Re: [xml] OS/390 compatibility (EBCDIC)

[Daniel Veillard <veillard redhat com>]

On Wed, May 12, 2010 at 03:15:02PM +0300, Alon Bar-Lev wrote:
> Thank you for your comments.
>
> I found the first problem, the correct code page should be used in
> order to interpret header, patch attached.
>
> But libxml does not work, it cannot work in EBCDIC environment.
> As it convert the stream into UTF-8, it then tries to parse it using
> native literals.
>
> For example:
> ---
> if (c == 'a')
> ---
>
> Will not work, as 'a' is in EBCDIC and it is compared to c which is
> UTF-8. Unlike ANSI, the character value is different between UTF-8
> (latin1) and EBCDIC.

  Fujitsu used to have the problem, until they found a compiler
switch to tell the compiler that the source had to be interpreted as
ASCII, and then their problem was solved (this is from memory from
half a decade ago).

> I tried to use #pragma convert("ISO8859-1"), and also tried to use
> -qconvlit=ISO8859-1 compiler option, but both have too wide effect in
> order to solve this.

  Triple check your compiler documentation, that's probably there.
I don't understand what you meant by "too wide effect", I don't see
why this would be a problem for compiling libxml2.

> Correct solution is to use:
> #define UTF8_CHARACTER_A '\x41'
> #define UTF8_CHARACTER_GT '\x3c'
>
> And use these in the parsers.

  Nahh. Correct solution is that any form of text where the encoding
is not made explicit or part of the metadata is broken. C is broken
from this respect.
  there is many places too where libxml2 code assumes things like
a...z are stored in alphabetical order etc ... I'm all for portability
but to the limit it doesn't completely penalize maintainability or
code efficiency.

Daniel

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