ack/lang/m2/libm2/RealConver.mod

323 lines
6.6 KiB
Modula-2

(*$R-*)
IMPLEMENTATION MODULE RealConversions;
FROM EM IMPORT FIF;
PROCEDURE RealToString(arg: REAL;
width, digits: INTEGER;
VAR str: ARRAY OF CHAR;
VAR ok: BOOLEAN);
BEGIN
LongRealToString(LONG(arg), width, digits, str, ok);
END RealToString;
PROCEDURE LongRealToString(arg: LONGREAL;
width, digits: INTEGER;
VAR str: ARRAY OF CHAR;
VAR ok: BOOLEAN);
VAR pointpos: INTEGER;
i: CARDINAL;
ecvtflag: BOOLEAN;
r, intpart, fractpart: LONGREAL;
ind1, ind2 : CARDINAL;
sign: BOOLEAN;
tmp : CHAR;
ndigits: CARDINAL;
dummy, dig: LONGREAL;
BEGIN
r := arg;
IF digits < 0 THEN
ecvtflag := TRUE;
ndigits := -digits;
ELSE
ecvtflag := FALSE;
ndigits := digits;
END;
IF (HIGH(str) < ndigits + 3) THEN
str[0] := 0C; ok := FALSE; RETURN
END;
pointpos := 0;
sign := r < 0.0D;
IF sign THEN r := -r END;
r := FIF(r, 1.0D, intpart);
fractpart := r;
pointpos := 0;
ind1 := 0;
ok := TRUE;
(*
Do integer part, which is now in "intpart". "r" now contains the
fraction part.
*)
IF intpart # 0.0D THEN
ind2 := 0;
WHILE intpart # 0.0D DO
IF ind2 > HIGH(str) THEN
IF NOT ecvtflag THEN
str[0] := 0C;
ok := FALSE;
RETURN;
END;
FOR ind1 := 1 TO HIGH(str) DO
str[ind1-1] := str[ind1];
END;
DEC(ind2);
END;
dummy := FIF(FIF(intpart, 0.1D, intpart),10.0D, dig);
IF (dummy > 0.5D) AND (dig < 9.0D) THEN
dig := dig + 1.0D;
END;
str[ind2] := CHR(TRUNC(dig+0.5D) + ORD('0'));
INC(ind2);
INC(pointpos);
END;
i := 0;
ind1 := ind2;
WHILE ind2 > i DO
DEC(ind2);
tmp := str[i];
str[i] := str[ind2];
str[ind2] := tmp;
INC(i);
END;
ELSE
INC(pointpos);
IF r > 0.0D THEN
WHILE r < 1.0D DO
fractpart := r;
r := r * 10.0D;
DEC(pointpos);
END;
END;
END;
ind2 := ndigits;
IF NOT ecvtflag THEN
IF INTEGER(ind2) + pointpos < 0 THEN
ind2 := ndigits;
FOR i := 0 TO ndigits DO str[i] := '0'; END;
ind1 := ndigits+1;
ELSE
ind2 := INTEGER(ind2) + pointpos
END;
END;
IF ind2 > HIGH(str) THEN
ok := FALSE;
str[0] := 0C;
RETURN;
END;
WHILE ind1 <= ind2 DO
fractpart := FIF(fractpart, 10.0D, r);
str[ind1] := CHR(TRUNC(r)+ORD('0'));
INC(ind1);
END;
ind1 := ind2;
str[ind2] := CHR(ORD(str[ind2])+5);
WHILE str[ind2] > '9' DO
str[ind2] := '0';
IF ind2 > 0 THEN
DEC(ind2);
str[ind2] := CHR(ORD(str[ind2])+1);
ELSE
str[ind2] := '1';
INC(pointpos);
IF NOT ecvtflag THEN
IF ind1 > 0 THEN str[ind1] := '0'; END;
INC(ind1);
END;
END;
END;
IF ecvtflag THEN
FOR i := ind1 TO 2 BY -1 DO
str[i] := str[i-1];
END;
str[1] := '.';
INC(ind1);
IF sign THEN
FOR i := ind1 TO 1 BY -1 DO
str[i] := str[i-1];
END;
INC(ind1);
str[0] := '-';
END;
IF (ind1 + 4) > HIGH(str) THEN
str[0] := 0C;
ok := FALSE;
RETURN;
END;
str[ind1] := 'E'; INC(ind1);
DEC(pointpos);
IF pointpos < 0 THEN
pointpos := -pointpos;
str[ind1] := '-';
ELSE
str[ind1] := '+';
END;
INC(ind1);
str[ind1] := CHR(ORD('0') + CARDINAL(pointpos DIV 100));
pointpos := pointpos MOD 100;
INC(ind1);
str[ind1] := CHR(ORD('0') + CARDINAL(pointpos DIV 10));
INC(ind1);
str[ind1] := CHR(ORD('0') + CARDINAL(pointpos MOD 10));
ELSE
IF pointpos <= 0 THEN
FOR i := ind1 TO 1 BY -1 DO
str[i+CARDINAL(-pointpos)] := str[i-1];
END;
FOR i := 0 TO CARDINAL(-pointpos) DO
str[i] := '0';
END;
ind1 := ind1 + CARDINAL(1 - pointpos);
pointpos := 1;
END;
FOR i := ind1 TO CARDINAL(pointpos+1) BY -1 DO
str[i] := str[i-1];
END;
IF ndigits = 0 THEN
str[pointpos] := 0C;
ELSE
str[pointpos] := '.';
END;
IF sign THEN
FOR i := ind1 TO 0 BY -1 DO
str[i+1] := str[i];
END;
str[0] := '-';
INC(ind1);
END;
END;
IF (ind1+1) <= HIGH(str) THEN str[ind1+1] := 0C; END;
IF ind1 >= CARDINAL(width) THEN
ok := FALSE;
RETURN;
END;
IF width > 0 THEN
DEC(width);
END;
IF (width > 0) AND (ind1 < CARDINAL(width)) THEN
FOR i := ind1 TO 0 BY -1 DO
str[i + CARDINAL(width) - ind1] := str[i];
END;
FOR i := 0 TO CARDINAL(width)-(ind1+1) DO
str[i] := ' ';
END;
ind1 := CARDINAL(width);
IF (ind1+1) <= HIGH(str) THEN
FOR ind1 := ind1+1 TO HIGH(str) DO
str[ind1] := 0C;
END;
END;
END;
END LongRealToString;
PROCEDURE StringToReal(str: ARRAY OF CHAR;
VAR r: REAL; VAR ok: BOOLEAN);
VAR x: LONGREAL;
BEGIN
StringToLongReal(str, x, ok);
IF ok THEN
r := x;
END;
END StringToReal;
PROCEDURE StringToLongReal(str: ARRAY OF CHAR;
VAR r: LONGREAL; VAR ok: BOOLEAN);
CONST BIG = 1.0D17;
TYPE SETOFCHAR = SET OF CHAR;
VAR pow10 : INTEGER;
i : INTEGER;
e : LONGREAL;
ch : CHAR;
signed: BOOLEAN;
signedexp: BOOLEAN;
iB: CARDINAL;
BEGIN
r := 0.0D;
pow10 := 0;
iB := 0;
ok := TRUE;
signed := FALSE;
WHILE (str[iB] = ' ') OR (str[iB] = CHR(9)) DO
INC(iB);
IF iB > HIGH(str) THEN
ok := FALSE;
RETURN;
END;
END;
IF str[iB] = '-' THEN signed := TRUE; INC(iB)
ELSIF str[iB] = '+' THEN INC(iB)
END;
ch := str[iB]; INC(iB);
IF NOT (ch IN SETOFCHAR{'0'..'9'}) THEN ok := FALSE; RETURN END;
REPEAT
IF r>BIG THEN INC(pow10) ELSE r:= 10.0D*r+FLOATD(ORD(ch)-ORD('0')) END;
IF iB <= HIGH(str) THEN
ch := str[iB]; INC(iB);
END;
UNTIL (iB > HIGH(str)) OR NOT (ch IN SETOFCHAR{'0'..'9'});
IF (ch = '.') AND (iB <= HIGH(str)) THEN
ch := str[iB]; INC(iB);
IF NOT (ch IN SETOFCHAR{'0'..'9'}) THEN ok := FALSE; RETURN END;
REPEAT
IF r < BIG THEN
r := 10.0D * r + FLOATD(ORD(ch)-ORD('0'));
DEC(pow10);
END;
IF iB <= HIGH(str) THEN
ch := str[iB]; INC(iB);
END;
UNTIL (iB > HIGH(str)) OR NOT (ch IN SETOFCHAR{'0'..'9'});
END;
IF (ch = 'E') THEN
IF iB > HIGH(str) THEN
ok := FALSE;
RETURN;
ELSE
ch := str[iB]; INC(iB);
END;
i := 0;
signedexp := FALSE;
IF (ch = '-') OR (ch = '+') THEN
signedexp := ch = '-';
IF iB > HIGH(str) THEN
ok := FALSE;
RETURN;
ELSE
ch := str[iB]; INC(iB);
END;
END;
IF NOT (ch IN SETOFCHAR{'0'..'9'}) THEN ok := FALSE; RETURN END;
REPEAT
i := i*10 + INTEGER(ORD(ch) - ORD('0'));
IF iB <= HIGH(str) THEN
ch := str[iB]; INC(iB);
END;
UNTIL (iB > HIGH(str)) OR NOT (ch IN SETOFCHAR{'0'..'9'});
IF signedexp THEN i := -i END;
pow10 := pow10 + i;
END;
IF pow10 < 0 THEN i := -pow10; ELSE i := pow10; END;
e := 1.0D;
DEC(i);
WHILE i >= 10 DO
e := e * 10000000000.0D;
DEC(i,10);
END;
WHILE i >= 0 DO
e := e * 10.0D;
DEC(i)
END;
IF pow10<0 THEN
r := r / e;
ELSE
r := r * e;
END;
IF signed THEN r := -r; END;
IF (iB <= HIGH(str)) AND (ORD(ch) > ORD(' ')) THEN ok := FALSE; END
END StringToLongReal;
END RealConversions.