Merge pull request erlang#7590 from juhlig/binary_replace_fun

Binary replacement with a function OTP-18742
bjorng · Aug 30, 2023 · 334589a · 334589a
2 parents 98b158d + 6ec2a71
commit 334589a
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diff --git a/lib/stdlib/doc/src/binary.xml b/lib/stdlib/doc/src/binary.xml
@@ -512,41 +512,60 @@ store(Binary, GBSet) ->
       <name name="replace" arity="4" since="OTP R14B"/>
       <fsummary>Replace bytes in a binary according to a pattern.</fsummary>
       <type_desc variable="OnePos">An integer() =&lt; byte_size(<anno>Replacement</anno>)
-      </type_desc>
+        if <anno>Replacement</anno> is given as a binary.</type_desc>
       <desc>
-      <p>Constructs a new binary by replacing the parts in
-      <c><anno>Subject</anno></c> matching <c><anno>Pattern</anno></c> with
-      the content of <c><anno>Replacement</anno></c>.</p>
-
-      <p>If the matching subpart of <c><anno>Subject</anno></c> giving raise
-      to the replacement is to be inserted in the result, option
-      <c>{insert_replaced, <anno>InsPos</anno>}</c> inserts the matching part
-      into <c><anno>Replacement</anno></c> at the specified position (or
-      positions) before inserting <c><anno>Replacement</anno></c> into
-      <c><anno>Subject</anno></c>.</p>
+        <p>Constructs a new binary by replacing the parts in
+          <c><anno>Subject</anno></c> matching <c><anno>Pattern</anno></c> with
+          <c><anno>Replacement</anno></c> if given as a literal <c>binary()</c>
+          or with the result of applying <c><anno>Replacement</anno></c> to a matching
+          subpart if given as a <c>fun</c>.</p>
+
+        <p>If <c><anno>Replacement</anno></c> is given as a <c>binary()</c> and the
+          matching subpart of <c><anno>Subject</anno></c> giving raise
+          to the replacement is to be inserted in the result, option
+          <c>{insert_replaced, <anno>InsPos</anno>}</c> inserts the matching part
+          into <c><anno>Replacement</anno></c> at the specified position (or
+          positions) before inserting <c><anno>Replacement</anno></c> into
+          <c><anno>Subject</anno></c>. If <c><anno>Replacement</anno></c> is given
+          as a <c>fun</c> instead, this option is ignored.</p>
 
-      <p><em>Example:</em></p>
+        <p>If any position specified in <c><anno>InsPos</anno></c> &gt; size
+          of the replacement binary, a <c>badarg</c> exception is raised.</p>
 
-<code>
-1> binary:replace(&lt;&lt;"abcde"&gt;&gt;,&lt;&lt;"b"&gt;&gt;,&lt;&lt;"[]"&gt;&gt;, [{insert_replaced,1}]).
+        <p>Options <c>global</c> and <c>{scope, part()}</c> work as for
+          <seemfa marker="#split/3"><c>split/3</c></seemfa>.
+          The return type is always a <c>binary()</c>.</p>
+
+        <p>For a description of <c><anno>Pattern</anno></c>, see
+          <seemfa marker="#compile_pattern/1"><c>compile_pattern/1</c></seemfa>.</p>
+        <p><em>Examples:</em></p>
+
+<pre>
+1> <input>binary:replace(&lt;&lt;"abcde"&gt;&gt;, [&lt;&lt;"b"&gt;&gt;, &lt;&lt;"d"&gt;&gt;], &lt;&lt;"X"&gt;&gt;, []).</input>
+&lt;&lt;"aXcde"&gt;&gt;
+
+2> <input>binary:replace(&lt;&lt;"abcde"&gt;&gt;, [&lt;&lt;"b"&gt;&gt;, &lt;&lt;"d"&gt;&gt;], &lt;&lt;"X"&gt;&gt;, [global]).</input>
+&lt;&lt;"aXcXe"&gt;&gt;
+
+3> <input>binary:replace(&lt;&lt;"abcde"&gt;&gt;, &lt;&lt;"b"&gt;&gt;, &lt;&lt;"[]"&gt;&gt;, [{insert_replaced, 1}]).</input>
 &lt;&lt;"a[b]cde"&gt;&gt;
-2> binary:replace(&lt;&lt;"abcde"&gt;&gt;,[&lt;&lt;"b"&gt;&gt;,&lt;&lt;"d"&gt;&gt;],&lt;&lt;"[]"&gt;&gt;,[global,{insert_replaced,1}]).
+
+4> <input>binary:replace(&lt;&lt;"abcde"&gt;&gt;, [&lt;&lt;"b"&gt;&gt;, &lt;&lt;"d"&gt;&gt;], &lt;&lt;"[]"&gt;&gt;, [global, {insert_replaced, 1}]).</input>
 &lt;&lt;"a[b]c[d]e"&gt;&gt;
-3> binary:replace(&lt;&lt;"abcde"&gt;&gt;,[&lt;&lt;"b"&gt;&gt;,&lt;&lt;"d"&gt;&gt;],&lt;&lt;"[]"&gt;&gt;,[global,{insert_replaced,[1,1]}]).
+
+5> <input>binary:replace(&lt;&lt;"abcde"&gt;&gt;, [&lt;&lt;"b"&gt;&gt;, &lt;&lt;"d"&gt;&gt;], &lt;&lt;"[]"&gt;&gt;, [global, {insert_replaced, [1, 1]}]).</input>
 &lt;&lt;"a[bb]c[dd]e"&gt;&gt;
-4> binary:replace(&lt;&lt;"abcde"&gt;&gt;,[&lt;&lt;"b"&gt;&gt;,&lt;&lt;"d"&gt;&gt;],&lt;&lt;"[-]"&gt;&gt;,[global,{insert_replaced,[1,2]}]).
-&lt;&lt;"a[b-b]c[d-d]e"&gt;&gt;</code>
 
-        <p>If any position specified in <c><anno>InsPos</anno></c> &gt; size
-        of the replacement binary, a <c>badarg</c> exception is raised.</p>
+6> <input>binary:replace(&lt;&lt;"abcde"&gt;&gt;, [&lt;&lt;"b"&gt;&gt;, &lt;&lt;"d"&gt;&gt;], &lt;&lt;"[-]"&gt;&gt;, [global, {insert_replaced, [1, 2]}]).</input>
+&lt;&lt;"a[b-b]c[d-d]e"&gt;&gt;
 
-        <p>Options <c>global</c> and <c>{scope, part()}</c> work as for
-        <seemfa marker="#split/3"><c>split/3</c></seemfa>.
-        The return type is always a <c>binary()</c>.</p>
+7> <input>binary:replace(&lt;&lt;"abcde"&gt;&gt;, [&lt;&lt;"b"&gt;&gt;, &lt;&lt;"d"&gt;&gt;], fun(M) -> &lt;&lt;$[, M/binary, $]&gt;&gt; end, []).</input>
+&lt;&lt;"a[b]cde"&gt;&gt;
+
+8> <input>binary:replace(&lt;&lt;"abcde"&gt;&gt;, [&lt;&lt;"b"&gt;&gt;, &lt;&lt;"d"&gt;&gt;], fun(M) -> &lt;&lt;$[, M/binary, $]&gt;&gt; end, [global]).</input>
+&lt;&lt;"a[b]c[d]e"&gt;&gt;
+</pre>
 
-        <p>For a description of <c><anno>Pattern</anno></c>, see
-        <seemfa marker="#compile_pattern/1"><c>compile_pattern/1</c></seemfa>.
-        </p>
       </desc>
     </func>
 

diff --git a/lib/stdlib/src/binary.erl b/lib/stdlib/src/binary.erl
@@ -276,7 +276,7 @@ split(_, _, _) ->
       Subject :: binary(),
       Pattern :: PatternBinary | [PatternBinary,...] | cp(),
       PatternBinary :: nonempty_binary(),
-      Replacement :: binary(),
+      Replacement :: binary() | fun((binary()) -> binary()),
       Result :: binary().
 
 replace(H,N,R) ->
@@ -291,7 +291,7 @@ replace(H,N,R) ->
       Subject :: binary(),
       Pattern :: PatternBinary | [PatternBinary,...] | cp(),
       PatternBinary :: nonempty_binary(),
-      Replacement :: binary(),
+      Replacement :: binary() | fun((binary()) -> binary()),
       Options :: [Option],
       Option :: global | {scope, part()} | {insert_replaced, InsPos},
       InsPos :: OnePos | [ OnePos ],
@@ -300,7 +300,7 @@ replace(H,N,R) ->
 
 replace(Haystack,Needles,Replacement,Options) ->
     try
-	true = is_binary(Replacement), % Make badarg instead of function clause
+	true = is_binary(Replacement) orelse is_function(Replacement, 1), % Make badarg instead of function clause
 	{Part,Global,Insert} = get_opts_replace(Options,{no,false,[]}),
 	Moptlist = case Part of
 		       no ->
@@ -317,13 +317,17 @@ replace(Haystack,Needles,Replacement,Options) ->
 			    Match -> [Match]
 			end
 		end,
-	ReplList = case Insert of
+	ReplList = case is_function(Replacement, 1) orelse Insert of
+		       true ->
+ 			    Replacement;
 		       [] ->
-			   Replacement;
+			   fun(_) -> Replacement end;
 		       Y when is_integer(Y) ->
-			   splitat(Replacement,0,[Y]);
+			   <<ReplFront:Y/binary, ReplRear/binary>> = Replacement,
+			   fun(M) -> [ReplFront, M, ReplRear] end;
 		       Li when is_list(Li) ->
-			   splitat(Replacement,0,lists:sort(Li))
+			   Splits = splitat(Replacement,0,lists:sort(Li)),
+			   fun(M) -> lists:join(M, Splits) end
 		   end,
 	erlang:iolist_to_binary(do_replace(Haystack,MList,ReplList,0))
    catch
@@ -337,19 +341,7 @@ replace(Haystack,Needles,Replacement,Options) ->
 do_replace(H,[],_,N) ->
     [binary:part(H,{N,byte_size(H)-N})];
 do_replace(H,[{A,B}|T],Replacement,N) ->
-    [binary:part(H,{N,A-N}),
-     if
-	 is_list(Replacement) ->
-	     do_insert(Replacement, binary:part(H,{A,B}));
-	 true ->
-	     Replacement
-     end
-     | do_replace(H,T,Replacement,A+B)].
-
-do_insert([X],_) ->
-    [X];
-do_insert([H|T],R) ->
-    [H,R|do_insert(T,R)].
+    [binary:part(H,{N,A-N}), Replacement(binary:part(H, {A, B})) | do_replace(H,T,Replacement,A+B)].
 
 splitat(H,N,[]) ->
     [binary:part(H,{N,byte_size(H)-N})];

diff --git a/lib/stdlib/test/binary_module_SUITE.erl b/lib/stdlib/test/binary_module_SUITE.erl
@@ -495,28 +495,51 @@ do_interesting(Module) ->
     [] = binary:split(<<>>, <<",">>, [global,trim]),
     [] = binary:split(<<>>, <<",">>, [global,trim_all]),
 
+    ReplaceFn = fun(Match) -> << <<(B + 1)>> || <<B>> <= Match >> end,
     badarg = ?MASK_ERROR(
 		Module:replace(<<1,2,3,4,5,6,7,8>>,
 			       [<<4,5>>,<<7>>,<<8>>],<<99>>,
 			       [global,trim,{scope,{0,5}}])),
+    badarg = ?MASK_ERROR(
+		Module:replace(<<1,2,3,4,5,6,7,8>>,
+			       [<<4,5>>,<<7>>,<<8>>],ReplaceFn,
+			       [global,trim,{scope,{0,5}}])),
     <<1,2,3,99,6,7,8>> = Module:replace(<<1,2,3,4,5,6,7,8>>,
 					[<<4,5>>,<<7>>,<<8>>],<<99>>,[]),
+    <<1,2,3,5,6,6,7,8>> = Module:replace(<<1,2,3,4,5,6,7,8>>,
+					[<<4,5>>,<<7>>,<<8>>],ReplaceFn,[]),
     <<1,2,3,99,6,99,99>> = Module:replace(<<1,2,3,4,5,6,7,8>>,
 					  [<<4,5>>,<<7>>,<<8>>],<<99>>,
 					  [global]),
+    <<1,2,3,5,6,6,8,9>> = Module:replace(<<1,2,3,4,5,6,7,8>>,
+					  [<<4,5>>,<<7>>,<<8>>],ReplaceFn,
+					  [global]),
     <<1,2,3,99,6,7,8>> = Module:replace(<<1,2,3,4,5,6,7,8>>,
 					[<<4,5>>,<<7>>,<<8>>],<<99>>,
 					[global,{scope,{0,5}}]),
+    <<1,2,3,5,6,6,7,8>> = Module:replace(<<1,2,3,4,5,6,7,8>>,
+					[<<4,5>>,<<7>>,<<8>>],ReplaceFn,
+					[global,{scope,{0,5}}]),
     <<1,2,3,99,6,7,8>> = Module:replace(<<1,2,3,4,5,6,7,8>>,
 					[<<4,5>>,<<7>>,<<8>>],<<99>>,
 					[global,{scope,{0,5}}]),
+    <<1,2,3,5,6,6,7,8>> = Module:replace(<<1,2,3,4,5,6,7,8>>,
+					[<<4,5>>,<<7>>,<<8>>],ReplaceFn,
+					[global,{scope,{0,5}}]),
     <<1,2,3,99,6,7,8>> = Module:replace(<<1,2,3,4,5,6,7,8>>,
 					[<<4,5>>,<<7>>,<<8>>],<<99>>,
 					[global,{scope,{0,5}}]),
+    <<1,2,3,5,6,6,7,8>> = Module:replace(<<1,2,3,4,5,6,7,8>>,
+					[<<4,5>>,<<7>>,<<8>>],ReplaceFn,
+					[global,{scope,{0,5}}]),
     badarg = ?MASK_ERROR(Module:replace(<<1,2,3,4,5,6,7,8>>,
 					[<<4,5>>,<<7>>,<<8>>],<<99>>,
 					[global,{scope,{0,5}},
 					 {insert,1}])),
+    badarg = ?MASK_ERROR(Module:replace(<<1,2,3,4,5,6,7,8>>,
+					[<<4,5>>,<<7>>,<<8>>],ReplaceFn,
+					[global,{scope,{0,5}},
+					 {insert,1}])),
     <<1,2,3,99,4,5,6,7,8>> = Module:replace(<<1,2,3,4,5,6,7,8>>,
 					    [<<4,5>>,<<7>>,<<8>>],<<99>>,
 					    [global,{scope,{0,5}},

diff --git a/lib/stdlib/test/binref.erl b/lib/stdlib/test/binref.erl
@@ -228,7 +228,7 @@ replace(Haystack,Needles0,Replacement,Options) ->
 		      true ->
 			  exit(badtype)
 		  end,
-	true = is_binary(Replacement), % Make badarg instead of function clause
+	true = is_binary(Replacement) orelse is_function(Replacement, 1), % Make badarg instead of function clause
 	{Part,Global,Insert} = get_opts_replace(Options,{nomatch,false,[]}),
 	{Start,End,NewStack} =
 	    case Part of
@@ -254,7 +254,9 @@ replace(Haystack,Needles0,Replacement,Options) ->
 				[X]
 			end
 		end,
-	ReplList = case Insert of
+	ReplList = case is_binary(Replacement) andalso Insert of
+		       false ->
+			   Replacement;
 		       [] ->
 			   Replacement;
 		       Y when is_integer(Y) ->
@@ -274,6 +276,8 @@ do_replace(H,[],_,N) ->
 do_replace(H,[{A,B}|T],Replacement,N) ->
     [part(H,{N,A-N}),
      if
+	 is_function(Replacement) ->
+	     Replacement(part(H, {A, B}));
 	 is_list(Replacement) ->
 	     do_insert(Replacement, part(H,{A,B}));
 	 true ->