This is a library for reading FSDB formatted datasets (which is a typically tab-separated format containing additional information, such as types and commands used to execute the code).
Other FSDB supported languages:
To build the library, run make which will build libfsdb.a and test
it against a test binary in tests/
Automated installation: TBD
Consider an example test.fsdb files as follows:
#fsdb -F s column_one:s column_two:l
life 42
universe 42000
An example file that opens this test.fsdb for reading should look something like this:
#include <stdio.h>
#include <fsdb.h>
int main(int argc, char **argv) {
FSDB *fsdb = fsdb_create_context();
FILE *file_handle = fopen(filename, "r");
int result;
fsdb->save_rows = FSDB_TRUE;
result = fsdb_parse_file_header(file_handle, fsdb);
assert (result == FSDB_NO_ERROR);Once opened, the file can be loaded using fsdb_parse_file_contents
(note as implemented today, this reads the entire file contents into memory):
result = fsdb_parse_file_contents(file_handle, fsdb);
assert (result == FSDB_NO_ERROR);Once in memory, data can be best accessed with the FSDB_DATA macro,
which will return a pointer to the proper fsdb_data structure
containing the data:
printf("row 0 column 1 is a long: %d\n",
FSDB_DATA(fsdb, 0, 1).data.v_long);
printf("row 1 column 0 is a string: %s\n",
FSDB_DATA(fsdb, 1, 0).data.v_string);
}The fsdb_data structure contains both a copy of the raw data of the
column in raw_string, and a union of converted types in the data
struct field:
typedef union {
int v_integer;
unsigned int v_u_integer;
long v_long;
unsigned long v_u_long;
float v_float;
double v_double;
char * v_string;
} converted_fsdb_data;
typedef struct fsdb_data_s {
converted_fsdb_data data;
char *raw_string;
} fsdb_data;The FSDB structure itself contains a list of data (but please use the FSDB_DATA macro for accessing in case storage changes in the future), a list of data_types (e.g. FSDB_TYPE_U_LONG), and a list of column names and other information:
typedef struct fsdb {
/* public configuration */
FSDB_BOOL save_rows;
FSDB_TYPE_TYPE *data_types; /* Allocated array of types */
/* public outputs */
char *separator;
char *header;
char **columns; /* note: pointers to sections of _header_tokens */
size_t columns_len;
fsdb_data *rows; /* note: alloc = [rows_len][columns_len] */
size_t rows_len;
char **row_string; /* note: alloc = [rows_len] of duplicated rows */
/* internal */
char *_header_tokens;
size_t _rows_allocated;
} FSDB;Since columns may move around in the input data, flexible code should use the fsdb_get_column_number() function to retrieve the column number of a given column name:
int colnum = fsdb_get_column_number(fsdb, "column_one"); int coltwo = fsdb_get_column_number(fsdb, "column_two");
int i;
long total = 0;
/* check that it's the data type we expect */
assert(fsdb->data_types[coltwo] == FSDB_TYPE_LONG);
/* sum all the values */
for (i = 0; i < fsdb->rows_len; i++) {
total += FSDB_DATA(fsdb, i, coltwo).data.v_long;
}To free the associated memory:
fsdb_free_context(fsdb);