+let extract_int32_le_unsigned data off len flen =
+ let v, off, len = extract_int32_be_unsigned data off len flen in
+ let v = I32.byteswap v flen in
+ v, off, len
+
+let extract_int32_ne_unsigned =
+ if nativeendian = BigEndian
+ then extract_int32_be_unsigned
+ else extract_int32_le_unsigned
+
+let _make_int64_be c0 c1 c2 c3 c4 c5 c6 c7 =
+ Int64.logor
+ (Int64.logor
+ (Int64.logor
+ (Int64.logor
+ (Int64.logor
+ (Int64.logor
+ (Int64.logor
+ (Int64.shift_left c0 56)
+ (Int64.shift_left c1 48))
+ (Int64.shift_left c2 40))
+ (Int64.shift_left c3 32))
+ (Int64.shift_left c4 24))
+ (Int64.shift_left c5 16))
+ (Int64.shift_left c6 8))
+ c7
+
+let _make_int64_le c0 c1 c2 c3 c4 c5 c6 c7 =
+ _make_int64_be c7 c6 c5 c4 c3 c2 c1 c0
+
+(* Extract [1..64] bits. We have to consider endianness and signedness. *)
+let extract_int64_be_unsigned data off len flen =
+ let byteoff = off lsr 3 in
+
+ let strlen = String.length data in
+
+ let word =
+ (* Optimize the common (byte-aligned) case. *)
+ if off land 7 = 0 then (
+ let word =
+ let c0 = _get_byte64 data byteoff strlen in
+ let c1 = _get_byte64 data (byteoff+1) strlen in
+ let c2 = _get_byte64 data (byteoff+2) strlen in
+ let c3 = _get_byte64 data (byteoff+3) strlen in
+ let c4 = _get_byte64 data (byteoff+4) strlen in
+ let c5 = _get_byte64 data (byteoff+5) strlen in
+ let c6 = _get_byte64 data (byteoff+6) strlen in
+ let c7 = _get_byte64 data (byteoff+7) strlen in
+ _make_int64_be c0 c1 c2 c3 c4 c5 c6 c7 in
+ Int64.shift_right_logical word (64 - flen)
+ ) else (
+ (* Extract the next 64 bits, slow method. *)
+ let word =
+ let c0, off, len = extract_char_unsigned data off len 8 in
+ let c1, off, len = extract_char_unsigned data off len 8 in
+ let c2, off, len = extract_char_unsigned data off len 8 in
+ let c3, off, len = extract_char_unsigned data off len 8 in
+ let c4, off, len = extract_char_unsigned data off len 8 in
+ let c5, off, len = extract_char_unsigned data off len 8 in
+ let c6, off, len = extract_char_unsigned data off len 8 in
+ let c7, _, _ = extract_char_unsigned data off len 8 in
+ let c0 = Int64.of_int c0 in
+ let c1 = Int64.of_int c1 in
+ let c2 = Int64.of_int c2 in
+ let c3 = Int64.of_int c3 in
+ let c4 = Int64.of_int c4 in
+ let c5 = Int64.of_int c5 in
+ let c6 = Int64.of_int c6 in
+ let c7 = Int64.of_int c7 in
+ _make_int64_be c0 c1 c2 c3 c4 c5 c6 c7 in
+ Int64.shift_right_logical word (64 - flen)
+ ) in
+ word, off+flen, len-flen
+
+let extract_int64_le_unsigned data off len flen =
+ let byteoff = off lsr 3 in
+
+ let strlen = String.length data in
+
+ let word =
+ (* Optimize the common (byte-aligned) case. *)
+ if off land 7 = 0 then (
+ let word =
+ let c0 = _get_byte64 data byteoff strlen in
+ let c1 = _get_byte64 data (byteoff+1) strlen in
+ let c2 = _get_byte64 data (byteoff+2) strlen in
+ let c3 = _get_byte64 data (byteoff+3) strlen in
+ let c4 = _get_byte64 data (byteoff+4) strlen in
+ let c5 = _get_byte64 data (byteoff+5) strlen in
+ let c6 = _get_byte64 data (byteoff+6) strlen in
+ let c7 = _get_byte64 data (byteoff+7) strlen in
+ _make_int64_le c0 c1 c2 c3 c4 c5 c6 c7 in
+ Int64.logand word (I64.mask flen)
+ ) else (
+ (* Extract the next 64 bits, slow method. *)
+ let word =
+ let c0, off, len = extract_char_unsigned data off len 8 in
+ let c1, off, len = extract_char_unsigned data off len 8 in
+ let c2, off, len = extract_char_unsigned data off len 8 in
+ let c3, off, len = extract_char_unsigned data off len 8 in
+ let c4, off, len = extract_char_unsigned data off len 8 in
+ let c5, off, len = extract_char_unsigned data off len 8 in
+ let c6, off, len = extract_char_unsigned data off len 8 in
+ let c7, _, _ = extract_char_unsigned data off len 8 in
+ let c0 = Int64.of_int c0 in
+ let c1 = Int64.of_int c1 in
+ let c2 = Int64.of_int c2 in
+ let c3 = Int64.of_int c3 in
+ let c4 = Int64.of_int c4 in
+ let c5 = Int64.of_int c5 in
+ let c6 = Int64.of_int c6 in
+ let c7 = Int64.of_int c7 in
+ _make_int64_le c0 c1 c2 c3 c4 c5 c6 c7 in
+ Int64.logand word (I64.mask flen)
+ ) in
+ word, off+flen, len-flen
+
+let extract_int64_ne_unsigned =
+ if nativeendian = BigEndian
+ then extract_int64_be_unsigned
+ else extract_int64_le_unsigned
+
+(*----------------------------------------------------------------------*)
+(* Constructor functions. *)
+
+module Buffer = struct
+ type t = {
+ buf : Buffer.t;
+ mutable len : int; (* Length in bits. *)
+ (* Last byte in the buffer (if len is not aligned). We store
+ * it outside the buffer because buffers aren't mutable.
+ *)
+ mutable last : int;
+ }
+
+ let create () =
+ (* XXX We have almost enough information in the generator to
+ * choose a good initial size.
+ *)
+ { buf = Buffer.create 128; len = 0; last = 0 }
+
+ let contents { buf = buf; len = len; last = last } =
+ let data =
+ if len land 7 = 0 then
+ Buffer.contents buf
+ else
+ Buffer.contents buf ^ (String.make 1 (Char.chr last)) in
+ data, 0, len
+
+ (* Add exactly 8 bits. *)
+ let add_byte ({ buf = buf; len = len; last = last } as t) byte =
+ if byte < 0 || byte > 255 then invalid_arg "Bitmatch.Buffer.add_byte";
+ let shift = len land 7 in
+ if shift = 0 then
+ (* Target buffer is byte-aligned. *)
+ Buffer.add_char buf (Char.chr byte)
+ else (
+ (* Target buffer is unaligned. 'last' is meaningful. *)
+ let first = byte lsr shift in
+ let second = (byte lsl (8 - shift)) land 0xff in
+ Buffer.add_char buf (Char.chr (last lor first));
+ t.last <- second
+ );
+ t.len <- t.len + 8
+
+ (* Add exactly 1 bit. *)
+ let add_bit ({ buf = buf; len = len; last = last } as t) bit =
+ let shift = 7 - (len land 7) in
+ if shift > 0 then
+ (* Somewhere in the middle of 'last'. *)
+ t.last <- last lor ((if bit then 1 else 0) lsl shift)
+ else (
+ (* Just a single spare bit in 'last'. *)
+ let last = last lor if bit then 1 else 0 in
+ Buffer.add_char buf (Char.chr last);
+ t.last <- 0
+ );
+ t.len <- len + 1
+
+ (* Add a small number of bits (definitely < 8). This uses a loop
+ * to call add_bit so it's slow.
+ *)
+ let _add_bits t c slen =
+ if slen < 1 || slen >= 8 then invalid_arg "Bitmatch.Buffer._add_bits";
+ for i = slen-1 downto 0 do
+ let bit = c land (1 lsl i) <> 0 in
+ add_bit t bit
+ done
+
+ let add_bits ({ buf = buf; len = len } as t) str slen =
+ if slen > 0 then (
+ if len land 7 = 0 then (
+ if slen land 7 = 0 then
+ (* Common case - everything is byte-aligned. *)
+ Buffer.add_substring buf str 0 (slen lsr 3)
+ else (
+ (* Target buffer is aligned. Copy whole bytes then leave the
+ * remaining bits in last.
+ *)
+ 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))
+ );
+ 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.
+ *
+ * XXX This is going to be dog-slow.
+ *)
+ let slenbytes = slen lsr 3 in
+ for i = 0 to slenbytes-1 do
+ let byte = Char.code str.[i] in
+ add_byte t byte
+ done;
+ _add_bits t (Char.code str.[slenbytes]) (slen - (slenbytes lsl 3))
+ );
+ )
+end
+
+(* Construct a single bit. *)
+let construct_bit buf b _ _ =
+ Buffer.add_bit buf b
+
+(* Construct a field, flen = [2..8]. *)
+let construct_char_unsigned buf v flen exn =
+ let max_val = 1 lsl flen in
+ if v < 0 || v >= max_val then raise exn;
+ if flen = 8 then
+ Buffer.add_byte buf v
+ else
+ Buffer._add_bits buf v flen
+
+(* Construct a field of up to 31 bits. *)
+let construct_int_be_unsigned buf v flen exn =
+ (* Check value is within range. *)
+ if not (I.range_unsigned v flen) then raise exn;
+ (* Add the bytes. *)
+ I.map_bytes_be (Buffer._add_bits buf) (Buffer.add_byte buf) v flen
+
+let construct_int_ne_unsigned =
+ if nativeendian = BigEndian
+ then construct_int_be_unsigned
+ else (*construct_int_le_unsigned*)
+ fun _ _ _ _ -> failwith "construct_int_le_unsigned"
+
+(* Construct a field of exactly 32 bits. *)
+let construct_int32_be_unsigned buf v flen _ =
+ Buffer.add_byte buf
+ (Int32.to_int (Int32.shift_right_logical v 24));
+ 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.logand (Int32.shift_right_logical v 8) 0xff_l)));
+ Buffer.add_byte buf
+ (Int32.to_int (Int32.logand v 0xff_l))
+
+let construct_int32_ne_unsigned =
+ if nativeendian = BigEndian
+ then construct_int32_be_unsigned
+ else (*construct_int32_le_unsigned*)
+ fun _ _ _ _ -> failwith "construct_int32_le_unsigned"
+
+(* Construct a field of up to 64 bits. *)
+let construct_int64_be_unsigned buf v flen exn =
+ (* Check value is within range. *)
+ if not (I64.range_unsigned v flen) then raise exn;
+ (* Add the bytes. *)
+ I64.map_bytes_be (Buffer._add_bits buf) (Buffer.add_byte buf) v flen
+
+let construct_int64_ne_unsigned =
+ if nativeendian = BigEndian
+ then construct_int64_be_unsigned
+ else (*construct_int64_le_unsigned*)
+ fun _ _ _ _ -> failwith "construct_int64_le_unsigned"
+
+(* Construct from a string of bytes, exact multiple of 8 bits
+ * in length of course.
+ *)
+let construct_string buf str =
+ let len = String.length str in
+ Buffer.add_bits buf str (len lsl 3)
+
+(*----------------------------------------------------------------------*)
+(* Extract a string from a bitstring. *)
+
+let string_of_bitstring (data, off, len) =
+ if off land 7 = 0 && len land 7 = 0 then
+ (* Easy case: everything is byte-aligned. *)
+ String.sub data (off lsr 3) (len lsr 3)
+ else (
+ (* Bit-twiddling case. *)
+ let strlen = (len + 7) lsr 3 in
+ let str = String.make strlen '\000' in
+ let rec loop data off len i =
+ if len >= 8 then (
+ let c, off, len = extract_char_unsigned data off len 8 in
+ 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
+ )
+ in
+ loop data off len 0;
+ str
+ )
+
+(* To channel. *)
+
+let bitstring_to_chan ((data, off, len) as bits) chan =
+ (* Fail if the bitstring length isn't a multiple of 8. *)
+ if len land 7 <> 0 then invalid_arg "bitstring_to_chan";
+
+ if off land 7 = 0 then
+ (* Easy case: string is byte-aligned. *)
+ output chan data (off lsr 3) (len lsr 3)
+ else (
+ (* Bit-twiddling case: reuse string_of_bitstring *)
+ let str = string_of_bitstring bits in
+ output_string chan str
+ )
+
+let bitstring_to_file bits filename =
+ let chan = open_out_bin filename in
+ try
+ bitstring_to_chan bits chan;
+ close_out chan
+ with exn ->
+ close_out chan;
+ raise exn