X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=bitmatch.ml;h=2d1992b35840b3ce1148154df534f6db18451c98;hb=17eb38a5f2bc6e26634314dd7070ae4407924518;hp=2cba403cf1254a1f1eec03dc151118251e365c03;hpb=3be31e79a87b15872a222d11714e1dc4046fad4d;p=ocaml-bitstring.git

diff --git a/bitmatch.ml b/bitmatch.ml
index 2cba403..2d1992b 100644
--- a/bitmatch.ml
+++ b/bitmatch.ml
@@ -1,545 +1,27 @@
-(* Bitmatch library.
- * $Id: bitmatch.ml,v 1.6 2008-04-01 19:10:45 rjones Exp $
- *)
-
-open Printf
-
-(* Enable runtime debug messages.  Must also have been enabled
- * in pa_bitmatch.ml.
- *)
-let debug = ref false
-
-(* Exceptions. *)
-exception Construct_failure of string * string * int * int
-
-(* A bitstring is simply the data itself (as a string), and the
- * bitoffset and the bitlength within the string.  Note offset/length
- * are counted in bits, not bytes.
- *)
-type bitstring = string * int * int
-
-(* 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 create_bitstring len = make_bitstring len '\000'
-
-let bitstring_of_chan chan =
-  let tmpsize = 16384 in
-  let buf = Buffer.create tmpsize in
-  let tmp = String.create tmpsize in
-  let n = ref 0 in
-  while n := input chan 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 fname =
-  let chan = open_in_bin fname in
-  let bs = bitstring_of_chan chan in
-  close_in chan;
-  bs
-
-let bitstring_length (_, _, len) = len
-
-(*----------------------------------------------------------------------*)
-(* Bitwise functions.
+(** Bitmatch backwards compatibility library. *)
+(* Bitstring library.
+ * Copyright (C) 2008 Red Hat Inc., Richard W.M. Jones
  *
- * 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)
-  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
-      minus_one
-
-  (* 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
-    )
-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 pred = Int32.pred
-  let max_int = Int32.max_int
-  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
-      minus_one
-
-  (* 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
-    )
-end
-
-(*----------------------------------------------------------------------*)
-(* Extraction functions.
+ * 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,
+ * with the OCaml linking exception described in COPYING.LIB.
  *
- * NB: internal functions, called from the generated macros, and
- * the parameters should have been checked for sanity already).
- *)
-
-(* Bitstrings. *)
-let extract_bitstring data off len flen =
-  (data, off, flen), off+flen, len-flen
-
-let extract_remainder data off len =
-  (data, off, len), off+len, 0
-
-(* Extract and convert to numeric.  A single bit is returned as
- * a boolean.  There are no endianness or signedness considerations.
- *)
-let extract_bit data off len _ =	(* final param is always 1 *)
-  let byteoff = off lsr 3 in
-  let bitmask = 1 lsl (7 - (off land 7)) in
-  let b = Char.code data.[byteoff] land bitmask <> 0 in
-  b, off+1, len-1
-
-(* Returns 8 bit unsigned aligned bytes from the string.
- * If the string ends then this returns 0's.
- *)
-let _get_byte data byteoff strlen =
-  if strlen > byteoff then Char.code data.[byteoff] else 0
-let _get_byte32 data byteoff strlen =
-  if strlen > byteoff then Int32.of_int (Char.code data.[byteoff]) else 0l
-let _get_byte64 data byteoff strlen =
-  if strlen > byteoff then Int64.of_int (Char.code data.[byteoff]) else 0L
-
-(* Extract [2..8] bits.  Because the result fits into a single
- * byte we don't have to worry about endianness, only signedness.
+ * 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
+ *
+ * $Id$
  *)
-let extract_char_unsigned data off len flen =
-  let byteoff = off lsr 3 in
-
-  (* Optimize the common (byte-aligned) case. *)
-  if off land 7 = 0 then (
-    let byte = Char.code data.[byteoff] in
-    byte lsr (8 - flen), off+flen, len-flen
-  ) else (
-    (* Extract the 16 bits at byteoff and byteoff+1 (note that the
-     * second byte might not exist in the original string).
-     *)
-    let strlen = String.length data in
-
-    let word =
-      (_get_byte data byteoff strlen lsl 8) +
-	_get_byte data (byteoff+1) strlen in
-
-    (* Mask off the top bits. *)
-    let bitmask = (1 lsl (16 - (off land 7))) - 1 in
-    let word = word land bitmask in
-    (* Shift right to get rid of the bottom bits. *)
-    let shift = 16 - ((off land 7) + flen) in
-    let word = word lsr shift in
-
-    word, off+flen, len-flen
-  )
-
-(* Extract [9..31] bits.  We have to consider endianness and signedness. *)
-let extract_int_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 =
-	(_get_byte data byteoff strlen lsl 23) +
-	  (_get_byte data (byteoff+1) strlen lsl 15) +
-	  (_get_byte data (byteoff+2) strlen lsl 7) +
-	  (_get_byte data (byteoff+3) strlen lsr 1) in
-      word lsr (31 - flen)
-    ) else if flen <= 24 then (
-      (* Extract the 31 bits at byteoff .. byteoff+3. *)
-      let word =
-	(_get_byte data byteoff strlen lsl 23) +
-	  (_get_byte data (byteoff+1) strlen lsl 15) +
-	  (_get_byte data (byteoff+2) strlen lsl 7) +
-	  (_get_byte data (byteoff+3) strlen lsr 1) in
-      (* Mask off the top bits. *)
-      let bitmask = (1 lsl (31 - (off land 7))) - 1 in
-      let word = word land bitmask in
-      (* Shift right to get rid of the bottom bits. *)
-      let shift = 31 - ((off land 7) + flen) in
-      word lsr shift
-    ) else (
-      (* Extract the next 31 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 7 in
-	(c0 lsl 23) + (c1 lsl 15) + (c2 lsl 7) + c3 in
-      word lsr (31 - flen)
-    ) 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 _make_int32_be c0 c1 c2 c3 =
-  Int32.logor
-    (Int32.logor
-       (Int32.logor
-	  (Int32.shift_left c0 24)
-	  (Int32.shift_left c1 16))
-       (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
-
-  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_byte32 data byteoff strlen in
-	let c1 = _get_byte32 data (byteoff+1) strlen in
-	let c2 = _get_byte32 data (byteoff+2) strlen in
-	let c3 = _get_byte32 data (byteoff+3) strlen in
-	_make_int32_be c0 c1 c2 c3 in
-      Int32.shift_right_logical word (32 - flen)
-    ) else (
-      (* Extract the next 32 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, _, _ = extract_char_unsigned data off len 8 in
-	let c0 = Int32.of_int c0 in
-	let c1 = Int32.of_int c1 in
-	let c2 = Int32.of_int c2 in
-	let c3 = Int32.of_int c3 in
-	_make_int32_be c0 c1 c2 c3 in
-      Int32.shift_right_logical word (32 - flen)
-    ) 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 _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
-
-(* 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
-
-(*----------------------------------------------------------------------*)
-(* 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
-
-(* 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 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;
-
-  (* 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
-
-(*----------------------------------------------------------------------*)
-(* Display functions. *)
-
-let isprint c =
-  let c = Char.code c in
-  c >= 32 && c < 127
-
-let hexdump_bitstring chan (data, off, len) =
-  let count = ref 0 in
-  let off = ref off in
-  let len = ref len in
-  let linelen = ref 0 in
-  let linechars = String.make 16 ' ' in
-
-  fprintf chan "00000000  ";
-
-  while !len > 0 do
-    let bits = min !len 8 in
-    let byte, off', len' = extract_char_unsigned data !off !len bits in
-    off := off'; len := len';
-
-    let byte = byte lsl (8-bits) in
-    fprintf chan "%02x " byte;
-
-    incr count;
-    linechars.[!linelen] <-
-      (let c = Char.chr byte in
-       if isprint c then c else '.');
-    incr linelen;
-    if !linelen = 8 then fprintf chan " ";
-    if !linelen = 16 then (
-      fprintf chan " |%s|\n%08x  " linechars !count;
-      linelen := 0;
-      for i = 0 to 15 do linechars.[i] <- ' ' done
-    )
-  done;
+(** This is just for backwards compatibility with code
+    from when the library was called bitmatch.  You should
+    replace all references to this module with {!Bitstring}.
+*)
 
-  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
-  ) else
-    fprintf chan "\n%!"
+include Bitstring