erl_interface: Add ei encode/decode for maps

6 files changed, 93 insertions, 6 deletions

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>
@@ -417,6 +417,27 @@ ei_x_encode_empty_list(&amp;x);
       </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>
       <desc>
@@ -638,6 +659,19 @@ ei_x_encode_empty_list(&amp;x);
       </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>
       <desc>
diff --git a/lib/erl_interface/include/ei.h b/lib/erl_interface/include/ei.h
index 9b83385a46..a3eb437f88 100644
--- a/lib/erl_interface/include/ei.h
+++ b/lib/erl_interface/include/ei.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1998-2013. All Rights Reserved.
+ * Copyright Ericsson AB 1998-2014. 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
@@ -131,6 +131,7 @@
 #define ERL_SMALL_BIG_EXT     'n'
 #define ERL_LARGE_BIG_EXT     'o'
 #define ERL_NEW_FUN_EXT	      'p'
+#define ERL_MAP_EXT           't'
 #define ERL_FUN_EXT	      'u'
  
 #define ERL_NEW_CACHE         'N' /* c nodes don't know these two */
@@ -467,6 +468,8 @@ int ei_encode_list_header(char *buf, int *index, int arity);
 int ei_x_encode_list_header(ei_x_buff* x, long n);
 #define ei_encode_empty_list(buf,i) ei_encode_list_header(buf,i,0)
 int ei_x_encode_empty_list(ei_x_buff* x);
+int ei_encode_map_header(char *buf, int *index, int arity);
+int ei_x_encode_map_header(ei_x_buff* x, long n);
 
 /* 
  * ei_get_type() returns the type and "size" of the item at
@@ -507,6 +510,7 @@ int ei_decode_term(const char *buf, int *index, void *t); /* ETERM** actually */
 int ei_decode_trace(const char *buf, int *index, erlang_trace *p);
 int ei_decode_tuple_header(const char *buf, int *index, int *arity);
 int ei_decode_list_header(const char *buf, int *index, int *arity);
+int ei_decode_map_header(const char *buf, int *index, int *arity);
 
 /* 
  * ei_decode_ei_term() returns 1 if term is decoded, 0 if term is OK,
diff --git a/lib/erl_interface/src/decode/decode_tuple_header.c b/lib/erl_interface/src/decode/decode_tuple_header.c
index c0ba14ea47..698be1b97a 100644
--- a/lib/erl_interface/src/decode/decode_tuple_header.c
+++ b/lib/erl_interface/src/decode/decode_tuple_header.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  * 
- * Copyright Ericsson AB 1998-2009. All Rights Reserved.
+ * Copyright Ericsson AB 1998-2014. 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
@@ -45,3 +45,24 @@ int ei_decode_tuple_header(const char *buf, int *index, int *arity)
 
   return 0;
 }
+
+int ei_decode_map_header(const char *buf, int *index, int *arity)
+{
+  const char *s = buf + *index;
+  const char *s0 = s;
+  int i;
+
+  switch ((i=get8(s))) {
+  case ERL_MAP_EXT:
+    if (arity) *arity = get32be(s);
+    else s += 4;
+    break;
+
+  default:
+    return -1;
+  }
+
+  *index += s-s0;
+
+  return 0;
+}
diff --git a/lib/erl_interface/src/encode/encode_tuple_header.c b/lib/erl_interface/src/encode/encode_tuple_header.c
index 97a3d1f808..5b11e60447 100644
--- a/lib/erl_interface/src/encode/encode_tuple_header.c
+++ b/lib/erl_interface/src/encode/encode_tuple_header.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  * 
- * Copyright Ericsson AB 1998-2009. All Rights Reserved.
+ * Copyright Ericsson AB 1998-2014. 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
@@ -47,3 +47,20 @@ int ei_encode_tuple_header(char *buf, int *index, int arity)
   return 0;
 }
 
+int ei_encode_map_header(char *buf, int *index, int arity)
+{
+  char *s = buf + *index;
+  char *s0 = s;
+
+  if (arity < 0) return -1;
+
+  if (!buf) s += 5;
+  else {
+      put8(s,ERL_MAP_EXT);
+      put32be(s,arity);
+  }
+
+  *index += s-s0;
+
+  return 0;
+}
diff --git a/lib/erl_interface/src/misc/ei_decode_term.c b/lib/erl_interface/src/misc/ei_decode_term.c
index ce5ae5b19d..2e7317f781 100644
--- a/lib/erl_interface/src/misc/ei_decode_term.c
+++ b/lib/erl_interface/src/misc/ei_decode_term.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 2001-2013. All Rights Reserved.
+ * Copyright Ericsson AB 2001-2014. 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
@@ -100,6 +100,7 @@ int ei_decode_ei_term(const char* buf, int* index, ei_term* term)
 	term->size = get16be(s);
 	return 0;
     case ERL_LIST_EXT:
+    case ERL_MAP_EXT:
 	term->arity = get32be(s);
 	break;
     case ERL_BINARY_EXT:
diff --git a/lib/erl_interface/src/misc/ei_x_encode.c b/lib/erl_interface/src/misc/ei_x_encode.c
index 14d0b56b8f..10542c88a5 100644
--- a/lib/erl_interface/src/misc/ei_x_encode.c
+++ b/lib/erl_interface/src/misc/ei_x_encode.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  * 
- * Copyright Ericsson AB 2001-2013. All Rights Reserved.
+ * Copyright Ericsson AB 2001-2014. 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
@@ -206,6 +206,16 @@ int ei_x_encode_tuple_header(ei_x_buff* x, long n)
     return ei_encode_tuple_header(x->buff, &x->index, n);
 }
 
+int ei_x_encode_map_header(ei_x_buff* x, long n)
+{
+    int i = x->index;
+    if (ei_encode_map_header(NULL, &i, n) == -1)
+      return -1;
+    if (!x_fix_buff(x, i))
+	return -1;
+    return ei_encode_map_header(x->buff, &x->index, n);
+}
+
 int ei_x_encode_atom(ei_x_buff* x, const char* s)
 {
     return ei_x_encode_atom_len_as(x, s, strlen(s), ERLANG_LATIN1, ERLANG_LATIN1);