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Adding unix filename pattern matching to GNATCOLL
TN: T915-017 Change-Id: Ie1fabaccdaece97fc2d18a913172c19027a18409
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‎src/gnatcoll-utils.adb‎

Lines changed: 253 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -869,6 +869,259 @@ package body GNATCOLL.Utils is
869869
return Str'Last;
870870
end Line_End;
871871

872+
-----------
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-- Match --
874+
-----------
875+
876+
function Match (Str : String; Pattern : String) return Boolean
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is
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-- P_I and S_I are index to next character to read in respectively
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-- Pattern and String
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P_I : Natural := Pattern'First;
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S_I : Natural := Str'First;
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-- P_C and S_C contain the current character to be processed for
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-- Pattern and String
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P_C : Character;
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S_C : Character;
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procedure Next_Str_Char;
890+
-- Read the next chracter in String. Adjust S_C and S_I. When no
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-- character is available in String then S_C is set to ASCII.NUL.
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pragma Inline (Next_Str_Char);
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procedure Next_Pattern_Char;
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-- Read the next chracter in Pattern. Adjust P_C and P_I. When no
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-- character is available in Pattern then P_C is set to ASCII.NUL.
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pragma Inline (Next_Pattern_Char);
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899+
function Lookahead_Pattern
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(N : Positive)
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return Character;
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-- Return character which is at N position of the current one without
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-- updating P_I
904+
905+
function Bracket_Match return Boolean;
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-- Return True if next character in Str match a bracket expression.
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-------------------
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-- Bracket_Match --
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-------------------
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function Bracket_Match return Boolean is
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Saved_P_I : constant Natural := P_I;
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Is_Negation : Boolean := False;
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Has_Closing_Bracket : Boolean := False;
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Result : Boolean := False;
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begin
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if Lookahead_Pattern (1) in '^' | '!' then
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Is_Negation := True;
921+
Next_Pattern_Char;
922+
end if;
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loop
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Next_Pattern_Char;
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case P_C is
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when ASCII.NUL =>
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exit;
929+
when ']' =>
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Has_Closing_Bracket := True;
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exit;
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when others =>
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-- This is either a character match or a range
934+
declare
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Range_Start : constant Character := P_C;
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Range_End : Character := P_C;
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begin
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if Lookahead_Pattern (1) = '-' and then
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Lookahead_Pattern (2) not in ASCII.NUL | ']'
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then
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-- this is a range
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Next_Pattern_Char;
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Next_Pattern_Char;
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Range_End := P_C;
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end if;
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if S_C in Range_Start .. Range_End then
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Result := True;
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exit;
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end if;
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end;
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end case;
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end loop;
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if Result then
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-- Go to next closing bracket
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while P_C /= ASCII.NUL loop
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Next_Pattern_Char;
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if P_C = ']' then
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Has_Closing_Bracket := True;
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exit;
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end if;
962+
end loop;
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end if;
964+
965+
if not Has_Closing_Bracket then
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P_I := Saved_P_I;
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return S_C = '[';
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else
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if Is_Negation then
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return not Result;
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else
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return Result;
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end if;
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end if;
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end Bracket_Match;
976+
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-----------------------
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-- Lookahead_Pattern --
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-----------------------
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981+
function Lookahead_Pattern
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(N : Positive)
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return Character
984+
is
985+
begin
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987+
if P_I + N - 1 <= Pattern'Last then
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return Pattern (P_I + N - 1);
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else
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return ASCII.NUL;
991+
end if;
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end Lookahead_Pattern;
993+
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-----------------------
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-- Next_Pattern_Char --
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-----------------------
997+
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procedure Next_Pattern_Char is
999+
begin
1000+
if P_I <= Pattern'Last then
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P_C := Pattern (P_I);
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P_I := P_I + 1;
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else
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P_C := ASCII.NUL;
1005+
end if;
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end Next_Pattern_Char;
1007+
1008+
-------------------
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-- Next_Str_Char --
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-------------------
1011+
1012+
procedure Next_Str_Char is
1013+
begin
1014+
if S_I <= Str'Last then
1015+
S_C := Str (S_I);
1016+
S_I := S_I + 1;
1017+
else
1018+
S_C := ASCII.NUL;
1019+
end if;
1020+
end Next_Str_Char;
1021+
1022+
begin
1023+
1024+
-- Handle special cases in which Pattern is an empty string
1025+
if Pattern'Length = 0 then
1026+
if Str'Length = 0 then
1027+
return True;
1028+
else
1029+
return False;
1030+
end if;
1031+
end if;
1032+
1033+
while P_I <= Pattern'Last loop
1034+
Next_Pattern_Char;
1035+
1036+
case P_C is
1037+
when '?' =>
1038+
-- A '?' is a pattern that shall match any character.
1039+
-- The only case when match fails is when there is no more
1040+
-- character to read from Str.
1041+
Next_Str_Char;
1042+
if S_C = ASCII.NUL then
1043+
return False;
1044+
end if;
1045+
1046+
when '\' =>
1047+
-- Special characters can be escaped to remove their special
1048+
-- meaning by preceding them with a '\' character.
1049+
-- This escaping '\' is discarded. The sequence "\\"
1050+
-- represents one literal '\'.
1051+
1052+
-- Trailing backslash in the pattern result in an invalid
1053+
-- pattern.
1054+
if P_I > Pattern'Last then
1055+
return False;
1056+
end if;
1057+
1058+
Next_Pattern_Char;
1059+
Next_Str_Char;
1060+
1061+
if S_C /= P_C then
1062+
return False;
1063+
end if;
1064+
1065+
when '[' =>
1066+
Next_Str_Char;
1067+
if not Bracket_Match then
1068+
return False;
1069+
end if;
1070+
1071+
when '*' =>
1072+
-- Collapse multiple successive '?' and '*'.
1073+
-- For successive ' * ' there is nothing to do.
1074+
-- For '?' only a character on Str is needed.
1075+
while Lookahead_Pattern (1) in '*' | '?' loop
1076+
1077+
Next_Pattern_Char;
1078+
1079+
if P_C = '?' then
1080+
if S_C = ASCII.NUL then
1081+
return False;
1082+
end if;
1083+
1084+
Next_Str_Char;
1085+
end if;
1086+
1087+
end loop;
1088+
1089+
-- If we reach the end of the Pattern then match is ensured.
1090+
if P_I > Pattern'Last then
1091+
return True;
1092+
end if;
1093+
1094+
-- Try all string suffixes against remaining part of the
1095+
-- pattern. This simulates how many characters are consumed
1096+
-- by the '*'. (0, 1, ...).
1097+
-- The recursion is not infinite as next character in the
1098+
-- pattern will consume a character from Str
1099+
-- (i.e next character in Pattern is not a ' * ').
1100+
1101+
for Index in S_I .. Str'Last loop
1102+
if Match
1103+
(Str (Index .. Str'Last),
1104+
Pattern (P_I .. Pattern'Last))
1105+
then
1106+
return True;
1107+
end if;
1108+
end loop;
1109+
1110+
return False;
1111+
1112+
when others =>
1113+
Next_Str_Char;
1114+
if S_C /= P_C then
1115+
return False;
1116+
end if;
1117+
end case;
1118+
1119+
end loop;
1120+
1121+
return S_I > Str'Last;
1122+
1123+
end Match;
1124+
8721125
---------------
8731126
-- Next_Line --
8741127
---------------

‎src/gnatcoll-utils.ads‎

Lines changed: 8 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
------------------------------------------------------------------------------
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-- G N A T C O L L --
33
-- --
4-
-- Copyright (C) 2008-2020, AdaCore --
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-- Copyright (C) 2008-2022, AdaCore --
55
-- --
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-- This library is free software; you can redistribute it and/or modify it --
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-- under terms of the GNU General Public License as published by the Free --
@@ -234,6 +234,13 @@ package GNATCOLL.Utils is
234234
-- languages). It doesn't check whether the identifier starts with an
235235
-- underscore for instance, just whether the characters would be valid.
236236

237+
function Match (Str : String; Pattern : String) return Boolean;
238+
-- Implementation of POSIX pattern matching
239+
--
240+
-- @param Str string to check
241+
-- @param Pattern a posix pattern
242+
-- @return True if Str matches Pattern, False otherwise
243+
237244
------------
238245
-- Expect --
239246
------------

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