1558 !

  1559 

  1560 truncatedToPrecision

  1561     "truncates to the precision of the float.

  1562      This is slightly different from truncated.

  1563      Taking for example 1e32,

  1564      the printed representation will be 1e32,

  1565      but the actual value, when truncating to an integer

  1566      would be 100000003318135351409612647563264.

  1567 

  1568      This is due to the inaccuracy in the least significant bits,

  1569      and the way the print-converter compensates for this.

  1570      This method tries to generate an integer value which corresponds

  1571      to what is seen in the float's printString.

  1572 

  1573      Here, a slow fallback (generating and rescanning the printString)

  1574      is provided, which should work on any float number.

  1575      Specialized versions in subclasses may be added for more performance

  1576      (however, this is probably only used rarely)"

  1577 

  1578     |pow10 printString intVal s sign nFract ch expSign exp pI|

  1579 

  1580     pow10 := #(10 100 1000 10000 100000 1000000 10000000 100000000 1000000000).

  1581 

  1582     printString := self printString.

  1583     intVal := 0.

  1584     sign := 1.

  1585     nFract := 0.

  1586     exp := 0.

  1587 

  1588     "/ fetch the mantissa

  1589     s := printString readStream.

  1590     s peek == $- ifTrue:[

  1591         sign := -1.

  1592         s next.

  1593     ].

  1594     intVal := s nextDecimalInteger.

  1595     s peek == $. ifTrue:[

  1596         s next.

  1597         [(ch := s peek) notNil and:[ch isDigit]] whileTrue:[

  1598             intVal := intVal * 10 + (s next digitValue).

  1599             nFract := nFract + 1.

  1600         ].

  1601     ].

  1602     ('eEdDqQ' includes:s peek) ifTrue:[

  1603         expSign := 1.

  1604         s next.

  1605         (ch := s peek) == $- ifTrue:[

  1606             expSign := -1.

  1607             s next.

  1608         ] ifFalse:[

  1609             ch == $+ ifTrue:[

  1610                 s next.

  1611             ].

  1612         ].

  1613         exp := s nextDecimalInteger.

  1614         exp := exp * expSign.

  1615     ].

  1616     exp := exp - nFract.

  1617     exp < 0 ifTrue:[

  1618         [exp < 0] whileTrue:[

  1619             pI := (exp negated) min:pow10 size.

  1620             intVal := intVal / (pow10 at:pI).

  1621             exp := exp + pI.

  1622         ].

  1623         intVal := intVal asInteger.

  1624     ] ifFalse:[

  1625         [exp > 0] whileTrue:[

  1626             pI := exp min:pow10 size.

  1627             intVal := intVal * (pow10 at:pI).

  1628             exp := exp - pI.

  1629         ].

  1630     ].

  1631     ^ intVal

  1632 

  1633     "

  1634      1e32 asShortFloat truncated

  1635      1e32 asShortFloat truncatedToPrecision

  1636      1.234e10 asShortFloat truncatedToPrecision

  1637      1234e-1 asShortFloat truncatedToPrecision

  1638 

  1639      1e32 truncated

  1640      1e32 truncatedToPrecision

  1641      1.234e10 truncatedToPrecision

  1642      1234e-1 truncatedToPrecision

  1643 

  1644      1e32 asLongFloat truncated

  1645      1e32 asLongFloat truncatedToPrecision

  1646      1.234e10 asLongFloat truncatedToPrecision

  1647      1234e-1 asLongFloat truncatedToPrecision

  1648     "