X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=bitmatch.mli;h=672cb391f39c77ec432625da0e0cb480815cec92;hb=9598ebddee3b74b88aefcd3b47af8cf32dd8e096;hp=979e591aac783b5bfe64f36e38eaccf4076e00e2;hpb=97cd7dd22059a1c5ca72852130ac430aa713e968;p=ocaml-bitstring.git

diff --git a/bitmatch.mli b/bitmatch.mli
index 979e591..672cb39 100644
--- a/bitmatch.mli
+++ b/bitmatch.mli
@@ -634,7 +634,35 @@ val string_of_bitstring : bitstring -> string
     This function is inefficient.  In the best case when the bitstring
     is nicely byte-aligned we do a [String.sub] operation.  If the
     bitstring isn't aligned then this involves a lot of bit twiddling
-    and is particularly inefficient. *)
+    and is particularly inefficient.
+
+    If the bitstring is not a multiple of 8 bits wide then the
+    final byte of the string contains the high bits set to the
+    remaining bits and the low bits set to 0. *)
+
+val bitstring_to_file : bitstring -> string -> unit
+(** [bitstring_to_file bits filename] writes the bitstring [bits]
+    to the file [filename].  It overwrites the output file.
+
+    Some restrictions apply, see {!bitstring_to_chan}. *)
+
+val bitstring_to_chan : bitstring -> out_channel -> unit
+(** [bitstring_to_file bits filename] writes the bitstring [bits]
+    to the channel [chan].
+
+    Channels are made up of bytes, bitstrings can be any bit length
+    including fractions of bytes.  So this function only works
+    if the length of the bitstring is an exact multiple of 8 bits
+    (otherwise it raises [Invalid_argument "bitstring_to_chan"]).
+
+    Furthermore the function is efficient only in the case where
+    the bitstring is stored fully aligned, otherwise it has to
+    do inefficient bit twiddling like {!string_of_bitstring}.
+
+    In the common case where the bitstring was generated by the
+    [BITSTRING] operator and is an exact multiple of 8 bits wide,
+    then this function will always work efficiently.
+*)
 
 (** {3 Printing bitstrings} *)