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author | Steve Baird <baird@adacore.com> | 2021-07-14 16:55:28 -0700 |
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committer | Pierre-Marie de Rodat <derodat@adacore.com> | 2021-09-22 15:01:44 +0000 |
commit | e41e989b42c4f3ddda55b6c2068d14bf5aa7136c (patch) | |
tree | 644ac4687ebd306c42d88342659ab781fd21b052 /gcc | |
parent | 7e7c4aeb6e16dc367764a7bc028a9c4c6fc87449 (diff) | |
download | gcc-e41e989b42c4f3ddda55b6c2068d14bf5aa7136c.zip gcc-e41e989b42c4f3ddda55b6c2068d14bf5aa7136c.tar.gz gcc-e41e989b42c4f3ddda55b6c2068d14bf5aa7136c.tar.bz2 |
[Ada] Improve performance for case-insensitive regular expressions
gcc/ada/
* libgnat/s-regpat.adb (Match): Handle the case where Self.First
is not NUL (so we know the first character we are looking for),
but case-insensitive matching has
been specified.
(Optimize): In the case of an EXACTF Op, set Self.First as is
done in the EXACT case, except with the addition of a call to
Lower_Case.
Diffstat (limited to 'gcc')
-rw-r--r-- | gcc/ada/libgnat/s-regpat.adb | 63 |
1 files changed, 53 insertions, 10 deletions
diff --git a/gcc/ada/libgnat/s-regpat.adb b/gcc/ada/libgnat/s-regpat.adb index 7e33067..b40f682 100644 --- a/gcc/ada/libgnat/s-regpat.adb +++ b/gcc/ada/libgnat/s-regpat.adb @@ -3463,18 +3463,58 @@ package body System.Regpat is end; elsif Self.First /= ASCII.NUL then - -- We know what char it must start with + -- We know what char (modulo casing) it must start with - declare - Next_Try : Natural := Index (First_In_Data, Self.First); + if (Self.Flags and Case_Insensitive) = 0 + or else Self.First not in 'a' .. 'z' + then + declare + Next_Try : Natural := Index (First_In_Data, Self.First); + begin + while Next_Try /= 0 loop + Matched := Try (Next_Try); + exit when Matched; + Next_Try := Index (Next_Try + 1, Self.First); + end loop; + end; + else + declare + Uc_First : constant Character := To_Upper (Self.First); + + function Case_Insensitive_Index + (Start : Positive) return Natural; + -- Search for both Self.First and To_Upper (Self.First). + -- If both are nonzero, return the smaller one; if exactly + -- one is nonzero, return it; if both are zero, return zero. + + --------------------------- + -- Case_Insenstive_Index -- + --------------------------- + + function Case_Insensitive_Index + (Start : Positive) return Natural + is + Lc_Index : constant Natural := Index (Start, Self.First); + Uc_Index : constant Natural := Index (Start, Uc_First); + begin + if Lc_Index = 0 then + return Uc_Index; + elsif Uc_Index = 0 then + return Lc_Index; + else + return Natural'Min (Lc_Index, Uc_Index); + end if; + end Case_Insensitive_Index; - begin - while Next_Try /= 0 loop - Matched := Try (Next_Try); - exit when Matched; - Next_Try := Index (Next_Try + 1, Self.First); - end loop; - end; + Next_Try : Natural := Case_Insensitive_Index (First_In_Data); + begin + while Next_Try /= 0 loop + Matched := Try (Next_Try); + exit when Matched; + Next_Try := Case_Insensitive_Index (Next_Try + 1); + end loop; + end; + end if; else -- Messy cases: try all locations (including for the empty string) @@ -3634,6 +3674,9 @@ package body System.Regpat is if Program (Scan) = EXACT then Self.First := Program (String_Operand (Scan)); + elsif Program (Scan) = EXACTF then + Self.First := To_Lower (Program (String_Operand (Scan))); + elsif Program (Scan) = BOL or else Program (Scan) = SBOL or else Program (Scan) = MBOL |