bugGNU Octave - Bugs: bug #33456, Function handles save()ed with...


bug #33456: Function handles save()ed with "-binary" can't always be re-load()ed

Submitted by:  Olaf Till <i7tiol>
Submitted on:  Wed 01 Jun 2011 07:51:56 PM UTC  
Category:  None Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Other
Status:  Fixed Assigned to:  None
Originator Name:  Olaf Till Open/Closed:  Closed
Release:  dev Operating System:  GNU/Linux

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Tue 14 Jun 2011 07:31:56 PM UTC, comment #5: 

I'm bringing up the discussion of the correct branch for this patch on the Octave maintainers mailing list.

Rik <rik5>
Project Administrator
Wed 08 Jun 2011 10:47:01 AM UTC, comment #4: 

Thanks. But shouldn't this go rather (or also) into the stable branch?

Olaf Till <i7tiol>
Project Member
Tue 07 Jun 2011 03:28:13 AM UTC, comment #3: 

Thanks for the patch.  I verified it worked for me and have committed it in this changeset (http://hg.savannah.gnu.org/hgweb/octave/rev/65b7ce254ba3)

Rik <rik5>
Project Administrator
Thu 02 Jun 2011 02:57:39 PM UTC, comment #2: 

The reason is that the "load_binary()" function of function-handles uses std::istream::get(). I din't find it documented, but according to a test "stream.get (char c, int n)" or "stream.get (char c, int n, char b)", though loading n - 1 bytes into c as expected, cause stream.eof() to be true if the last read byte was the last byte of the file (i.e. without any trying to read over the file end --- weird). Luckily function-handles seem to be the only octave_values which use std::istream::get() in load_binary().

A changeset is attached which should fix this.

(file #23495)

Olaf Till <i7tiol>
Project Member
Thu 02 Jun 2011 12:00:12 AM UTC, comment #1: 


In particular, the following formats do save function handles: '-text', '-hdf5'.

The following formats do not accept function handles for saving at all: '-ascii', 'Matlab'

And lastly, '-binary' accepts function handles but doesn't actually save them.

Rik <rik5>
Project Administrator
Wed 01 Jun 2011 07:51:56 PM UTC, original submission:  

Release: stable branch, revision 5bf8af73fc34 of 01/06/2011 17:53

Description: Function handles save()ed with "-binary" can't always be re-load()ed.

Repeat by:

octave:1> a = @ sin
a = @sin
octave:2> save ("-binary", "testdata.dat", "a")
octave:3> clear a
octave:4> load ("testdata.dat")
octave:5> a
error: `a' undefined near line 5 column 1

Note that it also doesn't work if the handle is a structure field:

octave:5> a.b = @ sin
a =

  scalar structure containing the fields:

    b = @sin

octave:6> save ("-binary", "testdata.dat", "a")
octave:7> clear a
octave:8> load ("testdata.dat")
octave:9> a
error: `a' undefined near line 9 column 1

But it does work if there is a different structure field (no handle) present:

octave:9> a.b = @ sin
a =

  scalar structure containing the fields:

    b = @sin

octave:10> a.c = 1
a =

  scalar structure containing the fields:

    b = @sin
    c =  1

octave:11> save ("-binary", "testdata.dat", "a")
octave:12> clear a
octave:13> load ("testdata.dat")
octave:14> a
a =

  scalar structure containing the fields:

    b = @sin
    c =  1

Olaf Till <i7tiol>
Project Member


(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach Files:

Attached Files
file #23495:  fcn-handle-load-binary.changeset added by i7tiol (1KiB - application/octet-stream)


Depends on the following items: None found

Items that depend on this one: None found


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    Follow 4 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2011-06-07 rik5 StatusConfirmed => Fixed
        Open/ClosedOpen => Closed
    2011-06-02 i7tiol Attached File- => Added fcn-handle-load-binary.changeset, #23495
    2011-06-02 rik5 StatusNone => Confirmed

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