
return write(dbh->db_fd, cp, len);
}
int del_dbf_record(dbhead_t *dbh, long rec_num)
{
int ret = 0;
char *cp;
if (rec_num > dbh->db_records)
return -1;
if ((cp = get_dbf_record(dbh, rec_num))) {
*cp = DELETED_RECORD;
ret = put_dbf_record(dbh, rec_num, cp);
free(cp);
}
return ret;
}
void pack_dbf(dbhead_t *dbh)
{
long out_off, in_off;
int rec_cnt, new_cnt;
char *cp;
if ((cp = (char *)malloc(dbh->db_rlen)) == NULL) {
return;
}
in_off = out_off = dbh->db_hlen;
new_cnt = 0;
rec_cnt = dbh->db_records;
while (rec_cnt > 0) {
if (get_piece(dbh, in_off, cp, dbh->db_rlen) < 0)
break;
if (*cp != DELETED_RECORD) {
/* write the record into the file */
if (put_piece(dbh, out_off, cp, dbh->db_rlen) < 0)
break;
out_off += dbh->db_rlen;
new_cnt++;
}
in_off += dbh->db_rlen;
rec_cnt--;
}
free(cp);
if (rec_cnt == 0)
dbh->db_records = new_cnt;
}
/* routine to get a field from a record */
char *get_field_val(char *rp, dbfield_t *fldp, char *cp)
{
int flen = fldp->db_flen;
if ( !cp )
cp = (char *)malloc(flen + 1);
if ( cp ) {
strncpy(cp, &rp[fldp->db_foffset], flen);
cp[flen] = 0;
}
return cp;
}
void put_field_val(char *rp, dbfield_t *fldp, char *cp)
{
strncpy(&rp[fldp->db_foffset], cp, fldp->db_flen);
}
/*
* output a record
*/
void out_rec(dbhead_t *dbh, dbfield_t *dbf, char *cp)
{
dbfield_t *cur_f;
int nfields = dbh->db_nfields;
char *fnp = (char *)malloc(dbh->db_rlen);
printf("%c", *cp);
for (cur_f = dbf; cur_f < &dbf[nfields] ; cur_f++) {
printf(" ");
printf(cur_f->db_format, get_field_val(cp, cur_f, fnp));
}
printf("\n");
free(fnp);
}
/* check for record validity */
int is_valid_rec(char *cp)
{
if (cp && (*cp == VALID_RECORD))
return 1;
else
return 0;
}
/* get the next record */
char *dbf_get_next(dbhead_t *dbh)
{
return get_dbf_record(dbh, dbh->db_cur_rec + 1);
}
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