bson_iter_init_from_data_at_offset()#

Synopsis#

bool
bson_iter_init_from_data_at_offset (bson_iter_t *iter,
                                    const uint8_t *data,
                                    size_t length,
                                    uint32_t offset,
                                    uint32_t keylen);

Parameters#

iter: A bson_iter_t.
data: A buffer to initialize with. This is not validated.
length: The length of data in bytes. This is not validated.
offset: The offset of the field to start iterating. This is not validated. This should be an offset previously obtained from bson_iter_offset().
keylen: The string length of the key of the field to start iterating. This is not validated. This should be a length previously obtained from bson_iter_key_len().

Description#

Creates a bson_iter_t and starts iteration on a field at the offset.

bson_iter_init_from_data_at_offset() is useful for situations where the progress of a bson_iter_t must be saved and restored without relying on the bson_iter_t data layout. Saving the progress could be accomplished by:

Saving the current field’s key length with bson_iter_key_len()
Saving the current offset with bson_iter_offset()
Saving the data pointer of the iterated bson_t with bson_get_data()
Saving the data length of the iterated bson_t with the len struct field

Then later, these saved values can be passed to bson_iter_init_from_data_at_offset() to reconstruct the bson_iter_t in constant time.

Returns#

Returns true if the iter was successfully initialized.