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550 | -- --
-- package Strings_Edit Copyright (c) Dmitry A. Kazakov --
-- Implementation Luebeck --
-- Strings_Edit.Float_Edit Spring, 2000 --
-- --
-- Last revision : 18:40 01 Aug 2019 --
-- --
-- This library is free software; you can redistribute it and/or --
-- modify it under the terms of the GNU General Public License as --
-- published by the Free Software Foundation; either version 2 of --
-- the License, or (at your option) any later version. This library --
-- is distributed in the hope that it will be useful, but WITHOUT --
-- ANY WARRANTY; without even the implied warranty of --
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU --
-- General Public License for more details. You should have --
-- received a copy of the GNU General Public License along with --
-- this library; if not, write to the Free Software Foundation, --
-- Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from --
-- this unit, or you link this unit with other files to produce an --
-- executable, this unit does not by itself cause the resulting --
-- executable to be covered by the GNU General Public License. This --
-- exception does not however invalidate any other reasons why the --
-- executable file might be covered by the GNU Public License. --
--____________________________________________________________________--
with Ada.IO_Exceptions;
with Ada.Numerics.Elementary_Functions;
with Strings_Edit.Integers;
pragma Elaborate_All (Strings_Edit.Integers);
use Ada.IO_Exceptions;
use Ada.Numerics.Elementary_Functions;
use Strings_Edit.Integers;
package body Strings_Edit.Float_Edit is
--
-- Base-radix logarithms of the number of valid digits in machine
-- radix, i.e. how many base-radix digits one machine radix digit
-- represents.
--
Logs : constant array (NumberBase) of Float :=
( 2 => Log (Float (Number'Machine_Radix), 2.0),
3 => Log (Float (Number'Machine_Radix), 3.0),
4 => Log (Float (Number'Machine_Radix), 4.0),
5 => Log (Float (Number'Machine_Radix), 5.0),
6 => Log (Float (Number'Machine_Radix), 6.0),
7 => Log (Float (Number'Machine_Radix), 7.0),
8 => Log (Float (Number'Machine_Radix), 8.0),
9 => Log (Float (Number'Machine_Radix), 9.0),
10 => Log (Float (Number'Machine_Radix), 10.0),
11 => Log (Float (Number'Machine_Radix), 11.0),
12 => Log (Float (Number'Machine_Radix), 12.0),
13 => Log (Float (Number'Machine_Radix), 13.0),
14 => Log (Float (Number'Machine_Radix), 14.0),
15 => Log (Float (Number'Machine_Radix), 15.0),
16 => Log (Float (Number'Machine_Radix), 16.0)
);
--
-- GetExponentField -- Calculate the length of the exponent
--
-- Base - Of the number
--
-- This function calculates how many digits are necessary to
-- represent any Base-radix exponent in decimal the format.
--
-- Returns :
--
-- The exponent length
--
function GetExponentField (Base : NumberBase) return Natural is
begin
if Number'Machine_Emax > -Number'Machine_Emin then
return
Natural
( Log (Float (Number'Machine_Emax) * Logs (Base), 10.0)
+ 0.5
);
else
return
Natural
( Log (Float (-Number'Machine_Emin) * Logs (Base), 10.0)
+ 0.5
);
end if;
end GetExponentField;
--
-- The exponent lengths for different Bases
--
ExponentField : constant array (NumberBase) of Natural :=
( GetExponentField (2), GetExponentField (3),
GetExponentField (4), GetExponentField (5),
GetExponentField (6), GetExponentField (7),
GetExponentField (8), GetExponentField (9),
GetExponentField (10), GetExponentField (11),
GetExponentField (12), GetExponentField (13),
GetExponentField (14), GetExponentField (15),
GetExponentField (16)
);
--
-- GetExponent -- Get the exponent part from the string
--
-- Source - The string
-- Pointer - Within the string
-- Value - Of the exponent (output)
--
-- This procedure scans the Source string starting from the Pointer
-- position for the exponent part of a number. Spaces are skipped
-- first. The exponent can be introduced by either E or e. Its value
-- is a decimal number returned via Value. If no valid exponent part
-- present Value is set to zero (the Pointer remains intact).
--
procedure GetExponent
( Source : in String;
Pointer : in out Integer;
Value : out Integer
) is
Index : Integer := Pointer;
begin
Get (Source, Index);
if ( Index > Source'Last
or else
( Source (Index) /= 'E'
and
Source (Index) /= 'e'
) )
then
Value := 0;
else
Index := Index + 1;
Get (Source, Index);
Get (Source, Index, Value, 10, -1000, +1000, True, True);
Pointer := Index;
end if;
exception
when End_Error | Data_Error | Layout_Error | Constraint_Error =>
Value := 0;
end GetExponent;
procedure Get
( Source : in String;
Pointer : in out Integer;
Value : out Number'Base;
Base : in NumberBase := 10;
First : in Number'Base := Number'Base'First;
Last : in Number'Base := Number'Base'Last;
ToFirst : in Boolean := False;
ToLast : in Boolean := False
) is
Radix : constant Number'Base := Number'Base (Base);
Digit : Natural;
Exponent : Integer;
ExponentPart : Integer;
Mantissa : Number'Base := 0.0;
Multiplicand : Number'Base := 1.0;
Sign : Integer := 0;
Index : Integer := Pointer;
begin
if ( Pointer < Source'First
or else
( Pointer > Source'Last
and then
Pointer - 1 > Source'Last
) )
then
raise Layout_Error;
end if;
if Pointer <= Source'Last then
case Source (Index) is
when '-' =>
Index := Index + 1;
Sign := -1;
Get (Source, Index);
when '+' =>
Index := Index + 1;
Sign := 1;
Get (Source, Index);
when others =>
null;
end case;
end if;
ExponentPart := Index;
Exponent := Index;
while Index <= Source'Last loop
Digit := GetDigit (Source (Index));
exit when Digit >= Base;
Mantissa := Mantissa + Number'Base (Digit) * Multiplicand;
Multiplicand := Multiplicand / Radix;
Index := Index + 1;
end loop;
Exponent := Index - Exponent - 1;
if Index + 1 <= Source'Last and then Source (Index) = '.' then
Index := Index + 1;
Digit := GetDigit (Source (Index));
if Digit < Base then
loop
Mantissa :=
Mantissa + Number'Base (Digit) * Multiplicand;
Multiplicand := Multiplicand / Radix;
Index := Index + 1;
exit when Index > Source'Last;
Digit := GetDigit (Source (Index));
exit when Digit >= Base;
end loop;
else
Index := Index - 1;
end if;
end if;
if 0 = Sign then
if Pointer = Index then
raise End_Error; -- No fraction part - no number
end if;
Sign := 1;
else
if Pointer = Index - 1 then
raise Data_Error; -- Only a sign
end if;
end if;
if ( ExponentPart = Index - 1
and then
Source (ExponentPart) = '.'
)
then
raise Data_Error; -- Only decimal point is present
end if;
GetExponent (Source, Index, ExponentPart);
if Mantissa > 0.0 then
begin
Mantissa := Number'Base (Sign) * Mantissa;
Exponent := ExponentPart + Exponent;
ExponentPart :=
Integer (Float (Number'Machine_Emax) * Logs (Base) * 0.7);
if Exponent >= ExponentPart then
Multiplicand := Radix ** ExponentPart;
loop
Mantissa := Mantissa * Multiplicand;
Exponent := Exponent - ExponentPart;
exit when Exponent < ExponentPart;
end loop;
elsif Exponent <= -ExponentPart then
ExponentPart := -ExponentPart;
Multiplicand := Radix ** ExponentPart;
loop
Mantissa := Mantissa * Multiplicand;
Exponent := Exponent - ExponentPart;
exit when Exponent > ExponentPart;
end loop;
end if;
Mantissa := Mantissa * Radix ** Exponent;
if not Mantissa'Valid then
if Sign > 0 and ToLast then
Value := Last;
Pointer := Index;
return;
elsif Sign < 0 and ToFirst then
Value := First;
Pointer := Index;
return;
end if;
raise Constraint_Error;
end if;
exception
when Numeric_Error | Constraint_Error =>
if Sign > 0 and ToLast then
Value := Last;
Pointer := Index;
return;
elsif Sign < 0 and ToFirst then
Value := First;
Pointer := Index;
return;
end if;
raise Constraint_Error;
end;
end if;
if Mantissa < First then
if ToFirst then
Mantissa := First;
else
raise Constraint_Error;
end if;
elsif Mantissa > Last then
if ToLast then
Mantissa := Last;
else
raise Constraint_Error;
end if;
end if;
Value := Mantissa;
Pointer := Index;
end Get;
function Value
( Source : in String;
Base : in NumberBase := 10;
First : in Number'Base := Number'First;
Last : in Number'Base := Number'Last;
ToFirst : in Boolean := False;
ToLast : in Boolean := False
) return Number'Base is
Result : Number'Base;
Pointer : Integer := Source'First;
begin
Get (Source, Pointer, SpaceAndTab);
Get (Source, Pointer, Result, Base, First, Last, ToFirst, ToLast);
Get (Source, Pointer, SpaceAndTab);
if Pointer /= Source'Last + 1 then
raise Data_Error;
end if;
return Result;
end Value;
procedure Put
( Destination : in out String;
Pointer : in out Integer;
Value : in Number'Base;
Base : in NumberBase := 10;
PutPlus : in Boolean := False;
RelSmall : in Positive := MaxSmall;
AbsSmall : in Integer := -MaxSmall;
Field : in Natural := 0;
Justify : in Alignment := Left;
Fill : in Character := ' '
) is
--
-- Sign -- Make the sign of a number
--
-- Value - Of the number
-- PutPlus - Always put sign, if true
--
-- Returns :
--
-- The string to be used as the sign
--
function Sign
( Value : Number'Base;
PutPlus : Boolean
) return String is
begin
if Value < 0.0 then
return "-";
elsif PutPlus then
return "+";
else
return "";
end if;
end Sign;
--
-- PutExponent -- Make the exponent part
--
-- Value - Of the exponent part
-- Base - Of the mantissa
--
-- The exponent part is written in the fixed length format. It
-- always has sign. Leading zeros are added to make the length
-- fixed. The space is added in front of the exponent part for
-- bases 15 and 16.
--
-- Returns :
--
-- The string containing the exponent part
--
function PutExponent
( Value : Integer;
Base : NumberBase
) return String is
Result : String (1..32);
Exponent : Integer := Value;
Pointer : Integer := Result'First;
Sign : Character := '+';
begin
if Exponent < 0 then
Sign := '-';
Exponent := -Value;
end if;
Put
( Result,
Pointer,
Exponent,
Field => ExponentField (Base),
PutPlus => False,
Justify => Right,
Fill => '0'
);
if Base >= 15 then
return " e" & Sign & Result (Result'First..Pointer - 1);
else
return 'E' & Sign & Result (Result'First..Pointer - 1);
end if;
end PutExponent;
Precision : Integer := -- The maximal available precision
Integer
( Float (Number'Machine_Mantissa)
* Logs (Base)
);
Mantissa : Number'Base := abs Value;
Exponent : Integer := 0;
Increment : Integer := 0;
Radix : constant Number'Base := Number'Base (Base);
begin
if Mantissa <= 0.0 then
Put (Destination, Pointer, "0", Field, Justify, Fill);
return;
end if;
if RelSmall < Precision then
Precision := RelSmall;
end if;
--
-- Normalization. The goal is to bring the mantissa into the range
-- ]1..1/Base]
--
while Mantissa < 1.0 / Radix loop
Mantissa := Mantissa * Radix;
Exponent := Exponent - 1;
end loop;
while Mantissa >= 1.0 loop
Mantissa := Mantissa / Radix;
Exponent := Exponent + 1;
end loop;
if Exponent - AbsSmall < Precision then
Precision := Exponent - AbsSmall;
Increment := 1;
end if;
--
-- Rounding
--
Mantissa := Mantissa + 0.5 / Radix ** Precision;
if Mantissa >= 1.0 then
Mantissa := Mantissa / Radix;
Exponent := Exponent + 1;
Precision := Precision + Increment;
end if;
if Precision > 0 then
declare
ExponentPart : constant String :=
PutExponent (Exponent - 1, Base);
MantissaPart : String (1..Precision);
Digit : Natural;
begin
--
-- Convert the Mantissa to character string
--
for Index in MantissaPart'range loop
Mantissa := Mantissa * Radix;
Digit := Integer (Mantissa);
if Number'Base (Digit) > Mantissa then
Digit := Digit - 1;
end if;
Mantissa := Mantissa - Number'Base (Digit);
MantissaPart (Index) := Figures (Digit + Figures'First);
end loop;
if ( Exponent < - ExponentPart'Length
or Exponent > Precision
)
then
--
-- Format X.XXXXXeYYY
--
Put
( Destination,
Pointer,
( Sign (Value, PutPlus)
& MantissaPart (MantissaPart'First)
& '.'
& MantissaPart
( MantissaPart'First + 1
.. MantissaPart'Last
)
& ExponentPart
),
Field,
Justify,
Fill
);
elsif Exponent = Precision then
--
-- Format: XXXXXXX
--
Put
( Destination,
Pointer,
Sign (Value, PutPlus) & MantissaPart,
Field,
Justify,
Fill
);
elsif Exponent > 0 then
--
-- Format: XXXX.XXX
--
Put
( Destination,
Pointer,
( Sign (Value, PutPlus)
& MantissaPart
( MantissaPart'First
.. MantissaPart'First + Exponent - 1
)
& '.'
& MantissaPart
( MantissaPart'First + Exponent
.. MantissaPart'Last
) ),
Field,
Justify,
Fill
);
else
--
-- Format: 0.000XXXXX
--
Put
( Destination,
Pointer,
( Sign (Value, PutPlus)
& "0."
& String'(1..-Exponent => '0')
& MantissaPart
),
Field,
Justify,
Fill
);
end if;
end;
else
--
-- Zero
--
Put (Destination, Pointer, "0", Field, Justify, Fill);
end if;
end Put;
function Image
( Value : in Number'Base;
Base : in NumberBase := 10;
PutPlus : in Boolean := False;
RelSmall : in Positive := MaxSmall;
AbsSmall : in Integer := -MaxSmall
) return String is
Text : String (1..80);
Pointer : Integer := Text'First;
begin
Put (Text, Pointer, Value, Base, PutPlus, RelSmall, AbsSmall);
return Text (Text'First..Pointer - 1);
end Image;
end Strings_Edit.Float_Edit;
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