From: Eric Botcazou <ebotca...@adacore.com>
The extra digit returned by the function is supposed to be rounded, either
by Scan_Integral_Digits or by Scan_Decimal_Digits, but that is not the case
when it is the last digit read by Scan_Integral_Digits.
The problem is fixed by rounding it in Scan_Decimal_Digits in this case.
gcc/ada/ChangeLog:
* libgnat/s-valuer.adb (Scan_Decimal_Digits): Also pretend that the
precision limit was just reached if it was already reached.
(Scan_Integral_Digits): Add Extra_Rounded out parameter, set it to
False on entry and to True when Extra is rounded.
(Scan_Raw_Real): New Extra_Rounded local variable. Pass it in the
calls to Scan_Integral_Digits. If it is True, pass a dummy extra
digit to Scan_Decimal_Digits.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/libgnat/s-valuer.adb | 47 +++++++++++++++++++++++++++---------
1 file changed, 36 insertions(+), 11 deletions(-)
diff --git a/gcc/ada/libgnat/s-valuer.adb b/gcc/ada/libgnat/s-valuer.adb
index 46f85e11159..faedb884a6a 100644
--- a/gcc/ada/libgnat/s-valuer.adb
+++ b/gcc/ada/libgnat/s-valuer.adb
@@ -84,6 +84,7 @@ package body System.Value_R is
Scale : out Scale_Array;
N : out Positive;
Extra : out Char_As_Digit;
+ Extra_Rounded : out Boolean;
Base_Violation : in out Boolean);
-- Scan the integral part of a real (i.e. before decimal separator)
--
@@ -93,7 +94,7 @@ package body System.Value_R is
-- For each digit parsed, either Value := Value * Base + Digit or Scale
-- is incremented by 1 if precision limit is reached, in which case the
-- remaining digits are still parsed but ignored, except for the first
- -- which is stored in Extra.
+ -- which is stored in Extra, rounded if Extra_Rounded is True.
--
-- Base_Violation is set to True if a digit found is not part of the Base
--
@@ -207,18 +208,22 @@ package body System.Value_R is
-- Number of trailing zeros at a given point
begin
- -- If initial Scale is not 0 then it means that Precision_Limit was
+ -- If initial Scale is not 0, then this means that Precision_Limit was
-- reached during scanning of the integral part.
if Scale (Data_Index'Last) > 0 then
Precision_Limit_Reached := True;
+
+ if Round then
+ Precision_Limit_Just_Reached := True;
+ end if;
else
Extra := 0;
Precision_Limit_Reached := False;
- end if;
- if Round then
- Precision_Limit_Just_Reached := False;
+ if Round then
+ Precision_Limit_Just_Reached := False;
+ end if;
end if;
-- Initialize trailing zero counter
@@ -373,6 +378,7 @@ package body System.Value_R is
Scale : out Scale_Array;
N : out Positive;
Extra : out Char_As_Digit;
+ Extra_Rounded : out Boolean;
Base_Violation : in out Boolean)
is
pragma Assert (Base in 2 .. 16);
@@ -398,12 +404,13 @@ package body System.Value_R is
-- Temporary
begin
- -- Initialize N, Value, Scale and Extra
+ -- Initialize N, Value, Scale, Extra and Extra_Rounded
N := 1;
Value := (others => 0);
Scale := (others => 0);
Extra := 0;
+ Extra_Rounded := False;
Precision_Limit_Reached := False;
@@ -443,6 +450,7 @@ package body System.Value_R is
if Round and then Precision_Limit_Just_Reached then
Round_Extra (Digit, Base, Value (N), Scale (N), Extra);
+ Extra_Rounded := True;
Precision_Limit_Just_Reached := False;
end if;
@@ -536,6 +544,9 @@ package body System.Value_R is
-- If True some digits where not in the base. The real is still scanned
-- till the end even if an error will be raised.
+ Extra_Rounded : Boolean;
+ -- True if Extra has been rounded
+
N : Positive;
-- Index number of the current part
@@ -585,7 +596,7 @@ package body System.Value_R is
Scan_Integral_Digits
(Str, Index, Max, Base, False, Value, Scale, N,
- Char_As_Digit (Extra), Base_Violation);
+ Char_As_Digit (Extra), Extra_Rounded, Base_Violation);
-- A dot is allowed only if followed by a digit (RM 3.5(39.8))
@@ -599,6 +610,7 @@ package body System.Value_R is
Value := (others => 0);
Scale := (others => 0);
Extra := 0;
+ Extra_Rounded := False;
else
Bad_Value (Str);
@@ -648,7 +660,7 @@ package body System.Value_R is
Scan_Integral_Digits
(Str, Index, Max, Base, Base_Char /= ASCII.NUL, Value, Scale,
- N, Char_As_Digit (Extra), Base_Violation);
+ N, Char_As_Digit (Extra), Extra_Rounded, Base_Violation);
end if;
-- Do we have a dot?
@@ -673,9 +685,22 @@ package body System.Value_R is
if After_Point then
pragma Assert (Index <= Max);
- Scan_Decimal_Digits
- (Str, Index, Max, Base, Base_Char /= ASCII.NUL, Value, Scale,
- N, Char_As_Digit (Extra), Base_Violation);
+ -- If Extra has been rounded, we are done with it
+
+ if Extra_Rounded then
+ declare
+ Dummy : Unsigned := 0;
+ begin
+ Scan_Decimal_Digits
+ (Str, Index, Max, Base, Base_Char /= ASCII.NUL, Value, Scale,
+ N, Dummy, Base_Violation);
+ end;
+
+ else
+ Scan_Decimal_Digits
+ (Str, Index, Max, Base, Base_Char /= ASCII.NUL, Value, Scale,
+ N, Char_As_Digit (Extra), Base_Violation);
+ end if;
end if;
-- If an explicit base was specified ensure that the delimiter is found
--
2.43.0
