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Using results of a directory cataloguing

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  Using results of a directory cataloguing xltardy@gmail.com - 2018-06-10 20:13 -0700
    Re: Using results of a directory cataloguing "John Williams (News)" <UCEbin@tiscali.co.uk> - 2018-06-11 08:38 +0100
      Re: Using results of a directory cataloguing Alan Adams <alan@adamshome.org.uk> - 2018-06-11 10:20 +0100
    Re: Using results of a directory cataloguing jgh@mdfs.net - 2018-06-12 02:55 -0700
      Re: Using results of a directory cataloguing Martin <News03@avisoft.f9.co.uk> - 2018-06-12 13:34 +0100
      Re: Using results of a directory cataloguing druck <news@druck.org.uk> - 2018-06-12 18:25 +0100
        Re: Using results of a directory cataloguing xltardy@gmail.com - 2018-06-15 21:04 -0700
        Re: Using results of a directory cataloguing xltardy@gmail.com - 2018-06-15 21:20 -0700

#5463 — Using results of a directory cataloguing

Target machine : BBC A3000, RO 3.1x, BASIC program, single tasking.

I want to get all the file names in a directory, to be able to further use these file names (to do batch processing).
Language : BASIC (prefered) or ASM.
What should I do, to get sthing like (I presume) a pointer to a list of all file names in a chosen directory ?

Thanks in advance for your help.

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#5464

In article <2b768c7d-683e-4ccd-bb16-dae46badf4a6@googlegroups.com>,
   Xavier Louis Tardy <xltardy@gmail.com> wrote:

> I want to get all the file names in a directory, to be able to further
> use these file names (to do batch processing). Language : BASIC
> (prefered) or ASM. What should I do, to get sthing like (I presume) a
> pointer to a list of all file names in a chosen directory ?

I quite often use EnumDir to a file as a quick and easy way of doing this:

        EnumDir <Prune$Dir>.^ <Prune$Dir>.list
        SetType <Prune$Dir>.list text

in the Run file of the application. Then you simply have a sequential text
list to process as you wish. Of course all objects are listed, including
directories and the application itself.

The above is from my Prune program used to delete excess back-ups.

Hope this helps, 
 
John

-- 
John Williams, now back in the UK - no attachments to these addresses!
Non-RISC OS posters change user to johnrwilliams or put 'risc' in subject!
Who is John Williams? http://petit.four.free.fr/picindex/author/

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#5465

In message <570660a2afUCEbin@tiscali.co.uk>
          "John Williams (News)" <UCEbin@tiscali.co.uk> wrote:

> In article <2b768c7d-683e-4ccd-bb16-dae46badf4a6@googlegroups.com>,
>    Xavier Louis Tardy <xltardy@gmail.com> wrote:

>> I want to get all the file names in a directory, to be able to further
>> use these file names (to do batch processing). Language : BASIC
>> (prefered) or ASM. What should I do, to get sthing like (I presume) a
>> pointer to a list of all file names in a chosen directory ?

> I quite often use EnumDir to a file as a quick and easy way of doing this:

>         EnumDir <Prune$Dir>.^ <Prune$Dir>.list
>         SetType <Prune$Dir>.list text

> in the Run file of the application. Then you simply have a sequential text
> list to process as you wish. Of course all objects are listed, including
> directories and the application itself.

> The above is from my Prune program used to delete excess back-ups.

> Hope this helps,

> John

Within BASIC you can use OS_GBPB to return either one or a list of 
files to process. Asking for one at a time can make your program 
simpler.

Use OS_GBPB 12 with R3 set to 1 (fetch 1 entry). On return the block 
will include at offset 16 the object type - 1=file, 2=directory, 
3=application directory.

-- 
Alan Adams, from Northamptonshire
alan@adamshome.org.uk
http://www.nckc.org.uk/

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#5466

It's risky to demand all the filenames in a directory all at once
(on any system) as you don't know beforehand how many you'll get,
so could potentially fetch four billion filenames. It's best to
get them one at a time and do whatever processing you want to do
on each one as you go.

The following is portable across any platform with an Acorn/BBC API:
http://beebwiki.mdfs.net/Scanning_Directories_(Reading_Directory_Entries)

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#5467

On 12 Jun in article
<acecd7c9-5270-44b5-89d2-4d86775aff68@googlegroups.com>,
   <jgh@mdfs.net> wrote:
> It's risky to demand all the filenames in a directory all at once
> (on any system) as you don't know beforehand how many you'll get,
> so could potentially fetch four billion filenames. It's best to
> get them one at a time and do whatever processing you want to do
> on each one as you go.

Asking for *all* the files is obviously not a good thing to do, 
but asking for a number with limits is fine.

> The following is portable across any platform with an Acorn/BBC API:
> http://beebwiki.mdfs.net/Scanning_Directories_(Reading_Directory_Entries)

On a BBC computer, using CALL &FFD1 to call the old BBC MOS style
OSGBPB routine would be the (only) way to go. However, the OP is
using RISC OS v3.1, and I would suggest the new-style SYS "OS_GBPB"
would be much better even though CALL &FFD1 may still work.

Using SYS "OS_GBPB" with r0=9 to 12, you can decide how much
information you want to be returned for each file, and the maximum
number of files to be returned in one call. They may both depend on
on the buffer size that you can make available. The more files at
once, the faster it will be ... but does make the program slightly
more complex.

In BASIC the simple code is based on...
  max%  = ???   :REM max files that might be returned 
  blen% = ???   :REM to hold approx max% entries
  DIM buf% blen%
  next% = 0
  REPEAT
    SYS "OS_GBPB",xx,dir$,buf%,max%,next%,blen%,name$ TO,,,read%,next%
    IF read% <> 0 THEN 
        process buffer
    ENDIF
  UNTIL next% = -1

-- 
Martin Avison 
Note that unfortunately this email address will become invalid
without notice if (when) any spam is received. 

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#5468

On 12/06/2018 10:55, jgh@mdfs.net wrote:
> It's risky to demand all the filenames in a directory all at once
> (on any system) as you don't know beforehand how many you'll get,
> so could potentially fetch four billion filenames. It's best to
> get them one at a time and do whatever processing you want to do
> on each one as you go.

Attempting to reading all entries is perfectly OK, as long as...

> The following is portable across any platform with an Acorn/BBC API:
> http://beebwiki.mdfs.net/Scanning_Directories_(Reading_Directory_Entries)

...you use a sensible API. The above is the old Beeb style and shouldn't 
be used by any new code. Instead see:-

https://www.riscosopen.org/wiki/documentation/show/OS_GBPB

Use reason code 9,10,11 or 12 to read entries into a buffer of size you 
specify. If its big enough it will get all entries in one go. (Don't use 
8 as you can't specify the size).

Of course if the buffer isn't big enough, you need to repeat the call 
until all entries are read. To simplify matters people often only use a 
buffer large enough for one entry, and always repeat the call.

---druck

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#5469

Le mardi 12 juin 2018 19:25:33 UTC+2, druck a écrit :
> On 12/06/2018 10:55, xxxxxxxx.net wrote:
> > It's risky to demand all the filenames in a directory all at once
> > (on any system) as you don't know beforehand how many you'll get,
> > so could potentially fetch four billion filenames. It's best to
> > get them one at a time and do whatever processing you want to do
> > on each one as you go.
> 
> Attempting to reading all entries is perfectly OK, as long as...
> 
> > The following is portable across any platform with an Acorn/BBC API:
> > http://beebwiki.mdfs.net/Scanning_Directories_(Reading_Directory_Entries)
> 
> ...you use a sensible API. The above is the old Beeb style and shouldn't 
> be used by any new code. Instead see:-
> 
> https://www.riscosopen.org/wiki/documentation/show/OS_GBPB
> 
> Use reason code 9,10,11 or 12 to read entries into a buffer of size you 
> specify. If its big enough it will get all entries in one go. (Don't use 
> 8 as you can't specify the size).
> 
> Of course if the buffer isn't big enough, you need to repeat the call 
> until all entries are read. To simplify matters people often only use a 
> buffer large enough for one entry, and always repeat the call.
> 
> ---druck

Thanks to all of you for your help.
I think I'll have some time to try some of your solutions this week end, and will come back if I need more help.
That's for my project of porting SOTB to the Archie (free advertising to my YT channel : SOTB Archie playlist is here : https://www.youtube.com/view_all_playlists )

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#5470

Thanks to all of you for your help. 
I think I'll have some time to try some of your solutions this week end, and will come back if I need more help. 
That's for my project of porting SOTB to the Archie
(free advertising to my YT channel : SOTB Archie playlist is here :
 https://www.youtube.com/user/Archimedes75009/playlists ) 

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