(* Bitmatch library.
- * $Id: bitmatch.ml,v 1.5 2008-04-01 17:05:37 rjones Exp $
+ * Copyright (C) 2008 Red Hat Inc., Richard W.M. Jones
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * $Id$
*)
open Printf
+include Bitmatch_types
+include Bitmatch_config
+
(* Enable runtime debug messages. Must also have been enabled
* in pa_bitmatch.ml.
*)
let create_bitstring len = make_bitstring len '\000'
+let bitstring_of_string str = str, 0, String.length str lsl 3
+
let bitstring_of_chan chan =
let tmpsize = 16384 in
let buf = Buffer.create tmpsize in
done;
Buffer.contents buf, 0, Buffer.length buf lsl 3
+let bitstring_of_chan_max chan max =
+ let tmpsize = 16384 in
+ let buf = Buffer.create tmpsize in
+ let tmp = String.create tmpsize in
+ let len = ref 0 in
+ let rec loop () =
+ if !len < max then (
+ let r = min tmpsize (max - !len) in
+ let n = input chan tmp 0 r in
+ if n > 0 then (
+ Buffer.add_substring buf tmp 0 n;
+ len := !len + n;
+ loop ()
+ )
+ )
+ in
+ loop ();
+ Buffer.contents buf, 0, !len lsl 3
+
+let bitstring_of_file_descr fd =
+ let tmpsize = 16384 in
+ let buf = Buffer.create tmpsize in
+ let tmp = String.create tmpsize in
+ let n = ref 0 in
+ while n := Unix.read fd tmp 0 tmpsize; !n > 0 do
+ Buffer.add_substring buf tmp 0 !n;
+ done;
+ Buffer.contents buf, 0, Buffer.length buf lsl 3
+
+let bitstring_of_file_descr_max fd max =
+ let tmpsize = 16384 in
+ let buf = Buffer.create tmpsize in
+ let tmp = String.create tmpsize in
+ let len = ref 0 in
+ let rec loop () =
+ if !len < max then (
+ let r = min tmpsize (max - !len) in
+ let n = Unix.read fd tmp 0 r in
+ if n > 0 then (
+ Buffer.add_substring buf tmp 0 n;
+ len := !len + n;
+ loop ()
+ )
+ )
+ in
+ loop ();
+ Buffer.contents buf, 0, !len lsl 3
+
let bitstring_of_file fname =
let chan = open_in_bin fname in
- let bs = bitstring_of_chan chan in
- close_in chan;
- bs
+ try
+ let bs = bitstring_of_chan chan in
+ close_in chan;
+ bs
+ with exn ->
+ close_in chan;
+ raise exn
let bitstring_length (_, _, len) = len
(*----------------------------------------------------------------------*)
+(* Bitwise functions.
+ *
+ * We try to isolate all bitwise functions within these modules.
+ *)
+
+module I = struct
+ (* Bitwise operations on ints. Note that we assume int <= 31 bits. *)
+ let (<<) = (lsl)
+ let (>>) = (lsr)
+ external to_int : int -> int = "%identity"
+ let zero = 0
+ let one = 1
+ let minus_one = -1
+ let ff = 0xff
+
+ (* Create a mask so many bits wide. *)
+ let mask bits =
+ if bits < 30 then
+ pred (one << bits)
+ else if bits = 30 then
+ max_int
+ else if bits = 31 then
+ minus_one
+ else
+ invalid_arg "Bitmatch.I.mask"
+
+ (* Byte swap an int of a given size. *)
+ let byteswap v bits =
+ if bits <= 8 then v
+ else if bits <= 16 then (
+ let shift = bits-8 in
+ let v1 = v >> shift in
+ let v2 = (v land (mask shift)) << 8 in
+ v2 lor v1
+ ) else if bits <= 24 then (
+ let shift = bits - 16 in
+ let v1 = v >> (8+shift) in
+ let v2 = ((v >> shift) land ff) << 8 in
+ let v3 = (v land (mask shift)) << 16 in
+ v3 lor v2 lor v1
+ ) else (
+ let shift = bits - 24 in
+ let v1 = v >> (16+shift) in
+ let v2 = ((v >> (8+shift)) land ff) << 8 in
+ let v3 = ((v >> shift) land ff) << 16 in
+ let v4 = (v land (mask shift)) << 24 in
+ v4 lor v3 lor v2 lor v1
+ )
+
+ (* Check a value is in range 0 .. 2^bits-1. *)
+ let range_unsigned v bits =
+ let mask = lnot (mask bits) in
+ (v land mask) = zero
+
+ (* Call function g on the top bits, then f on each full byte
+ * (big endian - so start at top).
+ *)
+ let rec map_bytes_be g f v bits =
+ if bits >= 8 then (
+ map_bytes_be g f (v >> 8) (bits-8);
+ let lsb = v land ff in
+ f (to_int lsb)
+ ) else if bits > 0 then (
+ let lsb = v land (mask bits) in
+ g (to_int lsb) bits
+ )
+end
+
+module I32 = struct
+ (* Bitwise operations on int32s. Note we try to keep it as similar
+ * as possible to the I module above, to make it easier to track
+ * down bugs.
+ *)
+ let (<<) = Int32.shift_left
+ let (>>) = Int32.shift_right_logical
+ let (land) = Int32.logand
+ let (lor) = Int32.logor
+ let lnot = Int32.lognot
+ let pred = Int32.pred
+ let max_int = Int32.max_int
+ let to_int = Int32.to_int
+ let zero = Int32.zero
+ let one = Int32.one
+ let minus_one = Int32.minus_one
+ let ff = 0xff_l
+
+ (* Create a mask so many bits wide. *)
+ let mask bits =
+ if bits < 31 then
+ pred (one << bits)
+ else if bits = 31 then
+ max_int
+ else if bits = 32 then
+ minus_one
+ else
+ invalid_arg "Bitmatch.I32.mask"
+
+ (* Byte swap an int of a given size. *)
+ let byteswap v bits =
+ if bits <= 8 then v
+ else if bits <= 16 then (
+ let shift = bits-8 in
+ let v1 = v >> shift in
+ let v2 = (v land (mask shift)) << 8 in
+ v2 lor v1
+ ) else if bits <= 24 then (
+ let shift = bits - 16 in
+ let v1 = v >> (8+shift) in
+ let v2 = ((v >> shift) land ff) << 8 in
+ let v3 = (v land (mask shift)) << 16 in
+ v3 lor v2 lor v1
+ ) else (
+ let shift = bits - 24 in
+ let v1 = v >> (16+shift) in
+ let v2 = ((v >> (8+shift)) land ff) << 8 in
+ let v3 = ((v >> shift) land ff) << 16 in
+ let v4 = (v land (mask shift)) << 24 in
+ v4 lor v3 lor v2 lor v1
+ )
+
+ (* Check a value is in range 0 .. 2^bits-1. *)
+ let range_unsigned v bits =
+ let mask = lnot (mask bits) in
+ (v land mask) = zero
+
+ (* Call function g on the top bits, then f on each full byte
+ * (big endian - so start at top).
+ *)
+ let rec map_bytes_be g f v bits =
+ if bits >= 8 then (
+ map_bytes_be g f (v >> 8) (bits-8);
+ let lsb = v land ff in
+ f (to_int lsb)
+ ) else if bits > 0 then (
+ let lsb = v land (mask bits) in
+ g (to_int lsb) bits
+ )
+end
+
+module I64 = struct
+ (* Bitwise operations on int64s. Note we try to keep it as similar
+ * as possible to the I/I32 modules above, to make it easier to track
+ * down bugs.
+ *)
+ let (<<) = Int64.shift_left
+ let (>>) = Int64.shift_right_logical
+ let (land) = Int64.logand
+ let (lor) = Int64.logor
+ let lnot = Int64.lognot
+ let pred = Int64.pred
+ let max_int = Int64.max_int
+ let to_int = Int64.to_int
+ let zero = Int64.zero
+ let one = Int64.one
+ let minus_one = Int64.minus_one
+ let ff = 0xff_L
+
+ (* Create a mask so many bits wide. *)
+ let mask bits =
+ if bits < 63 then
+ pred (one << bits)
+ else if bits = 63 then
+ max_int
+ else if bits = 64 then
+ minus_one
+ else
+ invalid_arg "Bitmatch.I64.mask"
+
+ (* Byte swap an int of a given size. *)
+ (* let byteswap v bits = *)
+
+ (* Check a value is in range 0 .. 2^bits-1. *)
+ let range_unsigned v bits =
+ let mask = lnot (mask bits) in
+ (v land mask) = zero
+
+ (* Call function g on the top bits, then f on each full byte
+ * (big endian - so start at top).
+ *)
+ let rec map_bytes_be g f v bits =
+ if bits >= 8 then (
+ map_bytes_be g f (v >> 8) (bits-8);
+ let lsb = v land ff in
+ f (to_int lsb)
+ ) else if bits > 0 then (
+ let lsb = v land (mask bits) in
+ g (to_int lsb) bits
+ )
+end
+
+(*----------------------------------------------------------------------*)
(* Extraction functions.
*
* NB: internal functions, called from the generated macros, and
) in
word, off+flen, len-flen
+let extract_int_le_unsigned data off len flen =
+ let v, off, len = extract_int_be_unsigned data off len flen in
+ let v = I.byteswap v flen in
+ v, off, len
+
+let extract_int_ne_unsigned =
+ if nativeendian = BigEndian
+ 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
(Int32.shift_left c2 8))
c3
+let _make_int32_le c0 c1 c2 c3 =
+ Int32.logor
+ (Int32.logor
+ (Int32.logor
+ (Int32.shift_left c3 24)
+ (Int32.shift_left c2 16))
+ (Int32.shift_left c1 8))
+ c0
+
(* Extract exactly 32 bits. We have to consider endianness and signedness. *)
let extract_int32_be_unsigned data off len flen =
let byteoff = off lsr 3 in
) in
word, off+flen, len-flen
+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 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
(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
) 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
+
+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
(* Construct a single bit. *)
-let construct_bit buf b _ =
+let construct_bit buf b _ _ =
Buffer.add_bit buf b
(* Construct a field, flen = [2..8]. *)
else
Buffer._add_bits buf v flen
-(* Generate a mask with the lower 'bits' bits set. *)
-let mask64 bits =
- if bits < 63 then Int64.pred (Int64.shift_left 1L bits)
- else if bits = 63 then Int64.max_int
- else if bits = 64 then -1L
- else invalid_arg "Bitmatch.mask64"
+(* 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"
+
+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
+ (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_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
+
+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 =
(* Check value is within range. *)
- let m = Int64.lognot (mask64 flen) in
- if Int64.logand v m <> 0L then raise exn;
-
+ if not (I64.range_unsigned v flen) then raise exn;
(* Add the bytes. *)
- let rec loop v flen =
- if flen > 8 then (
- loop (Int64.shift_right_logical v 8) (flen-8);
- let lsb = Int64.to_int (Int64.logand v 0xffL) in
- Buffer.add_byte buf lsb
- ) else if flen > 0 then (
- let lsb = Int64.to_int (Int64.logand v (mask64 flen)) in
- Buffer._add_bits buf lsb flen
- )
- in
- loop v flen
+ 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"
+
+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 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 (
+ let c, _, _ = extract_char_unsigned data off len len in
+ str.[i] <- Char.chr (c lsl (8-len))
+ )
+ 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
(*----------------------------------------------------------------------*)
(* Display functions. *)
if !linelen > 0 then (
let skip = (16 - !linelen) * 3 + if !linelen < 8 then 1 else 0 in
for i = 0 to skip-1 do fprintf chan " " done;
- fprintf chan " |%s|\n" linechars
+ fprintf chan " |%s|\n%!" linechars
) else
- fprintf chan "\n"
+ fprintf chan "\n%!"
git.annexia.org / ocaml-bitstring.git / blobdiff