X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=bitmatch.ml;h=249bbff7ee0b774b3e0e02ed80436c03ab6dc895;hb=9c50223e129d33742f2d172edff5761f8b4b8195;hp=ff537bf5f518d9fef9f5579794585aecd8d94309;hpb=becf8636190d443cc047c82d2464d7af72eeda2f;p=ocaml-bitstring.git

diff --git a/bitmatch.ml b/bitmatch.ml
index ff537bf..249bbff 100644
--- a/bitmatch.ml
+++ b/bitmatch.ml
@@ -4,7 +4,8 @@
  * 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.
+ * version 2 of the License, or (at your option) any later version,
+ * with the OCaml linking exception described in COPYING.LIB.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -15,11 +16,14 @@
  * 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: bitmatch.ml,v 1.11 2008-05-07 14:37:00 rjones Exp $
+ * $Id$
  *)
 
 open Printf
 
+include Bitmatch_types
+include Bitmatch_config
+
 (* Enable runtime debug messages.  Must also have been enabled
  * in pa_bitmatch.ml.
  *)
@@ -37,10 +41,19 @@ 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 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 =
@@ -103,9 +116,13 @@ let bitstring_of_file_descr_max fd max =
 
 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
 
@@ -408,6 +425,16 @@ let extract_int_le_unsigned data off len flen =
   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
@@ -463,6 +490,16 @@ let extract_int32_le_unsigned data off len flen =
   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
@@ -480,6 +517,9 @@ let _make_int64_be c0 c1 c2 c3 c4 c5 c6 c7 =
        (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
@@ -524,6 +564,59 @@ let extract_int64_be_unsigned data off len 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
+
+let extract_int64_ee_unsigned = function
+  | BigEndian -> extract_int64_be_unsigned
+  | LittleEndian -> extract_int64_le_unsigned
+  | NativeEndian -> extract_int64_ne_unsigned
+
 (*----------------------------------------------------------------------*)
 (* Constructor functions. *)
 
@@ -603,13 +696,15 @@ module Buffer = struct
 	   *)
 	  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.
 	 *)
@@ -618,13 +713,20 @@ module Buffer = struct
 	  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]. *)
@@ -643,6 +745,49 @@ let construct_int_be_unsigned buf v flen 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. *)
@@ -650,6 +795,18 @@ let construct_int64_be_unsigned buf v flen 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"
+
+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.
  *)
@@ -657,6 +814,33 @@ let construct_string buf str =
   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. *)
 
@@ -674,14 +858,38 @@ let string_of_bitstring (data, off, len) =
 	str.[i] <- Char.chr c;
 	loop data off len (i+1)
       ) else if len > 0 then (
-	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;
     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. *)