BSON ObjectID Abstraction

SYNOPSIS

#include <bson/bson.h>
typedef struct {


   uint8_t bytes[12];
} bson_oid_t;

DESCRIPTION

The bson_oid_t structure contains the 12-byte ObjectId notation defined by the BSON ObjectID specification.

ObjectId is a 12-byte BSON type, constructed using:

a 4-byte value representing the seconds since the Unix epoch (in Big Endian).
a 5-byte random value.
a 3-byte counter (Big Endian), starting with a random value.

STRING CONVERSION

You can convert an Object ID to a string using bson_oid_to_string() and back with bson_oid_init_from_string().

HASHING

A bson_oid_t can be used in hashtables using the function bson_oid_hash() and bson_oid_equal().

COMPARING

A bson_oid_t can be compared to another using bson_oid_compare() for qsort() style comparing and bson_oid_equal() for direct equality.

VALIDATING

You can validate that a string containing a hex-encoded ObjectID is valid using the function bson_oid_is_valid().

EXAMPLE

#include <bson/bson.h>
#include <stdio.h>
int
main (int argc, char *argv[])
{


   bson_oid_t oid;


   char str[25];


   bson_oid_init (&oid, NULL);


   bson_oid_to_string (&oid, str);


   printf ("%s\n", str);


   if (bson_oid_is_valid (str, sizeof str)) {


      bson_oid_init_from_string (&oid, str);


   }


   printf ("The UNIX time was: %u\n", (unsigned) bson_oid_get_time_t (&oid));


   return 0;
}

AUTHOR

MongoDB, Inc

COPYRIGHT

2009-present, MongoDB, Inc.