This XQuery Module contains functions to convert data between different formats.
Conventions
All functions and errors in this module are assigned to the http://basex.org/modules/convert
namespace, which is statically bound to the convert
prefix.
Strings
convert:binary-to-string
Signature
|
convert:binary-to-string(
$bytes as xs:anyAtomicType,
$encoding as xs:string := (),
$fallback as xs:boolean? := false()
) as xs:string
|
Summary
|
Converts the specifed $bytes (xs:base64Binary , xs:hexBinary ) to a string:
- The UTF-8 default encoding can be overwritten with the optional
$encoding argument.
- By default, invalid characters will be rejected. If
$fallback is set to true, these characters will be replaced with the Unicode replacement character FFFD (�).
|
Errors
|
string : The input is an invalid XML string, or the wrong encoding has been specified.
BXCO0002 : The specified encoding is invalid or not supported.
|
Examples
|
convert:binary-to-string(xs:hexBinary('48656c6c6f576f726c64')) yields HelloWorld .
|
convert:string-to-base64
Signature
|
convert:string-to-base64(
$string as xs:string,
$encoding as xs:string := ()
) as xs:base64Binary
|
Summary
|
Converts the specified $string to an xs:base64Binary item. If the default encoding is chosen, conversion will be cheap, as strings and binaries are both internally represented as byte arrays. The UTF-8 default encoding can be overwritten with the optional $encoding argument.
|
Errors
|
binary : The input cannot be represented in the specified encoding.
encoding : The specified encoding is invalid or not supported.
|
Examples
|
string(convert:string-to-base64('HelloWorld')) yields SGVsbG9Xb3JsZA== .
|
convert:string-to-hex
Signature
|
convert:string-to-hex(
$string as xs:string,
$encoding as xs:string := ()
) as xs:hexBinary
|
Summary
|
Converts the specified $string to an xs:hexBinary item. If the default encoding is chosen, conversion will be cheap, as strings and binaries are both internally represented as byte arrays. The UTF-8 default encoding can be overwritten with the optional $encoding argument.
|
Errors
|
binary : The input cannot be represented in the specified encoding.
encoding : The specified encoding is invalid or not supported.
|
Examples
|
string(convert:string-to-hex('HelloWorld')) yields 48656C6C6F576F726C64 .
|
Binary Data
convert:integers-to-base64
Signature
|
convert:integers-to-base64(
$integers as xs:integer*
) as xs:base64Binary
|
Summary
|
Converts the specified $integers to an item of type xs:base64Binary :
- Only the first 8 bits of the supplied integers will be considered.
- Conversion of byte sequences is very efficient, as items of binary type are internally represented as byte arrays.
|
Examples
|
convert:integers-to-base64(Q{java:java.lang.String}get-bytes('abc')) converts a byte sequence to a xs:base64Binary item.
|
convert:integers-to-hex
Signature
|
convert:integers-to-hex(
$integers as xs:integer*
) as xs:hexBinary
|
Summary
|
Converts the specified $integers to an item of type xs:hexBinary :
- Only the first 8 bits of the supplied integers will be considered.
- Conversion of byte sequences is very efficient, as items of binary type are internally represented as byte arrays.
|
convert:binary-to-integers
Signature
|
convert:binary-to-integers(
$binary as xs:anyAtomicType
) as xs:integer*
|
Summary
|
Returns the specified $binary (xs:base64Binary , xs:hexBinary ) as a sequence of unsigned integers (octets).
|
Examples
|
convert:binary-to-integers(xs:hexBinary('FF')) yields 255 .
|
convert:binary-to-bytes
Signature
|
convert:binary-to-bytes(
$binary as xs:anyAtomicType
) as xs:byte*
|
Summary
|
Returns the specified $binary (xs:base64Binary , xs:hexBinary ) as a sequence of bytes. The conversion is very cheap and takes no additional memory, as items of binary type are internally represented as byte arrays.
|
Examples
|
convert:binary-to-bytes(xs:base64Binary('QmFzZVggaXMgY29vbA==')) yields the sequence (66, 97, 115, 101, 88, 32, 105, 115, 32, 99, 111, 111, 108) .
convert:binary-to-bytes(xs:hexBinary("4261736558")) yields the sequence (66 97 115 101 88) .
|
Numbers
convert:integer-to-base
Signature
|
convert:integer-to-base(
$number as xs:integer,
$base as xs:integer
) as xs:string
|
Summary
|
Converts $number to a string, using the specified $base , interpreting it as a 64-bit unsigned integer. The first base elements of the sequence '0',..,'9','a',..,'z' are used as digits. Valid bases are 2, .., 36 .
|
Errors
|
base : The specified base is not in the range 2-36.
|
Examples
|
convert:integer-to-base(-1, 16) yields 'ffffffffffffffff' .
convert:integer-to-base(22, 5) yields '42' .
|
convert:integer-from-base
Signature
|
convert:integer-from-base(
$string as xs:string,
$base as xs:integer
) as xs:integer
|
Summary
|
Decodes an integer from $string , using the specified $base . The first base elements of the sequence '0',..,'9','a',..,'z' are allowed as digits; case does not matter. Valid bases are 2 - 36. If the supplied string contains more than 64 bits of information, the result will be truncated.
|
Errors
|
base : The specified base is not in the range 2-36.
integer : The specified digit is not valid for the given range.
|
Examples
|
convert:integer-from-base('ffffffffffffffff', 16) yields -1 .
convert:integer-from-base('CAFEBABE', 16) yields 3405691582 .
convert:integer-from-base('42', 5) yields 22 .
convert:integer-from-base(convert:integer-to-base(123, 7), 7) yields 123 .
|
Dates and Durations
convert:integer-to-dateTime
Signature
|
convert:integer-to-dateTime(
$milliseconds as xs:integer
) as xs:dateTime
|
Summary
|
Converts the specified number of $milliseconds since 1 Jan 1970 to an item of type xs:dateTime.
|
Examples
|
convert:integer-to-dateTime(0) yields 1970-01-01T00:00:00Z .
convert:integer-to-dateTime(1234567890123) yields 2009-02-13T23:31:30.123Z .
convert:integer-to-dateTime(prof:current-ms()) returns the current miliseconds in the xs:dateTime format.
|
convert:dateTime-to-integer
Signature
|
convert:dateTime-to-integer(
$dateTime as xs:dateTime
) as xs:integer
|
Summary
|
Converts the specified $dateTime item to the number of milliseconds since 1 Jan 1970.
|
Examples
|
convert:dateTime-to-integer(xs:dateTime('1970-01-01T00:00:00Z')) yields 0 .
|
convert:integer-to-dayTime
Signature
|
convert:integer-to-dayTime(
$milliseconds as xs:integer
) as xs:dayTimeDuration
|
Summary
|
Converts the specified number of $milliseconds to an item of type xs:dayTimeDuration.
|
Examples
|
convert:integer-to-dayTime(1234) yields PT1.234S .
|
convert:dayTime-to-integer
Signature
|
convert:dayTime-to-integer(
$dayTime as xs:dayTimeDuration
) as xs:integer
|
Summary
|
Converts the specified $dayTime duration to milliseconds represented by an integer.
|
Examples
|
convert:dayTime-to-integer(xs:dayTimeDuration('PT1S')) yields 1000 .
|
Keys
The key conversion is employed by the JSON Module and the CSV Module to encode strings to valid element names and back to the original representation:
- If lax conversion is disabled, invalid characters are replaced with underscores or (when invalid as first character of an element name) prefixed with an underscore. The resulting string may be better readable, but it cannot necessarily be converted back to the original form.
- With lax conversion enabled, a string is encoded to a valid NCName representation:
- An empty string is converted to a single underscore (
_
).
- Existing underscores are rewritten to two underscores (
__
).
- Characters that are no valid NCName characters are rewritten to an underscore and the character’s four-digit Unicode. For example, the exclamation mark
?
is transformed to _003f
.
convert:encode-key
Signature
|
convert:encode-key(
$key as xs:string,
$lax as xs:boolean? := false()
) as xs:string
|
Summary
|
Encodes the specified $key (with the optional $lax conversion method) to a valid NCName representation, which can be used to create an element node. This encoding is employed by the JSON Module and the CSV Module.
|
Examples
|
element { convert:encode-key("!") } { } creates a new element with an encoded name: <_0021/> .
|
convert:decode-key
Signature
|
convert:decode-key(
$key as xs:string,
$lax as xs:boolean? := false()
) as xs:string
|
Summary
|
Decodes the specified $key (with the optional $lax conversion method) to the original string representation. Keys supplied to this function can be element names that have been created by the JSON Module or CSV Module.
|
Examples
|
convert:decode-key(name(<_0021/>)) yields ! .
json:doc("doc.json")//* ! convert:decode-key(name()) yields the original string representation of all names of a JSON document.
|
Errors
|
key : The specified key cannot be decoded to its original representation.
|
Errors
Code
|
Description
|
base
|
The specified base is not in the range 2-36.
|
binary
|
The input cannot be converted to a binary representation.
|
encoding
|
The specified encoding is invalid or not supported.
|
integer
|
The specified digit is not valid for the given range.
|
key
|
The specified key cannot be decoded to its original representation.
|
string
|
The input is an invalid XML string, or the wrong encoding has been specified.
|
Changelog
- Version 9.4
- Version 9.0
- Version 8.5
- Version 7.5
The module was introduced with Version 7.3. Some of the functions have been adopted from the obsolete Utility Module.