-(* Bitmatch library.
- * $Id: bitmatch.ml,v 1.4 2008-04-01 10:58:53 rjones Exp $
- *)
-
-open Printf
-
-(* 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
-
-(*----------------------------------------------------------------------*)
-(* Extraction functions.
+(** Bitmatch backwards compatibility library. *)
+(* Bitstring library.
+ * Copyright (C) 2008 Red Hat Inc., Richard W.M. Jones
*
- * 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 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.
+ *
+ * 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
-
-(* 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 =
- Int32.add
- (Int32.add
- (Int32.add
- (Int32.shift_left (_get_byte32 data byteoff strlen) 24)
- (Int32.shift_left (_get_byte32 data (byteoff+1) strlen) 16))
- (Int32.shift_left (_get_byte32 data (byteoff+2) strlen) 8))
- (_get_byte32 data (byteoff+3) strlen) in
- Int32.shift_right 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, off, len = extract_char_unsigned data off len 8 in
- let c0 = Int32.shift_left (Int32.of_int c0) 24 in
- let c1 = Int32.shift_left (Int32.of_int c1) 16 in
- let c2 = Int32.shift_left (Int32.of_int c2) 8 in
- let c3 = Int32.of_int c3 in
- Int32.add c0 (Int32.add c1 (Int32.add c2 c3)) in
- Int32.shift_right word (32 - flen)
- ) in
- word, off+flen, len-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
git.annexia.org / ocaml-bitstring.git / blobdiff