On Tue, 5 Mar 2019 23:23:20 -0600
"Karl O. Pinc" <k...@meme.com> wrote:
> Added documentation for hex and escape encodings,
> including output formats and what are acceptable
> inputs.
Attached: doc_base64_v6.patch
Added index entries for encode and decode functions
above the encoding documentation. As index entries
are currently generated this does not make any
difference. But this paragraph is very far
from the other encode/decode index targets on
the page.
Regards,
Karl <k...@meme.com>
Free Software: "You don't pay back, you pay forward."
-- Robert A. Heinlein
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6765b0d584..bf724d3dee 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1752,6 +1752,9 @@
<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>
@@ -1769,16 +1772,25 @@
<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="hex-encoding"><literal>hex</literal></link>,
+ <link linkend="escape-encoding"><literal>escape</literal></link>.
</entry>
<entry><literal>encode('123\000\001', 'base64')</literal></entry>
<entry><literal>MTIzAAE=</literal></entry>
@@ -2365,6 +2377,90 @@
<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>
+ The string and the binary <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 carriage-return, newline, space, and tab characters are
+ ignored by <function>decode</function>. Otherwise, an error is
+ raised when <function>decode</function> is supplied invalid
+ base64 data — including when trailing padding is incorrect.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry id="hex-encoding">
+ <term>hex</term>
+ <listitem>
+ <para>
+ <literal>hex</literal> 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
+ — including when given an odd number of characters.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry id="escape-encoding">
+ <term>escape</term>
+ <listitem>
+ <para>
+ <literal>escape</literal> 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 any number of
+ 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>
+ </variablelist>
+ </para>
+
<para>
See also the aggregate function <function>string_agg</function> in
<xref linkend="functions-aggregate"/>.
@@ -3577,16 +3673,25 @@ SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
<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="hex-encoding"><literal>hex</literal></link>,
+ <link linkend="escape-encoding"><literal>escape</literal></link>.
</entry>
<entry><literal>encode('123\000456'::bytea, 'escape')</literal></entry>
<entry><literal>123\000456</literal></entry>
