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authorSverker Eriksson <[email protected]>2014-03-12 20:11:10 +0100
committerSverker Eriksson <[email protected]>2014-03-14 15:08:23 +0100
commitc543d5bff7fb23c3f44cc4817c0654117de78919 (patch)
tree2ef05bcb7ea4a167b69a2938009fe25a137cc6aa /lib/erl_interface/doc
parent8fbe76d64e7d55eb41943484602b928658313a65 (diff)
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erts: Change external format for maps
to be: 116,Arity, K1,V1,K2,V2,...,Kn,Vn instead of: 116,Arity, K1,K2,...,Kn, V1,V2,....,Vn We think this will be better for future internal map structures like HAMT. Would be bad if we need to iterate twice over HAMT in term_to_binary, one for keys and one for values.
Diffstat (limited to 'lib/erl_interface/doc')
-rw-r--r--lib/erl_interface/doc/src/ei.xml18
1 files changed, 8 insertions, 10 deletions
diff --git a/lib/erl_interface/doc/src/ei.xml b/lib/erl_interface/doc/src/ei.xml
index 1756ee8a7d..90495eebd6 100644
--- a/lib/erl_interface/doc/src/ei.xml
+++ b/lib/erl_interface/doc/src/ei.xml
@@ -422,19 +422,18 @@ ei_x_encode_empty_list(&amp;x);
<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>
+ <c>arity*2</c> terms encoded will be the keys and values of the map
+ encoded in the following order: <c>K1, V1, K2, V2, ..., Kn, Vn</c>.
+ </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_atom(&amp;x, "b");
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>
+ <p>A correctly encoded map can not have duplicate keys.</p>
</desc>
</func>
<func>
@@ -664,10 +663,9 @@ ei_x_encode_string(&amp;x, "Banana");
<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.
+ <c>*arity</c>. Keys and values follow in the following order:
+ <c>K1, V1, K2, V2, ..., Kn, Vn</c>. This makes a total of
+ <c>arity*2</c> terms. If <c>arity</c> is zero, it's an empty map.
A correctly encoded map does not have duplicate keys.</p>
</desc>
</func>