postgresql/contrib/dbase/dbf.c
2005-10-15 02:49:52 +00:00

519 lines
11 KiB
C

/* Routines to read and write xBase-files (.dbf)
By Maarten Boekhold, 29th of oktober 1995
Modified by Frank Koormann (fkoorman@usf.uni-osnabrueck.de), Jun 10 1996
prepare dataarea with memset
get systemtime and set filedate
set formatstring for real numbers
*/
#include "postgres_fe.h"
#include <fcntl.h>
#include <ctype.h>
#include <time.h>
#include <unistd.h>
#include "dbf.h"
/* open a dbf-file, get it's field-info and store this information */
dbhead *
dbf_open(char *file, int flags)
{
int file_no;
dbhead *dbh;
f_descr *fields;
dbf_header *head;
dbf_field *fieldc;
int t;
if ((dbh = (dbhead *) malloc(sizeof(dbhead))) == NULL)
return (dbhead *) DBF_ERROR;
if ((head = (dbf_header *) malloc(sizeof(dbf_header))) == NULL)
{
free(dbh);
return (dbhead *) DBF_ERROR;
}
if ((fieldc = (dbf_field *) malloc(sizeof(dbf_field))) == NULL)
{
free(head);
free(dbh);
return (dbhead *) DBF_ERROR;
}
if ((file_no = open(file, flags)) == -1)
{
free(fieldc);
free(head);
free(dbh);
return (dbhead *) DBF_ERROR;
}
/* read in the disk-header */
if (read(file_no, head, sizeof(dbf_header)) == -1)
{
close(file_no);
free(fieldc);
free(head);
free(dbh);
return (dbhead *) DBF_ERROR;
}
if (!(head->dbh_dbt & DBH_NORMAL))
{
close(file_no);
free(fieldc);
free(head);
free(dbh);
return (dbhead *) DBF_ERROR;
}
dbh->db_fd = file_no;
if (head->dbh_dbt & DBH_MEMO)
dbh->db_memo = 1;
else
dbh->db_memo = 0;
dbh->db_year = head->dbh_year;
dbh->db_month = head->dbh_month;
dbh->db_day = head->dbh_day;
dbh->db_hlen = get_short((u_char *) &head->dbh_hlen);
dbh->db_records = get_long((u_char *) &head->dbh_records);
dbh->db_currec = 0;
dbh->db_rlen = get_short((u_char *) &head->dbh_rlen);
dbh->db_nfields = (dbh->db_hlen - sizeof(dbf_header)) / sizeof(dbf_field);
/*
* dbh->db_hlen - sizeof(dbf_header) isn't the correct size, cos dbh->hlen
* is in fact a little more cos of the 0x0D (and possibly another byte,
* 0x4E, I have seen this somewhere). Because of rounding everything turns
* out right :)
*/
if ((fields = (f_descr *) calloc(dbh->db_nfields, sizeof(f_descr)))
== NULL)
{
close(file_no);
free(fieldc);
free(head);
free(dbh);
return (dbhead *) DBF_ERROR;
}
for (t = 0; t < dbh->db_nfields; t++)
{
/* Maybe I have calculated the number of fields incorrectly. This can happen
when programs reserve lots of space at the end of the header for future
expansion. This will catch this situation */
if (fields[t].db_name[0] == 0x0D)
{
dbh->db_nfields = t;
break;
}
read(file_no, fieldc, sizeof(dbf_field));
strncpy(fields[t].db_name, fieldc->dbf_name, DBF_NAMELEN);
fields[t].db_type = fieldc->dbf_type;
fields[t].db_flen = fieldc->dbf_flen;
fields[t].db_dec = fieldc->dbf_dec;
}
dbh->db_offset = dbh->db_hlen;
dbh->db_fields = fields;
if ((dbh->db_buff = (u_char *) malloc(dbh->db_rlen)) == NULL)
return (dbhead *) DBF_ERROR;
free(fieldc);
free(head);
return dbh;
}
int
dbf_write_head(dbhead * dbh)
{
dbf_header head;
time_t now;
struct tm *dbf_time;
if (lseek(dbh->db_fd, 0, SEEK_SET) == -1)
return DBF_ERROR;
/* fill up the diskheader */
/* Set dataarea of head to '\0' */
memset(&head, '\0', sizeof(dbf_header));
head.dbh_dbt = DBH_NORMAL;
if (dbh->db_memo)
head.dbh_dbt = DBH_MEMO;
now = time((time_t *) NULL);
dbf_time = localtime(&now);
head.dbh_year = dbf_time->tm_year;
head.dbh_month = dbf_time->tm_mon + 1; /* Months since January + 1 */
head.dbh_day = dbf_time->tm_mday;
put_long(head.dbh_records, dbh->db_records);
put_short(head.dbh_hlen, dbh->db_hlen);
put_short(head.dbh_rlen, dbh->db_rlen);
if (write(dbh->db_fd, &head, sizeof(dbf_header)) != sizeof(dbf_header))
return DBF_ERROR;
return 0;
}
int
dbf_put_fields(dbhead * dbh)
{
dbf_field field;
u_long t;
u_char end = 0x0D;
if (lseek(dbh->db_fd, sizeof(dbf_header), SEEK_SET) == -1)
return DBF_ERROR;
/* Set dataarea of field to '\0' */
memset(&field, '\0', sizeof(dbf_field));
for (t = 0; t < dbh->db_nfields; t++)
{
strncpy(field.dbf_name, dbh->db_fields[t].db_name, DBF_NAMELEN - 1);
field.dbf_type = dbh->db_fields[t].db_type;
field.dbf_flen = dbh->db_fields[t].db_flen;
field.dbf_dec = dbh->db_fields[t].db_dec;
if (write(dbh->db_fd, &field, sizeof(dbf_field)) != sizeof(dbf_field))
return DBF_ERROR;
}
if (write(dbh->db_fd, &end, 1) != 1)
return DBF_ERROR;
return 0;
}
int
dbf_add_field(dbhead * dbh, char *name, u_char type,
u_char length, u_char dec)
{
f_descr *ptr;
u_char *foo;
u_long size,
field_no;
size = (dbh->db_nfields + 1) * sizeof(f_descr);
if (!(ptr = (f_descr *) realloc(dbh->db_fields, size)))
return DBF_ERROR;
dbh->db_fields = ptr;
field_no = dbh->db_nfields;
strncpy(dbh->db_fields[field_no].db_name, name, DBF_NAMELEN);
dbh->db_fields[field_no].db_type = type;
dbh->db_fields[field_no].db_flen = length;
dbh->db_fields[field_no].db_dec = dec;
dbh->db_nfields++;
dbh->db_hlen += sizeof(dbf_field);
dbh->db_rlen += length;
if (!(foo = (u_char *) realloc(dbh->db_buff, dbh->db_rlen)))
return DBF_ERROR;
dbh->db_buff = foo;
return 0;
}
dbhead *
dbf_open_new(char *name, int flags)
{
dbhead *dbh;
if (!(dbh = (dbhead *) malloc(sizeof(dbhead))))
return (dbhead *) DBF_ERROR;
if (flags & O_CREAT)
{
if ((dbh->db_fd = open(name, flags, DBF_FILE_MODE)) == -1)
{
free(dbh);
return (dbhead *) DBF_ERROR;
}
}
else
{
if ((dbh->db_fd = open(name, flags)) == -1)
{
free(dbh);
return (dbhead *) DBF_ERROR;
}
}
dbh->db_offset = 0;
dbh->db_memo = 0;
dbh->db_year = 0;
dbh->db_month = 0;
dbh->db_day = 0;
dbh->db_hlen = sizeof(dbf_header) + 1;
dbh->db_records = 0;
dbh->db_currec = 0;
dbh->db_rlen = 1;
dbh->db_nfields = 0;
dbh->db_buff = NULL;
dbh->db_fields = (f_descr *) NULL;
return dbh;
}
void
dbf_close(dbhead * dbh)
{
int t;
close(dbh->db_fd);
for (t = 0; t < dbh->db_nfields; t++)
free(&dbh->db_fields[t]);
if (dbh->db_buff != NULL)
free(dbh->db_buff);
free(dbh);
}
int
dbf_get_record(dbhead * dbh, field * fields, u_long rec)
{
u_char *data;
int t,
i,
offset;
u_char *dbffield,
*end;
/* calculate at which offset we have to read. *DON'T* forget the
0x0D which seperates field-descriptions from records!
Note (april 5 1996): This turns out to be included in db_hlen
*/
offset = dbh->db_hlen + (rec * dbh->db_rlen);
if (lseek(dbh->db_fd, offset, SEEK_SET) == -1)
{
lseek(dbh->db_fd, 0, SEEK_SET);
dbh->db_offset = 0;
return DBF_ERROR;
}
dbh->db_offset = offset;
dbh->db_currec = rec;
data = dbh->db_buff;
read(dbh->db_fd, data, dbh->db_rlen);
if (data[0] == DBF_DELETED)
return DBF_DELETED;
dbffield = &data[1];
for (t = 0; t < dbh->db_nfields; t++)
{
strncpy(fields[t].db_name, dbh->db_fields[t].db_name, DBF_NAMELEN);
fields[t].db_type = dbh->db_fields[t].db_type;
fields[t].db_flen = dbh->db_fields[t].db_flen;
fields[t].db_dec = dbh->db_fields[t].db_dec;
if (fields[t].db_type == 'C')
{
end = &dbffield[fields[t].db_flen - 1];
i = fields[t].db_flen;
while (i > 0 && !isprint(*end))
{
end--;
i--;
}
strncpy((char *) fields[t].db_contents, (char *) dbffield, i);
fields[t].db_contents[i] = '\0';
}
else
{
end = dbffield;
i = fields[t].db_flen;
while (i > 0 && !isprint(*end))
{
end++;
i--;
}
strncpy((char *) fields[t].db_contents, (char *) end, i);
fields[t].db_contents[i] = '\0';
}
dbffield += fields[t].db_flen;
}
dbh->db_offset += dbh->db_rlen;
return DBF_VALID;
}
field *
dbf_build_record(dbhead * dbh)
{
int t;
field *fields;
if (!(fields = (field *) calloc(dbh->db_nfields, sizeof(field))))
return (field *) DBF_ERROR;
for (t = 0; t < dbh->db_nfields; t++)
{
if (!(fields[t].db_contents =
(u_char *) malloc(dbh->db_fields[t].db_flen + 1)))
{
for (t = 0; t < dbh->db_nfields; t++)
{
if (fields[t].db_contents != 0)
{
free(fields[t].db_contents);
free(fields);
}
return (field *) DBF_ERROR;
}
}
strncpy(fields[t].db_name, dbh->db_fields[t].db_name, DBF_NAMELEN);
fields[t].db_type = dbh->db_fields[t].db_type;
fields[t].db_flen = dbh->db_fields[t].db_flen;
fields[t].db_dec = dbh->db_fields[t].db_dec;
}
return fields;
}
void
dbf_free_record(dbhead * dbh, field * rec)
{
int t;
for (t = 0; t < dbh->db_nfields; t++)
free(rec[t].db_contents);
free(rec);
}
int
dbf_put_record(dbhead * dbh, field * rec, u_long where)
{
u_long offset,
new,
idx,
t,
h,
length;
u_char *data,
end = 0x1a;
double fl;
char foo[128],
format[32];
/* offset: offset in file for this record
new: real offset after lseek
idx: index to which place we are inside the 'hardcore'-data for this
record
t: field-counter
data: the hardcore-data that is put on disk
h: index into the field-part in the hardcore-data
length: length of the data to copy
fl: a float used to get the right precision with real numbers
foo: copy of db_contents when field is not 'C'
format: sprintf format-string to get the right precision with real numbers
NOTE: this declaration of 'foo' can cause overflow when the contents-field
is longer the 127 chars (which is highly unlikely, because it is not used
in text-fields).
*/
/* REMEMBER THAT THERE'S A 0x1A AT THE END OF THE FILE, SO DON'T
DO A SEEK_END WITH 0!!!!!! USE -1 !!!!!!!!!!
*/
if (where > dbh->db_records)
{
if ((new = lseek(dbh->db_fd, -1, SEEK_END)) == -1)
return DBF_ERROR;
dbh->db_records++;
}
else
{
offset = dbh->db_hlen + (where * dbh->db_rlen);
if ((new = lseek(dbh->db_fd, offset, SEEK_SET)) == -1)
return DBF_ERROR;
}
dbh->db_offset = new;
data = dbh->db_buff;
/* Set dataarea of data to ' ' (space) */
memset(data, ' ', dbh->db_rlen);
/* data[0] = DBF_VALID; */
idx = 1;
for (t = 0; t < dbh->db_nfields; t++)
{
/* if field is empty, don't do a thing */
if (rec[t].db_contents[0] != '\0')
{
/* Handle text */
if (rec[t].db_type == 'C')
{
if (strlen((char *) rec[t].db_contents) > rec[t].db_flen)
length = rec[t].db_flen;
else
length = strlen((char *) rec[t].db_contents);
strncpy((char *) data + idx, (char *) rec[t].db_contents,
length);
}
else
{
/* Handle the rest */
/* Numeric is special, because of real numbers */
if ((rec[t].db_type == 'N') && (rec[t].db_dec != 0))
{
fl = atof((char *) rec[t].db_contents);
snprintf(format, 32, "%%.%df", rec[t].db_dec);
snprintf(foo, 128, format, fl);
}
else
strncpy(foo, (char *) rec[t].db_contents, 128);
if (strlen(foo) > rec[t].db_flen)
length = rec[t].db_flen;
else
length = strlen(foo);
h = rec[t].db_flen - length;
strncpy((char *) (data + idx + h), foo, length);
}
}
idx += rec[t].db_flen;
}
if (write(dbh->db_fd, data, dbh->db_rlen) != dbh->db_rlen)
return DBF_ERROR;
/* There's a 0x1A at the end of a dbf-file */
if (where == dbh->db_records)
{
if (write(dbh->db_fd, &end, 1) != 1)
return DBF_ERROR;
}
dbh->db_offset += dbh->db_rlen;
return 0;
}