- Added CStrings function definitions

- Added code for CString.Compare

src/cstrings.d

@@ -1,7 +1,7 @@
 (****************************************************************************
  * File name:       CSTRINGS.D
  * Created On:      Fri 02 Oct 2020 07:27:00 PM CEST
- * Last Modified:   Fri 02 Oct 2020 07:46:49 PM CEST
+ * Last Modified:   Sat 03 Oct 2020 01:59:46 PM CEST
  * Author:          Jali <jali@orca-central.de>
  ****************************************************************************
  * Header file for an implementation of C-Like strings                          
@@ -20,20 +20,88 @@ CONST
 
 TYPE
     CString : POINTER TO CHAR;
+    CompareResult = ( Before, Equal, After ); (* The sort order for Compare() *)
 
-PROCEDURE Length(str : CString) : LONGCARD
-    VAR
-        count : LONGCARD;
-        countPtr : POINTER TO CHAR;
-BEGIN
-    count = 0;
-    countPtr = str;
-    WHILE (countPtr^ <> NULL) BEGIN
-        count += 1;
-    END; (* WHILE *)
+(*
+ * Compare two CStrings and return a CompareResult
+ * that indicates their relative position in the sort order
+ * 
+ * # Parameters:
+ * - strA: The first string to compare
+ * - strB: The second string to compare
+ *
+ * # Returns:
+ * An integer, which is 
+ * - less than zero, if strA is before strB in the sort order
+ * - zero if both strings are identical
+ * - greater than zero, if str
+ *)
+PROCEDURE Compare(strA, strB : CString) : CompareResult;
 
-    RETURN count;
-END Length;
+(*
+ * Concatanates two strings, and returns a new string, that contains of both
+ * strings.
+ *
+ * # Parameters:
+ * - strA: The original string
+ * - strB: The second string to add to strA
+ *
+ * # Retruns:
+ * A new CString, that consists of strA followed by strB
+ *)
+PROCEDURE Concat(strA, strB : CString) : CString;
+
+(*
+ * Checks if *subString* is contained in *string*, and returns the result.
+ *
+ * # Parameters:
+ * - string: The string to compare to
+ * - subString: The substring to search
+ * 
+ * # Returns:
+ * TRUE, if subString is part of string, else false.
+ *)
+PROCEDURE Contains(string, subString : CString) : BOOLEAN;
+
+(*
+ * Checks, if the CString is NIL or the the string only contains a NULL char.
+ *
+ * # Parameters:
+ * - string: The string to check
+ *
+ * # Returns:
+ * TRUE, if the CString is NIL, or only contains the NULL character
+ *)
+PROCEDURE IsNilOrEmpty(string : CString) : BOOLEAN;
+
+(*
+ * Checks, if the CString is NIL or the the string only contains a white space
+ * characters.
+ *
+ * # Parameters:
+ * - string: The string to check
+ *
+ * # Returns:
+ * TRUE, if the CString is NIL, or only contains a white space character
+ *)
+PROCEDURE IsNilOrWhiteSpace(string : CString) : BOOLEAN;
+
+(* 
+ * Returns the length of the string stored in 
+ * the CString. 
+ *)
+PROCEDURE Length(str : CString) : LONGCARD;
+
+(*
+ * Converts the string into a dynamic ARRAY OF CHAR.
+ * 
+ * # Parameters: 
+ * - string: The string to convert
+ *
+ * # Returns:
+ * An ARRAY OF CHAR that contains the original string.
+ *)
+PROCEDURE ToArray(string : CString) : ARRAY OF CHAR;
 
 END CStrings;
 

src/cstrings.i

@@ -1 +1,49 @@
+(****************************************************************************
+ * File name:       CSTRINGS.I
+ * Created On:      Sat 03 Oct 2020 03:18:19 PM CEST
+ * Last Modified:   Sat 03 Oct 2020 03:18:19 PM CEST
+ * Author:          Jali <jali@orca-central.de>
+ ****************************************************************************
+ * Implementation for handling C-Like strings                          
+ ****************************************************************************)
+
+IMPLEMENTATION MODULE CStrings;
+
+PROCEDURE Compare(strA : CString, strB : CString) : CompareResult
+(* $L- *)
+BEGIN
+    ASSEMBLER
+        MOVE.L  -(A3),A1    ; Read strB from the stack
+        MOVE.L  -(A3),A0    ; Read strA from the stack
+        MOVE.W 1,D2         ; Preset the return value to CompareResult.Equal
+    Loop:
+        MOVE.S  D0,(A0)+    ; Read a byte from strA into D0, and increase the pointer
+        CMP.S   0,D0        ; Check if the value is NULL
+        BEQ     Return      ; Reached the end of the first string; break
+        MOVE.S  D1,(A1)+    ; Read a byte from strB into S1 and increase the pointer
+        CMP.S   0,D0        ; Check if the byte is NULL
+        BEQ     Return      ; Reached the end of the second string; break
+        CMP.S   D0,D1       ; Compare the two values for equality
+        BEQ     Loop        ; If equal, continue with the next bytes.
+        MOVE.W  2,D2        ; Set the result register to ComepareResult.After
+        BHI     Return      ; Break and retrun result
+        MOVE.W  0,D2        ; Set the result register to CompareResult.Before
+    Return:
+        MOVE    D2,(A3)+    ; Push the result to the stack
+    END;
+(* $L+ *)    
+END Compare;
+
+PROCEDURE Concat(strA, strB : CString) : CString 
+    VAR
+        len : LONGCARD;
+        newString : ARRAY
+        resultString : POINTER TO CHAR;
+BEGIN
+    len := Length(strA) + Length(strB);
+    
+END Concat;
+
+END CStrings;
+
 (* vim: set filetype=modula2: *)