gm2-libs/DynamicStrings (The GNU Modula-2 Compiler)

#### 4.1.12 gm2-libs/DynamicStrings ¶

    DEFINITION MODULE DynamicStrings ;

    FROM SYSTEM IMPORT ADDRESS ;
    EXPORT QUALIFIED String,
                     InitString, KillString, Fin, InitStringCharStar,
                     InitStringChar, Index, RIndex, ReverseIndex,
                     Mark, Length, ConCat, ConCatChar, Assign, Dup, Add,
                     Equal, EqualCharStar, EqualArray, ToUpper, ToLower,
                     CopyOut, Mult, Slice, ReplaceChar,
                     RemoveWhitePrefix, RemoveWhitePostfix, RemoveComment,
                     char, string,
                     InitStringDB, InitStringCharStarDB, InitStringCharDB,
                     MultDB, DupDB, SliceDB,
                     PushAllocation, PopAllocation, PopAllocationExemption ;

    TYPE
       String ;

    (*
       InitString - creates and returns a String type object.
                    Initial contents are, a.
    *)

    PROCEDURE InitString (a: ARRAY OF CHAR) : String ;

    (*
       KillString - frees String, s, and its contents.
                    NIL is returned.
    *)

    PROCEDURE KillString (s: String) : String ;

    (*
       Fin - finishes with a string, it calls KillString with, s.
             The purpose of the procedure is to provide a short cut
             to calling KillString and then testing the return result.
    *)

    PROCEDURE Fin (s: String) ;

    (*
       InitStringCharStar - initializes and returns a String to contain
                            the C string.
    *)

    PROCEDURE InitStringCharStar (a: ADDRESS) : String ;

    (*
       InitStringChar - initializes and returns a String to contain the
                        single character, ch.
    *)

    PROCEDURE InitStringChar (ch: CHAR) : String ;

    (*
       Mark - marks String, s, ready for garbage collection.
    *)

    PROCEDURE Mark (s: String) : String ;

    (*
       Length - returns the length of the String, s.
    *)

    PROCEDURE Length (s: String) : CARDINAL ;

    (*
       ConCat - returns String, a, after the contents of, b,
                have been appended.
    *)

    PROCEDURE ConCat (a, b: String) : String ;

    (*
       ConCatChar - returns String, a, after character, ch,
                    has been appended.
    *)

    PROCEDURE ConCatChar (a: String; ch: CHAR) : String ;

    (*
       Assign - assigns the contents of, b, into, a.
                String, a, is returned.
    *)

    PROCEDURE Assign (a, b: String) : String ;

    (*
       ReplaceChar - returns string s after it has changed all
                     occurances of from to to.
    *)

    PROCEDURE ReplaceChar (s: String; from, to: CHAR) : String ;

    (*
       Dup - duplicate a String, s, returning the copy of s.
    *)

    PROCEDURE Dup (s: String) : String ;

    (*
       Add - returns a new String which contains the contents of a and b.
    *)

    PROCEDURE Add (a, b: String) : String ;

    (*
       Equal - returns TRUE if String, a, and, b, are equal.
    *)

    PROCEDURE Equal (a, b: String) : BOOLEAN ;

    (*
       EqualCharStar - returns TRUE if contents of String, s, is
                       the same as the string, a.
    *)

    PROCEDURE EqualCharStar (s: String; a: ADDRESS) : BOOLEAN ;

    (*
       EqualArray - returns TRUE if contents of String, s, is the
                    same as the string, a.
    *)

    PROCEDURE EqualArray (s: String; a: ARRAY OF CHAR) : BOOLEAN ;

    (*
       Mult - returns a new string which is n concatenations of String, s.
              If n<=0 then an empty string is returned.
    *)

    PROCEDURE Mult (s: String; n: CARDINAL) : String ;

    (*
       Slice - returns a new string which contains the elements
               low..high-1

               strings start at element 0
               Slice(s, 0, 2)  will return elements 0, 1 but not 2
               Slice(s, 1, 3)  will return elements 1, 2 but not 3
               Slice(s, 2, 0)  will return elements 2..max
               Slice(s, 3, -1) will return elements 3..max-1
               Slice(s, 4, -2) will return elements 4..max-2
    *)

    PROCEDURE Slice (s: String; low, high: INTEGER) : String ;

    (*
       Index - returns the indice of the first occurance of, ch, in
               String, s. -1 is returned if, ch, does not exist.
               The search starts at position, o.
    *)

    PROCEDURE Index (s: String; ch: CHAR; o: CARDINAL) : INTEGER ;

    (*
       RIndex - returns the indice of the last occurance of, ch,
                in String, s.  The search starts at position, o.
                -1 is returned if ch is not found.  The search
                is performed left to right.
    *)

    PROCEDURE RIndex (s: String; ch: CHAR; o: CARDINAL) : INTEGER ;

    (*
       ReverseIndex - returns the indice of the last occurance of ch
                      in String s.  The search starts at position o
                      and searches from right to left.  The start position
                      may be indexed negatively from the right (-1 is the
                      last index).
                      The return value if ch is found will always be positive.
                      -1 is returned if ch is not found.
    *)

    PROCEDURE ReverseIndex (s: String; ch: CHAR; o: INTEGER) : INTEGER ;

    (*
       RemoveComment - assuming that, comment, is a comment delimiter
                       which indicates anything to its right is a comment
                       then strip off the comment and also any white space
                       on the remaining right hand side.
                       It leaves any white space on the left hand side
                       alone.
    *)

    PROCEDURE RemoveComment (s: String; comment: CHAR) : String ;

    (*
       RemoveWhitePrefix - removes any leading white space from String, s.
                           A new string is returned.
    *)

    PROCEDURE RemoveWhitePrefix (s: String) : String ;

    (*
       RemoveWhitePostfix - removes any leading white space from String, s.
                            A new string is returned.
    *)

    PROCEDURE RemoveWhitePostfix (s: String) : String ;

    (*
       ToUpper - returns string, s, after it has had its lower case
                 characters replaced by upper case characters.
                 The string, s, is not duplicated.
    *)

    PROCEDURE ToUpper (s: String) : String ;

    (*
       ToLower - returns string, s, after it has had its upper case
                 characters replaced by lower case characters.
                 The string, s, is not duplicated.
    *)

    PROCEDURE ToLower (s: String) : String ;

    (*
       CopyOut - copies string, s, to a.
    *)

    PROCEDURE CopyOut (VAR a: ARRAY OF CHAR; s: String) ;

    (*
       char - returns the character, ch, at position, i, in String, s.
              As Slice the index can be negative so:

              char(s, 0) will return the first character
              char(s, 1) will return the second character
              char(s, -1) will return the last character
              char(s, -2) will return the penultimate character

              a nul character is returned if the index is out of range.
    *)

    PROCEDURE char (s: String; i: INTEGER) : CHAR ;

    (*
       string - returns the C style char * of String, s.
    *)

    PROCEDURE string (s: String) : ADDRESS ;

    (*
       to easily debug an application using this library one could use
       use the following macro processing defines:

       #define InitString(X) InitStringDB(X, __FILE__, __LINE__)
       #define InitStringCharStar(X) InitStringCharStarDB(X, \
         __FILE__, __LINE__)
       #define InitStringChar(X) InitStringCharDB(X, __FILE__, __LINE__)
       #define Mult(X,Y) MultDB(X, Y, __FILE__, __LINE__)
       #define Dup(X) DupDB(X, __FILE__, __LINE__)
       #define Slice(X,Y,Z) SliceDB(X, Y, Z, __FILE__, __LINE__)

       and then invoke gm2 with the -fcpp flag.
    *)

    (*
       InitStringDB - the debug version of InitString.
    *)

    PROCEDURE InitStringDB (a: ARRAY OF CHAR;
                            file: ARRAY OF CHAR; line: CARDINAL) : String ;

    (*
       InitStringCharStarDB - the debug version of InitStringCharStar.
    *)

    PROCEDURE InitStringCharStarDB (a: ADDRESS;
                                    file: ARRAY OF CHAR;
                                    line: CARDINAL) : String ;

    (*
       InitStringCharDB - the debug version of InitStringChar.
    *)

    PROCEDURE InitStringCharDB (ch: CHAR;
                                file: ARRAY OF CHAR;
                                line: CARDINAL) : String ;

    (*
       MultDB - the debug version of MultDB.
    *)

    PROCEDURE MultDB (s: String; n: CARDINAL;
                      file: ARRAY OF CHAR; line: CARDINAL) : String ;

    (*
       DupDB - the debug version of Dup.
    *)

    PROCEDURE DupDB (s: String;
                     file: ARRAY OF CHAR; line: CARDINAL) : String ;

    (*
       SliceDB - debug version of Slice.
    *)

    PROCEDURE SliceDB (s: String; low, high: INTEGER;
                       file: ARRAY OF CHAR; line: CARDINAL) : String ;

    (*
       PushAllocation - pushes the current allocation/deallocation lists.
    *)

    PROCEDURE PushAllocation ;

    (*
       PopAllocation - test to see that all strings are deallocated since
                       the last push.  Then it pops to the previous
                       allocation/deallocation lists.

                       If halt is true then the application terminates
                       with an exit code of 1.
    *)

    PROCEDURE PopAllocation (halt: BOOLEAN) ;

    (*
       PopAllocationExemption - test to see that all strings are
                                deallocated, except string e since
                                the last push.
                                Post-condition: it pops to the previous
                                allocation/deallocation lists.

                                If halt is true then the application
                                terminates with an exit code of 1.

                                The string, e, is returned unmodified,
    *)

    PROCEDURE PopAllocationExemption (halt: BOOLEAN; e: String) : String ;

    END DynamicStrings.