simdjson-decode.xml

<?xml version="1.0" encoding="utf-8"?>
<refentry xml:id="function.simdjson-decode" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>simdjson_decode</refname>
  <refpurpose>Decodes a JSON string</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>mixed</type><methodname>simdjson_decode</methodname>
   <methodparam><type>string</type><parameter>json</parameter></methodparam>
   <methodparam choice="opt"><type>bool</type><parameter>associative</parameter><initializer>&false;</initializer></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>depth</parameter><initializer>512</initializer></methodparam>
  </methodsynopsis>
  <para>
   Takes a JSON encoded string and converts it into a PHP value.
   This uses a faster Simultaneous Instruction, Multiple Data implementation
   than <function>json_decode</function> when it is supported by the computer architecture.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <variablelist>
   <varlistentry>
    <term><parameter>json</parameter></term>
    <listitem>
     <para>
      The <parameter>json</parameter> <type>string</type> being decoded.
     </para>
     <para>
      This function only works with UTF-8 encoded strings.
     </para>
     <para>
      This function parses valid inputs which
      <function>json_decode</function> can decode,
      provided that they are less than 4 GiB long.
     </para>
    </listitem>
   </varlistentry>
   <varlistentry>
    <term><parameter>associative</parameter></term>
    <listitem>
     <para>
      When &true;, JSON objects will be returned as
      associative &array;s; when &false;, JSON objects will be returned as &object;s.
     </para>
    </listitem>
   </varlistentry>
   <varlistentry>
    <term><parameter>depth</parameter></term>
    <listitem>
     <para>
      Maximum nesting depth of the structure being decoded.
      The value must be greater than <literal>0</literal>,
      and less than or equal to <literal>2147483647</literal>.

      Callers should use reasonably small values,
      because larger depths require more buffer space and will
      increase the recursion depth, unlike the current <function>json_decode</function> implementation.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns the value encoded in <parameter>json</parameter> in appropriate
   PHP type. Values <literal>true</literal>, <literal>false</literal> and
   <literal>null</literal> are returned as &true;, &false; and &null;
   respectively.
  </para>
 </refsect1>

 <refsect1 role="errors">
  &reftitle.errors;
  <para>
   If <parameter>json</parameter> is invalid, a <classname>SimdJsonException</classname> is thrown as of PECL simdjson 2.1.0,
   while previously, a <classname>RuntimeException</classname> was thrown.
  </para>
  <para>
   If <parameter>depth</parameter> is outside the allowed range,
   a <classname>SimdJsonValueError</classname> is thrown as of PECL simdjson 3.0.0,
   while previously, an error of level <constant>E_WARNING</constant> was raised.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>simdjson_decode</function> examples</title>
    <programlisting role="php">
<![CDATA[
<?php
$json = '{"a":1,"b":2,"c":3}';

var_dump(simdjson_decode($json));
var_dump(simdjson_decode($json, true));

?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
object(stdClass)#1 (3) {
  ["a"]=>
  int(1)
  ["b"]=>
  int(2)
  ["c"]=>
  int(3)
}
array(3) {
  ["a"]=>
  int(1)
  ["b"]=>
  int(2)
  ["c"]=>
  int(3)
}
]]>
    </screen>
   </example>
   <example>
    <title>Accessing invalid object properties</title>
    <simpara>
     Accessing elements within an object that contain characters not
     permitted under PHP's naming convention (e.g. the hyphen) can be
     accomplished by encapsulating the element name within braces and the apostrophe.
    </simpara>
    <programlisting role="php">
<![CDATA[
<?php

$json = '{"foo-bar": 12345}';

$obj = simdjson_decode($json);
print $obj->{'foo-bar'}; // 12345

?>
]]>
    </programlisting>
   </example>
   <example>
    <title>common mistakes using <function>simdjson_decode</function></title>
    <programlisting role="php">
<![CDATA[
<?php

// the following strings are valid JavaScript but not valid JSON

// the name and value must be enclosed in double quotes
// single quotes are not valid
$bad_json = "{ 'bar': 'baz' }";
simdjson_decode($bad_json); // Throws SimdJsonException

// the name must be enclosed in double quotes
$bad_json = '{ bar: "baz" }';
simdjson_decode($bad_json); // Throws SimdJsonException

// trailing commas are not allowed
$bad_json = '{ bar: "baz", }';
simdjson_decode($bad_json); // Throws SimdJsonException

?>
]]>
    </programlisting>
   </example>
   <example>
    <title><parameter>depth</parameter> errors</title>
    <programlisting role="php">
<![CDATA[
<?php
// Encode some data with a maximum depth of 4
// (array -> array -> array -> string)
$json = json_encode(
    [
        1 => [
            'English' => [
                'One',
                'January'
            ],
            'French' => [
                'Une',
                'Janvier'
            ]
        ]
    ]
);

// Show the errors for different depths.
var_dump(simdjson_decode($json, true, 4));
try {
    var_dump(simdjson_decode($json, true, 3));
} catch (SimdJsonException $e) {
     echo "Caught: ", $e->getMessage(), "\n";
}
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
array(1) {
  [1]=>
  array(2) {
    ["English"]=>
    array(2) {
      [0]=>
      string(3) "One"
      [1]=>
      string(7) "January"
    }
    ["French"]=>
    array(2) {
      [0]=>
      string(3) "Une"
      [1]=>
      string(7) "Janvier"
    }
  }
}
Caught: The JSON document was too deep (too many nested objects and arrays)
]]>
    </screen>
   </example>
   <example>
    <title><function>simdjson_decode</function> of large integers</title>
    <programlisting role="php">
<![CDATA[
<?php
$json = '{"number": 12345678901234567890}';

var_dump(simdjson_decode($json));

?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
<![CDATA[
object(stdClass)#1 (1) {
  ["number"]=>
  float(1.2345678901235E+19)
}
]]>
    </screen>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    The JSON spec is not JavaScript, but a subset of JavaScript.
   </para>
  </note>
  <note>
   <para>
    In the event of a failure to decode,
    a <classname>SimdJsonException</classname> is thrown
    and <methodname>SimdJsonException::getCode</methodname> and
    <methodname>SimdJsonException::getMessage</methodname> can be used
    to determine the exact nature of the error.
   </para>
  </note>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>json_encode</function></member>
    <member><function>json_decode</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>
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