Module Bitstring_persistent

module Bitstring_persistent: sig .. end
Bitstring persistent patterns.

type patt = Camlp4.PreCast.Syntax.Ast.patt 
type expr = Camlp4.PreCast.Syntax.Ast.expr 
type loc_t = Camlp4.PreCast.Syntax.Ast.Loc.t 
Just short names for the camlp4 types.
type 'a field 
A field in a persistent pattern or persistent constructor.
type pattern = patt field list 
A persistent pattern (used in bitmatch operator), is just a list of pattern fields.
type constructor = expr field list 
A persistent constructor (used in BITSTRING operator), is just a list of constructor fields.
type named = string * alt 
type alt = 
| Pattern of pattern (*
Pattern
*)
| Constructor of constructor (*
Constructor
*)
A named pattern or constructor.

The name is used when binding a pattern from a file, but is otherwise ignored.

val string_of_pattern : pattern -> string
val string_of_constructor : constructor -> string
val string_of_pattern_field : patt field -> string
val string_of_constructor_field : expr field -> string
Convert patterns, constructors or individual fields into printable strings for debugging purposes.

The strings look similar to the syntax used by bitmatch, but some things cannot be printed fully, eg. length expressions.

val named_to_channel : Pervasives.out_channel -> named -> unit
Save a pattern/constructor to an output channel.
val named_to_string : named -> string
Serialize a pattern/constructor to a string.
val named_to_buffer : string -> int -> int -> named -> int
Serialize a pattern/constructor to part of a string, return the length.
val named_from_channel : Pervasives.in_channel -> named
Load a pattern/constructor from an output channel.

Note: This is not type safe. The pattern/constructor must have been written out under the same version of OCaml and the same version of bitstring.

val named_from_string : string -> int -> named
Load a pattern/constructor from a string at offset within the string.

Note: This is not type safe. The pattern/constructor must have been written out under the same version of OCaml and the same version of bitstring.

val create_pattern_field : loc_t ->
patt field
Create a pattern field.

The pattern is unbound, the type is set to int, bit length to 32, endianness to BigEndian, signedness to unsigned (false), source code location to the _loc parameter, and no offset expression.

To create a complete field you need to call the set_* functions. For example, to create { len : 8 : int } you would do:

    let field = create_pattern_field _loc in
    let field = set_lident_patt field "len" in
    let field = set_length_int field 8 in

val set_lident_patt : patt field ->
string -> patt field
Sets the pattern to the pattern binding an identifier given in the string.

The effect is that the field { len : 8 : int } could be created by calling set_lident_patt field "len".

val set_int_patt : patt field ->
int -> patt field
Sets the pattern field to the pattern which matches an integer.

The effect is that the field { 2 : 8 : int } could be created by calling set_int_patt field 2.

val set_string_patt : patt field ->
string -> patt field
Sets the pattern field to the pattern which matches a string.

The effect is that the field { "MAGIC" : 8*5 : string } could be created by calling set_int_patt field "MAGIC".

val set_unbound_patt : patt field ->
patt field
Sets the pattern field to the unbound pattern (usually written _).

The effect is that the field { _ : 8 : int } could be created by calling set_unbound_patt field.

val set_patt : patt field ->
patt ->
patt field
Sets the pattern field to an arbitrary OCaml pattern match.
val set_length_int : 'a field -> int -> 'a field
Sets the length in bits of a field to a constant integer.

The effect is that the field { len : 8 : string } could be created by calling set_length field 8.

val set_length : 'a field ->
expr -> 'a field
Sets the length in bits of a field to an OCaml expression.

The effect is that the field { len : 2*i : string } could be created by calling set_length field <:expr< 2*i >>.

val set_endian : 'a field ->
Bitstring.endian -> 'a field
Sets the endianness of a field to the constant endianness.

The effect is that the field { _ : 16 : bigendian } could be created by calling set_endian field Bitstring.BigEndian.

val set_endian_expr : 'a field ->
expr -> 'a field
Sets the endianness of a field to an endianness expression.

The effect is that the field { _ : 16 : endian(e) } could be created by calling set_endian_expr field e.

val set_signed : 'a field -> bool -> 'a field
Sets the signedness of a field to a constant signedness.

The effect is that the field { _ : 16 : signed } could be created by calling set_signed field true.

val set_type_int : 'a field -> 'a field
Sets the type of a field to int.

The effect is that the field { _ : 16 : int } could be created by calling set_type_int field.

val set_type_string : 'a field -> 'a field
Sets the type of a field to string.

The effect is that the field { str : 16 : string } could be created by calling set_type_string field.

val set_type_bitstring : 'a field -> 'a field
Sets the type of a field to bitstring.

The effect is that the field { _ : 768 : bitstring } could be created by calling set_type_bitstring field.

val set_location : 'a field ->
loc_t -> 'a field
Sets the source code location of a field. This is used when pa_bitstring displays error messages.
val set_offset_int : 'a field -> int -> 'a field
Set the offset expression for a field to the given number.

The effect is that the field { _ : 8 : offset(160) } could be created by calling set_offset_int field 160.

val set_offset : 'a field ->
expr -> 'a field
Set the offset expression for a field to the given expression.

The effect is that the field { _ : 8 : offset(160) } could be created by calling set_offset_int field <:expr< 160 >>.

val set_no_offset : 'a field -> 'a field
Remove the offset expression from a field. The field will follow the previous field, or if it is the first field will be at offset zero.
val set_check : 'a field ->
expr -> 'a field
Set the check expression for a field to the given expression.
val set_no_check : 'a field -> 'a field
Remove the check expression from a field.
val set_bind : 'a field ->
expr -> 'a field
Set the bind-expression for a field to the given expression.
val set_no_bind : 'a field -> 'a field
Remove the bind-expression from a field.
val set_save_offset_to : 'a field ->
patt -> 'a field
Set the save_offset_to pattern for a field to the given pattern.
val set_save_offset_to_lident : 'a field -> string -> 'a field
Set the save_offset_to pattern for a field to identifier.
val set_no_save_offset_to : 'a field -> 'a field
Remove the save_offset_to from a field.
val create_constructor_field : loc_t ->
expr field
Create a constructor field.

The defaults are the same as for Bitstring_persistent.create_pattern_field except that the expression is initialized to 0.

val set_lident_expr : expr field ->
string -> expr field
Sets the expression in a constructor field to an expression which uses the identifier.

The effect is that the field { len : 8 : int } could be created by calling set_lident_expr field "len".

val set_int_expr : expr field ->
int -> expr field
Sets the expression to the value of the integer.

The effect is that the field { 2 : 8 : int } could be created by calling set_int_expr field 2.

val set_string_expr : expr field ->
string -> expr field
Sets the expression to the value of the string.

The effect is that the field { "MAGIC" : 8*5 : string } could be created by calling set_int_expr field "MAGIC".

val set_expr : expr field ->
expr ->
expr field
Sets the expression field to an arbitrary OCaml expression.
val get_patt : patt field ->
patt
Get the pattern from a pattern field.
val get_expr : expr field ->
expr
Get the expression from an expression field.
val get_length : 'a field -> expr
Get the length in bits from a field. Note that what is returned is an OCaml expression, since lengths can be non-constant.
type endian_expr = 
| ConstantEndian of Bitstring.endian
| EndianExpr of expr
val get_endian : 'a field -> endian_expr
Get the endianness of a field. This is an Bitstring_persistent.endian_expr which could be a constant or an OCaml expression.
val get_signed : 'a field -> bool
Get the signedness of a field.
type field_type = 
| Int
| String
| Bitstring
val get_type : 'a field -> field_type
Get the type of a field, Int, String or Bitstring.
val get_location : 'a field -> loc_t
Get the source code location of a field.
val get_offset : 'a field -> expr option
Get the offset expression of a field, or None if there is none.
val get_check : 'a field -> expr option
Get the check expression of a field, or None if there is none.
val get_bind : 'a field -> expr option
Get the bind expression of a field, or None if there is none.
val get_save_offset_to : 'a field -> patt option
Get the save_offset_to pattern of a field, or None if there is none.