+(** {3 Bitstring manipulation} *)
+
+val bitstring_length : bitstring -> int
+(** [bitstring_length bitstring] returns the length of
+ the bitstring in bits.
+
+ Note this just returns the third field in the {!bitstring} tuple. *)
+
+val subbitstring : bitstring -> int -> int -> bitstring
+(** [subbitstring bits off len] returns a sub-bitstring
+ of the bitstring, starting at offset [off] bits and
+ with length [len] bits.
+
+ If the original bitstring is not long enough to do this
+ then the function raises [Invalid_argument "subbitstring"].
+
+ Note that this function just changes the offset and length
+ fields of the {!bitstring} tuple, so is very efficient. *)
+
+val dropbits : int -> bitstring -> bitstring
+(** Drop the first n bits of the bitstring and return a new
+ bitstring which is shorter by n bits.
+
+ If the length of the original bitstring is less than n bits,
+ this raises [Invalid_argument "dropbits"].
+
+ Note that this function just changes the offset and length
+ fields of the {!bitstring} tuple, so is very efficient. *)
+
+val takebits : int -> bitstring -> bitstring
+(** Take the first n bits of the bitstring and return a new
+ bitstring which is exactly n bits long.
+
+ If the length of the original bitstring is less than n bits,
+ this raises [Invalid_argument "takebits"].
+
+ Note that this function just changes the offset and length
+ fields of the {!bitstring} tuple, so is very efficient. *)
+
+(** {3 Constructing bitstrings} *)