(* Functions to create and load bitstrings. *)
let empty_bitstring = "", 0, 0
-let make_bitstring len c = String.make ((len+7) lsr 3) c, 0, len
+let make_bitstring len c =
+ if len >= 0 then String.make ((len+7) lsr 3) c, 0, len
+ else
+ invalid_arg (
+ sprintf "make_bitstring/create_bitstring: len %d < 0" len
+ )
let create_bitstring len = make_bitstring len '\000'
+let zeroes_bitstring = create_bitstring
+
+let ones_bitstring len = make_bitstring len '\xff'
+
let bitstring_of_string str = str, 0, String.length str lsl 3
let bitstring_of_chan chan =
then extract_int_be_unsigned
else extract_int_le_unsigned
+let extract_int_ee_unsigned = function
+ | BigEndian -> extract_int_be_unsigned
+ | LittleEndian -> extract_int_le_unsigned
+ | NativeEndian -> extract_int_ne_unsigned
+
let _make_int32_be c0 c1 c2 c3 =
Int32.logor
(Int32.logor
then extract_int32_be_unsigned
else extract_int32_le_unsigned
+let extract_int32_ee_unsigned = function
+ | BigEndian -> extract_int32_be_unsigned
+ | LittleEndian -> extract_int32_le_unsigned
+ | NativeEndian -> extract_int32_ne_unsigned
+
let _make_int64_be c0 c1 c2 c3 c4 c5 c6 c7 =
Int64.logor
(Int64.logor
then extract_int64_be_unsigned
else extract_int64_le_unsigned
+let extract_int64_ee_unsigned = function
+ | BigEndian -> extract_int64_be_unsigned
+ | LittleEndian -> extract_int64_le_unsigned
+ | NativeEndian -> extract_int64_ne_unsigned
+
(*----------------------------------------------------------------------*)
(* Constructor functions. *)
*)
let slenbytes = slen lsr 3 in
if slenbytes > 0 then Buffer.add_substring buf str 0 slenbytes;
- t.last <- Char.code str.[slenbytes] lsl (8 - (slen land 7))
+ let last = Char.code str.[slenbytes] in (* last char *)
+ let mask = 0xff lsl (8 - (slen land 7)) in
+ t.last <- last land mask
);
t.len <- len + slen
) else (
(* Target buffer is unaligned. Copy whole bytes using
* add_byte which knows how to deal with an unaligned
- * target buffer, then call _add_bits for the remaining < 8 bits.
+ * target buffer, then call add_bit for the remaining < 8 bits.
*
* XXX This is going to be dog-slow.
*)
let byte = Char.code str.[i] in
add_byte t byte
done;
- _add_bits t (Char.code str.[slenbytes]) (slen - (slenbytes lsl 3))
+ let bitsleft = slen - (slenbytes lsl 3) in
+ if bitsleft > 0 then (
+ let c = Char.code str.[slenbytes] in
+ for i = 0 to bitsleft - 1 do
+ let bit = c land (0x80 lsr i) <> 0 in
+ add_bit t bit
+ done
+ )
);
)
end
else (*construct_int_le_unsigned*)
fun _ _ _ _ -> failwith "construct_int_le_unsigned"
+let construct_int_ee_unsigned = function
+ | BigEndian -> construct_int_be_unsigned
+ | LittleEndian -> (*construct_int_le_unsigned*)
+ (fun _ _ _ _ -> failwith "construct_int_le_unsigned")
+ | NativeEndian -> construct_int_ne_unsigned
+
(* Construct a field of exactly 32 bits. *)
let construct_int32_be_unsigned buf v flen _ =
Buffer.add_byte buf
Buffer.add_byte buf
(Int32.to_int (Int32.logand v 0xff_l))
+let construct_int32_le_unsigned buf v flen _ =
+ Buffer.add_byte buf
+ (Int32.to_int (Int32.logand v 0xff_l));
+ Buffer.add_byte buf
+ (Int32.to_int ((Int32.logand (Int32.shift_right_logical v 8) 0xff_l)));
+ Buffer.add_byte buf
+ (Int32.to_int ((Int32.logand (Int32.shift_right_logical v 16) 0xff_l)));
+ Buffer.add_byte buf
+ (Int32.to_int (Int32.shift_right_logical v 24))
+
let construct_int32_ne_unsigned =
if nativeendian = BigEndian
then construct_int32_be_unsigned
- else (*construct_int32_le_unsigned*)
- fun _ _ _ _ -> failwith "construct_int32_le_unsigned"
+ else construct_int32_le_unsigned
+
+let construct_int32_ee_unsigned = function
+ | BigEndian -> construct_int32_be_unsigned
+ | LittleEndian -> construct_int32_le_unsigned
+ | NativeEndian -> construct_int32_ne_unsigned
(* Construct a field of up to 64 bits. *)
let construct_int64_be_unsigned buf v flen exn =
else (*construct_int64_le_unsigned*)
fun _ _ _ _ -> failwith "construct_int64_le_unsigned"
+let construct_int64_ee_unsigned = function
+ | BigEndian -> construct_int64_be_unsigned
+ | LittleEndian -> (*construct_int64_le_unsigned*)
+ (fun _ _ _ _ -> failwith "construct_int64_le_unsigned")
+ | NativeEndian -> construct_int64_ne_unsigned
+
(* Construct from a string of bytes, exact multiple of 8 bits
* in length of course.
*)
let len = String.length str in
Buffer.add_bits buf str (len lsl 3)
+(* Construct from a bitstring. *)
+let construct_bitstring buf (data, off, len) =
+ (* Add individual bits until we get to the next byte boundary of
+ * the underlying string.
+ *)
+ let blen = 7 - ((off + 7) land 7) in
+ let blen = min blen len in
+ let rec loop off len blen =
+ if blen = 0 then (off, len)
+ else (
+ let b, off, len = extract_bit data off len 1 in
+ Buffer.add_bit buf b;
+ loop off len (blen-1)
+ )
+ in
+ let off, len = loop off len blen in
+ assert (len = 0 || (off land 7) = 0);
+
+ (* Add the remaining 'len' bits. *)
+ let data =
+ let off = off lsr 3 in
+ (* XXX dangerous allocation *)
+ if off = 0 then data
+ else String.sub data off (String.length data - off) in
+
+ Buffer.add_bits buf data len
+
(*----------------------------------------------------------------------*)
(* Extract a string from a bitstring. *)
str.[i] <- Char.chr c;
loop data off len (i+1)
) else if len > 0 then (
- (* XXX Is this correct? It should write into the high bits
- * of the last byte.
- *)
- let c, off, len = extract_char_unsigned data off len len in
- str.[i] <- Char.chr c
+ let c, _, _ = extract_char_unsigned data off len len in
+ str.[i] <- Char.chr (c lsl (8-len))
)
in
loop data off len 0;
git.annexia.org / ocaml-bitstring.git / blobdiff