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authorBjörn Gustavsson <[email protected]>2015-02-18 12:51:57 +0100
committerBjörn Gustavsson <[email protected]>2015-02-18 12:51:57 +0100
commit9d8327c62a981bcc436e5f9fc5466f5539dce3dc (patch)
tree13c8fe46f845d5079d688d7dfedc57e6fb3e4feb /lib
parent34d000d6cd35b3ae3a8b37b8dcf494d8ed5840c1 (diff)
parent53288b441ec721ce3bbdcc4ad65b75e11acc5e1b (diff)
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Merge branch 'bjorn/stdlib/string-tokens/OTP-12422'
* bjorn/stdlib/string-tokens/OTP-12422: Optimize string:tokens/2 Modernize and strengthen the test case for string:tokens/2
Diffstat (limited to 'lib')
-rw-r--r--lib/stdlib/src/string.erl46
-rw-r--r--lib/stdlib/test/string_SUITE.erl40
2 files changed, 64 insertions, 22 deletions
diff --git a/lib/stdlib/src/string.erl b/lib/stdlib/src/string.erl
index f9b083a56d..f6903d1c3d 100644
--- a/lib/stdlib/src/string.erl
+++ b/lib/stdlib/src/string.erl
@@ -221,23 +221,47 @@ substr2([_|String], S) -> substr2(String, S-1).
Tokens :: [Token :: nonempty_string()].
tokens(S, Seps) ->
- tokens1(S, Seps, []).
+ case Seps of
+ [] ->
+ case S of
+ [] -> [];
+ [_|_] -> [S]
+ end;
+ [C] ->
+ tokens_single_1(reverse(S), C, []);
+ [_|_] ->
+ tokens_multiple_1(reverse(S), Seps, [])
+ end.
-tokens1([C|S], Seps, Toks) ->
+tokens_single_1([Sep|S], Sep, Toks) ->
+ tokens_single_1(S, Sep, Toks);
+tokens_single_1([C|S], Sep, Toks) ->
+ tokens_single_2(S, Sep, Toks, [C]);
+tokens_single_1([], _, Toks) ->
+ Toks.
+
+tokens_single_2([Sep|S], Sep, Toks, Tok) ->
+ tokens_single_1(S, Sep, [Tok|Toks]);
+tokens_single_2([C|S], Sep, Toks, Tok) ->
+ tokens_single_2(S, Sep, Toks, [C|Tok]);
+tokens_single_2([], _Sep, Toks, Tok) ->
+ [Tok|Toks].
+
+tokens_multiple_1([C|S], Seps, Toks) ->
case member(C, Seps) of
- true -> tokens1(S, Seps, Toks);
- false -> tokens2(S, Seps, Toks, [C])
+ true -> tokens_multiple_1(S, Seps, Toks);
+ false -> tokens_multiple_2(S, Seps, Toks, [C])
end;
-tokens1([], _Seps, Toks) ->
- reverse(Toks).
+tokens_multiple_1([], _Seps, Toks) ->
+ Toks.
-tokens2([C|S], Seps, Toks, Cs) ->
+tokens_multiple_2([C|S], Seps, Toks, Tok) ->
case member(C, Seps) of
- true -> tokens1(S, Seps, [reverse(Cs)|Toks]);
- false -> tokens2(S, Seps, Toks, [C|Cs])
+ true -> tokens_multiple_1(S, Seps, [Tok|Toks]);
+ false -> tokens_multiple_2(S, Seps, Toks, [C|Tok])
end;
-tokens2([], _Seps, Toks, Cs) ->
- reverse([reverse(Cs)|Toks]).
+tokens_multiple_2([], _Seps, Toks, Tok) ->
+ [Tok|Toks].
-spec chars(Character, Number) -> String when
Character :: char(),
diff --git a/lib/stdlib/test/string_SUITE.erl b/lib/stdlib/test/string_SUITE.erl
index fccd1bef95..a55c710d50 100644
--- a/lib/stdlib/test/string_SUITE.erl
+++ b/lib/stdlib/test/string_SUITE.erl
@@ -217,21 +217,39 @@ substr(Config) when is_list(Config) ->
?line {'EXIT',_} = (catch string:substr("1234", "1")),
ok.
-tokens(suite) ->
- [];
-tokens(doc) ->
- [];
tokens(Config) when is_list(Config) ->
- ?line [] = string:tokens("",""),
- ?line [] = string:tokens("abc","abc"),
- ?line ["abc"] = string:tokens("abc", ""),
- ?line ["1","2 34","4","5"] = string:tokens("1,2 34,4;5", ";,"),
- %% invalid arg type
- ?line {'EXIT',_} = (catch string:tokens('x,y', ",")),
+ [] = string:tokens("",""),
+ [] = string:tokens("abc","abc"),
+ ["abc"] = string:tokens("abc", ""),
+ ["1","2 34","45","5","6","7"] = do_tokens("1,2 34,45;5,;6;,7", ";,"),
+
%% invalid arg type
- ?line {'EXIT',_} = (catch string:tokens("x,y", ',')),
+ {'EXIT',_} = (catch string:tokens('x,y', ",")),
+ {'EXIT',_} = (catch string:tokens("x,y", ',')),
ok.
+do_tokens(S0, Sep0) ->
+ [H|T] = Sep0,
+ S = [replace_sep(C, T, H) || C <- S0],
+ Sep = [H],
+ io:format("~p ~p\n", [S0,Sep0]),
+ io:format("~p ~p\n", [S,Sep]),
+
+ Res = string:tokens(S0, Sep0),
+ Res = string:tokens(Sep0++S0, Sep0),
+ Res = string:tokens(S0++Sep0, Sep0),
+
+ Res = string:tokens(S, Sep),
+ Res = string:tokens(Sep++S, Sep),
+ Res = string:tokens(S++Sep, Sep),
+
+ Res.
+
+replace_sep(C, Seps, New) ->
+ case lists:member(C, Seps) of
+ true -> New;
+ false -> C
+ end.
chars(suite) ->
[];