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author | Erlang/OTP <[email protected]> | 2009-11-20 14:54:40 +0000 |
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committer | Erlang/OTP <[email protected]> | 2009-11-20 14:54:40 +0000 |
commit | 84adefa331c4159d432d22840663c38f155cd4c1 (patch) | |
tree | bff9a9c66adda4df2106dfd0e5c053ab182a12bd /lib/inets/src/inets_app/inets_regexp.erl | |
download | otp-84adefa331c4159d432d22840663c38f155cd4c1.tar.gz otp-84adefa331c4159d432d22840663c38f155cd4c1.tar.bz2 otp-84adefa331c4159d432d22840663c38f155cd4c1.zip |
The R13B03 release.OTP_R13B03
Diffstat (limited to 'lib/inets/src/inets_app/inets_regexp.erl')
-rw-r--r-- | lib/inets/src/inets_app/inets_regexp.erl | 413 |
1 files changed, 413 insertions, 0 deletions
diff --git a/lib/inets/src/inets_app/inets_regexp.erl b/lib/inets/src/inets_app/inets_regexp.erl new file mode 100644 index 0000000000..a065533236 --- /dev/null +++ b/lib/inets/src/inets_app/inets_regexp.erl @@ -0,0 +1,413 @@ +%% +%% %CopyrightBegin% +%% +%% Copyright Ericsson AB 2009. All Rights Reserved. +%% +%% The contents of this file are subject to the Erlang Public License, +%% Version 1.1, (the "License"); you may not use this file except in +%% compliance with the License. You should have received a copy of the +%% Erlang Public License along with this software. If not, it can be +%% retrieved online at http://www.erlang.org/. +%% +%% Software distributed under the License is distributed on an "AS IS" +%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See +%% the License for the specific language governing rights and limitations +%% under the License. +%% +%% %CopyrightEnd% +%% + +-module(inets_regexp). + +-export([parse/1, match/2, first_match/2, split/2, sub/3, gsub/3]). + + +%%%========================================================================= +%%% API +%%%========================================================================= + +%% parse(RegExp) -> {ok, RE} | {error, E}. +%% Parse the regexp described in the string RegExp. + +parse(S) -> + case (catch reg(S)) of + {R, []} -> + {ok, R}; + {_R, [C|_]} -> + {error, {illegal, [C]}}; + {error, E} -> + {error, E} + end. + + +%% Find the longest match of RegExp in String. + +match(S, RegExp) when is_list(RegExp) -> + case parse(RegExp) of + {ok,RE} -> match(S, RE); + {error,E} -> {error,E} + end; +match(S, RE) -> + case match(RE, S, 1, 0, -1) of + {Start,Len} when Len >= 0 -> + {match, Start, Len}; + {_Start,_Len} -> + nomatch + end. + +%% Find the first match of RegExp in String. + +first_match(S, RegExp) when is_list(RegExp) -> + case parse(RegExp) of + {ok, RE} -> + first_match(S, RE); + {error, E} -> + {error, E} + end; +first_match(S, RE) -> + case first_match(RE, S, 1) of + {Start,Len} when Len >= 0 -> + {match, Start,Len}; + nomatch -> + nomatch + end. + +first_match(RE, S, St) when S =/= [] -> + case re_apply(S, St, RE) of + {match, P, _Rest} -> + {St, P-St}; + nomatch -> + first_match(RE, tl(S), St+1) + end; +first_match(_RE, [], _St) -> + nomatch. + + +match(RE, S, St, Pos, L) -> + case first_match(RE, S, St) of + {St1, L1} -> + Nst = St1 + 1, + if L1 > L -> + match(RE, lists:nthtail(Nst-St, S), Nst, St1, L1); + true -> + match(RE, lists:nthtail(Nst-St, S), Nst, Pos, L) + end; + nomatch -> + {Pos, L} + end. + + +%% Split a string into substrings where the RegExp describes the +%% field seperator. The RegExp " " is specially treated. + +split(String, " ") -> %This is really special + {ok, RE} = parse("[ \t]+"), + case split_apply(String, RE, true) of + [[]|Ss] -> + {ok,Ss}; + Ss -> + {ok,Ss} + end; +split(String, RegExp) when is_list(RegExp) -> + case parse(RegExp) of + {ok, RE} -> + {ok, split_apply(String, RE, false)}; + {error, E} -> + {error,E} + end; +split(String, RE) -> + {ok, split_apply(String, RE, false)}. + + +%% Substitute the first match of the regular expression RegExp +%% with the string Replace in String. Accept pre-parsed regular +%% expressions. + +sub(String, RegExp, Rep) when is_list(RegExp) -> + case parse(RegExp) of + {ok, RE} -> + sub(String, RE, Rep); + {error, E} -> + {error, E} + end; +sub(String, RE, Rep) -> + Ss = sub_match(String, RE, 1), + {ok, sub_repl(Ss, Rep, String, 1), length(Ss)}. + + +%% Substitute every match of the regular expression RegExp with +%% the string New in String. Accept pre-parsed regular expressions. + +gsub(String, RegExp, Rep) when is_list(RegExp) -> + case parse(RegExp) of + {ok, RE} -> + gsub(String, RE, Rep); + {error, E} -> + {error, E} + end; +gsub(String, RE, Rep) -> + Ss = matches(String, RE, 1), + {ok, sub_repl(Ss, Rep, String, 1), length(Ss)}. + + +%%%======================================================================== +%%% Internal functions +%%%======================================================================== + +%% This is the regular expression grammar used. It is equivalent to the +%% one used in AWK, except that we allow ^ $ to be used anywhere and fail +%% in the matching. +%% +%% reg -> reg1 : '$1'. +%% reg1 -> reg1 "|" reg2 : {'or','$1','$2'}. +%% reg1 -> reg2 : '$1'. +%% reg2 -> reg2 reg3 : {concat,'$1','$2'}. +%% reg2 -> reg3 : '$1'. +%% reg3 -> reg3 "*" : {kclosure,'$1'}. +%% reg3 -> reg3 "+" : {pclosure,'$1'}. +%% reg3 -> reg3 "?" : {optional,'$1'}. +%% reg3 -> reg4 : '$1'. +%% reg4 -> "(" reg ")" : '$2'. +%% reg4 -> "\\" char : '$2'. +%% reg4 -> "^" : bos. +%% reg4 -> "$" : eos. +%% reg4 -> "." : char. +%% reg4 -> "[" class "]" : {char_class,char_class('$2')} +%% reg4 -> "[" "^" class "]" : {comp_class,char_class('$3')} +%% reg4 -> "\"" chars "\"" : char_string('$2') +%% reg4 -> char : '$1'. +%% reg4 -> empty : epsilon. +%% The grammar of the current regular expressions. The actual parser +%% is a recursive descent implementation of the grammar. + +reg(S) -> reg1(S). + +%% reg1 -> reg2 reg1' +%% reg1' -> "|" reg2 +%% reg1' -> empty + +reg1(S0) -> + {L,S1} = reg2(S0), + reg1p(S1, L). + +reg1p([$||S0], L) -> + {R,S1} = reg2(S0), + reg1p(S1, {'or',L,R}); +reg1p(S, L) -> {L,S}. + +%% reg2 -> reg3 reg2' +%% reg2' -> reg3 +%% reg2' -> empty + +reg2(S0) -> + {L,S1} = reg3(S0), + reg2p(S1, L). + +reg2p([C|S0], L) when (C =/= $|) andalso (C =/= $)) -> + {R,S1} = reg3([C|S0]), + reg2p(S1, {concat,L,R}); +reg2p(S, L) -> {L,S}. + +%% reg3 -> reg4 reg3' +%% reg3' -> "*" reg3' +%% reg3' -> "+" reg3' +%% reg3' -> "?" reg3' +%% reg3' -> empty + +reg3(S0) -> + {L,S1} = reg4(S0), + reg3p(S1, L). + +reg3p([$*|S], L) -> reg3p(S, {kclosure,L}); +reg3p([$+|S], L) -> reg3p(S, {pclosure,L}); +reg3p([$?|S], L) -> reg3p(S, {optional,L}); +reg3p(S, L) -> {L,S}. + +reg4([$(|S0]) -> + case reg(S0) of + {R,[$)|S1]} -> {R,S1}; + {_R,_S} -> throw({error,{unterminated,"("}}) + end; +reg4([$\\,O1,O2,O3|S]) + when ((O1 >= $0) andalso + (O1 =< $7) andalso + (O2 >= $0) andalso + (O2 =< $7) andalso + (O3 >= $0) andalso + (O3 =< $7)) -> + {(O1*8 + O2)*8 + O3 - 73*$0,S}; +reg4([$\\,C|S]) -> + {escape_char(C),S}; +reg4([$\\]) -> + throw({error, {unterminated,"\\"}}); +reg4([$^|S]) -> + {bos,S}; +reg4([$$|S]) -> + {eos,S}; +reg4([$.|S]) -> + {{comp_class,"\n"},S}; +reg4("[^" ++ S0) -> + case char_class(S0) of + {Cc,[$]|S1]} -> {{comp_class,Cc},S1}; + {_Cc,_S} -> throw({error,{unterminated,"["}}) + end; +reg4([$[|S0]) -> + case char_class(S0) of + {Cc,[$]|S1]} -> {{char_class,Cc},S1}; + {_Cc,_S1} -> throw({error,{unterminated,"["}}) + end; +reg4([C|S]) + when (C =/= $*) andalso (C =/= $+) andalso (C =/= $?) andalso (C =/= $]) -> + {C, S}; +reg4([C|_S]) -> + throw({error,{illegal,[C]}}); +reg4([]) -> + {epsilon,[]}. + +escape_char($n) -> $\n; %\n = LF +escape_char($r) -> $\r; %\r = CR +escape_char($t) -> $\t; %\t = TAB +escape_char($v) -> $\v; %\v = VT +escape_char($b) -> $\b; %\b = BS +escape_char($f) -> $\f; %\f = FF +escape_char($e) -> $\e; %\e = ESC +escape_char($s) -> $\s; %\s = SPACE +escape_char($d) -> $\d; %\d = DEL +escape_char(C) -> C. + +char_class([$]|S]) -> char_class(S, [$]]); +char_class(S) -> char_class(S, []). + +char($\\, [O1,O2,O3|S]) when + O1 >= $0, O1 =< $7, O2 >= $0, O2 =< $7, O3 >= $0, O3 =< $7 -> + {(O1*8 + O2)*8 + O3 - 73*$0,S}; +char($\\, [C|S]) -> {escape_char(C),S}; +char(C, S) -> {C,S}. + +char_class([C1|S0], Cc) when C1 =/= $] -> + case char(C1, S0) of + {Cf,[$-,C2|S1]} when C2 =/= $] -> + case char(C2, S1) of + {Cl,S2} when Cf < Cl -> char_class(S2, [{Cf,Cl}|Cc]); + {Cl,_S2} -> throw({error,{char_class,[Cf,$-,Cl]}}) + end; + {C,S1} -> char_class(S1, [C|Cc]) + end; +char_class(S, Cc) -> {Cc,S}. + + +%% re_apply(String, StartPos, RegExp) -> re_app_res(). +%% +%% Apply the (parse of the) regular expression RegExp to String. If +%% there is a match return the position of the remaining string and +%% the string if else return 'nomatch'. BestMatch specifies if we want +%% the longest match, or just a match. +%% +%% StartPos should be the real start position as it is used to decide +%% if we ae at the beginning of the string. +%% +%% Pass two functions to re_apply_or so it can decide, on the basis +%% of BestMatch, whether to just any take any match or try both to +%% find the longest. This is slower but saves duplicatng code. + +re_apply(S, St, RE) -> re_apply(RE, [], S, St). + +re_apply(epsilon, More, S, P) -> %This always matches + re_apply_more(More, S, P); +re_apply({'or',RE1,RE2}, More, S, P) -> + re_apply_or(re_apply(RE1, More, S, P), + re_apply(RE2, More, S, P)); +re_apply({concat,RE1,RE2}, More, S0, P) -> + re_apply(RE1, [RE2|More], S0, P); +re_apply({kclosure,CE}, More, S, P) -> + %% Be careful with the recursion, explicitly do one call before + %% looping. + re_apply_or(re_apply_more(More, S, P), + re_apply(CE, [{kclosure,CE}|More], S, P)); +re_apply({pclosure,CE}, More, S, P) -> + re_apply(CE, [{kclosure,CE}|More], S, P); +re_apply({optional,CE}, More, S, P) -> + re_apply_or(re_apply_more(More, S, P), + re_apply(CE, More, S, P)); +re_apply(bos, More, S, 1) -> re_apply_more(More, S, 1); +re_apply(eos, More, [$\n|S], P) -> re_apply_more(More, S, P); +re_apply(eos, More, [], P) -> re_apply_more(More, [], P); +re_apply({char_class,Cc}, More, [C|S], P) -> + case in_char_class(C, Cc) of + true -> re_apply_more(More, S, P+1); + false -> nomatch + end; +re_apply({comp_class,Cc}, More, [C|S], P) -> + case in_char_class(C, Cc) of + true -> nomatch; + false -> re_apply_more(More, S, P+1) + end; +re_apply(C, More, [C|S], P) when is_integer(C) -> + re_apply_more(More, S, P+1); +re_apply(_RE, _More, _S, _P) -> nomatch. + +%% re_apply_more([RegExp], String, Length) -> re_app_res(). + +re_apply_more([RE|More], S, P) -> re_apply(RE, More, S, P); +re_apply_more([], S, P) -> {match,P,S}. + +%% in_char_class(Char, Class) -> bool(). + +in_char_class(C, [{C1,C2}|_Cc]) when C >= C1, C =< C2 -> true; +in_char_class(C, [C|_Cc]) -> true; +in_char_class(C, [_|Cc]) -> in_char_class(C, Cc); +in_char_class(_C, []) -> false. + +%% re_apply_or(Match1, Match2) -> re_app_res(). +%% If we want the best match then choose the longest match, else just +%% choose one by trying sequentially. + +re_apply_or({match,P1,S1}, {match,P2,_S2}) when P1 >= P2 -> {match,P1,S1}; +re_apply_or({match,_P1,_S1}, {match,P2,S2}) -> {match,P2,S2}; +re_apply_or(nomatch, R2) -> R2; +re_apply_or(R1, nomatch) -> R1. + + +matches(S, RE, St) -> + case first_match(RE, S, St) of + {St1,0} -> + [{St1,0}|matches(string:substr(S, St1+2-St), RE, St1+1)]; + {St1,L1} -> + [{St1,L1}|matches(string:substr(S, St1+L1+1-St), RE, St1+L1)]; + nomatch -> + [] + end. + +sub_match(S, RE, St) -> + case first_match(RE, S, St) of + {St1,L1} -> [{St1,L1}]; + nomatch -> [] + end. + +sub_repl([{St,L}|Ss], Rep, S, Pos) -> + Rs = sub_repl(Ss, Rep, S, St+L), + string:substr(S, Pos, St-Pos) ++ + sub_repl(Rep, string:substr(S, St, L), Rs); +sub_repl([], _Rep, S, Pos) -> + string:substr(S, Pos). + +sub_repl([$&|Rep], M, Rest) -> M ++ sub_repl(Rep, M, Rest); +sub_repl("\\&" ++ Rep, M, Rest) -> [$&|sub_repl(Rep, M, Rest)]; +sub_repl([C|Rep], M, Rest) -> [C|sub_repl(Rep, M, Rest)]; +sub_repl([], _M, Rest) -> Rest. + +split_apply(S, RE, Trim) -> split_apply(S, 1, RE, Trim, []). + +split_apply([], _P, _RE, true, []) -> + []; +split_apply([], _P, _RE, _T, Sub) -> + [lists:reverse(Sub)]; +split_apply(S, P, RE, T, Sub) -> + case re_apply(S, P, RE) of + {match,P,_Rest} -> + split_apply(tl(S), P+1, RE, T, [hd(S)|Sub]); + {match,P1,Rest} -> + [lists:reverse(Sub)|split_apply(Rest, P1, RE, T, [])]; + nomatch -> + split_apply(tl(S), P+1, RE, T, [hd(S)|Sub]) + end. |