From 6941af88ad016141f568279f065cb181074f1f9f Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Thu, 6 Mar 2014 15:13:34 +0100
Subject: erl_interface: Add ei encode/decode for maps

---
 lib/erl_interface/doc/src/ei.xml | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

(limited to 'lib/erl_interface/doc')

diff --git a/lib/erl_interface/doc/src/ei.xml b/lib/erl_interface/doc/src/ei.xml
index ab185c9179..1756ee8a7d 100644
--- a/lib/erl_interface/doc/src/ei.xml
+++ b/lib/erl_interface/doc/src/ei.xml
@@ -4,7 +4,7 @@
 <cref>
   <header>
     <copyright>
-      <year>2001</year><year>2013</year>
+      <year>2001</year><year>2014</year>
       <holder>Ericsson AB. All Rights Reserved.</holder>
     </copyright>
     <legalnotice>
@@ -416,6 +416,27 @@ ei_x_encode_empty_list(&amp;x);
           tail of a list.</p>
       </desc>
     </func>
+    <func>
+      <name><ret>int</ret><nametext>ei_encode_map_header(char *buf, int *index, int arity)</nametext></name>
+      <name><ret>int</ret><nametext>ei_x_encode_map_header(ei_x_buff* x, int arity)</nametext></name>
+      <fsummary>Encode a map</fsummary>
+      <desc>
+        <p>This function encodes a map header, with a specified arity. The next
+	   <c>arity</c> terms encoded will be the keys of the map, and the next
+	   <c>arity</c> terms after that will be the corresponding values in
+	   same order.</p>
+        <p>E.g. to encode the map <c>#{a => "Apple", b => "Banana"}</c>:</p>
+        <pre>
+ei_x_encode_map_header(&amp;x, 2);
+ei_x_encode_atom(&amp;x, "a");
+ei_x_encode_atom(&amp;x, "b");
+ei_x_encode_string(&amp;x, "Apple");
+ei_x_encode_string(&amp;x, "Banana");
+        </pre>
+	<p>A correctly encoded map can not have duplicate keys, but no check
+	for duplicate keys is done by this function.</p>
+      </desc>
+    </func>
     <func>
       <name><ret>int</ret><nametext>ei_get_type(const char *buf, const int *index, int *type, int *size)</nametext></name>
       <fsummary>Fetch the type and size of an encoded term</fsummary>
@@ -637,6 +658,19 @@ ei_x_encode_empty_list(&amp;x);
           instead.</p>
       </desc>
     </func>
+    <func>
+      <name><ret>int</ret><nametext>ei_decode_map_header(const char *buf, int *index, int *arity)</nametext></name>
+      <fsummary>Decode a map</fsummary>
+      <desc>
+        <p>This function decodes a map header from the binary
+          format. The number of key-value pairs is returned in
+          <c>arity</c>. Keys and values follows, first all keys and then all values,
+	  which makes a total of <c>arity*2</c> terms.
+	  Keys and values are paired according to their order, the first key
+	  with the first value and so on. If <c>arity</c> is zero, it's an empty map.
+	  A correctly encoded map does not have duplicate keys.</p>
+      </desc>
+    </func>
     <func>
       <name><ret>int</ret><nametext>ei_decode_ei_term(const char* buf, int* index, ei_term* term)</nametext></name>
       <fsummary>Decode a term, without prior knowledge of type</fsummary>
-- 
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