RosettaCodeData/Task/String-matching/Component-Pascal/string-matching.pas

114 lines
3.2 KiB
ObjectPascal

MODULE StringMatch;
IMPORT StdLog,Strings;
CONST
strSize = 1024;
patSize = 256;
TYPE
Matcher* = POINTER TO LIMITED RECORD
str: ARRAY strSize OF CHAR;
pat: ARRAY patSize OF CHAR;
pos: INTEGER
END;
PROCEDURE NewMatcher*(IN str: ARRAY OF CHAR): Matcher;
VAR
m: Matcher;
BEGIN
NEW(m);m.str := str$;m.pos:= 0;
RETURN m
END NewMatcher;
PROCEDURE (m: Matcher) Match*(IN pat: ARRAY OF CHAR): INTEGER,NEW;
VAR
pos: INTEGER;
BEGIN
m.pat := pat$;
pos := m.pos;
Strings.Find(m.str,m.pat,pos,m.pos);
RETURN m.pos
END Match;
PROCEDURE (m: Matcher) Next*(): INTEGER, NEW;
VAR
pos: INTEGER;
BEGIN
pos := m.pos + LEN(m.pat$);
Strings.Find(m.str,m.pat,pos,m.pos);
RETURN m.pos;
END Next;
(* Some Helper functions based on Strings module *)
PROCEDURE StartsWith(IN str: ARRAY OF CHAR;IN pat: ARRAY OF CHAR): BOOLEAN;
VAR
pos: INTEGER;
BEGIN
Strings.Find(str,pat,0,pos);
RETURN pos = 0
END StartsWith;
PROCEDURE Contains(IN str: ARRAY OF CHAR;IN pat: ARRAY OF CHAR; OUT pos: INTEGER): BOOLEAN;
BEGIN
Strings.Find(str,pat,0,pos);
RETURN pos >= 0
END Contains;
PROCEDURE EndsWith(IN str: ARRAY OF CHAR;IN pat: ARRAY OF CHAR): BOOLEAN;
VAR
pos: INTEGER;
BEGIN
Strings.Find(str,pat,0,pos);
RETURN pos + LEN(pat$) = LEN(str$)
END EndsWith;
PROCEDURE Do*;
CONST
aStr = "abcdefghijklmnopqrstuvwxyz";
VAR
pat: ARRAY 128 OF CHAR;
res: BOOLEAN;
at: INTEGER;
m: Matcher;
BEGIN
(* StartsWith *)
pat := "abc";
StdLog.String(aStr + " startsWith " + pat + " :>");StdLog.Bool(StartsWith(aStr,pat));StdLog.Ln;
pat := "cba";
StdLog.String(aStr + " startsWith " + pat + " :>");StdLog.Bool(StartsWith(aStr,pat));StdLog.Ln;
pat := "def";
StdLog.String(aStr + " startsWith " + pat + " :>");StdLog.Bool(StartsWith(aStr,pat));StdLog.Ln;
StdLog.Ln;
(* Contains *)
pat := 'def';
StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at));
StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln;
pat := 'efd';
StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at));
StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln;
pat := 'abc';
StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at));
StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln;
pat := 'xyz';
StdLog.String(aStr + " contains " + pat + " :>");StdLog.Bool(Contains(aStr,pat,at));
StdLog.String(" at: ");StdLog.Int(at);StdLog.Ln;
StdLog.Ln;
(* EndsWith *)
pat := 'xyz';
StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln;
pat := 'zyx';
StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln;
pat := 'abc';
StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln;
pat:= 'def';
StdLog.String(aStr + " endsWith " + pat + " :>");StdLog.Bool(EndsWith(aStr,pat));StdLog.Ln;
StdLog.Ln;
m := NewMatcher("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz");
StdLog.String("Matching 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz' against 'abc':> ");
StdLog.Ln;
StdLog.String("Match at: ");StdLog.Int(m.Match("abc"));StdLog.Ln;
StdLog.String("Match at: ");StdLog.Int(m.Next());StdLog.Ln;
StdLog.String("Match at: ");StdLog.Int(m.Next());StdLog.Ln
END Do;
END StringMatch.