[Fribidi-discuss] (Justified?) compilation warning (fwd)

[Shachar Shemesh]

Hey everyone, and Behdad (without trying to claim that Behdad is not 
part of everyone, of course).

I was wondering whether you had time to look at my proposed way, and 
whether there were any comments. I would like to get this ball rolling, 
at least to the point where there is some sort of UTF-16 support in a 
released package (so I can get the patches into Wine).

If noone has any objections, I can try and work on fribidi patches that 
will incorporate this approach.

                Shachar


Shachar Shemesh wrote:

> Shachar Shemesh wrote:
>
>>
>> The actual attached code will come in a little while, in a seperate 
>> mail.
>>
>>                Shachar
>
>
>
> Ok, here's the explanation of what's going on here.
>
> fribidi_utf.h - project's header file.
> This is where both the specific encodings functions and types are 
> declared, and a default is selected. The default is selected based on 
> the value of a macro called "FRIBIDI_CHAR_BYTES". If that is not 
> defined, it is set to 4 (and thus, backwards compatibility is fully 
> maintained).
>
> fribidi_utf.c - The library's source
> In here, the function fribidi_log2vis is defined for one encoding 
> only. You will notice the lack of #ifdef in this file (actually, I 
> cheated a little to print the string's width, by placing a #define 
> that didn't really belong there in the header files. This would not 
> happen in a library that actually does something, however, and the 
> only #ifdef we are expected to see in the real implementation is when 
> actual alogrithm differ between the different widths, probably due to 
> optimizations).
>
> main.c - A source to an extrenal program that uses fribid.
> This program nicely shows how both the default encoding can be used 
> (and selected based on the default required), as well as non-default 
> encodings used when applicable.
>
> Makefile - don't you know what that is?
> There are two special tricks performed in this makefile.
> The first is for compiling fribidi_utf.c three times, selecting a 
> different default each time. The three .o files are then merged into a 
> single library.
> The second should not be in fribidi's Makefile, and will probably not 
> be necessary for the using program's Makefile either. It is therefor 
> ok that it is a little patchy. It allows compiling the test program in 
> three flavours. Please notice, however, that all three flavours are 
> linked against the same library.
>
> In order to build the three test programs, run "make main8", "make 
> main16" and "make main32". You will get three programs with apropriate 
> names.
>
> Notice that no conversions were used throughout the sources, static 
> typing is kept whether you use the default or override it. A program 
> that needs the default most of the time but occasionally needs a 
> different encoding will still get a warning if the wrong function is 
> called by mistake. The entire thing compiles without a single warning.
>
>                Shachar
>
>------------------------------------------------------------------------
>
>#include <stdio.h>
>#include <stdlib.h>
>
>#include "fribidi_utf.h"
>
>
>int fribidi_log2vis(fribidi_chartype *str, int nextpar)
>{
>	return printf(NUM_BYTES_STR" %d\n", nextpar );
>}
>
>  
>
>------------------------------------------------------------------------
>
>#ifndef FRIBIDI_CHAR_BYTES
>#define FRIBIDI_CHAR_BYTES 4 /* Or whatever we think should be the default encoding */
>#endif
>
>typedef char fribidi_chartype1;
>typedef short fribidi_chartype2;
>typedef long fribidi_chartype4;
>
>int fribidi_log2vis4( fribidi_chartype4 *str, int nextpar );
>int fribidi_log2vis2( fribidi_chartype2 *str, int nextpar );
>int fribidi_log2vis1( fribidi_chartype1 *str, int nextpar );
>
>#if FRIBIDI_CHAR_BYTES==4
>
>typedef fribidi_chartype4 fribidi_chartype;
>#define fribidi_log2vis fribidi_log2vis4
>#define NUM_BYTES_STR "4"
>
>#elif FRIBIDI_CHAR_BYTES==2
>
>typedef fribidi_chartype2 fribidi_chartype;
>#define fribidi_log2vis fribidi_log2vis2
>#define NUM_BYTES_STR "2"
>
>#else
>
>typedef fribidi_chartype1 fribidi_chartype;
>#define fribidi_log2vis fribidi_log2vis1
>#define NUM_BYTES_STR "1"
>
>#endif
>
>  
>
>------------------------------------------------------------------------
>
>#include "fribidi_utf.h"
>
>int main()
>{
>	fribidi_chartype str0[]={'H','e','l','l','o','\0'};
>	fribidi_chartype1 str1[]={'H','e','l','l','o','\0'};
>	fribidi_chartype2 str2[]={'H','e','l','l','o','\0'};
>	fribidi_chartype4 str4[]={'H','e','l','l','o','\0'};
>	
>	fribidi_log2vis(str0, 0);
>	fribidi_log2vis1(str1, 1);
>	fribidi_log2vis2(str2, 2);
>	fribidi_log2vis4(str4, 4);
>
>	return 0;
>}
>  
>