bson_oid_t (3) - Linux Manuals

bson_oid_t: BSON ObjectID Abstraction

NAME

bson_oid_t - BSON ObjectID Abstraction

SYNOPSIS

#include <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 specificiation \&.

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

\[bu]

a 4-byte value representing the seconds since the Unix epoch (in Big Endian)

\[bu]

a 3-byte machine identifier

\[bu]

a 2-byte process id (Big Endian), and

\[bu]

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(3) and back with bson_oid_init_from_string(3) \&.

HASHING

A bson_oid_t can be used in hashtables using the function bson_oid_hash(3) and bson_oid_equal(3) \&.

COMPARING

A bson_oid_t can be compared to another using bson_oid_compare(3) for qsort(3) style comparing and bson_oid_equal(3) for direct equality.

VALIDATING

You can validate that a string containing a hex-encoded ObjectID is valid using the function bson_oid_is_valid(3) \&.

EXAMPLE

#include <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;
}

COLOPHON

This page is part of libbson. Please report any bugs at https://jira.mongodb.org/browse/CDRIVER.