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Reading Date Stamp of a file

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  Reading Date Stamp of a file Roger Darlington <rogerarm@freeuk.com> - 2011-05-13 10:55 +0100
    Re: Reading Date Stamp of a file Roger Darlington <rogerarm@freeuk.com> - 2011-05-13 11:20 +0100
      Re: Reading Date Stamp of a file Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2011-05-14 03:10 +0200
    Re: Reading Date Stamp of a file Graham Pickles <graham@durain.demon.co.uk> - 2011-05-13 11:39 +0100
      Re: Reading Date Stamp of a file jgh@arcade.demon.co.uk (Jonathan Graham Harston) - 2011-05-14 00:35 +0100
      Re: Reading Date Stamp of a file Roger Darlington <rogerarm@freeuk.com> - 2011-05-18 13:44 +0100
        Re: Reading Date Stamp of a file Chris Johnson <chrisjohnson+news@spamcop.net> - 2011-05-18 15:23 +0100
          Re: Reading Date Stamp of a file Roger Darlington <rogerarm@freeuk.com> - 2011-05-19 09:30 +0100
            Re: Reading Date Stamp of a file druck <news@druck.org.uk> - 2011-05-19 21:14 +0100

#295 — Reading Date Stamp of a file

In BBC BASIC/RISC OS there is always more than one command to perform 
any one function.

Could the readers tell me which is the SIMPLEST command to use to read 
the date stamp of a file within a program, and in what format is the 
date stamp returned?  I don't need the time stamp, just the date. (I 
realise I may get both date and time anyway).


-- 

Cheers
Roger
Too lazy to turn over your CD?: Get a CD-re-winder.

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#296

On 13 May 2011, Roger Darlington  wrote:

> In BBC BASIC/RISC OS there is always more than one command to perform
> any one function.

> Could the readers tell me which is the SIMPLEST command to use to read
> the date stamp of a file within a program, and in what format is the
> date stamp returned?  I don't need the time stamp, just the date. (I
> realise I may get both date and time anyway).


Actually, thinking more about it, I need it to compare the date/time 
stamp of two files within the program, and if one is newer than the 
other, then I want to perform some actions (which don't involve 
copying).

If there is a command that might return the date/time stamp as a 
single number (rather than as 17-Jan-2010) then I wont need to convert 
17-Jan-2010 to some single number.

-- 

Cheers
Roger
"An invisibility cloak that works at optical wavelengths is nowhere in 
sight"

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#300

On 13/05/2011 12:20, Roger Darlington wrote:

> Actually, thinking more about it, I need it to compare the date/time
> stamp of two files within the program, and if one is newer than the
> other, then I want to perform some actions (which don't involve
> copying).

You will need to call OS_File 17.

On entry:
   R0 is 17.
   R1 is a string giving the filename (with path).

On exit:
   R0 is the object type: 0-not found, 1-File, 2-Dir, 3-Image
   R2 is the load address
   R3 is the exec address
   R4 is the length (if you need this)
   R5 are the file attributes (RW/rw stuff, if you need this)

Load & exec are a hangover from the 6502 days. On a RISC OS system (at 
least for the older versions, not sure if 4+ changes things), Load and 
Exec are a 64 bit value split up as follows:

   Load     Exec
   FFFtttdd dddddddd

Where FFF is &FFF (i.e. upper 12 bits are all set). "ttt" is the 
filetype (0 to &FFF), and the rest ('ddd...') is the file's time stamp. 
Note well that the value is a five byte value, so a simple word 
comparison ( IF !blah% = !meh% THEN ...) won't work.
You could use OS_ConvertDateAndTime with a format string to convert the 
date/time to something more manageable - for example 
"%CE%YR%MN%DY%24%MI%SE" will return a value such as "20110514030754" 
(2011/05/14, 03h07.54) which could be parsed into a number and compared. 
As we're running in decreasing magnitude, a higher number is a later date...


> If there is a command that might return the date/time stamp as a
> single number (rather than as 17-Jan-2010) then I wont need to convert
> 17-Jan-2010 to some single number.

There is no simple command in BASIC, however the SYS command offers easy 
access to a multitude of OS functions, which can do exactly what is 
required.


Best wishes,

Rick.

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#297

In message <416aadd251.rogerarm@rogerarm.freeuk.com>
          Roger Darlington <rogerarm@freeuk.com> wrote:


> In BBC BASIC/RISC OS there is always more than one command to perform
> any one function.

> Could the readers tell me which is the SIMPLEST command to use to read
> the date stamp of a file within a program, and in what format is the
> date stamp returned?  I don't need the time stamp, just the date. (I
> realise I may get both date and time anyway).

How about


DIM stamp% 5,date% 32
REM next line is up to you...
filespec$="HostFS::HardDisc4.$.Folders"
SYS "XOS_File",17,filespec$ TO found%,,load%,exec%
stamp%!0=exec%:stamp%?4=load%
SYS "OS_ConvertStandardDateAndTime",stamp%,date%,32 TO date$
PRINT RIGHT$(date$,11)

Regards,

-- 
Graham Pickles
www.whitbymuseum.org.uk     Whitby Museum
Those who get too big for their britches will be exposed in the end

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#301

graham@durain.demon.co.uk wrote:
> > Could the readers tell me which is the SIMPLEST command to use to read
> > the date stamp of a file within a program, and in what format is the
> 
> SYS "XOS_File",17,filespec$ TO found%,,load%,exec%
> stamp%!0=exec%:stamp%?4=load%
 
...and the 5-byte number stamp%?0 to stamp%?4 /is/ the single
number that can be used to compare with other datestamps. It is a
centisecond count from 00:00:00-01-Jan-1900.
 
-- 
J.G.Harston - jgh@mdfs.net - mdfs.net/jgh

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#306

On 13 May 2011, Graham Pickles  wrote:
> In message <416aadd251.rogerarm@rogerarm.freeuk.com>
>           Roger Darlington <rogerarm@freeuk.com> wrote:


>> In BBC BASIC/RISC OS there is always more than one command to perform
>> any one function.

>> Could the readers tell me which is the SIMPLEST command to use to read
>> the date stamp of a file within a program, and in what format is the
>> date stamp returned?  I don't need the time stamp, just the date. (I
>> realise I may get both date and time anyway).

> How about


> DIM stamp% 5,date% 32
> REM next line is up to you...
> filespec$="HostFS::HardDisc4.$.Folders"
> SYS "XOS_File",17,filespec$ TO found%,,load%,exec%
> stamp%!0=exec%:stamp%?4=load%

Well, I have run with this one.

Here's the program I have:

FOR loop to get different files

load%=0 : exec%=0 : length%=0

filespec$="<Obey$Dir>"  +  "."  +  AZletter$ + "." + SubName$ + "." + 
SubName$ + "/htm"

filespec$="HostFS::HardDisc4.$.~IYO4.Default.Sep03.!WildFlowers.Flowers"  
+  "."  +  AZletter$ + "." + SubName$ + "." + SubName$ + "/htm"

PRINT filespec$

SYS"OS_File",17,filespec$ TO found%,,load%,exec%,length%

PRINT ~load%, ~exec%, length%'

NEXT


GIVES THE FOLLOWING PRINTOUT:

Note that I have deleted the XOS_File and used OS_File, so as to prove 
it never errors.

HostFS::HardDisc4.$.~IYO4.Default.Sep03.!WildFlowers.Flowers.A.Aconite(Winter).A 
conite(Winter)/htm
         0   3834830  29368192

The load address is always '0', the exec address is always &3834830 
and the size is always 29368192bytes.


for every file it comes across (BTW the files it comes across are only 
of order 30kB in size, NOT 29MB!!)











-- 

Cheers
Roger
My friends think I'm surreal, but I've never been near a sword

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#307

In article <d61650d551.rogerarm@rogerarm.freeuk.com>,
   Roger Darlington <rogerarm@freeuk.com> wrote:
> SYS"OS_File",17,filespec$ TO found%,,load%,exec%,length%

> PRINT ~load%, ~exec%, length%'

> NEXT

You should check the value of found% - if it is 0, object was not
found, 1 is a file, 2 is a dir, 3 is an image file.

If found% = 0, then you need to check the contents of filespec$. The
PRM states that the values of R2, R3, R4, R5 are corrupted if object
not found (found% = 0).

-- 
Chris Johnson

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#312

On 18 May 2011, Chris Johnson  wrote:
> In article <d61650d551.rogerarm@rogerarm.freeuk.com>,
>    Roger Darlington <rogerarm@freeuk.com> wrote:
>> SYS"OS_File",17,filespec$ TO found%,,load%,exec%,length%

>> PRINT ~load%, ~exec%, length%'

>> NEXT

> You should check the value of found% - if it is 0, object was not
> found, 1 is a file, 2 is a dir, 3 is an image file.

> If found% = 0, then you need to check the contents of filespec$. The
> PRM states that the values of R2, R3, R4, R5 are corrupted if object
> not found (found% = 0).

Many thanks to all respondents, I have now got it going successfully 
:-)

Actually, I can't help thinking that there might have been some clever 
way of hi-jacking the *Copy command to achieve the same end, by making 
it error, trapping the error, and doing my own thing rather than 
letting it copy 'newer', but that is just theoretical now. I have done 
it using one of the above respondents method.


-- 

Cheers
Roger
All who wander are not lost

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#313

On 19/05/2011 09:30, Roger Darlington wrote:
> Actually, I can't help thinking that there might have been some clever
> way of hi-jacking the *Copy command to achieve the same end,

You don't touch *Copy programically, use the appropriate OS_FSControl 
reason code, which is what the command line tool calls.

> by making
> it error, trapping the error, and doing my own thing rather than
> letting it copy 'newer', but that is just theoretical now.

That's not so easy without nastiness.

---druck

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