?? db_seq.c
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/****************************************************************************/
/* */
/* */
/* db_seq.c v1.3 (c) 1987-1990 Ken Harris */
/* */
/* */
/****************************************************************************/
/* */
/* This software is made available on an AS-IS basis. Unrestricted */
/* use is granted provided that the copyright notice remains intact. */
/* The author makes no warranties expressed or implied. */
/* */
/****************************************************************************/
#include "dblib.h"
/*
* db_add_seq - Add a record to a sequential file
*/
void db_add_seq(df, user_data)
DATA_FILE df;
char *user_data;
{
FILE_HDR fh;
BUFFER buf;
char *rbuf;
db_error = 0;
fh = (FILE_HDR) df->df_fhdr->buf_data;
buf = df->df_buf;
db_get_next_avail(df, buf);
if (db_error) return;
db_add_blk = buf->buf_cur_blk;
db_add_rec = buf->buf_rec_inx;
rbuf = buf->buf_data + (buf->buf_rec_inx - 1) * fh->fh_rec_size;
memcpy(rbuf+fh->fh_ctl_size, user_data, fh->fh_data_size);
fh->fh_rec_cnt++;
db_put_blk(df,df->df_fhdr);
db_put_blk(df,buf);
}
/*
* db_read_first_seq - Read First Record in a Sequential File
*/
void db_read_first_seq(df, user_data)
DATA_FILE df;
char *user_data;
{
FILE_HDR fh;
BUFFER buf;
SEQ_REC seq;
ulong blk;
ushort rec;
char *rbuf;
db_error = 0;
fh = (FILE_HDR) df->df_fhdr->buf_data;
buf = df->df_buf;
for (blk=1; blk <= fh->fh_last_block; blk++)
{ db_get_blk(df, blk, buf);
if (db_error) return;
rbuf = buf->buf_data;
for (rec=1; rec <= fh->fh_recs_per_blk; rec++)
{ seq = (SEQ_REC) rbuf;
if (seq->seq_stat == DB_INUSE)
{ buf->buf_rec_inx = rec;
memcpy(user_data, rbuf+fh->fh_ctl_size,
fh->fh_data_size);
return;
}
rbuf += fh->fh_rec_size;
}
}
db_error= DB_END_OF_FILE;
}
/*
* db_read_next_seq - Read Next Record in a Sequential File
*/
void db_read_next_seq(df, user_data)
DATA_FILE df;
char *user_data;
{
FILE_HDR fh;
BUFFER buf;
SEQ_REC seq;
ulong blk;
ushort rec;
char *rbuf;
db_error = 0;
fh = (FILE_HDR) df->df_fhdr->buf_data;
buf = df->df_buf;
db_get_blk(df, df->df_prev_blk, buf);
if (db_error) return;
buf->buf_rec_inx = df->df_prev_rec + 1;
rbuf = buf->buf_data + (buf->buf_rec_inx - 1) * fh->fh_rec_size;
for (rec=buf->buf_rec_inx; rec <= fh->fh_recs_per_blk; rec++)
{ seq = (SEQ_REC) rbuf;
if (seq->seq_stat == DB_INUSE)
{ buf->buf_rec_inx = rec;
memcpy(user_data, rbuf+fh->fh_ctl_size, fh->fh_data_size);
return;
}
rbuf += fh->fh_rec_size;
}
for (blk=buf->buf_cur_blk+1; blk <= fh->fh_last_block; blk++)
{ db_get_blk(df, blk, buf);
if (db_error) return;
rbuf = buf->buf_data;
for (rec=1; rec <= fh->fh_recs_per_blk; rec++)
{ seq = (SEQ_REC) rbuf;
if (seq->seq_stat == DB_INUSE)
{ buf->buf_rec_inx = rec;
memcpy(user_data, rbuf+fh->fh_ctl_size,
fh->fh_data_size);
return;
}
rbuf += fh->fh_rec_size;
}
}
db_error= DB_END_OF_FILE;
}
/*
* db_read_last_seq - Read Last Record in a Sequential File
*/
void db_read_last_seq(df, user_data)
DATA_FILE df;
char *user_data;
{
FILE_HDR fh;
BUFFER buf;
SEQ_REC seq;
ulong blk;
ushort rec;
char *rbuf;
db_error = 0;
fh = (FILE_HDR) df->df_fhdr->buf_data;
buf = df->df_buf;
for (blk=fh->fh_last_block; blk >= 1; blk--)
{ db_get_blk(df, blk, buf);
if (db_error) return;
rbuf = buf->buf_data + (fh->fh_recs_per_blk - 1) * fh->fh_rec_size;
for (rec=fh->fh_recs_per_blk; rec >= 1; rec--)
{ seq = (SEQ_REC) rbuf;
if (seq->seq_stat == DB_INUSE)
{ buf->buf_rec_inx = rec;
memcpy(user_data, rbuf+fh->fh_ctl_size,
fh->fh_data_size);
return;
}
rbuf -= fh->fh_rec_size;
}
}
db_error= DB_END_OF_FILE;
}
/*
* db_read_prev_seq - Read Prev Record in a Sequential File
*/
void db_read_prev_seq(df, user_data)
DATA_FILE df;
char *user_data;
{
FILE_HDR fh;
BUFFER buf;
SEQ_REC seq;
ulong blk;
ushort rec;
char *rbuf;
db_error = 0;
fh = (FILE_HDR) df->df_fhdr->buf_data;
buf = df->df_buf;
db_get_blk(df, df->df_prev_blk, buf);
if (db_error) return;
buf->buf_rec_inx = df->df_prev_rec - 1;
rbuf = buf->buf_data + (buf->buf_rec_inx - 1) * fh->fh_rec_size;
for (rec=buf->buf_rec_inx; rec >= 1; rec--)
{ seq = (SEQ_REC) rbuf;
if (seq->seq_stat == DB_INUSE)
{ buf->buf_rec_inx = rec;
memcpy(user_data, rbuf+fh->fh_ctl_size, fh->fh_data_size);
return;
}
rbuf -= fh->fh_rec_size;
}
for (blk=buf->buf_cur_blk-1; blk >= 1; blk--)
{ db_get_blk(df, blk, buf);
if (db_error) return;
rbuf = buf->buf_data + (fh->fh_recs_per_blk - 1) * fh->fh_rec_size;
for (rec=fh->fh_recs_per_blk; rec >= 1; rec--)
{ seq = (SEQ_REC) rbuf;
if (seq->seq_stat == DB_INUSE)
{ buf->buf_rec_inx = rec;
memcpy(user_data, rbuf+fh->fh_ctl_size,
fh->fh_data_size);
return;
}
rbuf -= fh->fh_rec_size;
}
}
db_error= DB_END_OF_FILE;
}
/*
* db_update_seq - Update Record in a Sequential File
*/
void db_update_seq(df, user_data)
DATA_FILE df;
char *user_data;
{
FILE_HDR fh;
BUFFER buf;
SEQ_REC seq;
char *rbuf;
db_error = 0;
fh = (FILE_HDR) df->df_fhdr->buf_data;
buf = df->df_buf;
if (buf->buf_cur_blk == 0 || buf->buf_rec_inx == 0)
{ db_error = DB_NO_CURRENT_REC;
return;
}
rbuf = buf->buf_data + (buf->buf_rec_inx - 1) * fh->fh_rec_size;
seq = (SEQ_REC) rbuf;
if (seq->seq_stat != DB_INUSE)
{ db_error = DB_DELETED_REC;
return;
}
memcpy(rbuf+fh->fh_ctl_size, user_data, fh->fh_data_size);
db_put_blk(df, buf);
}
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