X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=pa_bitmatch.ml;h=82818f6453c5b67c502bc5787c18aa9cfd119a78;hb=091a76c07b4ddd25c3459b7e6a9fd3e1245a57a7;hp=83bb5d4988ab5ea539a4dcfa3b6b26825a829a4e;hpb=edd992287c4ee26b6a16d39927649c80ede7f860;p=ocaml-bitstring.git diff --git a/pa_bitmatch.ml b/pa_bitmatch.ml index 83bb5d4..82818f6 100644 --- a/pa_bitmatch.ml +++ b/pa_bitmatch.ml @@ -15,7 +15,7 @@ * 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: pa_bitmatch.ml,v 1.11 2008-04-25 14:57:11 rjones Exp $ + * $Id$ *) open Printf @@ -24,6 +24,9 @@ open Camlp4.PreCast open Syntax open Ast +open Bitmatch +module P = Bitmatch_persistent + (* If this is true then we emit some debugging code which can * be useful to tell what is happening during matches. You * also need to do 'Bitmatch.debug := true' in your main program. @@ -32,26 +35,41 @@ open Ast *) let debug = false -(* A field when used in a bitmatch (a pattern). *) -type fpatt = { - fpatt : patt; (* field matching pattern *) - fpc : fcommon; -} -(* A field when used in a BITSTRING constructor (an expression). *) -and fexpr = { - fexpr : expr; (* field value *) - fec : fcommon; -} - -and fcommon = { - flen : expr; (* length in bits, may be non-const *) - endian : endian; (* endianness *) - signed : bool; (* true if signed, false if unsigned *) - t : t; (* type *) - _loc : Loc.t; (* location in source code *) -} -and endian = BigEndian | LittleEndian | NativeEndian -and t = Int | String | Bitstring +(* Work out if an expression is an integer constant. + * + * Returns [Some i] if so (where i is the integer value), else [None]. + * + * Fairly simplistic algorithm: we can only detect simple constant + * expressions such as [k], [k+c], [k-c] etc. + *) +let rec expr_is_constant = function + | <:expr< $int:i$ >> -> (* Literal integer constant. *) + Some (int_of_string i) + | <:expr< $a$ + $b$ >> -> (* Addition of constants. *) + (match expr_is_constant a, expr_is_constant b with + | Some a, Some b -> Some (a+b) + | _ -> None) + | <:expr< $a$ - $b$ >> -> (* Subtraction. *) + (match expr_is_constant a, expr_is_constant b with + | Some a, Some b -> Some (a-b) + | _ -> None) + | <:expr< $a$ * $b$ >> -> (* Multiplication. *) + (match expr_is_constant a, expr_is_constant b with + | Some a, Some b -> Some (a*b) + | _ -> None) + | <:expr< $a$ / $b$ >> -> (* Division. *) + (match expr_is_constant a, expr_is_constant b with + | Some a, Some b -> Some (a/b) + | _ -> None) + | <:expr< $a$ lsl $b$ >> -> (* Shift left. *) + (match expr_is_constant a, expr_is_constant b with + | Some a, Some b -> Some (a lsl b) + | _ -> None) + | <:expr< $a$ lsr $b$ >> -> (* Shift right. *) + (match expr_is_constant a, expr_is_constant b with + | Some a, Some b -> Some (a lsr b) + | _ -> None) + | _ -> None (* Anything else is not constant. *) (* Generate a fresh, unique symbol each time called. *) let gensym = @@ -60,147 +78,100 @@ let gensym = incr i; let i = !i in sprintf "__pabitmatch_%s_%d" name i -let rec parse_patt_field _loc fpatt flen qs = - let fpc = parse_field_common _loc flen qs in - { fpatt = fpatt; fpc = fpc } - -and parse_constr_field _loc fexpr flen qs = - let fec = parse_field_common _loc flen qs in - { fexpr = fexpr; fec = fec } - (* Deal with the qualifiers which appear for a field of both types. *) -and parse_field_common _loc flen qs = - let endian, signed, t = +let parse_field _loc field qs = + let endian_set, signed_set, type_set, field = match qs with - | None -> (None, None, None) + | None -> (false, false, false, field) | Some qs -> List.fold_left ( - fun (endian, signed, t) q -> - match q with - | "bigendian" -> - if endian <> None then + fun (endian_set, signed_set, type_set, field) qual_expr -> + match qual_expr with + | "bigendian", None -> + if endian_set then Loc.raise _loc (Failure "an endian flag has been set already") else ( - let endian = Some BigEndian in - (endian, signed, t) + let field = P.set_endian field BigEndian in + (true, signed_set, type_set, field) ) - | "littleendian" -> - if endian <> None then + | "littleendian", None -> + if endian_set then Loc.raise _loc (Failure "an endian flag has been set already") else ( - let endian = Some LittleEndian in - (endian, signed, t) + let field = P.set_endian field LittleEndian in + (true, signed_set, type_set, field) ) - | "nativeendian" -> - if endian <> None then + | "nativeendian", None -> + if endian_set then Loc.raise _loc (Failure "an endian flag has been set already") else ( - let endian = Some NativeEndian in - (endian, signed, t) + let field = P.set_endian field NativeEndian in + (true, signed_set, type_set, field) ) - | "signed" -> - if signed <> None then + | "endian", Some expr -> + if endian_set then + Loc.raise _loc (Failure "an endian flag has been set already") + else ( + let field = P.set_endian_expr field expr in + (true, signed_set, type_set, field) + ) + | "signed", None -> + if signed_set then Loc.raise _loc (Failure "a signed flag has been set already") else ( - let signed = Some true in - (endian, signed, t) + let field = P.set_signed field true in + (endian_set, true, type_set, field) ) - | "unsigned" -> - if signed <> None then + | "unsigned", None -> + if signed_set then Loc.raise _loc (Failure "a signed flag has been set already") else ( - let signed = Some false in - (endian, signed, t) + let field = P.set_signed field false in + (endian_set, true, type_set, field) ) - | "int" -> - if t <> None then + | "int", None -> + if type_set then Loc.raise _loc (Failure "a type flag has been set already") else ( - let t = Some Int in - (endian, signed, t) + let field = P.set_type_int field in + (endian_set, signed_set, true, field) ) - | "string" -> - if t <> None then + | "string", None -> + if type_set then Loc.raise _loc (Failure "a type flag has been set already") else ( - let t = Some String in - (endian, signed, t) + let field = P.set_type_string field in + (endian_set, signed_set, true, field) ) - | "bitstring" -> - if t <> None then + | "bitstring", None -> + if type_set then Loc.raise _loc (Failure "a type flag has been set already") else ( - let t = Some Bitstring in - (endian, signed, t) + let field = P.set_type_bitstring field in + (endian_set, signed_set, true, field) ) - | s -> - Loc.raise _loc (Failure (s ^ ": unknown qualifier")) - ) (None, None, None) qs in + | s, Some _ -> + Loc.raise _loc (Failure (s ^ ": unknown qualifier, or qualifier should not be followed by an expression")) + | s, None -> + Loc.raise _loc (Failure (s ^ ": unknown qualifier, or qualifier should be followed by an expression")) + ) (false, false, false, field) qs in (* If type is set to string or bitstring then endianness and * signedness qualifiers are meaningless and must not be set. *) - if (t = Some Bitstring || t = Some String) - && (endian <> None || signed <> None) then + let () = + let t = P.get_type field in + if (t = P.Bitstring || t = P.String) && (endian_set || signed_set) then Loc.raise _loc ( Failure "string types and endian or signed qualifiers cannot be mixed" - ); - - (* Default endianness, signedness, type. *) - let endian = match endian with None -> BigEndian | Some e -> e in - let signed = match signed with None -> false | Some s -> s in - let t = match t with None -> Int | Some t -> t in - - { - flen = flen; - endian = endian; - signed = signed; - t = t; - _loc = _loc; - } - -let string_of_endian = function - | BigEndian -> "bigendian" - | LittleEndian -> "littleendian" - | NativeEndian -> "nativeendian" - -let string_of_t = function - | Int -> "int" - | String -> "string" - | Bitstring -> "bitstring" - -let rec string_of_patt_field { fpatt = fpatt; fpc = fpc } = - let fpc = string_of_field_common fpc in - let fpatt = - match fpatt with - | <:patt< $lid:id$ >> -> id - | _ -> "[pattern]" in - fpatt ^ " : " ^ fpc - -and string_of_constr_field { fexpr = fexpr; fec = fec } = - let fec = string_of_field_common fec in - let fexpr = - match fexpr with - | <:expr< $lid:id$ >> -> id - | _ -> "[expression]" in - fexpr ^ " : " ^ fec - -and string_of_field_common { flen = flen; - endian = endian; signed = signed; t = t; - _loc = _loc } = - let flen = - match flen with - | <:expr< $int:i$ >> -> i - | _ -> "[non-const-len]" in - let endian = string_of_endian endian in - let signed = if signed then "signed" else "unsigned" in - let t = string_of_t t in - let loc_fname = Loc.file_name _loc in - let loc_line = Loc.start_line _loc in - let loc_char = Loc.start_off _loc - Loc.start_bol _loc in + ) in - sprintf "%s : %s, %s, %s @ (%S, %d, %d)" - flen t endian signed loc_fname loc_line loc_char + (* Default endianness, signedness, type if not set already. *) + let field = if endian_set then field else P.set_endian field BigEndian in + let field = if signed_set then field else P.set_signed field false in + let field = if type_set then field else P.set_type_int field in + + field (* Generate the code for a constructor, ie. 'BITSTRING ...'. *) let output_constructor _loc fields = @@ -222,57 +193,96 @@ let output_constructor _loc fields = (* Convert each field to a simple bitstring-generating expression. *) let fields = List.map ( - fun {fexpr=fexpr; fec={flen=flen; endian=endian; signed=signed; - t=t; _loc=_loc}} -> + fun field -> + let fexpr = P.get_expr field in + let flen = P.get_length field in + let endian = P.get_endian field in + let signed = P.get_signed field in + let t = P.get_type field in + let _loc = P.get_location field in + (* Is flen an integer constant? If so, what is it? This * is very simple-minded and only detects simple constants. *) - let flen_is_const = - match flen with - | <:expr< $int:i$ >> -> Some (int_of_string i) - | _ -> None in - - let name_of_int_construct_const = function - (* XXX As an enhancement we should allow a 64-bit-only - * mode which lets us use 'int' up to 63 bits and won't - * compile on 32-bit platforms. - *) + let flen_is_const = expr_is_constant flen in + + (* Choose the right constructor function. *) + let int_construct_const = function (* XXX The meaning of signed/unsigned breaks down at * 31, 32, 63 and 64 bits. *) - | (1, _, _) -> "construct_bit" - | ((2|3|4|5|6|7|8), _, false) -> "construct_char_unsigned" - | ((2|3|4|5|6|7|8), _, true) -> "construct_char_signed" - | (i, BigEndian, false) when i <= 31 -> "construct_int_be_unsigned" - | (i, BigEndian, true) when i <= 31 -> "construct_int_be_signed" - | (i, LittleEndian, false) when i <= 31 -> "construct_int_le_unsigned" - | (i, LittleEndian, true) when i <= 31 -> "construct_int_le_signed" - | (i, NativeEndian, false) when i <= 31 -> "construct_int_ne_unsigned" - | (i, NativeEndian, true) when i <= 31 -> "construct_int_ne_signed" - | (32, BigEndian, false) -> "construct_int32_be_unsigned" - | (32, BigEndian, true) -> "construct_int32_be_signed" - | (32, LittleEndian, false) -> "construct_int32_le_unsigned" - | (32, LittleEndian, true) -> "construct_int32_le_signed" - | (32, NativeEndian, false) -> "construct_int32_ne_unsigned" - | (32, NativeEndian, true) -> "construct_int32_ne_signed" - | (_, BigEndian, false) -> "construct_int64_be_unsigned" - | (_, BigEndian, true) -> "construct_int64_be_signed" - | (_, LittleEndian, false) -> "construct_int64_le_unsigned" - | (_, LittleEndian, true) -> "construct_int64_le_signed" - | (_, NativeEndian, false) -> "construct_int64_ne_unsigned" - | (_, NativeEndian, true) -> "construct_int64_ne_signed" + | (1, _, _) -> + <:expr> + | ((2|3|4|5|6|7|8), _, false) -> + <:expr> + | ((2|3|4|5|6|7|8), _, true) -> + <:expr> + | (i, P.ConstantEndian BigEndian, false) when i <= 31 -> + <:expr> + | (i, P.ConstantEndian BigEndian, true) when i <= 31 -> + <:expr> + | (i, P.ConstantEndian LittleEndian, false) when i <= 31 -> + <:expr> + | (i, P.ConstantEndian LittleEndian, true) when i <= 31 -> + <:expr> + | (i, P.ConstantEndian NativeEndian, false) when i <= 31 -> + <:expr> + | (i, P.ConstantEndian NativeEndian, true) when i <= 31 -> + <:expr> + | (i, P.EndianExpr expr, false) when i <= 31 -> + <:expr> + | (i, P.EndianExpr expr, true) when i <= 31 -> + <:expr> + | (32, P.ConstantEndian BigEndian, false) -> + <:expr> + | (32, P.ConstantEndian BigEndian, true) -> + <:expr> + | (32, P.ConstantEndian LittleEndian, false) -> + <:expr> + | (32, P.ConstantEndian LittleEndian, true) -> + <:expr> + | (32, P.ConstantEndian NativeEndian, false) -> + <:expr> + | (32, P.ConstantEndian NativeEndian, true) -> + <:expr> + | (32, P.EndianExpr expr, false) -> + <:expr> + | (32, P.EndianExpr expr, true) -> + <:expr> + | (_, P.ConstantEndian BigEndian, false) -> + <:expr> + | (_, P.ConstantEndian BigEndian, true) -> + <:expr> + | (_, P.ConstantEndian LittleEndian, false) -> + <:expr> + | (_, P.ConstantEndian LittleEndian, true) -> + <:expr> + | (_, P.ConstantEndian NativeEndian, false) -> + <:expr> + | (_, P.ConstantEndian NativeEndian, true) -> + <:expr> + | (_, P.EndianExpr expr, false) -> + <:expr> + | (_, P.EndianExpr expr, true) -> + <:expr> in - let name_of_int_construct = function - (* XXX As an enhancement we should allow users to - * specify that a field length can fit into a char/int/int32 - * (of course, this would have to be checked at runtime). - *) - | (BigEndian, false) -> "construct_int64_be_unsigned" - | (BigEndian, true) -> "construct_int64_be_signed" - | (LittleEndian, false) -> "construct_int64_le_unsigned" - | (LittleEndian, true) -> "construct_int64_le_signed" - | (NativeEndian, false) -> "construct_int64_ne_unsigned" - | (NativeEndian, true) -> "construct_int64_ne_signed" + let int_construct = function + | (P.ConstantEndian BigEndian, false) -> + <:expr> + | (P.ConstantEndian BigEndian, true) -> + <:expr> + | (P.ConstantEndian LittleEndian, false) -> + <:expr> + | (P.ConstantEndian LittleEndian, true) -> + <:expr> + | (P.ConstantEndian NativeEndian, false) -> + <:expr> + | (P.ConstantEndian NativeEndian, true) -> + <:expr> + | (P.EndianExpr expr, false) -> + <:expr> + | (P.EndianExpr expr, true) -> + <:expr> in let expr = @@ -283,17 +293,15 @@ let output_constructor _loc fields = * because that's a lot simpler w.r.t. types. It might * be better to move them here. XXX *) - | Int, Some i when i > 0 && i <= 64 -> - let construct_func = - name_of_int_construct_const (i,endian,signed) in + | P.Int, Some i when i > 0 && i <= 64 -> + let construct_fn = int_construct_const (i,endian,signed) in exn_used := true; <:expr< - Bitmatch.$lid:construct_func$ $lid:buffer$ $fexpr$ $flen$ - $lid:exn$ + $construct_fn$ $lid:buffer$ $fexpr$ $`int:i$ $lid:exn$ >> - | Int, Some _ -> + | P.Int, Some _ -> Loc.raise _loc (Failure "length of int field must be [1..64]") (* Int field, non-constant length. We need to perform a runtime @@ -303,14 +311,13 @@ let output_constructor _loc fields = * because that's a lot simpler w.r.t. types. It might * be better to move them here. XXX *) - | Int, None -> - let construct_func = name_of_int_construct (endian,signed) in + | P.Int, None -> + let construct_fn = int_construct (endian,signed) in exn_used := true; <:expr< if $flen$ >= 1 && $flen$ <= 64 then - Bitmatch.$lid:construct_func$ $lid:buffer$ $fexpr$ $flen$ - $lid:exn$ + $construct_fn$ $lid:buffer$ $fexpr$ $flen$ $lid:exn$ else raise (Bitmatch.Construct_failure ("length of int field must be [1..64]", @@ -319,11 +326,12 @@ let output_constructor _loc fields = >> (* String, constant length > 0, must be a multiple of 8. *) - | String, Some i when i > 0 && i land 7 = 0 -> + | P.String, Some i when i > 0 && i land 7 = 0 -> let bs = gensym "bs" in + let j = i lsr 3 in <:expr< let $lid:bs$ = $fexpr$ in - if String.length $lid:bs$ = ($flen$ lsr 3) then + if String.length $lid:bs$ = $`int:j$ then Bitmatch.construct_string $lid:buffer$ $lid:bs$ else raise (Bitmatch.Construct_failure @@ -335,20 +343,20 @@ let output_constructor _loc fields = (* String, constant length -1, means variable length string * with no checks. *) - | String, Some (-1) -> + | P.String, Some (-1) -> <:expr< Bitmatch.construct_string $lid:buffer$ $fexpr$ >> (* String, constant length = 0 is probably an error, and so is * any other value. *) - | String, Some _ -> + | P.String, Some _ -> Loc.raise _loc (Failure "length of string must be > 0 and a multiple of 8, or the special value -1") (* String, non-constant length. * We check at runtime that the length is > 0, a multiple of 8, * and matches the declared length. *) - | String, None -> + | P.String, None -> let bslen = gensym "bslen" in let bs = gensym "bs" in <:expr< @@ -376,11 +384,11 @@ let output_constructor _loc fields = >> (* Bitstring, constant length > 0. *) - | Bitstring, Some i when i > 0 -> + | P.Bitstring, Some i when i > 0 -> let bs = gensym "bs" in <:expr< let $lid:bs$ = $fexpr$ in - if Bitmatch.bitstring_length $lid:bs$ = $flen$ then + if Bitmatch.bitstring_length $lid:bs$ = $`int:i$ then Bitmatch.construct_bitstring $lid:buffer$ $lid:bs$ else raise (Bitmatch.Construct_failure @@ -392,13 +400,13 @@ let output_constructor _loc fields = (* Bitstring, constant length -1, means variable length bitstring * with no checks. *) - | Bitstring, Some (-1) -> + | P.Bitstring, Some (-1) -> <:expr< Bitmatch.construct_bitstring $lid:buffer$ $fexpr$ >> (* Bitstring, constant length = 0 is probably an error, and so is * any other value. *) - | Bitstring, Some _ -> + | P.Bitstring, Some _ -> Loc.raise _loc (Failure "length of bitstring must be > 0 or the special value -1") @@ -407,7 +415,7 @@ let output_constructor _loc fields = * We check at runtime that the length is > 0 and matches * the declared length. *) - | Bitstring, None -> + | P.Bitstring, None -> let bslen = gensym "bslen" in let bs = gensym "bs" in <:expr< @@ -482,103 +490,136 @@ let output_bitmatch _loc bs cases = let rec output_field_extraction inner = function | [] -> inner | field :: fields -> - let {fpatt=fpatt; fpc={flen=flen; endian=endian; signed=signed; - t=t; _loc=_loc}} - = field in + let fpatt = P.get_patt field in + let flen = P.get_length field in + let endian = P.get_endian field in + let signed = P.get_signed field in + let t = P.get_type field in + let _loc = P.get_location field in (* Is flen an integer constant? If so, what is it? This * is very simple-minded and only detects simple constants. *) - let flen_is_const = - match flen with - | <:expr< $int:i$ >> -> Some (int_of_string i) - | _ -> None in - - let name_of_int_extract_const = function - (* XXX As an enhancement we should allow a 64-bit-only - * mode which lets us use 'int' up to 63 bits and won't - * compile on 32-bit platforms. - *) + let flen_is_const = expr_is_constant flen in + + let int_extract_const = function (* XXX The meaning of signed/unsigned breaks down at * 31, 32, 63 and 64 bits. *) - | (1, _, _) -> "extract_bit" - | ((2|3|4|5|6|7|8), _, false) -> "extract_char_unsigned" - | ((2|3|4|5|6|7|8), _, true) -> "extract_char_signed" - | (i, BigEndian, false) when i <= 31 -> "extract_int_be_unsigned" - | (i, BigEndian, true) when i <= 31 -> "extract_int_be_signed" - | (i, LittleEndian, false) when i <= 31 -> "extract_int_le_unsigned" - | (i, LittleEndian, true) when i <= 31 -> "extract_int_le_signed" - | (i, NativeEndian, false) when i <= 31 -> "extract_int_ne_unsigned" - | (i, NativeEndian, true) when i <= 31 -> "extract_int_ne_signed" - | (32, BigEndian, false) -> "extract_int32_be_unsigned" - | (32, BigEndian, true) -> "extract_int32_be_signed" - | (32, LittleEndian, false) -> "extract_int32_le_unsigned" - | (32, LittleEndian, true) -> "extract_int32_le_signed" - | (32, NativeEndian, false) -> "extract_int32_ne_unsigned" - | (32, NativeEndian, true) -> "extract_int32_ne_signed" - | (_, BigEndian, false) -> "extract_int64_be_unsigned" - | (_, BigEndian, true) -> "extract_int64_be_signed" - | (_, LittleEndian, false) -> "extract_int64_le_unsigned" - | (_, LittleEndian, true) -> "extract_int64_le_signed" - | (_, NativeEndian, false) -> "extract_int64_ne_unsigned" - | (_, NativeEndian, true) -> "extract_int64_ne_signed" + | (1, _, _) -> + <:expr> + | ((2|3|4|5|6|7|8), _, false) -> + <:expr> + | ((2|3|4|5|6|7|8), _, true) -> + <:expr> + | (i, P.ConstantEndian BigEndian, false) when i <= 31 -> + <:expr> + | (i, P.ConstantEndian BigEndian, true) when i <= 31 -> + <:expr> + | (i, P.ConstantEndian LittleEndian, false) when i <= 31 -> + <:expr> + | (i, P.ConstantEndian LittleEndian, true) when i <= 31 -> + <:expr> + | (i, P.ConstantEndian NativeEndian, false) when i <= 31 -> + <:expr> + | (i, P.ConstantEndian NativeEndian, true) when i <= 31 -> + <:expr> + | (i, P.EndianExpr expr, false) when i <= 31 -> + <:expr> + | (i, P.EndianExpr expr, true) when i <= 31 -> + <:expr> + | (32, P.ConstantEndian BigEndian, false) -> + <:expr> + | (32, P.ConstantEndian BigEndian, true) -> + <:expr> + | (32, P.ConstantEndian LittleEndian, false) -> + <:expr> + | (32, P.ConstantEndian LittleEndian, true) -> + <:expr> + | (32, P.ConstantEndian NativeEndian, false) -> + <:expr> + | (32, P.ConstantEndian NativeEndian, true) -> + <:expr> + | (32, P.EndianExpr expr, false) -> + <:expr> + | (32, P.EndianExpr expr, true) -> + <:expr> + | (_, P.ConstantEndian BigEndian, false) -> + <:expr> + | (_, P.ConstantEndian BigEndian, true) -> + <:expr> + | (_, P.ConstantEndian LittleEndian, false) -> + <:expr> + | (_, P.ConstantEndian LittleEndian, true) -> + <:expr> + | (_, P.ConstantEndian NativeEndian, false) -> + <:expr> + | (_, P.ConstantEndian NativeEndian, true) -> + <:expr> + | (_, P.EndianExpr expr, false) -> + <:expr> + | (_, P.EndianExpr expr, true) -> + <:expr> in - let name_of_int_extract = function - (* XXX As an enhancement we should allow users to - * specify that a field length can fit into a char/int/int32 - * (of course, this would have to be checked at runtime). - *) - | (BigEndian, false) -> "extract_int64_be_unsigned" - | (BigEndian, true) -> "extract_int64_be_signed" - | (LittleEndian, false) -> "extract_int64_le_unsigned" - | (LittleEndian, true) -> "extract_int64_le_signed" - | (NativeEndian, false) -> "extract_int64_ne_unsigned" - | (NativeEndian, true) -> "extract_int64_ne_signed" + let int_extract = function + | (P.ConstantEndian BigEndian, false) -> + <:expr> + | (P.ConstantEndian BigEndian, true) -> + <:expr> + | (P.ConstantEndian LittleEndian, false) -> + <:expr> + | (P.ConstantEndian LittleEndian, true) -> + <:expr> + | (P.ConstantEndian NativeEndian, false) -> + <:expr> + | (P.ConstantEndian NativeEndian, true) -> + <:expr> + | (P.EndianExpr expr, false) -> + <:expr> + | (P.EndianExpr expr, true) -> + <:expr> in let expr = match t, flen_is_const with (* Common case: int field, constant flen *) - | Int, Some i when i > 0 && i <= 64 -> - let extract_func = name_of_int_extract_const (i,endian,signed) in + | P.Int, Some i when i > 0 && i <= 64 -> + let extract_fn = int_extract_const (i,endian,signed) in let v = gensym "val" in <:expr< - if $lid:len$ >= $flen$ then ( + if $lid:len$ >= $`int:i$ then ( let $lid:v$, $lid:off$, $lid:len$ = - Bitmatch.$lid:extract_func$ $lid:data$ $lid:off$ $lid:len$ - $flen$ in + $extract_fn$ $lid:data$ $lid:off$ $lid:len$ $`int:i$ in match $lid:v$ with $fpatt$ when true -> $inner$ | _ -> () ) >> - | Int, Some _ -> + | P.Int, Some _ -> Loc.raise _loc (Failure "length of int field must be [1..64]") (* Int field, non-const flen. We have to test the range of * the field at runtime. If outside the range it's a no-match * (not an error). *) - | Int, None -> - let extract_func = name_of_int_extract (endian,signed) in + | P.Int, None -> + let extract_fn = int_extract (endian,signed) in let v = gensym "val" in <:expr< if $flen$ >= 1 && $flen$ <= 64 && $flen$ <= $lid:len$ then ( let $lid:v$, $lid:off$, $lid:len$ = - Bitmatch.$lid:extract_func$ $lid:data$ $lid:off$ $lid:len$ - $flen$ in + $extract_fn$ $lid:data$ $lid:off$ $lid:len$ $flen$ in match $lid:v$ with $fpatt$ when true -> $inner$ | _ -> () ) >> (* String, constant flen > 0. *) - | String, Some i when i > 0 && i land 7 = 0 -> + | P.String, Some i when i > 0 && i land 7 = 0 -> let bs = gensym "bs" in <:expr< - if $lid:len$ >= $flen$ then ( + if $lid:len$ >= $`int:i$ then ( let $lid:bs$, $lid:off$, $lid:len$ = Bitmatch.extract_bitstring $lid:data$ $lid:off$ $lid:len$ - $flen$ in + $`int:i$ in match Bitmatch.string_of_bitstring $lid:bs$ with | $fpatt$ when true -> $inner$ | _ -> () @@ -588,7 +629,7 @@ let output_bitmatch _loc bs cases = (* String, constant flen = -1, means consume all the * rest of the input. *) - | String, Some i when i = -1 -> + | P.String, Some i when i = -1 -> let bs = gensym "bs" in <:expr< let $lid:bs$, $lid:off$, $lid:len$ = @@ -598,13 +639,13 @@ let output_bitmatch _loc bs cases = | _ -> () >> - | String, Some _ -> + | P.String, Some _ -> Loc.raise _loc (Failure "length of string must be > 0 and a multiple of 8, or the special value -1") (* String field, non-const flen. We check the flen is > 0 * and a multiple of 8 (-1 is not allowed here), at runtime. *) - | String, None -> + | P.String, None -> let bs = gensym "bs" in <:expr< if $flen$ >= 0 && $flen$ <= $lid:len$ @@ -622,7 +663,7 @@ let output_bitmatch _loc bs cases = * At the moment all we can do is assign the bitstring to an * identifier. *) - | Bitstring, Some i when i >= 0 -> + | P.Bitstring, Some i when i >= 0 -> let ident = match fpatt with | <:patt< $lid:ident$ >> -> ident @@ -631,10 +672,10 @@ let output_bitmatch _loc bs cases = Loc.raise _loc (Failure "cannot compare a bitstring to a constant") in <:expr< - if $lid:len$ >= $flen$ then ( + if $lid:len$ >= $`int:i$ then ( let $lid:ident$, $lid:off$, $lid:len$ = Bitmatch.extract_bitstring $lid:data$ $lid:off$ $lid:len$ - $flen$ in + $`int:i$ in $inner$ ) >> @@ -642,10 +683,11 @@ let output_bitmatch _loc bs cases = (* Bitstring, constant flen = -1, means consume all the * rest of the input. *) - | Bitstring, Some i when i = -1 -> + | P.Bitstring, Some i when i = -1 -> let ident = match fpatt with | <:patt< $lid:ident$ >> -> ident + | <:patt< _ >> -> "_" | _ -> Loc.raise _loc (Failure "cannot compare a bitstring to a constant") in @@ -655,16 +697,17 @@ let output_bitmatch _loc bs cases = $inner$ >> - | Bitstring, Some _ -> + | P.Bitstring, Some _ -> Loc.raise _loc (Failure "length of bitstring must be >= 0 or the special value -1") (* Bitstring field, non-const flen. We check the flen is >= 0 * (-1 is not allowed here) at runtime. *) - | Bitstring, None -> + | P.Bitstring, None -> let ident = match fpatt with | <:patt< $lid:ident$ >> -> ident + | <:patt< _ >> -> "_" | _ -> Loc.raise _loc (Failure "cannot compare a bitstring to a constant") in @@ -681,7 +724,7 @@ let output_bitmatch _loc bs cases = (* Emit extra debugging code. *) let expr = if not debug then expr else ( - let field = string_of_patt_field field in + let field = P.string_of_field field in <:expr< if !Bitmatch.debug then ( @@ -758,15 +801,25 @@ let output_bitmatch _loc bs cases = EXTEND Gram GLOBAL: expr; + (* Qualifiers are a list of identifiers ("string", "bigendian", etc.) + * followed by an optional expression (used in certain cases). Note + * that we are careful not to declare any explicit reserved words. + *) qualifiers: [ - [ LIST0 [ q = LIDENT -> q ] SEP "," ] + [ LIST0 + [ q = LIDENT; + e = OPT [ "("; e = expr; ")" -> e ] -> (q, e) ] + SEP "," ] ]; (* Field used in the bitmatch operator (a pattern). *) patt_field: [ [ fpatt = patt; ":"; len = expr LEVEL "top"; qs = OPT [ ":"; qs = qualifiers -> qs ] -> - parse_patt_field _loc fpatt len qs + let field = P.create_pattern_field _loc in + let field = P.set_patt field fpatt in + let field = P.set_length field len in + parse_field _loc field qs ] ]; @@ -786,7 +839,10 @@ EXTEND Gram constr_field: [ [ fexpr = expr LEVEL "top"; ":"; len = expr LEVEL "top"; qs = OPT [ ":"; qs = qualifiers -> qs ] -> - parse_constr_field _loc fexpr len qs + let field = P.create_constructor_field _loc in + let field = P.set_expr field fexpr in + let field = P.set_length field len in + parse_field _loc field qs ] ];