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#71
Expert questions / Re: _readdir() translates some...
Last post by John Z - August 27, 2026, 09:02:17 AMHi,
Well here is Mr. Sanders brief:
"The libdirtrav library provides a way to recursively read folder contents using callback functions. This is done using opendir() and readdir() functions, except for Windows where native FindFirstFile()/FindFirstFileEx() and FindNextFile() functions are used. On Windows a wide version is available which uses wchar_t* as string type for Unicode UTF-16 support"
So one sees he also recommends FindFirst etc for windows.
There are two issues 1) codepages being used for Filenames 2) codepages being used within a program or data. #1 is most difficult to handle as you pointed out it is possible in windows which uses UTF-16 to have many different languages for filenames . #2 is not so hard. Most legacy programs or data files have some identifier to inform about the codepage. VCF contact files for example before VCF 3 used CHARSET= some name (not always standardized). VCF3 pushed UTF-8 as a recommendation and VCF4 requires it.
Handling codepage changes within a program is not difficult. In most cases the end user will be able to see the information is weird so can change the codepage and re-read the data. An example dialog from my vCardz_i program for vcf contact cards for changing the code page as needed. Data is read in as binary and and converted from the codepage into UTF-8 or UTF-16 to display. If looks bogus another codepage can be selected, tedious to be sure and hopefully not often needed.
John Z
Well here is Mr. Sanders brief:
"The libdirtrav library provides a way to recursively read folder contents using callback functions. This is done using opendir() and readdir() functions, except for Windows where native FindFirstFile()/FindFirstFileEx() and FindNextFile() functions are used. On Windows a wide version is available which uses wchar_t* as string type for Unicode UTF-16 support"
So one sees he also recommends FindFirst etc for windows.
There are two issues 1) codepages being used for Filenames 2) codepages being used within a program or data. #1 is most difficult to handle as you pointed out it is possible in windows which uses UTF-16 to have many different languages for filenames . #2 is not so hard. Most legacy programs or data files have some identifier to inform about the codepage. VCF contact files for example before VCF 3 used CHARSET= some name (not always standardized). VCF3 pushed UTF-8 as a recommendation and VCF4 requires it.
Handling codepage changes within a program is not difficult. In most cases the end user will be able to see the information is weird so can change the codepage and re-read the data. An example dialog from my vCardz_i program for vcf contact cards for changing the code page as needed. Data is read in as binary and and converted from the codepage into UTF-8 or UTF-16 to display. If looks bogus another codepage can be selected, tedious to be sure and hopefully not often needed.
John Z
#72
Expert questions / Re: _readdir() translates some...
Last post by Robert - August 27, 2026, 01:47:01 AMBrecht Sanders has a cross-platform library specific to readdir.
https://github.com/brechtsanders/libdirtrav
Warning! I have not tried using it, so I have no idea if it will work with Pelles C.
CodePages ?
The example file, "Art of Beksiński 1978 (MHS) (2).jpg", includes Polish characters. What if the next file is "Miró's L'escala de l'evasió.jpg"? How could you know that the filename is Spanish? And even if your app could figure that out, how could you switch codepages within the app?
https://github.com/brechtsanders/libdirtrav
Warning! I have not tried using it, so I have no idea if it will work with Pelles C.
CodePages ?
The example file, "Art of Beksiński 1978 (MHS) (2).jpg", includes Polish characters. What if the next file is "Miró's L'escala de l'evasió.jpg"? How could you know that the filename is Spanish? And even if your app could figure that out, how could you switch codepages within the app?
#73
Expert questions / Re: _readdir() translates some...
Last post by John Z - August 26, 2026, 09:34:41 PMHi,
You've not mentioned whether coding for DOS or Windows, Linux?
These non-std functions were provide to improve portability according to the help file.
Windows filenames are all in Unicode UTF-16. However AFAIK all OS files are ASCII and ASCII is supported intact within the lower UTF-16 codes, so 98% of the files on the system can be opened without using wide. The other 2% are user files which can be using any character in the UTF-16 set, which includes all (well almost all) characters sets in the world. A swag as the percentages but you get the gist.
IMO, you are better off using _wfindfirst64, and associated functions, then you are covered for all language nuances.
Otherwise codepages are not hard to use, the hard part is figuring out which one to activate....
John Z
You've not mentioned whether coding for DOS or Windows, Linux?
These non-std functions were provide to improve portability according to the help file.
Windows filenames are all in Unicode UTF-16. However AFAIK all OS files are ASCII and ASCII is supported intact within the lower UTF-16 codes, so 98% of the files on the system can be opened without using wide. The other 2% are user files which can be using any character in the UTF-16 set, which includes all (well almost all) characters sets in the world. A swag as the percentages but you get the gist.
IMO, you are better off using _wfindfirst64, and associated functions, then you are covered for all language nuances.
Otherwise codepages are not hard to use, the hard part is figuring out which one to activate....
John Z
#74
Expert questions / Re: _readdir() translates some...
Last post by RobertSteed - August 26, 2026, 08:12:04 PMQuote from: John Z on August 23, 2026, 10:09:58 PMHi,Cheers. I'm loathe to use codepages! What do you do for this kind of thing where you're dealing with Unicode file names? I guess the wide-character versions might work.
Well first I've never used these functions so a grain of salt with my comments.
Looking into the header there is no Unicode or wide character support for the functions. So support will be limited to code pages. If using ANSI code page ( I guess for the UK ?) for example then the 233 é exists and can be shown. However the ANSI code page does not include an n with diacritic in fact the only n is 241 ñ, so the closest substitution is made.
So try a different code page? I was going to suggest trying to get the 8.3 filename but it seems the same issue would hinder that too.
John Z
For example codepage 852 E4 is n with diacritic
#75
Expert questions / Re: _readdir() translates some...
Last post by RobertSteed - August 26, 2026, 08:09:52 PMQuote from: TimoVJL on August 23, 2026, 02:08:45 PMFunction fopen might be a problem too, as it works with ANSI filenames.That's a good point. What do you use for Unicode files?
I did some tests, even i don't like those functions, as i rather use Win32 API.
Why do you use the Win32 API rather than _findfirst64() etc?
#76
Assembly discussions / Re: Find characters inside a s...
Last post by Vortex - August 26, 2026, 07:07:38 PMAnother version assuming that the string to be searched contains only printable characters :
Code Select
OPTION PROLOGUE:NONE
OPTION EPILOGUE:NONE
FindChar PROC src:DWORD,char:DWORD
mov eax,DWORD PTR [esp+4]
mov ecx,DWORD PTR [esp+8]
dec eax
@@:
inc eax
mov dl,BYTE PTR [eax]
mov dh,dl
xor dl,cl
sub dx,0101h
or dl,dh
cmp dl,255
jnz @b
retn 8
FindChar ENDP
OPTION PROLOGUE:PrologueDef
OPTION EPILOGUE:EpilogueDef #77
Assembly discussions / Re: Find characters inside a s...
Last post by jack - August 25, 2026, 02:26:56 AM👍
#78
Assembly discussions / Re: Find characters inside a s...
Last post by Vortex - August 24, 2026, 10:07:48 PMHere is the 64-bit version :
Code Select
ExitProcess PROTO :QWORD
printf PROTO :QWORD,:VARARG
.data
mystr db 'This is a test.',0
f1 db 'Address of the string = %X',13,10
db 'Address of the character a = %X',0
.code
FindChar PROC src:QWORD,char:QWORD
mov rax,rcx
dec rax
@@:
inc rax
mov r8b,BYTE PTR [rax]
test r8b,r8b
setz cl
xor r8b,dl
setz ch
or cl,ch
jz @b
ret
FindChar ENDP
start PROC PARMAREA=4*SIZEOF(QWORD)
invoke FindChar,ADDR mystr,'a'
invoke printf,ADDR f1,ADDR mystr,rax
invoke ExitProcess,0
start ENDP
END start
#79
Expert questions / Re: _readdir() translates some...
Last post by John Z - August 24, 2026, 01:08:58 PMQuote from: TimoVJL on August 24, 2026, 12:09:34 PME4 is Lower case n with acute
Yup, thanks, I did not remember if it was acute or grave (up, or down) so just general term diacritic. Been a while since my French
John Z
#80
Expert questions / Re: _readdir() translates some...
Last post by TimoVJL - August 24, 2026, 12:09:34 PMQuote from: John Z on August 23, 2026, 10:09:58 PMFor example codepage 852 E4 is n with diacritichttps://www.ascii-codes.com/cp852.html
https://www.asciigrid.com/codepages/dos/852
E4 is Lower case n with acute
https://altcodeunicode.com/alt-codes-letter-n-with-accents/