Re: Can't read CString after serialization

"Tom Serface" <>
Tue, 11 Mar 2008 11:13:23 -0700
That is very cool and may prove (easily) to be more compact than XML. Of
course XML is slower and bigger, but much easier to read in Notepad so easy
to debug and update. I guess it all depends on the size of the data. If
the data is several megabytes or grows continuously, a better "database"
type file format is warranted, but if it's something like configuration data
or start up data or last state data then something extremely readable is
usually a great way to implement it imo.


"Joseph M. Newcomer" <> wrote in message

Prior to XML, we loved "tagged binary" format. In tagged-binary, you
would write out a
block which had a <type,length> pair, then each field had a <field-tag,
length> pair. The
nice thing was that it was backward-compatible without much effort, for
certain kinds of
backward-compatibility. Two approaches could be used (and the same
applies to XML): throw
away any tag you don't recognize (loses information), silently (pop up a
warning that a
newer version file is being read; upon save, pop up a warning that
information has been
discarded, do you want to overwrite, but no popups during read).
Alternatively, keep a
list of the unknown tags and write out verbatim on output (might work,
depends on what
info is in the tags). In the latter case, a header bit says that the file
had been
processed by an earlier version, and the newer version knew whether or not
it could trust
certain values, or if they had to be recomputed, discarded, etc.

The nice thing about tagged binary was that you could easily write a
simple program to
parse the file and show it (for example, a columnar display of tag id, tag
value in
decimal and hex, etc.). We could write out complex structures because we
used a technique
similar to based pointers, writing pointers out as relative offsets. If
the target had
not been written out, a set of fixup blocks were appended to the end of
the file and what
was stored was a flagged value that said "I'm a fixup reference" or "I'm a
real offset".
We built huge systems using these techniques. I specified this technique
back in 1977,
and it was ultimately used in our IDL system [Nestor, Newcomer, et al.,
"IDL: The Language
and its Implementation", Prentice-Hall, 1989].

On Tue, 11 Mar 2008 08:09:50 -0700, "Tom Serface"
<> wrote:

Oen of the biggest problem is similar to what OP is experiencing. It is
just too hard to read the resulting file so debugging it is very
If you don't want to use XML (perhaps too much overhead) even doing a
file with a format you know is better since you can open the file in
mode in VS and check it out. The serialized file structure was always
difficult for me to use especially when adding new items for future
releases. OK, I'll stop preaching now.


"Giovanni Dicanio" <> wrote in message

"Tom Serface" <> ha scritto nel messaggio

These kinds of problems are why I typically don't use serializing any
more. I like to use XML


Hi Tom,

I do agree with you.

The serialization mechanism of MFC template containers like CArchive is
not good IMHO; for example, I don't like very much the fact that we
define global helper functions template specializations for the
type to serialize.


Joseph M. Newcomer [MVP]
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