BSON_REFERENCE(3)

LIBBSON - API

A Cross Platform BSON Library for C

This site documents the API. For tutorials, guides, and explainers, see MongoDB C Driver.

  Introduction

libbson builds, parses, and iterates BSON documents, the native data format of MongoDB. It also converts BSON to and from JSON, and provides a platform compatibility layer for the MongoDB C Driver.

  API Reference

  bson_t

BSON Document Abstraction

  Synopsis

    #include <bson/bson.h>
    /**
     * bson_empty:
     * @b: a bson_t.
     *
     * Checks to see if @b is an empty BSON document. An empty BSON document is
     * a 5 byte document which contains the length (4 bytes) and a single NUL
     * byte indicating end of fields.
     */
    #define bson_empty(b) /* ... */
    /**
     * bson_empty0:
     *
     * Like bson_empty() but treats NULL the same as an empty bson_t document.
     */
    #define bson_empty0(b) /* ... */
    /**
     * bson_clear:
     *
     * Easily free a bson document and set it to NULL. Use like:
     *
     * bson_t *doc = bson_new();
     * bson_clear (&doc);
     * BSON_ASSERT (doc == NULL);
     */
    #define bson_clear(bptr) /* ... */
    /**
     * BSON_MAX_SIZE:
     *
     * The maximum size in bytes of a BSON document.
     */
    #define BSON_MAX_SIZE /* ... */
    #define BSON_APPEND_ARRAY(b, key, val) \
       bson_append_array (b, key, (int) strlen (key), val)
    #define BSON_APPEND_ARRAY_BEGIN(b, key, child) \
       bson_append_array_begin (b, key, (int) strlen (key), child)
    #define BSON_APPEND_BINARY(b, key, subtype, val, len) \
       bson_append_binary (b, key, (int) strlen (key), subtype, val, len)
    #define BSON_APPEND_BINARY_UNINIT(b, key, subtype, val, len) \
       bson_append_binary_uninit (b, key, (int) strlen (key), subtype, val, len)
    #define BSON_APPEND_BOOL(b, key, val) \
       bson_append_bool (b, key, (int) strlen (key), val)
    #define BSON_APPEND_CODE(b, key, val) \
       bson_append_code (b, key, (int) strlen (key), val)
    #define BSON_APPEND_CODE_WITH_SCOPE(b, key, val, scope) \
       bson_append_code_with_scope (b, key, (int) strlen (key), val, scope)
    #define BSON_APPEND_DBPOINTER(b, key, coll, oid) \
       bson_append_dbpointer (b, key, (int) strlen (key), coll, oid)
    #define BSON_APPEND_DOCUMENT_BEGIN(b, key, child) \
       bson_append_document_begin (b, key, (int) strlen (key), child)
    #define BSON_APPEND_DOUBLE(b, key, val) \
       bson_append_double (b, key, (int) strlen (key), val)
    #define BSON_APPEND_DOCUMENT(b, key, val) \
       bson_append_document (b, key, (int) strlen (key), val)
    #define BSON_APPEND_INT32(b, key, val) \
       bson_append_int32 (b, key, (int) strlen (key), val)
    #define BSON_APPEND_INT64(b, key, val) \
       bson_append_int64 (b, key, (int) strlen (key), val)
    #define BSON_APPEND_MINKEY(b, key) \
       bson_append_minkey (b, key, (int) strlen (key))
    #define BSON_APPEND_DECIMAL128(b, key, val) \
       bson_append_decimal128 (b, key, (int) strlen (key), val)
    #define BSON_APPEND_MAXKEY(b, key) \
       bson_append_maxkey (b, key, (int) strlen (key))
    #define BSON_APPEND_NULL(b, key) bson_append_null (b, key, (int) strlen (key))
    #define BSON_APPEND_OID(b, key, val) \
       bson_append_oid (b, key, (int) strlen (key), val)
    #define BSON_APPEND_REGEX(b, key, val, opt) \
       bson_append_regex (b, key, (int) strlen (key), val, opt)
    #define BSON_APPEND_UTF8(b, key, val) \
       bson_append_utf8 (b, key, (int) strlen (key), val, (int) strlen (val))
    #define BSON_APPEND_SYMBOL(b, key, val) \
       bson_append_symbol (b, key, (int) strlen (key), val, (int) strlen (val))
    #define BSON_APPEND_TIME_T(b, key, val) \
       bson_append_time_t (b, key, (int) strlen (key), val)
    #define BSON_APPEND_TIMEVAL(b, key, val) \
       bson_append_timeval (b, key, (int) strlen (key), val)
    #define BSON_APPEND_DATE_TIME(b, key, val) \
       bson_append_date_time (b, key, (int) strlen (key), val)
    #define BSON_APPEND_TIMESTAMP(b, key, val, inc) \
       bson_append_timestamp (b, key, (int) strlen (key), val, inc)
    #define BSON_APPEND_UNDEFINED(b, key) \
       bson_append_undefined (b, key, (int) strlen (key))
    #define BSON_APPEND_VALUE(b, key, val) \
       bson_append_value (b, key, (int) strlen (key), (val))
    typedef struct {
       uint32_t flags;       /* Internal flags for the bson_t. */
       uint32_t len;         /* Length of BSON data. */
       uint8_t padding[120]; /* Padding for stack allocation. */
    } bson_t;

  Description

The bson_t structure represents a BSON document. This structure manages the underlying BSON encoded buffer. For mutable documents, it can append new data to the document.

  Performance Notes

The bson_t structure attempts to use an inline allocation within the structure to speed up performance of small documents. When this internal buffer has been exhausted, a heap allocated buffer will be dynamically allocated. Therefore, it is essential to call bson_destroy() on allocated documents.

  Duplicate Keys

The BSON specification allows BSON documents to have duplicate keys. Documents are stored as an ordered list of key-value pairs. A bson_t may contain duplicate keys. Applications should refrain from generating such documents, because MongoDB server behavior is undefined when a BSON document contains duplicate keys.

  Example

    static void
    create_on_heap (void)
    {
       bson_t *b = bson_new ();
       BSON_APPEND_INT32 (b, "foo", 123);
       BSON_APPEND_UTF8 (b, "bar", "foo");
       BSON_APPEND_DOUBLE (b, "baz", 1.23f);
       bson_destroy (b);
    }

  bson_array_builder_t

    typedef struct _bson_array_builder_t bson_array_builder_t;

bson_array_builder_t may be used to build BSON arrays. bson_array_builder_t internally tracks and uses the array index as a key ("0", "1", "2", ...) when appending elements.

  Appending an array value

    typedef struct _bson_array_builder_t bson_array_builder_t;
    bool
    bson_append_array_builder_begin (bson_t *bson,
                                     const char *key,
                                     int key_length,
                                     bson_array_builder_t **child);
    bool
    bson_append_array_builder_end (bson_t *bson, bson_array_builder_t *child);
    #define BSON_APPEND_ARRAY_BUILDER_BEGIN(b, key, child) \
      bson_append_array_builder_begin (b, key, (int) strlen (key), child)

bson_append_array_builder_begin may be used to append an array as a value. Example:

    bson_t parent = BSON_INITIALIZER;
    bson_array_builder_t *bab;
    bson_append_array_builder_begin(&parent, "foo", 3, &bab);
    bson_array_builder_append_int32(bab, 9);
    bson_array_builder_append_int32(bab, 8);
    bson_array_builder_append_int32(bab, 7);
    bson_append_array_builder_end(&parent, bab);
    char *str = bson_as_relaxed_extended_json(&parent, NULL);
    printf("%s\n", str); // Prints: { "foo" : [ 9, 8, 7 ] }
    bson_free(str);
    bson_destroy(&parent);

  Creating a top-level array

    bson_array_builder_t * bson_array_builder_new (void);
    bool
    bson_array_builder_build (bson_array_builder_t *bab, bson_t *out);
    void
    bson_array_builder_destroy (bson_array_builder_t *bab);

bson_array_builder_new and bson_array_builder_build may be used to build a top-level BSON array. bson_array_builder_build initializes and moves BSON data to out. The bson_array_builder_t may be reused and will start appending a new array at index "0":

Example:

    bson_t out;
    bson_array_builder_t *bab = bson_array_builder_new();
    bson_array_builder_append_int32(bab, 9);
    bson_array_builder_append_int32(bab, 8);
    bson_array_builder_append_int32(bab, 7);
    bson_array_builder_build(bab, &out);
    char *str = bson_array_as_relaxed_extended_json(&out, NULL);
    printf("%s\n", str); // Prints: [ 9, 8, 7 ]
    bson_free(str);
    bson_array_builder_destroy(bab);

  Appending values to an array

bson_array_builder_append_* functions are provided to append values to a BSON array. The bson_array_builder_append_* functions internally use bson_append_* and provide the array index as a key:

    bool
    bson_array_builder_append_value (bson_array_builder_t *bab,
                                     const bson_value_t *value);
    bool
    bson_array_builder_append_array (bson_array_builder_t *bab,
                                     const bson_t *array);
    bool
    bson_array_builder_append_binary (bson_array_builder_t *bab,
                                      bson_subtype_t subtype,
                                      const uint8_t *binary,
                                      uint32_t length);
    bool
    bson_array_builder_append_binary_uninit (bson_array_builder_t *bab,
                                             bson_subtype_t subtype,
                                             uint8_t **binary,
                                             uint32_t length);
    bool
    bson_array_builder_append_bool (bson_array_builder_t *bab, bool value);
    bool
    bson_array_builder_append_code (bson_array_builder_t *bab,
                                    const char *javascript);
    bool
    bson_array_builder_append_code_with_scope (bson_array_builder_t *bab,
                                               const char *javascript,
                                               const bson_t *scope);
    bool
    bson_array_builder_append_dbpointer (bson_array_builder_t *bab,
                                         const char *collection,
                                         const bson_oid_t *oid);
    bool
    bson_array_builder_append_double (bson_array_builder_t *bab, double value);
    bool
    bson_array_builder_append_document (bson_array_builder_t *bab,
                                        const bson_t *value);
    bool
    bson_array_builder_append_document_begin (bson_array_builder_t *bab,
                                              bson_t *child);
    bool
    bson_array_builder_append_document_end (bson_array_builder_t *bab,
                                            bson_t *child);
    bool
    bson_array_builder_append_int32 (bson_array_builder_t *bab, int32_t value);
    bool
    bson_array_builder_append_int64 (bson_array_builder_t *bab, int64_t value);
    bool
    bson_array_builder_append_decimal128 (bson_array_builder_t *bab,
                                          const bson_decimal128_t *value);
    bool
    bson_array_builder_append_iter (bson_array_builder_t *bab,
                                    const bson_iter_t *iter);
    bool
    bson_array_builder_append_minkey (bson_array_builder_t *bab);
    bool
    bson_array_builder_append_maxkey (bson_array_builder_t *bab);
    bool
    bson_array_builder_append_null (bson_array_builder_t *bab);
    bool
    bson_array_builder_append_oid (bson_array_builder_t *bab,
                                   const bson_oid_t *oid);
    bool
    bson_array_builder_append_regex (bson_array_builder_t *bab,
                                     const char *regex,
                                     const char *options);
    bool
    bson_array_builder_append_regex_w_len (bson_array_builder_t *bab,
                                          const char *regex,
                                          int regex_length,
                                          const char *options);
    bool
    bson_array_builder_append_utf8 (bson_array_builder_t *bab,
                                    const char *value,
                                    int length);
    bool
    bson_array_builder_append_symbol (bson_array_builder_t *bab,
                                      const char *value,
                                      int length);
    bool
    bson_array_builder_append_time_t (bson_array_builder_t *bab, time_t value);
    bool
    bson_array_builder_append_timeval (bson_array_builder_t *bab,
                                       struct timeval *value);
    bool
    bson_array_builder_append_date_time (bson_array_builder_t *bab, int64_t value);
    bool
    bson_array_builder_append_now_utc (bson_array_builder_t *bab);
    bool
    bson_array_builder_append_timestamp (bson_array_builder_t *bab,
                                         uint32_t timestamp,
                                         uint32_t increment);
    bool
    bson_array_builder_append_undefined (bson_array_builder_t *bab);
    bool
    bson_array_builder_append_array_builder_begin (bson_array_builder_t *bab,
                                                   bson_array_builder_t **child);
    bool
    bson_array_builder_append_array_builder_end (bson_array_builder_t *bab,
                                                 bson_array_builder_t *child);

  bson_context_t

BSON OID Generation Context

  Synopsis

    #include <bson/bson.h>
    typedef enum {
      BSON_CONTEXT_NONE = 0,
      BSON_CONTEXT_DISABLE_PID_CACHE = (1 << 2),
    } bson_context_flags_t;
    typedef struct _bson_context_t bson_context_t;
    bson_context_t *
    bson_context_get_default (void);
    bson_context_t *
    bson_context_new (bson_context_flags_t flags);
    void
    bson_context_destroy (bson_context_t *context);

  Description

The bson_context_t structure is context for generation of BSON Object IDs. This context allows overriding behavior of generating ObjectIDs. The flags BSON_CONTEXT_NONE, BSON_CONTEXT_THREAD_SAFE, and BSON_CONTEXT_DISABLE_PID_CACHE are the only ones used. The others have no effect.

  Example

    #include <bson/bson.h>
    int
    main (int argc, char *argv[])
    {
       bson_context_t *ctx = NULL;
       bson_oid_t oid;
       /* use default context, via bson_context_get_default() */
       bson_oid_init (&oid, NULL);
       /* specify a local context for additional control */
       ctx = bson_context_new (BSON_CONTEXT_NONE);
       bson_oid_init (&oid, ctx);
       bson_context_destroy (ctx);
       return 0;
    }

  bson_decimal128_t

BSON Decimal128 Abstraction

  Synopsis

    #include <bson/bson.h>
    #define BSON_DECIMAL128_STRING 43
    #define BSON_DECIMAL128_INF "Infinity"
    #define BSON_DECIMAL128_NAN "NaN"
    typedef struct {
    #if BSON_BYTE_ORDER == BSON_LITTLE_ENDIAN
       uint64_t low;
       uint64_t high;
    #elif BSON_BYTE_ORDER == BSON_BIG_ENDIAN
       uint64_t high;
       uint64_t low;
    #endif
    } bson_decimal128_t;

  Description

The bson_decimal128_t structure represents the IEEE-754 Decimal128 data type. The type bson_decimal128_t is an aggregate that contains two uint64_ts, named high and low. The declaration and layout order between them depends on the endian order of the target platform: low will always correspond to the low-order bits of the Decimal128 object, while high corresponds to the high-order bits. The bson_decimal128_t always has a size of sixteen (16), and can be bit-cast to/from a _Decimal128.

  Example

    #include <bson/bson.h>
    #include <stdio.h>
    int
    main (int argc, char *argv[])
    {
       char string[BSON_DECIMAL128_STRING];
       bson_decimal128_t decimal128;
       bson_decimal128_from_string ("100.00", &decimal128);
       bson_decimal128_to_string (&decimal128, string);
       printf ("Decimal128 value: %s\n", string);
       return 0;
    }

  bson_error_t

BSON Error Encapsulation

  Synopsis

    #include <bson/bson.h>
    typedef struct {
       uint32_t domain;
       uint32_t code;
       char message[504];
    } bson_error_t;

  Description

The bson_error_t structure is used as an out-parameter to pass error information to the caller. It should be stack-allocated and does not requiring freeing.

See Handling Errors.

  Example

    bson_reader_t *reader;
    bson_error_t error;
    reader = bson_reader_new_from_file ("dump.bson", &error);
    if (!reader) {
       fprintf (
          stderr, "ERROR: %d.%d: %s\n", error.domain, error.code, error.message);
    }

  bson_iter_t

BSON Document Iterator

  Synopsis

    #include <bson/bson.h>
    #define BSON_ITER_HOLDS_DOUBLE(iter) /* ... */
    #define BSON_ITER_HOLDS_UTF8(iter) /* ... */
    #define BSON_ITER_HOLDS_DOCUMENT(iter) /* ... */
    #define BSON_ITER_HOLDS_ARRAY(iter) /* ... */
    #define BSON_ITER_HOLDS_BINARY(iter) /* ... */
    #define BSON_ITER_HOLDS_VECTOR(iter) /* ... */
    #define BSON_ITER_HOLDS_VECTOR_INT8(iter) /* ... */
    #define BSON_ITER_HOLDS_VECTOR_FLOAT32(iter) /* ... */
    #define BSON_ITER_HOLDS_VECTOR_PACKED_BIT(iter) /* ... */
    #define BSON_ITER_HOLDS_UNDEFINED(iter) /* ... */
    #define BSON_ITER_HOLDS_OID(iter) /* ... */
    #define BSON_ITER_HOLDS_BOOL(iter) /* ... */
    #define BSON_ITER_HOLDS_DATE_TIME(iter) /* ... */
    #define BSON_ITER_HOLDS_NULL(iter) /* ... */
    #define BSON_ITER_HOLDS_REGEX(iter) /* ... */
    #define BSON_ITER_HOLDS_DBPOINTER(iter) /* ... */
    #define BSON_ITER_HOLDS_CODE(iter) /* ... */
    #define BSON_ITER_HOLDS_SYMBOL(iter) /* ... */
    #define BSON_ITER_HOLDS_CODEWSCOPE(iter) /* ... */
    #define BSON_ITER_HOLDS_INT32(iter) /* ... */
    #define BSON_ITER_HOLDS_TIMESTAMP(iter) /* ... */
    #define BSON_ITER_HOLDS_INT64(iter) /* ... */
    #define BSON_ITER_HOLDS_DECIMAL128(iter) /* ... */
    #define BSON_ITER_HOLDS_MAXKEY(iter) /* ... */
    #define BSON_ITER_HOLDS_MINKEY(iter) /* ... */
    #define BSON_ITER_HOLDS_INT(iter) \
       (BSON_ITER_HOLDS_INT32 (iter) || BSON_ITER_HOLDS_INT64 (iter))
    #define BSON_ITER_HOLDS_NUMBER(iter) \
       (BSON_ITER_HOLDS_INT (iter) || BSON_ITER_HOLDS_DOUBLE (iter))
    #define BSON_ITER_IS_KEY(iter, key) \
       (0 == strcmp ((key), bson_iter_key ((iter))))
    typedef struct {
       /*< private >*/
    } bson_iter_t;

  Description

bson_iter_t is a structure used to iterate through the elements of a bson_t. It is meant to be used on the stack and can be discarded at any time as it contains no external allocation. The contents of the structure should be considered private and may change between releases, however the structure size will not change.

The bson_t MUST be valid for the lifetime of the iter and it is an error to modify the bson_t while using the iter.

  Examples

    bson_iter_t iter;
    if (bson_iter_init (&iter, my_bson_doc)) {
       while (bson_iter_next (&iter)) {
          printf ("Found a field named: %s\n", bson_iter_key (&iter));
       }
    }

    bson_iter_t iter;
    if (bson_iter_init (&iter, my_bson_doc) && bson_iter_find (&iter, "my_field")) {
       printf ("Found the field named: %s\n", bson_iter_key (&iter));
    }

    bson_iter_t iter;
    bson_iter_t sub_iter;
    if (bson_iter_init_find (&iter, my_bson_doc, "mysubdoc") &&
        (BSON_ITER_HOLDS_DOCUMENT (&iter) || BSON_ITER_HOLDS_ARRAY (&iter)) &&
        bson_iter_recurse (&iter, &sub_iter)) {
       while (bson_iter_next (&sub_iter)) {
          printf ("Found key \"%s\" in sub document.\n", bson_iter_key (&sub_iter));
       }
    }

    bson_iter_t iter;
    if (bson_iter_init (&iter, my_doc) &&
        bson_iter_find_descendant (&iter, "a.b.c.d", &sub_iter)) {
       printf ("The type of a.b.c.d is: %d\n", (int) bson_iter_type (&sub_iter));
    }

  bson_json_reader_t

Bulk JSON to BSON conversion

  Synopsis

    #include <bson/bson.h>
    typedef struct _bson_json_reader_t bson_json_reader_t;
    typedef enum {
       BSON_JSON_ERROR_READ_CORRUPT_JS = 1,
       BSON_JSON_ERROR_READ_INVALID_PARAM,
       BSON_JSON_ERROR_READ_CB_FAILURE,
    } bson_json_error_code_t;

  Description

The bson_json_reader_t structure is used for reading a sequence of JSON documents and transforming them to bson_t documents.

This can often be useful if you want to perform bulk operations that are defined in a file containing JSON documents.

TIP: bson_json_reader_t works upon JSON documents formatted in MongoDB extended JSON format.

  Example

    /*
     * Copyright 2009-present MongoDB, Inc.
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *   http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    /*
     * This program will print each JSON document contained in the provided files
     * as a BSON string to STDOUT.
     */
    #include <bson/bson.h>
    #include <stdlib.h>
    #include <stdio.h>
    int
    main (int argc, char *argv[])
    {
       bson_json_reader_t *reader;
       bson_error_t error;
       const char *filename;
       bson_t doc = BSON_INITIALIZER;
       int i;
       int b;
       /*
        * Print program usage if no arguments are provided.
        */
       if (argc == 1) {
          fprintf (stderr, "usage: %s FILE...\n", argv[0]);
          return 1;
       }
       /*
        * Process command line arguments expecting each to be a filename.
        */
       for (i = 1; i < argc; i++) {
          filename = argv[i];
          /*
           * Open the filename provided in command line arguments.
           */
          if (0 == strcmp (filename, "-")) {
             reader = bson_json_reader_new_from_fd (STDIN_FILENO, false);
          } else {
             if (!(reader = bson_json_reader_new_from_file (filename, &error))) {
                fprintf (
                   stderr, "Failed to open \"%s\": %s\n", filename, error.message);
                continue;
             }
          }
          /*
           * Convert each incoming document to BSON and print to stdout.
           */
          while ((b = bson_json_reader_read (reader, &doc, &error))) {
             if (b < 0) {
                fprintf (stderr, "Error in json parsing:\n%s\n", error.message);
                abort ();
             }
             if (fwrite (bson_get_data (&doc), 1, doc.len, stdout) != doc.len) {
                fprintf (stderr, "Failed to write to stdout, exiting.\n");
                exit (1);
             }
             bson_reinit (&doc);
          }
          bson_json_reader_destroy (reader);
          bson_destroy (&doc);
       }
       return 0;
    }

  bson_oid_t

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;
    }

  bson_reader_t

Streaming BSON Document Reader

  Synopsis

    #include <bson/bson.h>
    typedef struct _bson_reader_t bson_reader_t;
    bson_reader_t *
    bson_reader_new_from_handle (void *handle,
                                 bson_reader_read_func_t rf,
                                 bson_reader_destroy_func_t df);
    bson_reader_t *
    bson_reader_new_from_fd (int fd, bool close_on_destroy);
    bson_reader_t *
    bson_reader_new_from_file (const char *path, bson_error_t *error);
    bson_reader_t *
    bson_reader_new_from_data (const uint8_t *data, size_t length);
    void
    bson_reader_destroy (bson_reader_t *reader);

  Description

bson_reader_t is a structure used for reading a sequence of BSON documents. The sequence can come from a file-descriptor, memory region, or custom callbacks.

  Example

    /*
     * Copyright 2009-present MongoDB, Inc.
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *   http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    /*
     * This program will print each BSON document contained in the provided files
     * as a JSON string to STDOUT.
     */
    #include <bson/bson.h>
    #include <stdio.h>
    int
    main (int argc, char *argv[])
    {
       bson_reader_t *reader;
       const bson_t *b;
       bson_error_t error;
       const char *filename;
       char *str;
       int i;
       /*
        * Print program usage if no arguments are provided.
        */
       if (argc == 1) {
          fprintf (stderr, "usage: %s [FILE | -]...\nUse - for STDIN.\n", argv[0]);
          return 1;
       }
       /*
        * Process command line arguments expecting each to be a filename.
        */
       for (i = 1; i < argc; i++) {
          filename = argv[i];
          if (strcmp (filename, "-") == 0) {
             reader = bson_reader_new_from_fd (STDIN_FILENO, false);
          } else {
             if (!(reader = bson_reader_new_from_file (filename, &error))) {
                fprintf (
                   stderr, "Failed to open \"%s\": %s\n", filename, error.message);
                continue;
             }
          }
          /*
           * Convert each incoming document to JSON and print to stdout.
           */
          while ((b = bson_reader_read (reader, NULL))) {
             str = bson_as_canonical_extended_json (b, NULL);
             fprintf (stdout, "%s\n", str);
             bson_free (str);
          }
          /*
           * Cleanup after our reader, which closes the file descriptor.
           */
          bson_reader_destroy (reader);
       }
       return 0;
    }

  Character and String Routines

We provide a small number of character and string routines to substitute for those that are not available on all platforms, and routines to make UTF-8 character manipulation convenient.

  bson_subtype_t

Binary Field Subtype

  Synopsis

    #include <bson/bson.h>
    typedef enum {
       BSON_SUBTYPE_BINARY = 0x00,
       BSON_SUBTYPE_FUNCTION = 0x01,
       BSON_SUBTYPE_BINARY_DEPRECATED = 0x02,
       BSON_SUBTYPE_UUID_DEPRECATED = 0x03,
       BSON_SUBTYPE_UUID = 0x04,
       BSON_SUBTYPE_MD5 = 0x05,
       BSON_SUBTYPE_COLUMN = 0x07,
       BSON_SUBTYPE_SENSITIVE = 0x08,
       BSON_SUBTYPE_VECTOR = 0x09,
       BSON_SUBTYPE_USER = 0x80,
    } bson_subtype_t;

  Description

This enumeration contains the various subtypes that may be used in a binary field. See http://bsonspec.org for more information.

  Example

    bson_t doc = BSON_INITIALIZER;
    BSON_APPEND_BINARY (&doc, "binary", BSON_SUBTYPE_BINARY, data, data_len);

  bson_type_t

BSON Type Enumeration

  Synopsis

    #include <bson/bson.h>
    typedef enum {
       BSON_TYPE_EOD = 0x00,
       BSON_TYPE_DOUBLE = 0x01,
       BSON_TYPE_UTF8 = 0x02,
       BSON_TYPE_DOCUMENT = 0x03,
       BSON_TYPE_ARRAY = 0x04,
       BSON_TYPE_BINARY = 0x05,
       BSON_TYPE_UNDEFINED = 0x06,
       BSON_TYPE_OID = 0x07,
       BSON_TYPE_BOOL = 0x08,
       BSON_TYPE_DATE_TIME = 0x09,
       BSON_TYPE_NULL = 0x0A,
       BSON_TYPE_REGEX = 0x0B,
       BSON_TYPE_DBPOINTER = 0x0C,
       BSON_TYPE_CODE = 0x0D,
       BSON_TYPE_SYMBOL = 0x0E,
       BSON_TYPE_CODEWSCOPE = 0x0F,
       BSON_TYPE_INT32 = 0x10,
       BSON_TYPE_TIMESTAMP = 0x11,
       BSON_TYPE_INT64 = 0x12,
       BSON_TYPE_DECIMAL128 = 0x13,
       BSON_TYPE_MAXKEY = 0x7F,
       BSON_TYPE_MINKEY = 0xFF,
    } bson_type_t;

  Description

The bson_type_t enumeration contains all of the types from the BSON Specification. It can be used to determine the type of a field at runtime.

  Example

    bson_iter_t iter;
    if (bson_iter_init_find (&iter, doc, "foo") &&
        (BSON_TYPE_INT32 == bson_iter_type (&iter))) {
       printf ("'foo' is an int32.\n");
    }

  bson_unichar_t

Unicode Character Abstraction

  Synopsis

    typedef uint32_t bson_unichar_t;

  Description

bson_unichar_t provides an abstraction on a single unicode character. It is the 32-bit representation of a character. As UTF-8 can contain multi-byte characters, this should be used when iterating through UTF-8 text.

  Example

    static void
    print_each_char (const char *str)
    {
       bson_unichar_t c;
       for (; *str; str = bson_utf8_next_char (str)) {
          c = bson_utf8_get_char (str);
          printf ("The numberic value is %u.\n", (unsigned) c);
       }
    }

  bson_validate_flags_t

Document validation options

  Synopsis

    #include <bson/bson-types.h>
    typedef enum {
      BSON_VALIDATE_NONE = 0,
      BSON_VALIDATE_UTF8 = (1 << 0),
      BSON_VALIDATE_DOLLAR_KEYS = (1 << 1),
      BSON_VALIDATE_DOT_KEYS = (1 << 2),
      BSON_VALIDATE_UTF8_ALLOW_NULL = (1 << 3),
      BSON_VALIDATE_EMPTY_KEYS = (1 << 4),
      BSON_VALIDATE_CORRUPT = (1 << 5),
    } bson_validate_flags_t;

  Description

bson_validate_flags_t is a set of binary flags which may be combined to specify a level of BSON document validation.

A value of 0, false, or BSON_VALIDATE_NONE equivalently requests the minimum applicable level of validation.

In the context of validation APIs bson_validate(), bson_validate_with_error(), and bson_validate_with_error_and_offset() the minimum validation still guarantees that a document can be successfully traversed by bson_iter_visit_all().

Higher level APIs using this type may have different minimum validation levels. For example, libmongoc functions that take bson_validate_flags_t use 0 to mean the document contents are not visited and malformed headers will not be detected by the client.

Each defined flag aside from BSON_VALIDATE_NONE describes an optional validation feature that may be enabled, alone or in combination with other features:

•   BSON_VALIDATE_NONE Minimum level of validation; in libbson, validates element headers.

•   BSON_VALIDATE_UTF8 All keys and string values are checked for invalid UTF-8.

•   BSON_VALIDATE_UTF8_ALLOW_NULL String values are allowed to have embedded NULL bytes. This has no effect unless BSON_VALIDATE_UTF8 is also passed.

•   BSON_VALIDATE_DOLLAR_KEYS Prohibit keys that start with $ outside of a "DBRef" subdocument.

•   BSON_VALIDATE_DOT_KEYS Prohibit keys that contain . anywhere in the string.

•   BSON_VALIDATE_EMPTY_KEYS Prohibit zero-length keys.

•   BSON_VALIDATE_CORRUPT is not a control flag, but is used as an error code when a validation routine encounters corrupt BSON data.

    SEE ALSO:
    bson_validate(), bson_validate_with_error(), bson_validate_with_error_and_offset().

    bson_visitor_t can be used for custom validation, Example Custom Validation.

  bson_value_t

BSON Boxed Container Type

  Synopsis

    #include <bson/bson.h>
    typedef struct _bson_value_t {
       bson_type_t value_type;
       union {
          bson_oid_t v_oid;
          int64_t v_int64;
          int32_t v_int32;
          int8_t v_int8;
          double v_double;
          bool v_bool;
          int64_t v_datetime;
          struct {
             uint32_t timestamp;
             uint32_t increment;
          } v_timestamp;
          struct {
             uint32_t len;
             char *str;
          } v_utf8;
          struct {
             uint32_t data_len;
             uint8_t *data;
          } v_doc;
          struct {
             uint32_t data_len;
             uint8_t *data;
             bson_subtype_t subtype;
          } v_binary;
          struct {
             char *regex;
             char *options;
          } v_regex;
          struct {
             char *collection;
             uint32_t collection_len;
             bson_oid_t oid;
          } v_dbpointer;
          struct {
             uint32_t code_len;
             char *code;
          } v_code;
          struct {
             uint32_t code_len;
             char *code;
             uint32_t scope_len;
             uint8_t *scope_data;
          } v_codewscope;
          struct {
             uint32_t len;
             char *symbol;
          } v_symbol;
          bson_decimal128_t v_decimal128;
       } value;
    } bson_value_t;

  Description

The bson_value_t structure is a boxed type for encapsulating a runtime determined type.

  Example

    const bson_value_t *value;
    value = bson_iter_value (&iter);
    if (value->value_type == BSON_TYPE_INT32) {
       printf ("%d\n", value->value.v_int32);
    }

  bson_visitor_t

  Synopsis

    #include <bson/bson.h>
    typedef struct {
       /* run before / after descending into a document */
       bool (*visit_before) (const bson_iter_t *iter, const char *key, void *data);
       bool (*visit_after) (const bson_iter_t *iter, const char *key, void *data);
       /* corrupt BSON, or unsupported type and visit_unsupported_type not set */
       void (*visit_corrupt) (const bson_iter_t *iter, void *data);
       /* normal bson field callbacks */
       bool (*visit_double) (const bson_iter_t *iter,
                             const char *key,
                             double v_double,
                             void *data);
       bool (*visit_utf8) (const bson_iter_t *iter,
                           const char *key,
                           size_t v_utf8_len,
                           const char *v_utf8,
                           void *data);
       bool (*visit_document) (const bson_iter_t *iter,
                               const char *key,
                               const bson_t *v_document,
                               void *data);
       bool (*visit_array) (const bson_iter_t *iter,
                            const char *key,
                            const bson_t *v_array,
                            void *data);
       bool (*visit_binary) (const bson_iter_t *iter,
                             const char *key,
                             bson_subtype_t v_subtype,
                             size_t v_binary_len,
                             const uint8_t *v_binary,
                             void *data);
       /* normal field with deprecated "Undefined" BSON type */
       bool (*visit_undefined) (const bson_iter_t *iter,
                                const char *key,
                                void *data);
       bool (*visit_oid) (const bson_iter_t *iter,
                          const char *key,
                          const bson_oid_t *v_oid,
                          void *data);
       bool (*visit_bool) (const bson_iter_t *iter,
                           const char *key,
                           bool v_bool,
                           void *data);
       bool (*visit_date_time) (const bson_iter_t *iter,
                                const char *key,
                                int64_t msec_since_epoch,
                                void *data);
       bool (*visit_null) (const bson_iter_t *iter, const char *key, void *data);
       bool (*visit_regex) (const bson_iter_t *iter,
                            const char *key,
                            const char *v_regex,
                            const char *v_options,
                            void *data);
       bool (*visit_dbpointer) (const bson_iter_t *iter,
                                const char *key,
                                size_t v_collection_len,
                                const char *v_collection,
                                const bson_oid_t *v_oid,
                                void *data);
       bool (*visit_code) (const bson_iter_t *iter,
                           const char *key,
                           size_t v_code_len,
                           const char *v_code,
                           void *data);
       bool (*visit_symbol) (const bson_iter_t *iter,
                             const char *key,
                             size_t v_symbol_len,
                             const char *v_symbol,
                             void *data);
       bool (*visit_codewscope) (const bson_iter_t *iter,
                                 const char *key,
                                 size_t v_code_len,
                                 const char *v_code,
                                 const bson_t *v_scope,
                                 void *data);
       bool (*visit_int32) (const bson_iter_t *iter,
                            const char *key,
                            int32_t v_int32,
                            void *data);
       bool (*visit_timestamp) (const bson_iter_t *iter,
                                const char *key,
                                uint32_t v_timestamp,
                                uint32_t v_increment,
                                void *data);
       bool (*visit_int64) (const bson_iter_t *iter,
                            const char *key,
                            int64_t v_int64,
                            void *data);
       bool (*visit_maxkey) (const bson_iter_t *iter, const char *key, void *data);
       bool (*visit_minkey) (const bson_iter_t *iter, const char *key, void *data);
       /* if set, called instead of visit_corrupt when an apparently valid BSON
        * includes an unrecognized field type (reading future version of BSON) */
       void (*visit_unsupported_type) (const bson_iter_t *iter,
                                       const char *key,
                                       uint32_t type_code,
                                       void *data);
       bool (*visit_decimal128) (const bson_iter_t *iter,
                                 const char *key,
                                 const bson_decimal128_t *v_decimal128,
                                 void *data);
       void *padding[7];
    } bson_visitor_t bson_visitor_t;

  Description

The bson_visitor_t structure provides a series of callbacks that can be called while iterating a BSON document. This may simplify the conversion of a bson_t to a higher level language structure.

If the optional callback visit_unsupported_type is set, it is called instead of visit_corrupt in the specific case of an unrecognized field type. (Parsing is aborted in either case.) Use this callback to report an error like "unrecognized type" instead of simply "corrupt BSON". This future-proofs code that may use an older version of libbson to parse future BSON formats.

  Basic Example

    #include <bson/bson.h>
    #include <stdio.h>
    static bool
    my_visit_before (const bson_iter_t *iter, const char *key, void *data)
    {
       int *count = (int *) data;
       (*count)++;
       /* returning true stops further iteration of the document */
       return false;
    }
    static void
    count_fields (bson_t *doc)
    {
       bson_visitor_t visitor = {0};
       bson_iter_t iter;
       int count = 0;
       visitor.visit_before = my_visit_before;
       if (bson_iter_init (&iter, doc)) {
          bson_iter_visit_all (&iter, &visitor, &count);
       }
       printf ("Found %d fields.\n", count);
    }

The example below demonstrates how to set your own callbacks to provide information about the location of corrupt or unsupported BSON document entries.

  Example Corruption Check

    #include <bson/bson.h>
    #include <stdio.h>
    typedef struct {
       ssize_t *err_offset;
    } my_state_t;
    static void
    my_visit_corrupt (const bson_iter_t *iter, void *data)
    {
       *(((my_state_t *) data)->err_offset) = iter->off;
    }
    static void
    my_visit_unsupported_type (const bson_iter_t *iter,
                               const char *key,
                               uint32_t type_code,
                               void *data)
    {
       *(((my_state_t *) data)->err_offset) = iter->off;
    }
    static void
    find_error_location (bson_t *doc)
    {
       bson_visitor_t visitors = {0};
       bson_iter_t iter;
       my_state_t state;
       ssize_t err_offset = -1;
       visitors.visit_corrupt = my_visit_corrupt;
       visitors.visit_unsupported_type = my_visit_unsupported_type;
       /* provide additional visitors as needed based on your requirements */
       state.err_offset = &err_offset;
       if (!bson_iter_init (&iter, doc)) {
          printf ("Could not initialize iterator!");
          exit (1);
       }
       if (bson_iter_visit_all (&iter, &visitors, &state) ||
           err_offset != -1) {
          printf ("Found error at offset %d.\n", err_offset);
       } else {
          printf ("BSON document had no errors.\n");
       }
    }

The example below demonstrates how to use a visitor to validate a BSON document's maximum depth.

  Example Custom Validation

bson-check-depth.c

    /* Reports the maximum nested depth of a BSON document. */
    #include <bson/bson.h>
    #include <assert.h>
    #include <inttypes.h>
    #include <stdio.h>
    #include <stdlib.h>
    typedef struct {
       uint32_t depth;
       uint32_t max_depth;
       bool valid;
    } check_depth_t;
    bool
    _check_depth_document(const bson_iter_t *iter, const char *key, const bson_t *v_document, void *data);
    static const bson_visitor_t check_depth_funcs = {
       NULL,
       NULL,
       NULL,
       NULL,
       NULL,
       _check_depth_document,
       _check_depth_document,
       NULL,
    };
    bool
    _check_depth_document(const bson_iter_t *iter, const char *key, const bson_t *v_document, void *data)
    {
       check_depth_t *state = (check_depth_t *)data;
       bson_iter_t child;
       BSON_UNUSED(iter);
       BSON_UNUSED(key);
       if (!bson_iter_init(&child, v_document)) {
          fprintf(stderr, "corrupt\n");
          return true; /* cancel */
       }
       state->depth++;
       if (state->depth > state->max_depth) {
          state->valid = false;
          return true; /* cancel */
       }
       bson_iter_visit_all(&child, &check_depth_funcs, state);
       state->depth--;
       return false; /* continue */
    }
    void
    check_depth(const bson_t *bson, uint32_t max_depth)
    {
       bson_iter_t iter;
       check_depth_t state = {0};
       if (!bson_iter_init(&iter, bson)) {
          fprintf(stderr, "corrupt\n");
       }
       state.valid = true;
       state.max_depth = max_depth;
       _check_depth_document(&iter, NULL, bson, &state);
       if (!state.valid) {
          printf("document exceeds maximum depth of %" PRIu32 "\n", state.max_depth);
       } else {
          char *as_json = bson_as_canonical_extended_json(bson, NULL);
          printf("document %s ", as_json);
          printf("is valid\n");
          bson_free(as_json);
       }
    }
    int
    main(int argc, char **argv)
    {
       bson_reader_t *bson_reader;
       const bson_t *bson;
       bool reached_eof;
       bson_error_t error;
       if (argc != 3) {
          fprintf(stderr, "usage: %s FILE MAX_DEPTH\n", argv[0]);
          fprintf(stderr, "Checks that the depth of the BSON contained in FILE\n");
          fprintf(stderr, "does not exceed MAX_DEPTH\n");
       }
       const char *const filename = argv[1];
       const int max_depth = atoi(argv[2]);
       bson_reader = bson_reader_new_from_file(filename, &error);
       if (!bson_reader) {
          printf("could not read %s: %s\n", filename, error.message);
          return 1;
       }
       BSON_ASSERT(max_depth >= 0 && (uint64_t)max_depth <= UINT32_MAX);
       while ((bson = bson_reader_read(bson_reader, &reached_eof))) {
          check_depth(bson, (uint32_t)max_depth);
       }
       if (!reached_eof) {
          printf("error reading BSON\n");
       }
       bson_reader_destroy(bson_reader);
       return 0;
    }

  bson_writer_t

Bulk BSON serialization Abstraction

  Synopsis

    #include <bson/bson.h>
    typedef struct _bson_writer_t bson_writer_t;
    bson_writer_t *
    bson_writer_new (uint8_t **buf,
                     size_t *buflen,
                     size_t offset,
                     bson_realloc_func realloc_func,
                     void *realloc_func_ctx);
    void
    bson_writer_destroy (bson_writer_t *writer);

  Description

The bson_writer_t API provides an abstraction for serializing many BSON documents to a single memory region. The memory region may be dynamically allocated and re-allocated as more memory is demanded. This can be useful when building network packets from a high-level language. For example, you can serialize a Python Dictionary directly to a single buffer destined for a TCP packet.

  Example

    #include <bson/bson.h>
    int
    main (int argc, char *argv[])
    {
       bson_writer_t *writer;
       uint8_t *buf = NULL;
       size_t buflen = 0;
       bson_t *doc;
       writer = bson_writer_new (&buf, &buflen, 0, bson_realloc_ctx, NULL);
       for (int i = 0; i < 1000; i++) {
          bson_writer_begin (writer, &doc);
          BSON_APPEND_INT32 (doc, "i", i);
          bson_writer_end (writer);
       }
       bson_writer_destroy (writer);
       bson_free (buf);
       return 0;
    }

  System Clock

BSON Clock Abstraction

  Synopsis

    int64_t
    bson_get_monotonic_time (void);
    int
    bson_gettimeofday (struct timeval *tv);

  Description

The clock abstraction in Libbson provides a cross-platform way to handle timeouts within the BSON library. It abstracts the differences in implementations of gettimeofday() as well as providing a monotonic (incrementing only) clock in microseconds.

  Memory Management

BSON Memory Abstraction.

  Description

Libbson contains a lightweight memory abstraction to make portability to new platforms easier. Additionally, it helps us integrate with interesting higher-level languages. One caveat, however, is that Libbson is not designed to deal with Out of Memory (OOM) situations. Doing so requires extreme diligence throughout the application stack that has rarely been implemented correctly. This may change in the future. As it stands now, Libbson will abort() under OOM situations.

To aid in language binding integration, Libbson allows for setting a custom memory allocator via bson_mem_set_vtable(). This allocation may be reversed via bson_mem_restore_vtable().

  BSON Binary Vector subtype

In Libbson, we use the term Vector to refer to a data representation for compact storage of uniform elements, defined by the BSON Binary Subtype 9 - Vector specification.

Libbson includes API support for Vectors:

•   The view APIs provide an efficient way to access elements of Vector fields that reside within bson_t storage.

•   Integration between views and other Libbson features: append, array builder, iter.

•   Vectors can be converted to and from a plain BSON Array, subject to the specification's type conversion rules.

    The specification currently defines three element types, which Libbson interprets as:

•   int8: signed integer elements, equivalent to C int8_t.

•   float32: IEEE 754 floating point, 32 bits per element, least-significant byte first. After alignment and byte swapping, elements are equivalent to C float.

•   packed_bit: single-bit integer elements, packed most-significant bit first. Accessible in packed form as C uint8_t or as unpacked elements using C bool.

  Vector Views

  bson_vector_int8_view_t

A reference to mutable non-owned BSON Binary data holding a valid Vector of int8 element type.

  Synopsis

    #include <bson/bson.h>
    typedef struct bson_vector_int8_view_t {
       /*< private >*/
    } bson_vector_int8_view_t;

  Description

bson_vector_int8_view_t is a structure that acts as an opaque reference to a block of memory that has been validated as an int8 vector.

It is meant to be passed by value and can be discarded at any time. The contents of the structure should be considered private.

The bson_t MUST be valid for the lifetime of the view and it is an error to modify the bson_t while using the view.

  Example

    static const int8_t values[] = {1, 2, 3};
    const size_t values_count = sizeof values / sizeof values[0];
    bson_vector_int8_view_t view;
    BSON_ASSERT (BSON_APPEND_VECTOR_INT8_UNINIT (&doc, "vector", values_count, &view));
    BSON_ASSERT (bson_vector_int8_view_write (view, values, values_count, 0));

SEE ALSO:
bson_append_vector_int8_uninit()
bson_vector_int8_const_view_t

  bson_vector_int8_const_view_t

A reference to non-owned const BSON Binary data holding a valid Vector of int8 element type.

  Synopsis

    #include <bson/bson.h>
    typedef struct bson_vector_int8_const_view_t {
       /*< private >*/
    } bson_vector_int8_const_view_t;

  Description

bson_vector_int8_const_view_t is a structure that acts as an opaque const reference to a block of memory that has been validated as an int8 vector.

It is meant to be passed by value and can be discarded at any time. The contents of the structure should be considered private.

The bson_t MUST be valid for the lifetime of the view and it is an error to modify the bson_t while using the view.

  Example

    bson_iter_t iter;
    bson_vector_int8_const_view_t view;
    if (bson_iter_init_find (&iter, &doc, "vector") && bson_vector_int8_const_view_from_iter (&view, &iter)) {
      size_t length = bson_vector_int8_const_view_length (view);
      printf ("Elements in 'vector':\n");
      for (size_t i = 0; i < length; i++) {
        int8_t element;
        BSON_ASSERT (bson_vector_int8_const_view_read (view, &element, 1, i));
        printf (" [%d] = %d\n", (int) i, (int) element);
      }
    }

SEE ALSO:
bson_vector_int8_view_t

  bson_vector_float32_view_t

A reference to mutable non-owned BSON Binary data holding a valid Vector of float32 element type.

  Synopsis

    #include <bson/bson.h>
    typedef struct bson_vector_float32_view_t {
       /*< private >*/
    } bson_vector_float32_view_t;

  Description

bson_vector_float32_view_t is a structure that acts as an opaque reference to a block of memory that has been validated as a float32 vector.

It is meant to be passed by value and can be discarded at any time. The contents of the structure should be considered private.

The bson_t MUST be valid for the lifetime of the view and it is an error to modify the bson_t while using the view.

  Example

    static const float values[] = {1.0f, 2.0f, 3.0f};
    const size_t values_count = sizeof values / sizeof values[0];
    bson_vector_float32_view_t view;
    BSON_ASSERT (BSON_APPEND_VECTOR_FLOAT32_UNINIT (&doc, "vector", values_count, &view));
    BSON_ASSERT (bson_vector_float32_view_write (view, values, values_count, 0));

SEE ALSO:
bson_append_vector_float32_uninit()
bson_vector_float32_const_view_t

  bson_vector_float32_const_view_t

A reference to non-owned const BSON Binary data holding a valid Vector of float32 element type.

  Synopsis

    #include <bson/bson.h>
    typedef struct bson_vector_float32_const_view_t {
       /*< private >*/
    } bson_vector_float32_const_view_t;

  Description

bson_vector_float32_const_view_t is a structure that acts as an opaque const reference to a block of memory that has been validated as a float32 vector.

It is meant to be passed by value and can be discarded at any time. The contents of the structure should be considered private.

The bson_t MUST be valid for the lifetime of the view and it is an error to modify the bson_t while using the view.

  Example

    bson_iter_t iter;
    bson_vector_float32_const_view_t view;
    if (bson_iter_init_find (&iter, &doc, "vector") && bson_vector_float32_const_view_from_iter (&view, &iter)) {
      size_t length = bson_vector_float32_const_view_length (view);
      printf ("Elements in 'vector':\n");
      for (size_t i = 0; i < length; i++) {
        float element;
        BSON_ASSERT (bson_vector_float32_const_view_read (view, &element, 1, i));
        printf (" [%d] = %f\n", (int) i, element);
      }
    }

SEE ALSO:
bson_vector_float32_view_t

  bson_vector_packed_bit_view_t

A reference to mutable non-owned BSON Binary data holding a valid Vector of packed_bit element type.

  Synopsis

    #include <bson/bson.h>
    typedef struct bson_vector_packed_bit_view_t {
       /*< private >*/
    } bson_vector_packed_bit_view_t;

  Description

bson_vector_packed_bit_view_t is a structure that acts as an opaque reference to a block of memory that has been validated as a packed_bit vector.

It is meant to be passed by value and can be discarded at any time. The contents of the structure should be considered private.

The bson_t MUST be valid for the lifetime of the view and it is an error to modify the bson_t while using the view.

  Example

    // Fill a new vector with individual boolean elements
    {
        static const bool bool_values[] = {true, false, true, true, false};
        const size_t bool_values_count = sizeof bool_values / sizeof bool_values[0];
        bson_vector_packed_bit_view_t view;
        BSON_ASSERT (BSON_APPEND_VECTOR_PACKED_BIT_UNINIT (&doc, "from_bool", bool_values_count, &view));
        BSON_ASSERT (bson_vector_packed_bit_view_pack_bool (view, bool_values, bool_values_count, 0));
    }
    // Fill another new vector with packed bytes
    {
        static const uint8_t packed_bytes[] = {0xb0};
        const size_t unused_bits_count = 3;
        const size_t packed_values_count = sizeof packed_bytes * 8 - unused_bits_count;
        bson_vector_packed_bit_view_t view;
        BSON_ASSERT (BSON_APPEND_VECTOR_PACKED_BIT_UNINIT (&doc, "from_packed", packed_values_count, &view));
        BSON_ASSERT (bson_vector_packed_bit_view_write_packed (view, packed_bytes, sizeof packed_bytes, 0));
    }
    // Compare both vectors. They match exactly.
    {
        bson_iter_t from_bool_iter, from_packed_iter;
        BSON_ASSERT (bson_iter_init_find (&from_bool_iter, &doc, "from_bool"));
        BSON_ASSERT (bson_iter_init_find (&from_packed_iter, &doc, "from_packed"));
        BSON_ASSERT (bson_iter_binary_equal (&from_bool_iter, &from_packed_iter));
    }

SEE ALSO:
bson_append_vector_packed_bit_uninit()
bson_vector_packed_bit_const_view_t

  bson_vector_packed_bit_const_view_t

A reference to non-owned const BSON Binary data holding a valid Vector of packed_bit element type.

  Synopsis

    #include <bson/bson.h>
    typedef struct bson_vector_packed_bit_const_view_t {
       /*< private >*/
    } bson_vector_packed_bit_const_view_t;

  Description

bson_vector_packed_bit_const_view_t is a structure that acts as an opaque const reference to a block of memory that has been validated as a packed_bit vector.

It is meant to be passed by value and can be discarded at any time. The contents of the structure should be considered private.

The bson_t MUST be valid for the lifetime of the view and it is an error to modify the bson_t while using the view.

  Example

    bson_iter_t iter;
    bson_vector_packed_bit_const_view_t view;
    if (bson_iter_init_find (&iter, &doc, "vector") && bson_vector_packed_bit_const_view_from_iter (&view, &iter)) {
      size_t length = bson_vector_packed_bit_const_view_length (view);
      size_t length_bytes = bson_vector_packed_bit_const_view_length_bytes (view);
      size_t padding = bson_vector_packed_bit_const_view_padding (view);
      printf ("Elements in 'vector':\n");
      for (size_t i = 0; i < length; i++) {
        bool element;
        BSON_ASSERT (bson_vector_packed_bit_const_view_unpack_bool (view, &element, 1, i));
        printf (" elements[%d] = %d\n", (int) i, (int) element);
      }
      printf ("Bytes in 'vector': (%d bits unused)\n", (int) padding);
      for (size_t i = 0; i < length_bytes; i++) {
        uint8_t packed_byte;
        BSON_ASSERT (bson_vector_packed_bit_const_view_read_packed (view, &packed_byte, 1, i));
        printf (" bytes[%d] = 0x%02x\n", (int) i, (unsigned) packed_byte);
      }
    }

SEE ALSO:
bson_vector_packed_bit_view_t

  Integration

•   Allocating Vectors inside bson_t:

  bson_append_vector_int8_uninit()

  Synopsis

    #define BSON_APPEND_VECTOR_INT8_UNINIT(b, key, count, view) \
       bson_append_vector_int8_uninit (b, key, (int) strlen (key), count, view)
    bool
    bson_append_vector_int8_uninit (bson_t *bson,
                                    const char *key,
                                    int key_length,
                                    size_t element_count,
                                    bson_vector_int8_view_t *view_out);

  Parameters

•   bson: A bson_t.

•   key: An ASCII C string containing the name of the field.

•   key_length: The length of key in bytes, or -1 to determine the length with strlen().

•   element_count: Number of elements to allocate space for.

•   view_out: Receives a bson_vector_int8_view_t with uninitialized elements.

  Description

Appends a new field to bson by allocating a Vector with the indicated number of int8 elements. The elements will be uninitialized. On success, the caller must write every element in the Vector if the resulting bson_t is to be used.

The view written to *view_out is only valid until bson is otherwise modified or freed.

  Returns

Returns true if the operation was applied successfully. The function fails if appending the array grows bson larger than INT32_MAX.

  bson_append_vector_float32_uninit()

  Synopsis

    #define BSON_APPEND_VECTOR_FLOAT32_UNINIT(b, key, count, view) \
       bson_append_vector_float32_uninit (b, key, (int) strlen (key), count, view)
    bool
    bson_append_vector_float32_uninit (bson_t *bson,
                                       const char *key,
                                       int key_length,
                                       size_t element_count,
                                       bson_vector_float32_view_t *view_out);

  Parameters

•   bson: A bson_t.

•   key: An ASCII C string containing the name of the field.

•   key_length: The length of key in bytes, or -1 to determine the length with strlen().

•   element_count: Number of elements to allocate space for.

•   view_out: Receives a bson_vector_float32_view_t with uninitialized elements.

  Description

Appends a new field to bson by allocating a Vector with the indicated number of float32 elements. The elements will be uninitialized. On success, the caller must write every element in the Vector if the resulting bson_t is to be used.

The view written to *view_out is only valid until bson is otherwise modified or freed.

  Returns

Returns true if the operation was applied successfully. The function fails if appending the array grows bson larger than INT32_MAX.

  bson_append_vector_packed_bit_uninit()

  Synopsis

    #define BSON_APPEND_VECTOR_PACKED_BIT_UNINIT(b, key, count, view) \
       bson_append_vector_packed_bit_uninit (b, key, (int) strlen (key), count, view)
    bool
    bson_append_vector_packed_bit_uninit (bson_t *bson,
                                          const char *key,
                                          int key_length,
                                          size_t element_count,
                                          bson_vector_packed_bit_view_t *view_out);

  Parameters

•   bson: A bson_t.

•   key: An ASCII C string containing the name of the field.

•   key_length: The length of key in bytes, or -1 to determine the length with strlen().

•   element_count: Number of elements to allocate space for.

•   view_out: Receives a bson_vector_packed_bit_view_t with uninitialized elements.

  Description

Appends a new field to bson by allocating a Vector with the indicated number of packed_bit elements. The elements will be uninitialized. On success, the caller must write every element in the Vector if the resulting bson_t is to be used.

The view written to *view_out is only valid until bson is otherwise modified or freed.

  Returns

Returns true if the operation was applied successfully. The function fails if appending the array grows bson larger than INT32_MAX.

•   Accessing an existing Vector via bson_iter_t:

        #define BSON_ITER_HOLDS_VECTOR(iter) /* ... */
        #define BSON_ITER_HOLDS_VECTOR_INT8(iter) /* ... */
        #define BSON_ITER_HOLDS_VECTOR_FLOAT32(iter) /* ... */
        #define BSON_ITER_HOLDS_VECTOR_PACKED_BIT(iter) /* ... */

  Array Conversion

•   Polymorphic array-from-vector:

  bson_append_array_from_vector()

  Synopsis

    #define BSON_APPEND_ARRAY_FROM_VECTOR(b, key, iter) \
       bson_append_array_from_vector (b, key, (int) strlen (key), iter)
    bool
    bson_append_array_from_vector (bson_t *bson,
                                   const char *key,
                                   int key_length,
                                   const bson_iter_t *iter);

  Parameters

•   bson: A bson_t.

•   key: An ASCII C string containing the name of the field.

•   key_length: The length of key in bytes, or -1 to determine the length with strlen().

•   iter: A bson_iter_t pointing to any supported BSON Binary Vector subtype field.

  Description

Converts the Vector pointed to by iter into a plain BSON Array, written to bson under the name key.

  Returns

Returns true if the operation was applied successfully. The function fails if appending the array grows bson larger than INT32_MAX, or if iter doesn't point to a valid recognized Vector type.

SEE ALSO:
bson_array_builder_append_vector_elements()

•   Type specific array-from-vector:

  bson_append_array_from_vector_int8()

  Synopsis

    #define BSON_APPEND_ARRAY_FROM_VECTOR_INT8(b, key, view) \
       bson_append_array_from_vector_int8 (b, key, (int) strlen (key), view)
    bool
    bson_append_array_from_vector_int8 (bson_t *bson,
                                        const char *key,
                                        int key_length,
                                        bson_vector_int8_const_view_t view);

  Parameters

•   bson: A bson_t.

•   key: An ASCII C string containing the name of the field.

•   key_length: The length of key in bytes, or -1 to determine the length with strlen().

•   view: A bson_vector_int8_const_view_t pointing to validated int8 BSON Binary Vector subtype data.

  Description

Converts the Vector pointed to by view into a plain BSON Array, written to bson under the name key.

  Returns

Returns true if the operation was applied successfully. The function fails if appending the array grows bson larger than INT32_MAX.

SEE ALSO:
bson_array_builder_append_vector_int8_elements()

  bson_append_array_from_vector_float32()

  Synopsis

    #define BSON_APPEND_ARRAY_FROM_VECTOR_FLOAT32(b, key, view) \
       bson_append_array_from_vector_float32 (b, key, (int) strlen (key), view)
    bool
    bson_append_array_from_vector_float32 (bson_t *bson,
                                           const char *key,
                                           int key_length,
                                           bson_vector_float32_const_view_t view);

  Parameters

•   bson: A bson_t.

•   key: An ASCII C string containing the name of the field.

•   key_length: The length of key in bytes, or -1 to determine the length with strlen().

•   view: A bson_vector_float32_const_view_t pointing to validated float32 BSON Binary Vector subtype data.

  Description

Converts the Vector pointed to by view into a plain BSON Array, written to bson under the name key.

  Returns

Returns true if the operation was applied successfully. The function fails if appending the array grows bson larger than INT32_MAX.

SEE ALSO:
bson_array_builder_append_vector_float32_elements()

  bson_append_array_from_vector_packed_bit()

  Synopsis

    #define BSON_APPEND_ARRAY_FROM_VECTOR_PACKED_BIT(b, key, view) \
       bson_append_array_from_vector_packed_bit (b, key, (int) strlen (key), view)
    bool
    bson_append_array_from_vector_packed_bit (bson_t *bson,
                                              const char *key,
                                              int key_length,
                                              bson_vector_packed_bit_const_view_t view);

  Parameters

•   bson: A bson_t.

•   key: An ASCII C string containing the name of the field.

•   key_length: The length of key in bytes, or -1 to determine the length with strlen().

•   view: A bson_vector_packed_bit_const_view_t pointing to validated packed_bit BSON Binary Vector subtype data.

  Description

Converts the Vector pointed to by view into a plain BSON Array, written to bson under the name key.

  Returns

Returns true if the operation was applied successfully. The function fails if appending the array grows bson larger than INT32_MAX.

SEE ALSO:
bson_array_builder_append_vector_packed_bit_elements()

•   Using bson_array_builder_t for array-from-vector:

  bson_array_builder_append_vector_int8_elements()

  Synopsis

    bool
    bson_array_builder_append_vector_int8_elements (bson_array_builder_t *builder,
                                                    bson_vector_int8_const_view_t view);

  Parameters

•   builder: A valid bson_array_builder_t.

•   view: A bson_vector_int8_const_view_t pointing to validated int8 BSON Binary Vector subtype data.

  Description

Converts the Vector pointed to by view into elements of a plain BSON Array, written to builder. Every element will be losslessly extended from int8_t to int32_t.

  Returns

Returns true if the operation was applied successfully. The function fails if appending the array grows bson larger than INT32_MAX.

SEE ALSO:
bson_append_array_from_vector()
bson_array_builder_append_vector_elements()

  bson_array_builder_append_vector_float32_elements()

  Synopsis

    bool
    bson_array_builder_append_vector_float32_elements (bson_array_builder_t *builder,
                                                       bson_vector_float32_const_view_t view);

  Parameters

•   builder: A valid bson_array_builder_t.

•   view: A bson_vector_float32_const_view_t pointing to validated float32 BSON Binary Vector subtype data.

  Description

Converts the Vector pointed to by view into elements of a plain BSON Array, written to builder. Every element will be converted from float to double precision.

  Returns

Returns true if the operation was applied successfully. The function fails if appending the array grows bson larger than INT32_MAX.

SEE ALSO:
bson_append_array_from_vector()
bson_array_builder_append_vector_elements()

  bson_array_builder_append_vector_packed_bit_elements()

  Synopsis

    bool
    bson_array_builder_append_vector_packed_bit_elements (bson_array_builder_t *builder,
                                                          bson_vector_packed_bit_const_view_t view);

  Parameters

•   builder: A valid bson_array_builder_t.

•   view: A bson_vector_packed_bit_const_view_t pointing to validated packed_bit BSON Binary Vector subtype data.

  Description

Converts the Vector pointed to by view into elements of a plain BSON Array, written to builder. Every element will be 0 or 1 written as a BSON_TYPE_INT32.

  Returns

Returns true if the operation was applied successfully. The function fails if appending the array grows bson larger than INT32_MAX.

SEE ALSO:
bson_append_array_from_vector()
bson_array_builder_append_vector_elements()

  bson_array_builder_append_vector_elements()

  Synopsis

    bool
    bson_array_builder_append_vector_elements (bson_array_builder_t *builder,
                                               const bson_iter_t *iter);

  Parameters

•   builder: A valid bson_array_builder_t.

•   iter: A bson_iter_t pointing to any supported BSON Binary Vector subtype field.

  Description

Converts the Vector pointed to by iter into elements of a plain BSON Array, written to builder. This conversion is polymorphic: A converted element type will be chosen based on the type of the input Vector. For details, see the type-specific versions of this function.

  Returns

Returns true if the operation was applied successfully. The function fails if appending the array grows bson larger than INT32_MAX, or if iter doesn't point to a valid recognized Vector type.

SEE ALSO:
bson_append_array_from_vector()
bson_array_builder_append_vector_int8_elements()
bson_array_builder_append_vector_float32_elements()
bson_array_builder_append_vector_packed_bit_elements()

•   Type specific vector-from-array:

  bson_append_vector_int8_from_array()

  Synopsis

    #define BSON_APPEND_VECTOR_INT8_FROM_ARRAY(b, key, iter, err) \
       bson_append_vector_int8_from_array (b, key, (int) strlen (key), iter, err)
    bool
    bson_append_vector_int8_from_array (bson_t *bson,
                                        const char *key,
                                        int key_length,
                                        const bson_iter_t *iter,
                                        bson_error_t *error);

  Parameters

•   bson: A bson_t.

•   key: An ASCII C string containing the name of the field.

•   key_length: The length of key in bytes, or -1 to determine the length with strlen().

•   iter: A bson_iter_t referencing array elements that will be converted.

•   error: Optional bson_error_t for detail about conversion failures.

  Description

Appends a new field to bson by converting an Array to a Vector of int8 elements.

For the conversion to succeed, every item in the Array must be an integer (BSON_TYPE_INT32 or BSON_TYPE_INT64) in the range INT8_MIN (-128) through INT8_MAX (127) inclusive. If any element has an incorrect type or an out-of-range value, the conversion fails with an error message providing details, and no changes are made to bson.

The provided iter must be positioned just prior to the first element of the BSON Array. If your input is a bare BSON Array, set up iter using bson_iter_init(). If the input is within a document field, use bson_iter_recurse().

  Returns

Returns true if the operation was applied successfully. On error, returns false and writes additional error information to error without modifying bson. The error will have a domain of BSON_ERROR_VECTOR and a code from bson_vector_error_code_t.

  bson_append_vector_float32_from_array()

  Synopsis

    #define BSON_APPEND_VECTOR_FLOAT32_FROM_ARRAY(b, key, iter, err) \
       bson_append_vector_float32_from_array (b, key, (int) strlen (key), iter, err)
    bool
    bson_append_vector_float32_from_array (bson_t *bson,
                                           const char *key,
                                           int key_length,
                                           const bson_iter_t *iter,
                                           bson_error_t *error);

  Parameters

•   bson: A bson_t.

•   key: An ASCII C string containing the name of the field.

•   key_length: The length of key in bytes, or -1 to determine the length with strlen().

•   iter: A bson_iter_t referencing array elements that will be converted.

•   error: Optional bson_error_t for detail about conversion failures.

  Description

Appends a new field to bson by converting an Array to a Vector of float32 elements.

For the conversion to succeed, every item in the Array must be double-precision floating point number. (BSON_TYPE_DOUBLE)

The provided iter must be positioned just prior to the first element of the BSON Array. If your input is a bare BSON Array, set up iter using bson_iter_init(). If the input is within a document field, use bson_iter_recurse().

  Returns

Returns true if the operation was applied successfully. On error, returns false and writes additional error information to error without modifying bson. The error will have a domain of BSON_ERROR_VECTOR and a code from bson_vector_error_code_t.

  bson_append_vector_packed_bit_from_array()

  Synopsis

    #define BSON_APPEND_VECTOR_PACKED_BIT_FROM_ARRAY(b, key, iter, err) \
       bson_append_vector_packed_bit_from_array (b, key, (int) strlen (key), iter, err)
    bool
    bson_append_vector_packed_bit_from_array (bson_t *bson,
                                              const char *key,
                                              int key_length,
                                              const bson_iter_t *iter,
                                              bson_error_t *error);

  Parameters

•   bson: A bson_t.

•   key: An ASCII C string containing the name of the field.

•   key_length: The length of key in bytes, or -1 to determine the length with strlen().

•   iter: A bson_iter_t referencing array elements that will be converted.

•   error: Optional bson_error_t for detail about conversion failures.

  Description

Appends a new field to bson by converting an Array to a Vector of packed_bit elements.

For the conversion to succeed, every item in the Array must be either an integer (BSON_TYPE_INT32 or BSON_TYPE_INT64) with the values 0 or 1, or boolean (BSON_TYPE_BOOL). If any element has an incorrect type or an out-of-range value, the conversion fails with an error message providing details, and no changes are made to bson.

The provided iter must be positioned just prior to the first element of the BSON Array. If your input is a bare BSON Array, set up iter using bson_iter_init(). If the input is within a document field, use bson_iter_recurse().

  Returns

Returns true if the operation was applied successfully. On error, returns false and writes additional error information to error without modifying bson. The error will have a domain of BSON_ERROR_VECTOR and a code from bson_vector_error_code_t.

  Additional Definitions

•   Binary subtype:

        typedef enum {
          BSON_SUBTYPE_VECTOR = 0x09,
          /* ... */
        } bson_subtype_t;

•   Byte length of the Vector header:

        // Length of the required header for BSON_SUBTYPE_VECTOR, in bytes
        #define BSON_VECTOR_HEADER_LEN 2

•   Byte length for a Vector with specific element type and count:

  bson_vector_int8_binary_data_length()

Calculate the size of a BSON Binary field that would be needed to store a Vector with the indicated number of int8 elements.

  Synopsis

    uint32_t
    bson_vector_int8_binary_data_length (size_t element_count);

  Parameters

•   element_count: Number of elements, as a size_t.

  Description

Checks element_count against the maximum representable size, and calculates the required Binary size.

  Returns

On success, returns the required Binary size as a uint32_t greater than or equal to BSON_VECTOR_HEADER_LEN. This length includes the 2-byte Vector header, but not the Binary subtype header or any other BSON headers. If the element_count is too large to represent, returns 0.

  bson_vector_float32_binary_data_length()

Calculate the size of a BSON Binary field that would be needed to store a Vector with the indicated number of float32 elements.

  Synopsis

    uint32_t
    bson_vector_float32_binary_data_length (size_t element_count);

  Parameters

•   element_count: Number of elements, as a size_t.

  Description

Checks element_count against the maximum representable size, and calculates the required Binary size.

  Returns

On success, returns the required Binary size as a uint32_t greater than or equal to BSON_VECTOR_HEADER_LEN. This length includes the 2-byte Vector header, but not the Binary subtype header or any other BSON headers. If the element_count is too large to represent, returns 0.

  bson_vector_packed_bit_binary_data_length()

Calculate the size of a BSON Binary field that would be needed to store a Vector with the indicated number of packed_bit elements.

  Synopsis

    uint32_t
    bson_vector_packed_bit_binary_data_length (size_t element_count);

  Parameters

•   element_count: Number of single-bit elements, as a size_t.

  Description

Checks element_count against the maximum representable size, and calculates the required Binary size.

  Returns

On success, returns the required Binary size as a uint32_t greater than or equal to BSON_VECTOR_HEADER_LEN. This length includes the 2-byte Vector header, but not the Binary subtype header or any other BSON headers. If the element_count is too large to represent, returns 0.

•   Errors:

        // Error "domain"
        #define BSON_ERROR_VECTOR 4

  bson_vector_error_code_t

BSON Error codes for BSON Binary Vector subtype operations that could fail in multiple ways.

  Synopsis

    #define BSON_ERROR_VECTOR 4
    typedef enum {
      BSON_VECTOR_ERROR_ARRAY_ELEMENT_TYPE = 1,
      BSON_VECTOR_ERROR_ARRAY_ELEMENT_VALUE = 2,
      BSON_VECTOR_ERROR_ARRAY_KEY = 3,
      BSON_VECTOR_ERROR_MAX_SIZE = 4,
    } bson_vector_error_code_t;

  Description

The error code values in bson_vector_error_code_t apply to bson_error_t values with a category of BSON_ERROR_CATEGORY and a domain of BSON_ERROR_VECTOR.

•   BSON_VECTOR_ERROR_ARRAY_ELEMENT_TYPE: An element was encountered with incorrect type. Location and type details in message.

•   BSON_VECTOR_ERROR_ARRAY_ELEMENT_VALUE: An element was encountered with out-of-range value. Location and value details in message.

•   BSON_VECTOR_ERROR_ARRAY_KEY: An input BSON Array did not contain the expected numeric key value. Expected and actual keys in message.

•   BSON_VECTOR_ERROR_MAX_SIZE: The BSON maximum document size would be exceeded. Equivalent to a failure from bson_append_* functions that do not return an error.

  Libbson Versioning

Versioning Macros and Functions

  Macros

The following preprocessor macros can be used to perform various checks based on the version of the library you are compiling against. This may be useful if you only want to enable a feature on a certain version of the library.

  Synopsis

    #define BSON_CHECK_VERSION(major, minor, micro)
    #define BSON_MAJOR_VERSION (1)
    #define BSON_MINOR_VERSION (4)
    #define BSON_MICRO_VERSION (1)
    #define BSON_VERSION_S "1.4.1"
    #define BSON_VERSION_HEX                                  \
       (BSON_MAJOR_VERSION << 24 | BSON_MINOR_VERSION << 16 | \
        BSON_MICRO_VERSION << 8)

Only compile a block on Libbson 1.1.0 and newer.

    #if BSON_CHECK_VERSION(1, 1, 0)
    static void
    do_something (void)
    {
    }
    #endif

  Libbson Legacy Extended JSON

libbson can produce a non-portable Legacy Extended JSON format.

WARNING: Use of the Legacy Extended JSON format is discouraged. Prefer Canonical Extended JSON or Relaxed Extended JSON for portability.

MongoDB Extended JSON (v2) describes the preferred Relaxed Extended JSON format and Canonical Extended Formats

libbson's Legacy Extended JSON format matches Relaxed Extended JSON with the following exceptions. Notation is borrowed from MongoDB Extended JSON (v2):
Type | Legacy Extended JSON
Binary | { "$binary": "<payload>", "$type": "<t>" }
Date | { "$date" : "<millis>" }
Regular Expression | { "$regex" : "<regexPattern>", "$options" : "<options>" }
DBPointer (deprecated) | { "$ref" : "<collection namespace>", "$id" : "<ObjectId bytes>" }
Symbol (deprecated) | "<string>"
Double infinity | infinity or inf without quotes. Implementation defined. Produces invalid JSON.
Double NaN | nan or nan(n-char-sequence). Implementation defined. Produces invalid JSON.

AUTHOR
MongoDB, Inc

COPYRIGHT
2009-present, MongoDB, Inc.