On 29. Aug 2017, at 21:51, Dave Day David.Day@duke-software.com wrote:

Greetings List,

I've got an 8 byte value that is the output of a Store Clock instruction on a mainframe.  The value created by the instruction is a 64 bit hex value where  bit 51 is equal to one microsecond. To get a value that is microseconds, the original clock value is shifted to the right 12 bits. The clock started at all 0's on January 1st, 1900.

I need to be able to store and do basic math(addition and subtraction) on the value in microseconds.  And, these values will need to be displayed on a browser in HH:MM:SS.TTTTTT format.

If I create the decimal value for the integer on the mainframe when creating the XML record, I will have to go thru some conversion logic.  There could be possibly millions of these records in one XML database.

It seems to me to make more sense to create the value as a hexBinary element, and then have some code running within  BaseX do the conversion to create the correct time value.

Is this the way to do something like this?

Regards,

-- Dave Day

Hi Dave,

regarding performance a more dedicated approach may be needed. However, to do some first experiments with XML data that originates form the mainframe, BaseX has extensions to do bit shifting and conversions. Following examples can be copied into the XQuery editor of the latest BaseX version for testing.

tl;dr:

```xquery <mainframe> <event start="00000000FF"/> </mainframe> /event/@start/string() => trace('t1: ') => convert:integer-from-base(16) => trace('t2: ') => bin:pack-integer(8, 'big-endian') => trace('t3: ') => bin:shift(-1) => trace('t4: ') => bin:unpack-integer(0, 8, 'big-endian') => trace('t5: ') => convert:integer-to-dateTime() => trace('t6: ') => fn:format-dateTime("[H01]:[m01]:[s01].[f000001]") => trace('t7: ') ```

```BaseX Query Info (trace output) t1: "00000000FF" t2: 255 t3: xs:base64Binary("AAAAAAAAAP8=") t4: xs:base64Binary("AAAAAAAAAH8=") t5: 127 t6: xs:dateTime("1970-01-01T00:00:00.127Z") t7: "00:00:00.127000" ```

============================================================

long version:

let's assume you have an input xml such as:

```xml <mainframe> <event start="00000000FF"/> </mainframe> ```

- you access the value using XPath as xs:string

```xquery <mainframe> <event start="0" start1="D2DE66B76C0FF200"/> </mainframe> /event/@start1/string() ```

```result D2DE66B76C0FF200 ```

- from (hex) xs:string to xs:integer one can use [1]:

```signature convert:integer-from-base($str as xs:string, $base as xs:integer) as xs:integer ```

```xquery convert:integer-from-base('0000000000FF', 16) ```

```result 255 ```

- bit operations work on xs:base64Binary

- from xs:integer to xs:base64Binary one can use [2]:

```signature bin:pack-integer($in as xs:integer, $size as xs:integer, $octet-order as xs:string) as xs:base64Binary ```

```xquery bin:pack-integer(255, 8, 'big-endian') ```

```result xs:base64Binary("AAAAAAAAAP8=") ```

- to perform bit shifting one can use [3]

```signature bin:shift($in as xs:base64Binary?, $by as xs:integer) as xs:base64Binary? ```

```xquery bin:shift(xs:base64Binary("AAAAAAAAAP8="), -1) ```

```result xs:base64Binary("AAAAAAAAAH8=") ```

- to go back from xs:base64Binary to xs:integer one can use [4]:

```signature bin:unpack-integer($in as xs:base64Binary, $offset as xs:integer, $size as xs:integer, $octet-order as xs:string) as xs:integer ```

```xquery bin:unpack-integer(xs:base64Binary("AAAAAAAAAH8="), 0, 8, 'big-endian') ```

```result 127 ```

- to interprete an xs:integer as xs:dateTime one can use [5]

```signature convert:integer-to-dateTime($ms as xs:integer) as xs:dateTime ```

```xquery convert:integer-to-dateTime(127) ```

```result 1970-01-01T00:00:00.127Z ```

- to display an xs:dateTime according to a pattern such as HH:MM:SS.TTTTTT one can use [6]

```signature fn:format-dateTime($value as xs:dateTime?, $picture as xs:string) as xs:string? ```

```xquery fn:format-dateTime( xs:dateTime("1970-01-01T00:00:00.127Z"), "[H01]:[m01]:[s01].[f000001]" ) ```

```result 00:00:00.127000 ```

Cheers, Alex

[1] http://docs.basex.org/wiki/Conversion_Module#convert:integer-from-base [2] http://docs.basex.org/wiki/Binary_Module#bin:pack-integer [3] http://docs.basex.org/wiki/Binary_Module#bin:shift [4] http://docs.basex.org/wiki/Binary_Module#bin:unpack-integer [5] http://docs.basex.org/wiki/Conversion_Module#convert:integer-to-dateTime [6] https://www.w3.org/TR/xpath-functions-30/#func-format-dateTime