(*  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.  See the copyright notice in the ACK home directory, in the file "Copyright".*)(*$R-*)IMPLEMENTATION MODULE Strings;(*  Module:       String manipulations  Author:       Ceriel J.H. Jacobs  Version:      $Header: /cvsup/minix/src/lib/ack/libm2/Strings.mod,v 1.1 2005/10/10 15:27:46 beng Exp $*)  PROCEDURE Assign(source: ARRAY OF CHAR; VAR dest: ARRAY OF CHAR);  (* Assign string source to dest  *)  VAR	i: CARDINAL;	max: CARDINAL;  BEGIN	max := HIGH(source);	IF HIGH(dest) < max THEN max := HIGH(dest); END;	i := 0;	WHILE (i <= max) AND (source[i] # 0C) DO		dest[i] := source[i];		INC(i);	END;	IF i < HIGH(dest) THEN dest[i] := 0C; END;  END Assign;  PROCEDURE Insert(substr: ARRAY OF CHAR; VAR str: ARRAY OF CHAR; inx: CARDINAL);  (* Insert the string substr into str, starting at str[inx].     If inx is equal to or greater than Length(str) then substr is appended     to the end of str.  *)  VAR	sublen, length, i: CARDINAL;  BEGIN	sublen := Length(substr);	IF sublen = 0 THEN RETURN; END;	length := Length(str);	IF inx > length THEN inx := length; END;	i := length;	IF i + sublen  - 1 > HIGH(str) THEN i := HIGH(str); END;	WHILE i > inx DO		str[i+sublen-1] := str[i-1];		DEC(i);	END;	FOR i := 0 TO sublen - 1 DO		IF i + inx <= HIGH(str) THEN			str[i + inx] := substr[i];		ELSE			RETURN;		END;	END;	IF length + sublen <= HIGH(str) THEN		str[length + sublen] := 0C;	END;  END Insert;  PROCEDURE Delete(VAR str: ARRAY OF CHAR; inx, len: CARDINAL);  (* Delete len characters from str, starting at str[inx].     If inx >= Length(str) then nothing happens.     If there are not len characters to delete, characters to the end of the     string are deleted.  *)  VAR	length: CARDINAL;  BEGIN	IF len = 0 THEN RETURN; END;	length := Length(str);	IF inx >= length THEN RETURN; END;	WHILE inx + len < length DO		str[inx] := str[inx + len];		INC(inx);	END;	str[inx] := 0C;  END Delete;  PROCEDURE Pos(substr, str: ARRAY OF CHAR): CARDINAL;  (* Return the index into str of the first occurrence of substr.     Pos returns a value greater than HIGH(str) of no occurrence is found.  *)  VAR	i, j, max, subl: CARDINAL;  BEGIN	max := Length(str);	subl := Length(substr);	IF subl > max THEN RETURN HIGH(str) + 1; END;	IF subl = 0 THEN RETURN 0; END;	max := max - subl;	FOR i := 0 TO max DO		j := 0;		WHILE (j <= subl-1) AND (str[i+j] = substr[j]) DO			INC(j);		END;		IF j = subl THEN RETURN i; END;	END;	RETURN HIGH(str) + 1;  END Pos;  PROCEDURE Copy(str: ARRAY OF CHAR;	         inx, len: CARDINAL;	         VAR result: ARRAY OF CHAR);  (* Copy at most len characters from str into result, starting at str[inx].  *)  VAR	i: CARDINAL;  BEGIN	IF Length(str) <= inx THEN RETURN END;	i := 0;	LOOP		IF i > HIGH(result) THEN RETURN; END;		IF len = 0 THEN EXIT; END;		IF inx > HIGH(str) THEN EXIT; END;		result[i] := str[inx];		INC(i); INC(inx); DEC(len);	END;	IF i <= HIGH(result) THEN result[i] := 0C; END;  END Copy;  PROCEDURE Concat(s1, s2: ARRAY OF CHAR; VAR result: ARRAY OF CHAR);  (* Concatenate two strings.  *)  VAR	i, j: CARDINAL;  BEGIN	i := 0;	WHILE (i <= HIGH(s1)) AND (s1[i] # 0C) DO		IF i > HIGH(result) THEN RETURN END;		result[i] := s1[i];		INC(i);	END;	j := 0;	WHILE (j <= HIGH(s2)) AND (s2[j] # 0C) DO		IF i > HIGH(result) THEN RETURN END;		result[i] := s2[j];		INC(i);		INC(j);	END;	IF i <= HIGH(result) THEN result[i] := 0C; END;  END Concat;  PROCEDURE Length(str: ARRAY OF CHAR): CARDINAL;  (* Return number of characters in str.  *)  VAR i: CARDINAL;  BEGIN	i := 0;	WHILE (i <= HIGH(str)) DO		IF str[i] = 0C THEN RETURN i; END;		INC(i);	END;	RETURN i;  END Length;  PROCEDURE CompareStr(s1, s2: ARRAY OF CHAR): INTEGER;  (* Compare two strings, return -1 if s1 < s2, 0 if s1 = s2, and 1 if s1 > s2.  *)  VAR	i: CARDINAL;	max: CARDINAL;  BEGIN	max := HIGH(s1);	IF HIGH(s2) < max THEN max := HIGH(s2); END;	i := 0;	WHILE (i <= max) DO		IF s1[i] < s2[i] THEN RETURN -1; END;		IF s1[i] > s2[i] THEN RETURN 1; END;		IF s1[i] = 0C THEN RETURN 0; END;		INC(i);	END;	IF (i <= HIGH(s1)) AND (s1[i] # 0C) THEN RETURN 1; END;	IF (i <= HIGH(s2)) AND (s2[i] # 0C) THEN RETURN -1; END;	RETURN 0;  END CompareStr;END Strings.