Changeset 63 for Deliverables/D4.1/Nibble.ml

Timestamp:

Sep 13, 2010, 11:04:55 AM (11 years ago)

Author:

mulligan

Message:

More work on bits, bytes, nibbles, and added modules for byte7s and
words.

File:

• Deliverables/D4.1/Nibble.ml (modified) (5 diffs)

Deliverables/D4.1/Nibble.ml

@@ -1 +1 @@
 (*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*)
-(* FILENAME: Nibble.ml                                                       *)
-(* DESCRIPTION: An ADT implementing nibbles, and common operations on them.  *)
-(* CREATED: 10/09/2010, Dominic Mulligan                                     *)
+(* FILENAME:    Nibble.ml                                                    *)
+(* DESCRIPTION: An ADT implementing 4 bit nibbles, and common operations on  *)
+(*              them.                                                        *)
+(* CREATED:     10/09/2010, Dominic Mulligan                                 *)
 (* BUGS:                                                                     *)
 (*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*^*)
@@ -13 +14 @@
   type nibble
 
-  val from_bits: bit -> bit -> nibble
+  val from_bits: bit -> bit -> bit -> bit -> nibble
+  val from_bit: bit -> nibble
   val from_int: int -> nibble option
+  val from_string: string -> nibble option
+
+  val to_bits: nibble -> (bit * bit * bit * bit)
+  val to_bit: nibble -> bit option
+  val to_int: nibble -> int
+  val to_string: nibble -> string
 
   val get_bit_at: int -> nibble -> bit option
@@ -29 +37 @@
   val iter_bit: (bit -> string) -> nibble -> string
   val zip_bit: (bit -> bit -> bit) -> nibble -> nibble -> nibble
-  val pretty: nibble -> string
 end
 
@@ -35 +42 @@
 struct
   type bit = Bit.bit
-  type nibble = bit * bit
+  type nibble = bit * bit * bit * bit
 
-  let from_bits l h = (l, h)
+  let from_bits b1 b2 b3 b4 = (b1, b2, b3, b4)
+  let from_bit h = (Bit.from_bool false, Bit.from_bool false, Bit.from_bool false, h)
   let from_int int_val =
     match int_val with
-      0 -> Some (Bit.from_int 0, Bit.from_int 0)
-    | 1 -> Some (Bit.from_int 0, Bit.from_int 1)
-    | 2 -> Some (Bit.from_int 1, Bit.from_int 0)
-    | 3 -> Some (Bit.from_int 1, Bit.from_int 1)
+      0 -> Some (Bit.from_int 0, Bit.from_int 0, Bit.from_int 0, Bit.from_int 0)
+    | 1 -> Some (Bit.from_int 0, Bit.from_int 0, Bit.from_int 0, Bit.from_int 1)
+    | 2 -> Some (Bit.from_int 0, Bit.from_int 0, Bit.from_int 1, Bit.from_int 0)
+    | 3 -> Some (Bit.from_int 0, Bit.from_int 0, Bit.from_int 1, Bit.from_int 1)
+    | 4 -> Some (Bit.from_int 0, Bit.from_int 1, Bit.from_int 0, Bit.from_int 0)
+    | 5 -> Some (Bit.from_int 0, Bit.from_int 1, Bit.from_int 0, Bit.from_int 1)
+    | 6 -> Some (Bit.from_int 0, Bit.from_int 1, Bit.from_int 1, Bit.from_int 0)
+    | 7 -> Some (Bit.from_int 0, Bit.from_int 1, Bit.from_int 1, Bit.from_int 1)
+    | 8 -> Some (Bit.from_int 1, Bit.from_int 0, Bit.from_int 0, Bit.from_int 0)
+    | 9 -> Some (Bit.from_int 1, Bit.from_int 0, Bit.from_int 0, Bit.from_int 1)
+    | 10 -> Some (Bit.from_int 1, Bit.from_int 0, Bit.from_int 1, Bit.from_int 0)
+    | 11 -> Some (Bit.from_int 1, Bit.from_int 0, Bit.from_int 1, Bit.from_int 1)
+    | 12 -> Some (Bit.from_int 1, Bit.from_int 1, Bit.from_int 0, Bit.from_int 0)
+    | 13 -> Some (Bit.from_int 1, Bit.from_int 1, Bit.from_int 0, Bit.from_int 1)
+    | 14 -> Some (Bit.from_int 1, Bit.from_int 1, Bit.from_int 1, Bit.from_int 0)
+    | 15 -> Some (Bit.from_int 1, Bit.from_int 1, Bit.from_int 1, Bit.from_int 1)
     | _ -> None
+  let from_string
+
+  let to_bit (l, h) =
+    let (bl, bh) = Bit.to_bool l, Bit.to_bool h in
+    match (bl, bh) with
+      (false, b) -> Some (Bit.from_bool b)
+    | (true, b) -> None
+  let to_int (l, h) = (2 * Bit.to_int l) + Bit.to_int h
+  let to_string = iter_bit Bit.to_string
 
   let get_bit_at index (l, h) =
@@ -79 +108 @@
       str_l ^ str_h
   let zip_bit f (l1, h1) (l2, h2) = (f l1 l2, f l2 h2)
-  let pretty = iter_bit Bit.pretty
 end