Comparison of data serialization formats

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This is a comparison of data serialization formats, various ways to convert complex objects to sequences of bits. It does not include markup languages used exclusively as document file formats.

Contents

Overview [edit]

Name Creator/Maintainer Based on Standardized? Specification Binary? Human-readable? Supports references?e Schema/IDL? Standard APIs
ASN.1 ISO, IEC, ITU-T N/A Yes ISO/IEC 8824; X.680 series of ITU-T Recommendations Yes
(BER, DER, PER, or custom via ECN)		 Yes
(XER, GSER, or custom via ECN)		 Partialf Yes (built-in) N/A
Bencode Bram Cohen (creator)
BitTorrent, Inc. (maintainer)		 N/A Yes Part of BitTorrent protocol specification Partially
(numbers and delimiters are ASCII)		 Partially No No No
BSON MongoDB JSON Yes BSON Specification Yes No No No No
Candle Markup Henry Luo XML, JSON, JavaFX Yes Candle Markup Reference No Yes Yes
(XPointer, XPath)		 Yes
(Candle Pattern Reference)		 Yes
(XQuery, XPath)
Comma-separated values (CSV) RFC author:
Yakov Shafranovich		 N/A Partial
(myriad informal variants used)		 RFC 4180
(among others)		 No Yes No No No
D-Bus Message Protocol freedesktop.org N/A Yes D-Bus Specification Yes Yes
(Type Signatures)		 No No Yes
(see D-Bus)
JSON Douglas Crockford JavaScript syntax Yes RFC 4627 No, but see BSON Yes Partial
(JSONPath, JPath, JSPON, json:select())		 Partial
(JSON Schema Proposal, Kwalify, Rx, Itemscript Schema)		 Partial: Clarinet (like SAX), JSONQuery (like XQuery), JSONPath (like XPath)
MessagePack Sadayuki Furuhashi JSON (loosely) Yes MessagePack format specification Yes No No No No
Netstrings Dan Bernstein N/A Yes netstrings.txt Yes Yes No No No
OGDL Rolf Veen ? Yes 1.0 Working draft Yes
(Binary 1.0 Working draft)		 Yes Yes
(Path 1.0 Working draft)		 Yes
(Schema WD)
Property list NeXT (creator)
Apple (maintainer)		 ? Partial Public DTD for XML format Yesa Yesb No ? Cocoa, CoreFoundation, OpenStep, GnuStep
Protocol Buffers Google N/A Partial Developer Guide: Encoding Yes Partiald No Yes (built-in)
S-expressions Internet Draft author:
Ron Rivest		 Lisp, Netstrings Partial
(largely de facto)		 "S-Expressions" Internet Draft Yes
("Canonical representation")		 Yes
("Advanced transport representation")		 No No
Sereal Yves Orton, Steffen Müller et al N/A Yes Sereal Specification Yes No Yes No No
Structured Data eXchange Formats Max Wildgrube N/A Yes RFC 3072 Yes No No No
Thrift Facebook (creator)
Apache (maintainer)		 N/A No Original whitepaper Yes Partialc No Yes (built-in)
eXternal Data Representation Sun Microsystems (creator)
IETF (maintainer)		 N/A Yes RFC 4506 Yes No Yes Yes Yes
XML W3C SGML Yes W3C Recommendations:
1.0 (Fifth Edition)
1.1 (Second Edition)		 Partial
(Binary XML)		 Yes Yes
(XPointer, XPath)		 Yes
(XML schema)		 Yes
(DOM, SAX, XQuery, XPath)
XML-RPC Dave Winer[1] XML, SOAP[1] Yes XML-RPC Specification No Yes No No No
YAML Clark Evans, Ingy döt Net, and Oren Ben-Kiki C, Java, Perl, Python, Ruby, Email, HTML, MIME, URI, XML, SAX, SOAP, JSON[2] Yes Version 1.2 No Yes Yes Partial
(Kwalify, Rx, built-in language type-defs)		 No
  • a. ^ The current default format is binary.
  • b. ^ The "classic" format is plain text, and an XML format is also supported.
  • c. ^ Theoretically possible due to abstraction, but no implementation is included.
  • d. ^ The primary format is binary, but a text format is available.[3]
  • e. ^ Means that generic tools/libraries know how to encode, decode, and dereference a reference to another piece of data in the same document. A tool may require the IDL file, but no more. Excludes custom, non-standardized referencing techniques.
  • f. ^ ASN.1 does offer OIDs, a standard format for globally unique identifiers. However, there is no standard for "marking"/"tagging" an arbitrary piece of data in a document with an OID. There is also no standard format for locally unique identifiers within a document. Therefore, a generic ASN.1 tool/library can not automatically encode/decode/resolve references within a document without help from custom-written program code.

Syntax comparison of human-readable formats [edit]

Format Null Boolean true Boolean false Integer Floating-point String Array Associative array/Object
ASN.1
(XML Encoding Rules)		 <foo /> <foo>true</foo> <foo>false</foo> <foo>685230</foo> <foo>6.8523015e+5</foo> <foo>A to Z</foo> 
<SeqOfUnrelatedDatatypes>
    <isMarried>true</isMarried>
    <hobby />
    <velocity>-42.1e7</velocity>
    <bookname>A to Z</bookname>
    <bookname>We said, "no".</bookname>
</SeqOfUnrelatedDatatypes>
An object (the key is a field name): 
<person>
    <isMarried>true</isMarried>
    <hobby />
    <height>1.85</height>
    <name>Bob Peterson</name>
</person>

A data mapping (the key is a data value):

<competition>
    <measurement>
        <name>John</name>
        <height>3.14</height>
    </measurement>
    <measurement>
        <name>Jane</name>
        <height>2.718</height>
    </measurement>
</competition>

a
Candle Markup (), "" true false 685230
-685230		 6.8523015e+5 "A to Z"
"""
A
to
Z
"""		 (true, (), -42.1e7, "A to Z") 
_{%342=true A%20to%20Z=(1, 2, 3)}
or 
_{
  _{key=42 value=true}
  _{key="A to Z" value=(1, 2, 3)}
}
CSVb nulla
(or an empty element in the row)a		 1a
truea		 0a
falsea		 685230
-685230a		 6.8523015e+5a A to Z
"We said, ""no""."		 true,,-42.1e7,"A to Z" 
42,1
A to Z,1,2,3
Netstringsc 0:,a
4:null,a		 1:1,a
4:true,a		 1:0,a
5:false,a		 6:685230,a 9:6.8523e+5,a 6:A to Z, 29:4:true,0:,7:-42.1e7,6:A to Z,, 41:9:2:42,1:1,,25:6:A to Z,12:1:1,1:2,1:3,,,,a
JSON null true false 685230
-685230		 6.8523015e+5 "A to Z" [true, null, -42.1e7, "A to Z"] {"42": true, "A to Z": [1, 2, 3]}
OGDL[verification needed] nulla truea falsea 685230a 6.8523015e+5a "A to Z"
'A to Z'
NoSpaces		 
true
null
-42.1e7
"A to Z"

(true, null, -42.1e7, "A to Z")

 
42
  true
"A to Z"
  1
  2
  3

42
  true
"A to Z", (1, 2, 3)
Property list
(plain text format)[4]		 N/A <*BY> <*BN> <*I685230> <*R6.8523015e+5> "A to Z" ( <*BY>, <*R-42.1e7>, "A to Z" ) 
{
    "42" = <*BY>;
    "A to Z" = ( <*I1>, <*I2>, <*I3> );
}
Property list
(XML format)[5][6]		 N/A <true /> <false /> <integer>685230</integer> <real>6.8523015e+5</real> <string>A to Z</string> 
<array>
    <true />
    <real>-42.1e7</real>
    <string>A to Z</string>
</array>

<dict>
    <key>42</key>
    <true />
    <key>A to Z</key>
    <array>
        <integer>1</integer>
        <integer>2</integer>
        <integer>3</integer>
    </array>
</dict>
S-expressions NIL
nil		 T
#te
true		 NIL
#fe
false		 685230 6.8523015e+5 abc
"abc"
#616263#
3:abc
{MzphYmM=}
|YWJj|		 (T NIL -42.1e7 "A to Z") ((42 T) ("A to Z" (1 2 3)))
YAML ~
null
Null
NULL[7]		 y
Y
yes
Yes
YES
on
On
ON
true
True
TRUE[8]		 n
N
no
No
NO
off
Off
OFF
false
False
FALSE[8]		 685230
+685_230
-685230
02472256
0x_0A_74_AE
0b1010_0111_0100_1010_1110
190:20:30[9]		 6.8523015e+5
685.230_15e+03
685_230.15
190:20:30.15
.inf
-.inf
.Inf
.INF
.NaN
.nan
.NAN[10]		 A to Z
"A to Z"
'A to Z'		 [y, ~, -42.1e7, "A to Z"] 
- y
-
- -42.1e7
- A to Z
{"John":3.14, "Jane":2.718} 
42: y
A to Z: [1, 2, 3]
XMLd <null />a <boolean val="true"/>a

<true />a

 <boolean val="false"/>a

<false />a

 <integer>685230</integer>a <float>6.8523015e+5</float>a A to Z a 
<array>
  <element type="boolean">true</element>
  <element type="null"/>
  <element type="float">-42.1e7</element>
  <element type="string">A to Z</element>
</array>
a 
<associative-array>
  <entry>
    <key type="integer">42</key>
    <value type="boolean">true</value>
  </entry>
  <entry>
    <key type="string">A to Z</key>
    <value>
      <array>
        <element type="integer" val="1"/>
        <element type="integer" val="2"/>
        <element type="integer" val="3"/>
      </array>
    </value>
  </entry>
</associative-array>
XML-RPC <value><boolean>1</boolean></value> <value><boolean>0</boolean></value> <value><int>685230</int></value> <value><double>6.8523015e+5</double></value> <value><string>A to Z</string></value> 
<value><array>
  <data>
  <value><boolean>1</boolean></value>
  <value><double>-42.1e7</double></value>
  <value><string>A to Z</string></value>
  </data>
  </array></value>

<value><struct>
  <member>
    <name>42</name>
    <value><boolean>1</boolean></value>
    </member>
  <member>
    <name>A to Z</name>
    <value>
      <array>
        <data>
          <value><int>1</int></value>
          <value><int>2</int></value>
          <value><int>3</int></value>
          </data>
        </array>
      </value>
    </member>
</struct>
  • a. ^ One possible encoding; the specification document does not specifically give an encoding for this datatype.
  • b. ^ The RFC CSV specification only deals with delimiters, newlines, and quote characters; it does not directly deal with serializing programming data structures.
  • c. ^ The netstrings specification only deals with nested byte strings; anything else is outside the scope of the specification.
  • d. ^ XML in and of itself is not a data serialization language, but many data serialization formats have been derived from it; as such, there are many different ways, in addition to those shown, to serialize programming data structures into XML.
  • e. ^ This syntax is not compatible with the Internet-Draft, but is used by some dialects of Lisp.

Comparison of binary formats [edit]

Format Null Booleans Integer Floating-point String Array Associative array/Object
ASN.1
(BER or PER encoding)		 NULL type BOOLEAN; BER as 1 byte in binary form INTEGER; variable length big-endian binary representation up to 2^2^1024 bits REAL; representation as IEEE double or as three integers (mantissa, base, exponent) Multiple valid types (VisibleString, PrintableString, GeneralString, UniversalString, UTF8String) data specifications SET OF (unordered) and SEQUENCE OF (guaranteed order) user definable type
BSON[11] Null type - 0 bytes for value True: one byte \x01
False: \x00		 int32: 32-bit little-endian 2's complement or int64: 64-bit little-endian 2's complement double: little-endian binary64 UTF-8 encoded, preceded by int32 encoded string length in bytes BSON embedded document with numeric keys BSON embedded document
MessagePack \xc0 True: \xc3
False: \xc2		 Single byte "fixnum" (values -32..127)

or typecode (one byte) + big-endian (u)int8/16/32/64

 Typecode (one byte) + IEEE single/double As "fixraw" (single-byte prefix + up to 31 raw bytes)

or typecode (one byte) + 2-4 bytes length + raw bytes

 As "fixarray" (single-byte prefix + up to 15 array items)

or typecode (one byte) + 2-4 bytes length + array items

 As "fixmap" (single-byte prefix + up to 15 key-value pairs)

or typecode (one byte) + 2-4 bytes length + key-value pairs
Netstrings 0:, True: 1:1,

False: 1:0,
OGDL Binary
Property list
(binary format)
Protocol Buffers[12] Variable encoding length signed 32-bit: varint encoding of "ZigZag"-encoded value (n << 1) XOR (n >> 31)

Variable encoding length signed 64-bit: varint encoding of "ZigZag"-encoded (n << 1) XOR (n >> 63)
Constant encoding length 32-bit: 32 bits in little-endian 2's complement
Constant encoding length 64-bit: 64 bits in little-endian 2's complement

 floats: little-endian binary32

doubles: little-endian binary64

 UTF-8 encoded, preceded by varint-encoded integer length of string in bytes Repeated value with the same tag N/A
Sereal 0x25 True: 0x3b
False: 0x3a		 Single byte POS/NEG (values -16..15)

or typecode (one byte) + "varint" encoded variable length integer or typecode (one byte) + "zigzag" encoded variable length integer

 Typecode (one byte) + IEEE single/double/quad As "SHORT_BINARY" (single-byte prefix + up to 31 raw bytes)

or typecode (one byte, including boolean UTF8-encoding flag) + "varint" encoded length + raw bytes

 As "ARRAYREF" (single-byte prefix + up to 15 array items)

or typecode (one byte) + "varint" encoded length + array items

 As "HASHREF" (single-byte prefix + up to 15 key-value pairs)

or typecode (one byte) + "varint" encoded length + key-value pairs. Distinguishes hashmaps from objects / class instances.
Thrift
Structured Data eXchange Formats (SDXF) big-endian signed 24bit or 32bit integer big-endian IEEE double either UTF-8 or ISO 8859-1 encoded list of elements with identical ID and size, preceded by array header with int16 length chunks can contain other chunks to arbitrary depth

See also [edit]

References [edit]

  1. ^ a b http://www.xml.com/pub/a/ws/2001/04/04/soap.html
  2. ^ Ben-Kiki, Oren; Evans, Clark; Net, Ingy döt (2009-10-01). "YAML Ain’t Markup Language (YAML) Version 1.2". The Official YAML Web Site. Retrieved 2012-02-10. 
  3. ^ https://developers.google.com/protocol-buffers/docs/reference/cpp/google.protobuf.text_format
  4. ^ http://www.gnustep.org/resources/documentation/Developer/Base/Reference/NSPropertyList.html
  5. ^ http://developer.apple.com/mac/library/documentation/Darwin/Reference/ManPages/man5/plist.5.html
  6. ^ http://developer.apple.com/mac/library/documentation/CoreFoundation/Conceptual/CFPropertyLists/Articles/XMLTags.html#//apple_ref/doc/uid/20001172-CJBEJBHH
  7. ^ "Null Language-Independent Type for YAML Version 1.1". YAML.org. 2005-01-18. Retrieved 2009-09-12. 
  8. ^ a b "Boolean Language-Independent Type for YAML Version 1.1". YAML.org. Clark C. Evans. 2005-01-18. Retrieved 2009-09-12. 
  9. ^ "Integer Language-Independent Type for YAML Version 1.1". YAML.org. Clark C. Evans. 2005-02-11. Retrieved 2009-09-12. 
  10. ^ "Floating-Point Language-Independent Type for YAML Version 1.1". YAML.org. Clark C. Evans. 2005-01-18. Retrieved 2009-09-12. 
  11. ^ http://bsonspec.org
  12. ^ https://developers.google.com/protocol-buffers/docs/encoding

External links [edit]

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