doc_base64_part3_v9.patch

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 22769e5031..14a587c281 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1711,13 +1711,18 @@
         <indexterm>
          <primary>decode</primary>
         </indexterm>
+        <indexterm>
+          <primary>base64 encoding</primary>
+        </indexterm>
         <literal><function>decode(<parameter>string</parameter> <type>text</type>,
         <parameter>format</parameter> <type>text</type>)</function></literal>
        </entry>
        <entry><type>bytea</type></entry>
        <entry>
         Decode binary data from textual representation in <parameter>string</parameter>.
-        Options for <parameter>format</parameter> are same as in <function>encode</function>.
+        <link linkend="encoding-options">Options
+        for <parameter>format</parameter></link> are same as
+        in <function>encode</function>.
        </entry>
        <entry><literal>decode('MTIzAAE=', 'base64')</literal></entry>
        <entry><literal>\x3132330001</literal></entry>
@@ -2263,6 +2268,89 @@
     <function>format</function> treats a NULL as a zero-element array.
    </para>
 
+   <indexterm>
+     <primary>encode</primary>
+   </indexterm>
+   <indexterm>
+     <primary>decode</primary>
+   </indexterm>
+   <indexterm>
+     <primary>base64 encoding</primary>
+   </indexterm>
+   <indexterm>
+    <primary>hex encoding</primary>
+   </indexterm>
+   <indexterm>
+    <primary>escape encoding</primary>
+   </indexterm>
+
+   <para id="encoding-options">
+     The <function>encode</function> and <function>decode</function> functions
+     support the following encodings:
+
+     <variablelist>
+       <varlistentry id="base64-encoding">
+         <term>base64</term>
+         <listitem>
+           <para>
+             The <literal>base64</literal> encoding is that
+             of <ulink url="https://tools.ietf.org/html/rfc2045#section-6.8">RFC
+             2045 Section 6.8</ulink>.  As per the RFC, encoded lines are
+             broken at 76 characters.  However instead of the MIME CRLF
+             end-of-line marker, only a newline is used for end-of-line.
+           </para>
+           <para>
+             The <function>decode</function> function ignores carriage-return,
+             newline, space, and tab characters.  Otherwise, an error is
+             raised when <function>decode</function> is supplied invalid
+             base64 data &mdash; including when trailing padding is incorrect.
+           </para>
+         </listitem>
+       </varlistentry>
+
+       <varlistentry id="escape-encoding">
+         <term>escape</term>
+         <listitem>
+           <para>
+             The <literal>escape</literal> encoding converts zero bytes and
+             high-bit-set bytes to octal sequences
+             (<literal>\</literal><replaceable>nnn</replaceable>) and doubles
+             backslashes.  Encoding always produces 4 characters for each
+             high-bit-set input byte.
+           </para>
+           <para>
+             The <function>decode</function> function accepts fewer than three
+             octal digits after a <literal>\</literal> character.  An error is
+             raised when <function>decode</function> is supplied a
+             single <literal>\</literal> not followed by an octal digit.
+           </para>
+         </listitem>
+       </varlistentry>
+
+       <varlistentry id="hex-encoding">
+         <term>hex</term>
+         <listitem>
+           <para>
+             The <literal>hex</literal> encoding represents each 4 bits of
+             data as a single hexadecimal digit, <literal>0</literal>
+             through <literal>f</literal>.  Encoding outputs
+             the <literal>a</literal>-<literal>f</literal> hex digits in lower
+             case.  Because the smallest unit of data is 8 bits there are
+             always an even number of characters returned
+             by <function>encode</function>.
+           </para>
+           <para>
+             The <function>decode</function> function
+             accepts <literal>a</literal>-<literal>f</literal> characters in
+             either upper or lower case.  An error is raised
+             when <function>decode</function> is supplied invalid hex data
+             &mdash; including when given an odd number of characters.
+           </para>
+         </listitem>
+       </varlistentry>
+     </variablelist>
+   </para>
+
    <para>
    See also the aggregate function <function>string_agg</function> in
    <xref linkend="functions-aggregate"/>.
@@ -3499,22 +3587,31 @@ SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
 
       <row>
        <entry>
-         <indexterm>
-          <primary>encode</primary>
-         </indexterm>
+        <indexterm>
+         <primary>encode</primary>
+        </indexterm>
+        <indexterm>
+         <primary>base64 encoding</primary>
+        </indexterm>
+        <indexterm>
+         <primary>hex encoding</primary>
+        </indexterm>
+        <indexterm>
+         <primary>escape encoding</primary>
+        </indexterm>
         <literal><function>encode(<parameter>data</parameter> <type>bytea</type>,
         <parameter>format</parameter> <type>text</type>)</function></literal>
        </entry>
        <entry><type>text</type></entry>
        <entry>
         Encode binary data into a textual representation.  Supported
-        formats are: <literal>base64</literal>, <literal>hex</literal>, <literal>escape</literal>.
-        <literal>escape</literal> converts zero bytes and high-bit-set bytes to
-        octal sequences (<literal>\</literal><replaceable>nnn</replaceable>) and
-        doubles backslashes.
+        formats are:
+        <link linkend="base64-encoding"><literal>base64</literal></link>,
+        <link linkend="escape-encoding"><literal>escape</literal></link>,
+        <link linkend="hex-encoding"><literal>hex</literal></link>.
        </entry>
-       <entry><literal>encode('123\000456'::bytea, 'escape')</literal></entry>
-       <entry><literal>123\000456</literal></entry>
+       <entry><literal>encode('123\000\001', 'base64')</literal></entry>
+       <entry><literal>MTIzAAE=</literal></entry>
       </row>
 
       <row>