Re: new:mbrtoc32.3: convert from to c32

Re: new:mbrtoc32.3: convert from to c32

[Bruno Haible]

> mbrtoc32, c32rtomb \- convert between multibyte sequence and 32-bit wide character

I would suggest two separate man pages for these functions.
Rationale:
It is rare that some code uses mbrtoc32 and c32rtomb in the same function.
(Basically, functions that do input call mbrtoc32, and functions that do
output call c32rtomb.) And the description of mbrtoc32 is a bit complex.

> Are there any important differences compared to the already-documented
> and C99-compliant mbrtowc(3) and wcrtomb(3)?  I mean, apart from the
> types of the parameters.

No for c32rtomb, but yes for mbrtoc32: mbrtowc has the special return
values (size_t)-1 and (size_t)-2, whereas mbrtoc32 also has the special
return value (size_t)-3. Although, on glibc currently this special
return value (size_t)-3 cannot occur. But IMO the man page should
mention it nevertheless, otherwise people write code that is not
future-proof.

Bruno

Re: new:mbrtoc32.3: convert from to c32

[Alejandro Colomar (man-pages)]

Hello Bruno,

On 7/4/21 12:26 PM, Bruno Haible wrote:
>> mbrtoc32, c32rtomb \- convert between multibyte sequence and 32-bit wide character
> 
> I would suggest two separate man pages for these functions.
> Rationale:
> It is rare that some code uses mbrtoc32 and c32rtomb in the same function.
> (Basically, functions that do input call mbrtoc32, and functions that do
> output call c32rtomb.) And the description of mbrtoc32 is a bit complex.

Okay.  Indeed, the *wc* functions are documented separately.

> 
>> Are there any important differences compared to the already-documented
>> and C99-compliant mbrtowc(3) and wcrtomb(3)?  I mean, apart from the
>> types of the parameters. >
> No for c32rtomb, but yes for mbrtoc32: mbrtowc has the special return
> values (size_t)-1 and (size_t)-2, whereas mbrtoc32 also has the special
> return value (size_t)-3. Although, on glibc currently this special
> return value (size_t)-3 cannot occur. But IMO the man page should
> mention it nevertheless, otherwise people write code that is not
> future-proof.

Thanks for those details!

Regards,

Alex


-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/

Re: new:mbrtoc32.3: convert from to c32

[Radisson]

Am 05.07.21 um 21:07 schrieb Alejandro Colomar (man-pages):
> Hello Bruno,
>
> On 7/4/21 12:26 PM, Bruno Haible wrote:
>>> mbrtoc32, c32rtomb \- convert between multibyte sequence and 32-bit
>>> wide character
>>
>> I would suggest two separate man pages for these functions.
>> Rationale:
>> It is rare that some code uses mbrtoc32 and c32rtomb in the same
>> function.
>> (Basically, functions that do input call mbrtoc32, and functions that do
>> output call c32rtomb.) And the description of mbrtoc32 is a bit complex.
>
> Okay.  Indeed, the *wc* functions are documented separately.

I beg your pardon,
we do not write a program, for the understanding of the function i found
it much helpful to see the from-to connection.

>
>>
>>> Are there any important differences compared to the already-documented
>>> and C99-compliant mbrtowc(3) and wcrtomb(3)?  I mean, apart from the
>>> types of the parameters. >
>> No for c32rtomb, but yes for mbrtoc32: mbrtowc has the special return
>> values (size_t)-1 and (size_t)-2, whereas mbrtoc32 also has the special
>> return value (size_t)-3. Although, on glibc currently this special
>> return value (size_t)-3 cannot occur. But IMO the man page should
>> mention it nevertheless, otherwise people write code that is not
>> future-proof.
>
> Thanks for those details!
>
> Regards,
>
> Alex
>
>

Re: new:mbrtoc32.3: convert from to c32

[Alejandro Colomar (man-pages)]

Hi,

On 7/5/21 11:09 PM, Radisson wrote:
> 
> 
> Am 05.07.21 um 21:07 schrieb Alejandro Colomar (man-pages):
>> Hello Bruno,
>>
>> On 7/4/21 12:26 PM, Bruno Haible wrote:
>>>> mbrtoc32, c32rtomb \- convert between multibyte sequence and 32-bit
>>>> wide character
>>>
>>> I would suggest two separate man pages for these functions.
>>> Rationale:
>>> It is rare that some code uses mbrtoc32 and c32rtomb in the same
>>> function.
>>> (Basically, functions that do input call mbrtoc32, and functions that do
>>> output call c32rtomb.) And the description of mbrtoc32 is a bit complex.
>>
>> Okay.  Indeed, the *wc* functions are documented separately.
> 
> I beg your pardon,
> we do not write a program, for the understanding of the function i found
> it much helpful to see the from-to connection.

No pardon needed :)
I don't have any strong feelings about how it should be organized in 
files.  There are 3 ways I see:

a) mbrtoc32 & mbrtowc together;  c32tombr & wctombr together
b) each one in a separate page
c) mbrtoc32 & c32tombr together;  mbrtowc separate from wctombr (as is now)

If you think any one is especially better than the rest, do it.


What I would like to especially make clear is the similarities and 
differences between those 2 sets of functions.  And not rewrite 
everything from scratch, because that causes 2 main problems:

* Maintainability: maintatining different pages that say the same in 
different ways is not a good thing, IMO.
* Confusion: Readers of the page may get the impression that the 2 sets 
of functions are considerably different if they are documented differently.

Thanks,

Alex

> 
>>
>>>
>>>> Are there any important differences compared to the already-documented
>>>> and C99-compliant mbrtowc(3) and wcrtomb(3)?  I mean, apart from the
>>>> types of the parameters. >
>>> No for c32rtomb, but yes for mbrtoc32: mbrtowc has the special return
>>> values (size_t)-1 and (size_t)-2, whereas mbrtoc32 also has the special
>>> return value (size_t)-3. Although, on glibc currently this special
>>> return value (size_t)-3 cannot occur. But IMO the man page should
>>> mention it nevertheless, otherwise people write code that is not
>>> future-proof.
>>
>> Thanks for those details!
>>
>> Regards,
>>
>> Alex
>>
>>


-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/

Re: new:mbrtoc32.3: convert from to c32

[Alejandro Colomar (man-pages)]

Hi,

On 7/5/21 10:31 PM, Radisson wrote:
>>
> I am no expert on the differences i will make contact with Bruno Haible,
> i hope he can help (he wrote already).

Okay.

>>>         void toc32( char *in,  int in_len, char32_t **outbuf, int *len)
>> Please, follow the style of other existing pages (it's similar to the
>> kernel coding style with some exceptions).
>> Especially, regarding spaces around parentheses and commas (and other
>> operators).
>> Also, please use a consistent indentation of 4 spaces.
>>
>> https://www.kernel.org/doc/html/v4.10/process/coding-style.html#spaces
>      can i use:    indent -i4 -linux ?

I don't know.  I guess that's an emacs thingy.  I use vim.
I don't have vim configured for that, but I'll do now (I use tabs for 
everything else, except YAML).  I don even have vim configured for man, 
because in my manual pages (for my code), I also use tabs.
But based on my vimrc, adapting it for 4-spaces in man, it could be 
something like:

set		nocindent
set		nosmartindent
set		noautoindent
set		indentexpr=
filetype	indent off
filetype	plugin indent off

" YAML only works with spaces :(
au filetype yaml	setlocal expandtab
au filetype yaml	setlocal shiftwidth=8
au filetype yaml	setlocal softtabstop=8
au filetype yaml	setlocal tabstop=8

au filetype man		setlocal expandtab
au filetype man		setlocal shiftwidth=4
au filetype man		setlocal softtabstop=4
au filetype man		setlocal tabstop=4


I hope it helps.

Regards,

Alex

-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/

Re: new:mbrtoc32.3: convert from to c32

[Radisson]

Am 03.07.21 um 20:01 schrieb Alejandro Colomar (man-pages):
> Hi Peter,
>
> Please see some comments below.
>
> Thanks,
>
> Alex
>
> On 7/3/21 7:40 PM, Alejandro Colomar (man-pages) wrote:
>> Hi Peter,
>>
>> On 6/20/21 10:29 PM, Radisson97@gmx.de wrote:
>>>  From eb1ee6439f85b6a349c84488fa63dc7b795e43a0 Mon Sep 17 00:00:00 2001
>>> From: Peter Radisson <--show-origin>
>>> Date: Sun, 20 Jun 2021 22:21:55 +0200
>>> Subject: [PATCH] convert between multibyte sequence and 32-bit wide character
>>>
>>> documentation including example
>>>
>>> Signed-off-by: Peter Radisson <--show-origin>
>> Thanks for the page.  I'll have a look at it.
>>
>> BTW, next time you document a glibc function from scratch, please CC
>> glibc <libc-alpha@sourceware.org> so that they can comment, and maybe
>> find some bugs that we may not be able to detect.
>>
>> Also, providing a rendered version of the page is good for glibc people
>> --who may not have cloned the man-pages-- to easily review it :)
>>
>> Rendered page:
>>
>> [[
>> MBRTOC32(3)         Linux Programmer's Manual        MBRTOC32(3)
>>
>> NAME
>>         mbrtoc32,  c32rtomb  - convert between multibyte sequence
>>         and 32‐bit wide character
>>
>> SYNOPSIS
>>         #include <uchar.h>
>>
>>         size_t t mbrtoc32 (char32_t * restrict c32 ,
>>                                  mbstate_t * restrict p);
> That prototype seems wrong.  See:
>
> .../glibc$ grep_glibc_prototype mbrtoc32;
> wcsmbs/uchar.h:57:
> extern size_t mbrtoc32 (char32_t *__restrict __pc32,
> 			const char *__restrict __s, size_t __n,
> 			mbstate_t *__restrict __p) __THROW;
easy fix, there is a typo that eats the line

>>         size_t c32rtomb (char * restrict s, char32_t  c32 ,
>>                              mbstate_t * restrict p );
>>
>> DESCRIPTION
> Are there any important differences compared to the already-documented
> and C99-compliant mbrtowc(3) and wcrtomb(3)?  I mean, apart from the
> types of the parameters.
>
> I think I would refer to mbrtowc(3) (and wcrtomb(3)) and specify here
> only differences specific to these functions, such as the type.
>
> Maybe?:
>
> [
> These functions are equivalent to mbrtowc(3) and wcrtomb(3), except that
> these functions act on char32_t instead of wchar_t.
> ]
>
> Otherwise we're unnecessarily repeating all of the information.  If we
> use the same wording, we're just duplicating maintenance issues.  If we
> use a different wording, readers might wonder why, if they seem to be
> the same.
>
> Also, when we need to repeat the text of those pages because of slight
> differences, please use the text as similar as possible from those
> pages, for the same reasons.
>
I am no expert on the differences i will make contact with Bruno Haible,
i hope he can help (he wrote already).

>>         The mbrtoc32() function inspects at most n bytes  of  the
>>         UTF‐8  multibyte string starting at s.  If a multibyte is
>>         identified as valid the corresponding UCS‐32 32‐bit  wide
>>         character  is stored in c32.  If  the  multibyte  charac‐
>>         ter is the null wide character, it resets the shift state
>>         *p to the initial state and returns 0.  If p is  NULL,  a
>>         static anonymous state known only to the function is used
>>         instead.
>>
>>         The  c32rtomb() function converts the 32‐bit wide charac‐
>>         ter stored in c32 into a mutability  sequence   into  the
>>         memory s.
>>
>> RETURN VALUES
>>         The  mbrtoc32() function returns 0 for the nul character.
>>         -1 for invalid input, -2 for a truncated  input,  -3  for
>>         multibyte  32‐bit wide character sequence that is written
>>         to *c32.  No bytes are processed from the input
>>
>>         Otherwise the number of bytes in the  multibyte  sequence
>>         is returned.
>>
>>         The c32tombr() function returns -1 on error otherwise the
>>         number of bytes used for the multibytes sequence.
>>
>> EXAMPLE>        The input sequence is written as byte sequence to allow a
>>         proper display. Note that the input is UTF‐8 and UTF‐32 ,
>>         it may not possible to convert every code.
>>
>>         #include <stdio.h>
>>         #include <stdlib.h>
>>         #include <locale.h>
>>         #include <uchar.h>
>>         #include <wchar.h>
>>
>>         void toc32( char *in,  int in_len, char32_t **outbuf, int *len)
> Please, follow the style of other existing pages (it's similar to the
> kernel coding style with some exceptions).
> Especially, regarding spaces around parentheses and commas (and other
> operators).
> Also, please use a consistent indentation of 4 spaces.
>
> https://www.kernel.org/doc/html/v4.10/process/coding-style.html#spaces
     can i use:    indent -i4 -linux ?

>>         {
>>             char *p_in , *end ;
>>             char32_t *p_out,*out;
>>             size_t rc;
>>
>>             out=malloc(in_len*sizeof(*out));
>>             p_out = out;
>>             p_in = in;
>>             end = in + in_len;
>>             while((rc = mbrtoc32(p_out, p_in, end ‐ p_in, NULL)))
>>             {
>>                 if(rc ==  ‐1)      // invalid input
>>                     break;
>>                 else if(rc == (size_t)‐2) // truncated input
>>                break;
>>                 else if(rc == (size_t)‐3) // UTF‐32 high surrogate
>>                     p_out += 1;
>>                 else {
>>                     p_in += rc;
>>                     p_out += 1;
>>                 };
>>             }
>>             // out_sz = p_out ‐ out + 1;
>>           *len=p_out ‐ out + 1;
>>           *outbuf=out;
>>         }
>>
>>         void fromc32(char32_t *in, int in_len, char **outbuf, int *len)
>>         {
>>           char *out,*p;
>>           int i;
>>            size_t rc;
>>           p=out=malloc(MB_CUR_MAX * in_len);
>>           for(i=0;i<in_len;i++) {
>>             rc=c32rtomb(p, in[i], NULL);
>>             if(rc == (size_t)‐1) break;
>>             p += rc;
>>             }
>>           *outbuf=out;
>>           *len=p‐out+1;
>>         }
>>
>>         void dump_u8(char *in, int len)
>>         {
>>             int i;
>>             printf("Processing %d UTF‐8 code units: [ ", len);
>>             for(i = 0; i <len ; ++i) printf("%#x ", (unsigned char)in[i]);
>>             puts("]");
>>         }
>>
>>         void dump_u32(char32_t *in, int len)
>>         {
>>             int i;
>>             printf("Processing %d UTF‐32 code units: [ ", len);
>>             for(i = 0; i < len; ++i) printf("0x%04x ", in[i]);
>>             puts("]");
>>
>>         }
>>
>>         int main(void){
>>           char in[] = "z00df6c34U0001F34C";
>>           char32_t *out;
>>           int out_len,len;
>>           char *p;
>>           // make sure we have utf8
>>           setlocale(LC_ALL, "de_DE.utf8");
>>           dump_u8(in,sizeof in / sizeof *in);
>>           toc32(in,sizeof in / sizeof *in,&out,&out_len);
>>           dump_u32(out,out_len);
>>           fromc32(out,out_len,&p,&len);
>>           dump_u8(p,len);
>>           return 0;
>>         }
>>
>>         This is a simple example and not production ready.
>>
>> CONFORMING TO
>>         C11
>>
>> SEE ALSO
>>         mbrtoc16(), c16tocmbr(), mbsrtowcs()
>>
>> Linux                      2021‐06‐02                MBRTOC32(3)
>> ]]
>>
>>> ---
>>>   man3/mbrtoc32.3 | 154 ++++++++++++++++++++++++++++++++++++++++++++++++
>>>   1 file changed, 154 insertions(+)
>>>   create mode 100644 man3/mbrtoc32.3
>>>
>>> diff --git a/man3/mbrtoc32.3 b/man3/mbrtoc32.3
>>> new file mode 100644
>>> index 000000000..8d0c33de1
>>> --- /dev/null
>>> +++ b/man3/mbrtoc32.3
>>> @@ -0,0 +1,154 @@
>>> +.TH  MBRTOC32  3 "2021-06-02" Linux "Linux Programmer's Manual"
>>> +.SH NAME
>>> +mbrtoc32, c32rtomb \- convert between multibyte sequence and 32-bit wide character
>>> +.SH SYNOPSIS
>>> +.nf
>>> +.B #include <uchar.h>
>>> +.PP
>>> +.BI "size_t t mbrtoc32 (char32_t * restrict "c32 " ,"
>>> +.BI"                          const char *" restrict s " , size_t " n " ,"
>>> +.BI "                         mbstate_t * restrict " p ");"
>>> +.PP
>>> +.BI "size_t c32rtomb (char * restrict " s ", char32_t  " c32 " ,"
>>> +.BI "                     mbstate_t * restrict " p " );"
>>> +.fi
>>> +.SH DESCRIPTION
>>> +The
>>> +.BR mbrtoc32  ()
>>> +function inspects at most
>>> +.I n
>>> +bytes of the UTF-8 multibyte string starting at
>>> +.IR s .
>>> +If a multibyte is identified as valid the corresponding UCS-32
>>> +32-bit wide character is stored in
>>> +.IR c32 .
>>> +If  the  multibyte  character is the null wide character, it
>>> +resets the shift state
>>> +.I *p
>>> +to the initial state and returns 0.
>>> +If
>>> +.I p
>>> +is  NULL,  a  static anonymous state known only to the
>>> +function is used instead.
>>> +.PP
>>> +The
>>> +.BR c32rtomb ()
>>> +function converts the 32-bit wide character stored in
>>> +.I c32
>>> +into a mutability sequence  into the memory
>>> +.IR s .
>>> +.SH "RETURN VALUES"
>>> +The
>>> +.BR mbrtoc32  ()
>>> +function returns
>>> +0 for the nul character.
>>> +\-1 for invalid input,
>>> +\-2 for a truncated input,
>>> +\-3 for multibyte 32-bit wide character sequence that is
>>> +written to
>>> +.IR *c32 .
>>> +No bytes are processed from the input
>>> +.PP
>>> +Otherwise the number of bytes in the multibyte sequence is returned.
>>> +.PP
>>> +The
>>> +.BR c32tombr  ()
>>> +function returns \-1 on error otherwise the number of bytes used
>>> +for the multibytes sequence.
>>> +.SH EXAMPLE
>>> +The input sequence is written as byte sequence to allow a proper
>>> +display. Note that the input is UTF-8 and UTF-32 , it may not possible
>>> +to convert every code.
>>> +.EX
>>> +.nf.
>>> +
>>> +#include <stdio.h>
>>> +#include <stdlib.h>
>>> +#include <locale.h>
>>> +#include <uchar.h>
>>> +#include <wchar.h>
>>> +
>>> +void toc32( char *in,  int in_len, char32_t **outbuf, int *len)
>>> +{
>>> +    char *p_in , *end ;
>>> +    char32_t *p_out,*out;
>>> +    size_t rc;
>>> +
>>> +    out=malloc(in_len*sizeof(*out));
>>> +    p_out = out;
>>> +    p_in = in;
>>> +    end = in + in_len;
>>> +    while((rc = mbrtoc32(p_out, p_in, end - p_in, NULL)))
>>> +    {
>>> +        if(rc ==  -1)      // invalid input
>>> +            break;
>>> +        else if(rc == (size_t)-2) // truncated input
>>> +	  break;
>>> +        else if(rc == (size_t)-3) // UTF-32 high surrogate
>>> +            p_out += 1;
>>> +        else {
>>> +            p_in += rc;
>>> +            p_out += 1;
>>> +        };
>>> +    }
>>> +    // out_sz = p_out - out + 1;
>>> +  *len=p_out - out + 1;
>>> +  *outbuf=out;
>>> +}
>>> +
>>> +void fromc32(char32_t *in, int in_len, char **outbuf, int *len)
>>> +{
>>> +  char *out,*p;
>>> +  int i;
>>> +   size_t rc;
>>> +  p=out=malloc(MB_CUR_MAX * in_len);
>>> +  for(i=0;i<in_len;i++) {
>>> +    rc=c32rtomb(p, in[i], NULL);
>>> +    if(rc == (size_t)-1) break;
>>> +    p += rc;
>>> +    }
>>> +  *outbuf=out;
>>> +  *len=p-out+1;
>>> +}
>>> +
>>> +void dump_u8(char *in, int len)
>>> +{
>>> +    int i;
>>> +    printf("Processing %d UTF-8 code units: [ ", len);
>>> +    for(i = 0; i <len ; ++i) printf("%#x ", (unsigned char)in[i]);
>>> +    puts("]");
>>> +}
>>> +
>>> +void dump_u32(char32_t *in, int len)
>>> +{
>>> +    int i;
>>> +    printf("Processing %d UTF-32 code units: [ ", len);
>>> +    for(i = 0; i < len; ++i) printf("0x%04x ", in[i]);
>>> +    puts("]");
>>> +
>>> +}
>>> +
>>> +int main(void){
>>> +  char in[] = "z\u00df\u6c34\U0001F34C";
>>> +  char32_t *out;
>>> +  int out_len,len;
>>> +  char *p;
>>> +  // make sure we have utf8
>>> +  setlocale(LC_ALL, "de_DE.utf8");
>>> +  dump_u8(in,sizeof in / sizeof *in);
>>> +  toc32(in,sizeof in / sizeof *in,&out,&out_len);
>>> +  dump_u32(out,out_len);
>>> +  fromc32(out,out_len,&p,&len);
>>> +  dump_u8(p,len);
>>> +  return 0;
>>> +}
>>> +
>>> +.fi
>>> +.EE
>>> +This is a simple example and not production ready.
>>> +.SH "CONFORMING TO"
>>> +C11
>>> +.SH "SEE ALSO"
>>> +.BR mbrtoc16 (),
>>> +.BR c16tocmbr (),
>>> +.BR mbsrtowcs ()
>>> --
>>> 2.26.2
>>>

Re: new:mbrtoc32.3: convert from to c32

[Alejandro Colomar (man-pages)]

Hi Peter,

Please see some comments below.

Thanks,

Alex

On 7/3/21 7:40 PM, Alejandro Colomar (man-pages) wrote:
> Hi Peter,
> 
> On 6/20/21 10:29 PM, Radisson97@gmx.de wrote:
>> From eb1ee6439f85b6a349c84488fa63dc7b795e43a0 Mon Sep 17 00:00:00 2001
>> From: Peter Radisson <--show-origin>
>> Date: Sun, 20 Jun 2021 22:21:55 +0200
>> Subject: [PATCH] convert between multibyte sequence and 32-bit wide character
>>
>> documentation including example
>>
>> Signed-off-by: Peter Radisson <--show-origin>
> 
> Thanks for the page.  I'll have a look at it.
> 
> BTW, next time you document a glibc function from scratch, please CC
> glibc <libc-alpha@sourceware.org> so that they can comment, and maybe
> find some bugs that we may not be able to detect.
> 
> Also, providing a rendered version of the page is good for glibc people
> --who may not have cloned the man-pages-- to easily review it :)
> 
> Rendered page:
> 
> [[
> MBRTOC32(3)         Linux Programmer's Manual        MBRTOC32(3)
> 
> NAME
>        mbrtoc32,  c32rtomb  - convert between multibyte sequence
>        and 32‐bit wide character
> 
> SYNOPSIS
>        #include <uchar.h>
> 
>        size_t t mbrtoc32 (char32_t * restrict c32 ,
>                                 mbstate_t * restrict p);

That prototype seems wrong.  See:

.../glibc$ grep_glibc_prototype mbrtoc32;
wcsmbs/uchar.h:57:
extern size_t mbrtoc32 (char32_t *__restrict __pc32,
			const char *__restrict __s, size_t __n,
			mbstate_t *__restrict __p) __THROW;

> 
>        size_t c32rtomb (char * restrict s, char32_t  c32 ,
>                             mbstate_t * restrict p );
> 
> DESCRIPTION

Are there any important differences compared to the already-documented
and C99-compliant mbrtowc(3) and wcrtomb(3)?  I mean, apart from the
types of the parameters.

I think I would refer to mbrtowc(3) (and wcrtomb(3)) and specify here
only differences specific to these functions, such as the type.

Maybe?:

[
These functions are equivalent to mbrtowc(3) and wcrtomb(3), except that
these functions act on char32_t instead of wchar_t.
]

Otherwise we're unnecessarily repeating all of the information.  If we
use the same wording, we're just duplicating maintenance issues.  If we
use a different wording, readers might wonder why, if they seem to be
the same.

Also, when we need to repeat the text of those pages because of slight
differences, please use the text as similar as possible from those
pages, for the same reasons.


>        The mbrtoc32() function inspects at most n bytes  of  the
>        UTF‐8  multibyte string starting at s.  If a multibyte is
>        identified as valid the corresponding UCS‐32 32‐bit  wide
>        character  is stored in c32.  If  the  multibyte  charac‐
>        ter is the null wide character, it resets the shift state
>        *p to the initial state and returns 0.  If p is  NULL,  a
>        static anonymous state known only to the function is used
>        instead.
> 
>        The  c32rtomb() function converts the 32‐bit wide charac‐
>        ter stored in c32 into a mutability  sequence   into  the
>        memory s.
> 
> RETURN VALUES
>        The  mbrtoc32() function returns 0 for the nul character.
>        -1 for invalid input, -2 for a truncated  input,  -3  for
>        multibyte  32‐bit wide character sequence that is written
>        to *c32.  No bytes are processed from the input
> 
>        Otherwise the number of bytes in the  multibyte  sequence
>        is returned.
> 
>        The c32tombr() function returns -1 on error otherwise the
>        number of bytes used for the multibytes sequence.
> 
> EXAMPLE>        The input sequence is written as byte sequence to allow a
>        proper display. Note that the input is UTF‐8 and UTF‐32 ,
>        it may not possible to convert every code.
> 
>        #include <stdio.h>
>        #include <stdlib.h>
>        #include <locale.h>
>        #include <uchar.h>
>        #include <wchar.h>
> 
>        void toc32( char *in,  int in_len, char32_t **outbuf, int *len)

Please, follow the style of other existing pages (it's similar to the
kernel coding style with some exceptions).
Especially, regarding spaces around parentheses and commas (and other
operators).
Also, please use a consistent indentation of 4 spaces.

https://www.kernel.org/doc/html/v4.10/process/coding-style.html#spaces

>        {
>            char *p_in , *end ;
>            char32_t *p_out,*out;
>            size_t rc;
> 
>            out=malloc(in_len*sizeof(*out));
>            p_out = out;
>            p_in = in;
>            end = in + in_len;
>            while((rc = mbrtoc32(p_out, p_in, end ‐ p_in, NULL)))
>            {
>                if(rc ==  ‐1)      // invalid input
>                    break;
>                else if(rc == (size_t)‐2) // truncated input
>               break;
>                else if(rc == (size_t)‐3) // UTF‐32 high surrogate
>                    p_out += 1;
>                else {
>                    p_in += rc;
>                    p_out += 1;
>                };
>            }
>            // out_sz = p_out ‐ out + 1;
>          *len=p_out ‐ out + 1;
>          *outbuf=out;
>        }
> 
>        void fromc32(char32_t *in, int in_len, char **outbuf, int *len)
>        {
>          char *out,*p;
>          int i;
>           size_t rc;
>          p=out=malloc(MB_CUR_MAX * in_len);
>          for(i=0;i<in_len;i++) {
>            rc=c32rtomb(p, in[i], NULL);
>            if(rc == (size_t)‐1) break;
>            p += rc;
>            }
>          *outbuf=out;
>          *len=p‐out+1;
>        }
> 
>        void dump_u8(char *in, int len)
>        {
>            int i;
>            printf("Processing %d UTF‐8 code units: [ ", len);
>            for(i = 0; i <len ; ++i) printf("%#x ", (unsigned char)in[i]);
>            puts("]");
>        }
> 
>        void dump_u32(char32_t *in, int len)
>        {
>            int i;
>            printf("Processing %d UTF‐32 code units: [ ", len);
>            for(i = 0; i < len; ++i) printf("0x%04x ", in[i]);
>            puts("]");
> 
>        }
> 
>        int main(void){
>          char in[] = "z00df6c34U0001F34C";
>          char32_t *out;
>          int out_len,len;
>          char *p;
>          // make sure we have utf8
>          setlocale(LC_ALL, "de_DE.utf8");
>          dump_u8(in,sizeof in / sizeof *in);
>          toc32(in,sizeof in / sizeof *in,&out,&out_len);
>          dump_u32(out,out_len);
>          fromc32(out,out_len,&p,&len);
>          dump_u8(p,len);
>          return 0;
>        }
> 
>        This is a simple example and not production ready.
> 
> CONFORMING TO
>        C11
> 
> SEE ALSO
>        mbrtoc16(), c16tocmbr(), mbsrtowcs()
> 
> Linux                      2021‐06‐02                MBRTOC32(3)
> ]]
> 
>> ---
>>  man3/mbrtoc32.3 | 154 ++++++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 154 insertions(+)
>>  create mode 100644 man3/mbrtoc32.3
>>
>> diff --git a/man3/mbrtoc32.3 b/man3/mbrtoc32.3
>> new file mode 100644
>> index 000000000..8d0c33de1
>> --- /dev/null
>> +++ b/man3/mbrtoc32.3
>> @@ -0,0 +1,154 @@
>> +.TH  MBRTOC32  3 "2021-06-02" Linux "Linux Programmer's Manual"
>> +.SH NAME
>> +mbrtoc32, c32rtomb \- convert between multibyte sequence and 32-bit wide character
>> +.SH SYNOPSIS
>> +.nf
>> +.B #include <uchar.h>
>> +.PP
>> +.BI "size_t t mbrtoc32 (char32_t * restrict "c32 " ,"
>> +.BI"                          const char *" restrict s " , size_t " n " ,"
>> +.BI "                         mbstate_t * restrict " p ");"
>> +.PP
>> +.BI "size_t c32rtomb (char * restrict " s ", char32_t  " c32 " ,"
>> +.BI "                     mbstate_t * restrict " p " );"
>> +.fi
>> +.SH DESCRIPTION
>> +The
>> +.BR mbrtoc32  ()
>> +function inspects at most
>> +.I n
>> +bytes of the UTF-8 multibyte string starting at
>> +.IR s .
>> +If a multibyte is identified as valid the corresponding UCS-32
>> +32-bit wide character is stored in
>> +.IR c32 .
>> +If  the  multibyte  character is the null wide character, it
>> +resets the shift state
>> +.I *p
>> +to the initial state and returns 0.
>> +If
>> +.I p
>> +is  NULL,  a  static anonymous state known only to the
>> +function is used instead.
>> +.PP
>> +The
>> +.BR c32rtomb ()
>> +function converts the 32-bit wide character stored in
>> +.I c32
>> +into a mutability sequence  into the memory
>> +.IR s .
>> +.SH "RETURN VALUES"
>> +The
>> +.BR mbrtoc32  ()
>> +function returns
>> +0 for the nul character.
>> +\-1 for invalid input,
>> +\-2 for a truncated input,
>> +\-3 for multibyte 32-bit wide character sequence that is
>> +written to
>> +.IR *c32 .
>> +No bytes are processed from the input
>> +.PP
>> +Otherwise the number of bytes in the multibyte sequence is returned.
>> +.PP
>> +The
>> +.BR c32tombr  ()
>> +function returns \-1 on error otherwise the number of bytes used
>> +for the multibytes sequence.
>> +.SH EXAMPLE
>> +The input sequence is written as byte sequence to allow a proper
>> +display. Note that the input is UTF-8 and UTF-32 , it may not possible
>> +to convert every code.
>> +.EX
>> +.nf.
>> +
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <locale.h>
>> +#include <uchar.h>
>> +#include <wchar.h>
>> +
>> +void toc32( char *in,  int in_len, char32_t **outbuf, int *len)
>> +{
>> +    char *p_in , *end ;
>> +    char32_t *p_out,*out;
>> +    size_t rc;
>> +
>> +    out=malloc(in_len*sizeof(*out));
>> +    p_out = out;
>> +    p_in = in;
>> +    end = in + in_len;
>> +    while((rc = mbrtoc32(p_out, p_in, end - p_in, NULL)))
>> +    {
>> +        if(rc ==  -1)      // invalid input
>> +            break;
>> +        else if(rc == (size_t)-2) // truncated input
>> +	  break;
>> +        else if(rc == (size_t)-3) // UTF-32 high surrogate
>> +            p_out += 1;
>> +        else {
>> +            p_in += rc;
>> +            p_out += 1;
>> +        };
>> +    }
>> +    // out_sz = p_out - out + 1;
>> +  *len=p_out - out + 1;
>> +  *outbuf=out;
>> +}
>> +
>> +void fromc32(char32_t *in, int in_len, char **outbuf, int *len)
>> +{
>> +  char *out,*p;
>> +  int i;
>> +   size_t rc;
>> +  p=out=malloc(MB_CUR_MAX * in_len);
>> +  for(i=0;i<in_len;i++) {
>> +    rc=c32rtomb(p, in[i], NULL);
>> +    if(rc == (size_t)-1) break;
>> +    p += rc;
>> +    }
>> +  *outbuf=out;
>> +  *len=p-out+1;
>> +}
>> +
>> +void dump_u8(char *in, int len)
>> +{
>> +    int i;
>> +    printf("Processing %d UTF-8 code units: [ ", len);
>> +    for(i = 0; i <len ; ++i) printf("%#x ", (unsigned char)in[i]);
>> +    puts("]");
>> +}
>> +
>> +void dump_u32(char32_t *in, int len)
>> +{
>> +    int i;
>> +    printf("Processing %d UTF-32 code units: [ ", len);
>> +    for(i = 0; i < len; ++i) printf("0x%04x ", in[i]);
>> +    puts("]");
>> +
>> +}
>> +
>> +int main(void){
>> +  char in[] = "z\u00df\u6c34\U0001F34C";
>> +  char32_t *out;
>> +  int out_len,len;
>> +  char *p;
>> +  // make sure we have utf8
>> +  setlocale(LC_ALL, "de_DE.utf8");
>> +  dump_u8(in,sizeof in / sizeof *in);
>> +  toc32(in,sizeof in / sizeof *in,&out,&out_len);
>> +  dump_u32(out,out_len);
>> +  fromc32(out,out_len,&p,&len);
>> +  dump_u8(p,len);
>> +  return 0;
>> +}
>> +
>> +.fi
>> +.EE
>> +This is a simple example and not production ready.
>> +.SH "CONFORMING TO"
>> +C11
>> +.SH "SEE ALSO"
>> +.BR mbrtoc16 (),
>> +.BR c16tocmbr (),
>> +.BR mbsrtowcs ()
>> --
>> 2.26.2
>>
> 

-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/

Re: new:mbrtoc32.3: convert from to c32

[Alejandro Colomar (man-pages)]

Hi Peter,

On 6/20/21 10:29 PM, Radisson97@gmx.de wrote:
> From eb1ee6439f85b6a349c84488fa63dc7b795e43a0 Mon Sep 17 00:00:00 2001
> From: Peter Radisson <--show-origin>
> Date: Sun, 20 Jun 2021 22:21:55 +0200
> Subject: [PATCH] convert between multibyte sequence and 32-bit wide character
> 
> documentation including example
> 
> Signed-off-by: Peter Radisson <--show-origin>

Thanks for the page.  I'll have a look at it.

BTW, next time you document a glibc function from scratch, please CC
glibc <libc-alpha@sourceware.org> so that they can comment, and maybe
find some bugs that we may not be able to detect.

Also, providing a rendered version of the page is good for glibc people
--who may not have cloned the man-pages-- to easily review it :)

Rendered page:

[[
MBRTOC32(3)         Linux Programmer's Manual        MBRTOC32(3)

NAME
       mbrtoc32,  c32rtomb  - convert between multibyte sequence
       and 32‐bit wide character

SYNOPSIS
       #include <uchar.h>

       size_t t mbrtoc32 (char32_t * restrict c32 ,
                                mbstate_t * restrict p);

       size_t c32rtomb (char * restrict s, char32_t  c32 ,
                            mbstate_t * restrict p );

DESCRIPTION
       The mbrtoc32() function inspects at most n bytes  of  the
       UTF‐8  multibyte string starting at s.  If a multibyte is
       identified as valid the corresponding UCS‐32 32‐bit  wide
       character  is stored in c32.  If  the  multibyte  charac‐
       ter is the null wide character, it resets the shift state
       *p to the initial state and returns 0.  If p is  NULL,  a
       static anonymous state known only to the function is used
       instead.

       The  c32rtomb() function converts the 32‐bit wide charac‐
       ter stored in c32 into a mutability  sequence   into  the
       memory s.

RETURN VALUES
       The  mbrtoc32() function returns 0 for the nul character.
       -1 for invalid input, -2 for a truncated  input,  -3  for
       multibyte  32‐bit wide character sequence that is written
       to *c32.  No bytes are processed from the input

       Otherwise the number of bytes in the  multibyte  sequence
       is returned.

       The c32tombr() function returns -1 on error otherwise the
       number of bytes used for the multibytes sequence.

EXAMPLE
       The input sequence is written as byte sequence to allow a
       proper display. Note that the input is UTF‐8 and UTF‐32 ,
       it may not possible to convert every code.

       #include <stdio.h>
       #include <stdlib.h>
       #include <locale.h>
       #include <uchar.h>
       #include <wchar.h>

       void toc32( char *in,  int in_len, char32_t **outbuf, int *len)
       {
           char *p_in , *end ;
           char32_t *p_out,*out;
           size_t rc;

           out=malloc(in_len*sizeof(*out));
           p_out = out;
           p_in = in;
           end = in + in_len;
           while((rc = mbrtoc32(p_out, p_in, end ‐ p_in, NULL)))
           {
               if(rc ==  ‐1)      // invalid input
                   break;
               else if(rc == (size_t)‐2) // truncated input
              break;
               else if(rc == (size_t)‐3) // UTF‐32 high surrogate
                   p_out += 1;
               else {
                   p_in += rc;
                   p_out += 1;
               };
           }
           // out_sz = p_out ‐ out + 1;
         *len=p_out ‐ out + 1;
         *outbuf=out;
       }

       void fromc32(char32_t *in, int in_len, char **outbuf, int *len)
       {
         char *out,*p;
         int i;
          size_t rc;
         p=out=malloc(MB_CUR_MAX * in_len);
         for(i=0;i<in_len;i++) {
           rc=c32rtomb(p, in[i], NULL);
           if(rc == (size_t)‐1) break;
           p += rc;
           }
         *outbuf=out;
         *len=p‐out+1;
       }

       void dump_u8(char *in, int len)
       {
           int i;
           printf("Processing %d UTF‐8 code units: [ ", len);
           for(i = 0; i <len ; ++i) printf("%#x ", (unsigned char)in[i]);
           puts("]");
       }

       void dump_u32(char32_t *in, int len)
       {
           int i;
           printf("Processing %d UTF‐32 code units: [ ", len);
           for(i = 0; i < len; ++i) printf("0x%04x ", in[i]);
           puts("]");

       }

       int main(void){
         char in[] = "z00df6c34U0001F34C";
         char32_t *out;
         int out_len,len;
         char *p;
         // make sure we have utf8
         setlocale(LC_ALL, "de_DE.utf8");
         dump_u8(in,sizeof in / sizeof *in);
         toc32(in,sizeof in / sizeof *in,&out,&out_len);
         dump_u32(out,out_len);
         fromc32(out,out_len,&p,&len);
         dump_u8(p,len);
         return 0;
       }

       This is a simple example and not production ready.

CONFORMING TO
       C11

SEE ALSO
       mbrtoc16(), c16tocmbr(), mbsrtowcs()

Linux                      2021‐06‐02                MBRTOC32(3)
]]

> ---
>  man3/mbrtoc32.3 | 154 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 154 insertions(+)
>  create mode 100644 man3/mbrtoc32.3
> 
> diff --git a/man3/mbrtoc32.3 b/man3/mbrtoc32.3
> new file mode 100644
> index 000000000..8d0c33de1
> --- /dev/null
> +++ b/man3/mbrtoc32.3
> @@ -0,0 +1,154 @@
> +.TH  MBRTOC32  3 "2021-06-02" Linux "Linux Programmer's Manual"
> +.SH NAME
> +mbrtoc32, c32rtomb \- convert between multibyte sequence and 32-bit wide character
> +.SH SYNOPSIS
> +.nf
> +.B #include <uchar.h>
> +.PP
> +.BI "size_t t mbrtoc32 (char32_t * restrict "c32 " ,"
> +.BI"                          const char *" restrict s " , size_t " n " ,"
> +.BI "                         mbstate_t * restrict " p ");"
> +.PP
> +.BI "size_t c32rtomb (char * restrict " s ", char32_t  " c32 " ,"
> +.BI "                     mbstate_t * restrict " p " );"
> +.fi
> +.SH DESCRIPTION
> +The
> +.BR mbrtoc32  ()
> +function inspects at most
> +.I n
> +bytes of the UTF-8 multibyte string starting at
> +.IR s .
> +If a multibyte is identified as valid the corresponding UCS-32
> +32-bit wide character is stored in
> +.IR c32 .
> +If  the  multibyte  character is the null wide character, it
> +resets the shift state
> +.I *p
> +to the initial state and returns 0.
> +If
> +.I p
> +is  NULL,  a  static anonymous state known only to the
> +function is used instead.
> +.PP
> +The
> +.BR c32rtomb ()
> +function converts the 32-bit wide character stored in
> +.I c32
> +into a mutability sequence  into the memory
> +.IR s .
> +.SH "RETURN VALUES"
> +The
> +.BR mbrtoc32  ()
> +function returns
> +0 for the nul character.
> +\-1 for invalid input,
> +\-2 for a truncated input,
> +\-3 for multibyte 32-bit wide character sequence that is
> +written to
> +.IR *c32 .
> +No bytes are processed from the input
> +.PP
> +Otherwise the number of bytes in the multibyte sequence is returned.
> +.PP
> +The
> +.BR c32tombr  ()
> +function returns \-1 on error otherwise the number of bytes used
> +for the multibytes sequence.
> +.SH EXAMPLE
> +The input sequence is written as byte sequence to allow a proper
> +display. Note that the input is UTF-8 and UTF-32 , it may not possible
> +to convert every code.
> +.EX
> +.nf.
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <locale.h>
> +#include <uchar.h>
> +#include <wchar.h>
> +
> +void toc32( char *in,  int in_len, char32_t **outbuf, int *len)
> +{
> +    char *p_in , *end ;
> +    char32_t *p_out,*out;
> +    size_t rc;
> +
> +    out=malloc(in_len*sizeof(*out));
> +    p_out = out;
> +    p_in = in;
> +    end = in + in_len;
> +    while((rc = mbrtoc32(p_out, p_in, end - p_in, NULL)))
> +    {
> +        if(rc ==  -1)      // invalid input
> +            break;
> +        else if(rc == (size_t)-2) // truncated input
> +	  break;
> +        else if(rc == (size_t)-3) // UTF-32 high surrogate
> +            p_out += 1;
> +        else {
> +            p_in += rc;
> +            p_out += 1;
> +        };
> +    }
> +    // out_sz = p_out - out + 1;
> +  *len=p_out - out + 1;
> +  *outbuf=out;
> +}
> +
> +void fromc32(char32_t *in, int in_len, char **outbuf, int *len)
> +{
> +  char *out,*p;
> +  int i;
> +   size_t rc;
> +  p=out=malloc(MB_CUR_MAX * in_len);
> +  for(i=0;i<in_len;i++) {
> +    rc=c32rtomb(p, in[i], NULL);
> +    if(rc == (size_t)-1) break;
> +    p += rc;
> +    }
> +  *outbuf=out;
> +  *len=p-out+1;
> +}
> +
> +void dump_u8(char *in, int len)
> +{
> +    int i;
> +    printf("Processing %d UTF-8 code units: [ ", len);
> +    for(i = 0; i <len ; ++i) printf("%#x ", (unsigned char)in[i]);
> +    puts("]");
> +}
> +
> +void dump_u32(char32_t *in, int len)
> +{
> +    int i;
> +    printf("Processing %d UTF-32 code units: [ ", len);
> +    for(i = 0; i < len; ++i) printf("0x%04x ", in[i]);
> +    puts("]");
> +
> +}
> +
> +int main(void){
> +  char in[] = "z\u00df\u6c34\U0001F34C";
> +  char32_t *out;
> +  int out_len,len;
> +  char *p;
> +  // make sure we have utf8
> +  setlocale(LC_ALL, "de_DE.utf8");
> +  dump_u8(in,sizeof in / sizeof *in);
> +  toc32(in,sizeof in / sizeof *in,&out,&out_len);
> +  dump_u32(out,out_len);
> +  fromc32(out,out_len,&p,&len);
> +  dump_u8(p,len);
> +  return 0;
> +}
> +
> +.fi
> +.EE
> +This is a simple example and not production ready.
> +.SH "CONFORMING TO"
> +C11
> +.SH "SEE ALSO"
> +.BR mbrtoc16 (),
> +.BR c16tocmbr (),
> +.BR mbsrtowcs ()
> --
> 2.26.2
> 

-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/

new:mbrtoc32.3: convert from to c32

[Radisson97]

From eb1ee6439f85b6a349c84488fa63dc7b795e43a0 Mon Sep 17 00:00:00 2001
From: Peter Radisson <--show-origin>
Date: Sun, 20 Jun 2021 22:21:55 +0200
Subject: [PATCH] convert between multibyte sequence and 32-bit wide character

documentation including example

Signed-off-by: Peter Radisson <--show-origin>
---
 man3/mbrtoc32.3 | 154 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 154 insertions(+)
 create mode 100644 man3/mbrtoc32.3

diff --git a/man3/mbrtoc32.3 b/man3/mbrtoc32.3
new file mode 100644
index 000000000..8d0c33de1
--- /dev/null
+++ b/man3/mbrtoc32.3
@@ -0,0 +1,154 @@
+.TH  MBRTOC32  3 "2021-06-02" Linux "Linux Programmer's Manual"
+.SH NAME
+mbrtoc32, c32rtomb \- convert between multibyte sequence and 32-bit wide character
+.SH SYNOPSIS
+.nf
+.B #include <uchar.h>
+.PP
+.BI "size_t t mbrtoc32 (char32_t * restrict "c32 " ,"
+.BI"                          const char *" restrict s " , size_t " n " ,"
+.BI "                         mbstate_t * restrict " p ");"
+.PP
+.BI "size_t c32rtomb (char * restrict " s ", char32_t  " c32 " ,"
+.BI "                     mbstate_t * restrict " p " );"
+.fi
+.SH DESCRIPTION
+The
+.BR mbrtoc32  ()
+function inspects at most
+.I n
+bytes of the UTF-8 multibyte string starting at
+.IR s .
+If a multibyte is identified as valid the corresponding UCS-32
+32-bit wide character is stored in
+.IR c32 .
+If  the  multibyte  character is the null wide character, it
+resets the shift state
+.I *p
+to the initial state and returns 0.
+If
+.I p
+is  NULL,  a  static anonymous state known only to the
+function is used instead.
+.PP
+The
+.BR c32rtomb ()
+function converts the 32-bit wide character stored in
+.I c32
+into a mutability sequence  into the memory
+.IR s .
+.SH "RETURN VALUES"
+The
+.BR mbrtoc32  ()
+function returns
+0 for the nul character.
+\-1 for invalid input,
+\-2 for a truncated input,
+\-3 for multibyte 32-bit wide character sequence that is
+written to
+.IR *c32 .
+No bytes are processed from the input
+.PP
+Otherwise the number of bytes in the multibyte sequence is returned.
+.PP
+The
+.BR c32tombr  ()
+function returns \-1 on error otherwise the number of bytes used
+for the multibytes sequence.
+.SH EXAMPLE
+The input sequence is written as byte sequence to allow a proper
+display. Note that the input is UTF-8 and UTF-32 , it may not possible
+to convert every code.
+.EX
+.nf.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <locale.h>
+#include <uchar.h>
+#include <wchar.h>
+
+void toc32( char *in,  int in_len, char32_t **outbuf, int *len)
+{
+    char *p_in , *end ;
+    char32_t *p_out,*out;
+    size_t rc;
+
+    out=malloc(in_len*sizeof(*out));
+    p_out = out;
+    p_in = in;
+    end = in + in_len;
+    while((rc = mbrtoc32(p_out, p_in, end - p_in, NULL)))
+    {
+        if(rc ==  -1)      // invalid input
+            break;
+        else if(rc == (size_t)-2) // truncated input
+	  break;
+        else if(rc == (size_t)-3) // UTF-32 high surrogate
+            p_out += 1;
+        else {
+            p_in += rc;
+            p_out += 1;
+        };
+    }
+    // out_sz = p_out - out + 1;
+  *len=p_out - out + 1;
+  *outbuf=out;
+}
+
+void fromc32(char32_t *in, int in_len, char **outbuf, int *len)
+{
+  char *out,*p;
+  int i;
+   size_t rc;
+  p=out=malloc(MB_CUR_MAX * in_len);
+  for(i=0;i<in_len;i++) {
+    rc=c32rtomb(p, in[i], NULL);
+    if(rc == (size_t)-1) break;
+    p += rc;
+    }
+  *outbuf=out;
+  *len=p-out+1;
+}
+
+void dump_u8(char *in, int len)
+{
+    int i;
+    printf("Processing %d UTF-8 code units: [ ", len);
+    for(i = 0; i <len ; ++i) printf("%#x ", (unsigned char)in[i]);
+    puts("]");
+}
+
+void dump_u32(char32_t *in, int len)
+{
+    int i;
+    printf("Processing %d UTF-32 code units: [ ", len);
+    for(i = 0; i < len; ++i) printf("0x%04x ", in[i]);
+    puts("]");
+
+}
+
+int main(void){
+  char in[] = "z\u00df\u6c34\U0001F34C";
+  char32_t *out;
+  int out_len,len;
+  char *p;
+  // make sure we have utf8
+  setlocale(LC_ALL, "de_DE.utf8");
+  dump_u8(in,sizeof in / sizeof *in);
+  toc32(in,sizeof in / sizeof *in,&out,&out_len);
+  dump_u32(out,out_len);
+  fromc32(out,out_len,&p,&len);
+  dump_u8(p,len);
+  return 0;
+}
+
+.fi
+.EE
+This is a simple example and not production ready.
+.SH "CONFORMING TO"
+C11
+.SH "SEE ALSO"
+.BR mbrtoc16 (),
+.BR c16tocmbr (),
+.BR mbsrtowcs ()
--
2.26.2

new:mbrtoc32.3: convert from to c32

[Radisson97]

From eb1ee6439f85b6a349c84488fa63dc7b795e43a0 Mon Sep 17 00:00:00 2001
From: Peter Radisson <--show-origin>
Date: Sun, 20 Jun 2021 22:21:55 +0200
Subject: [PATCH] convert between multibyte sequence and 32-bit wide character

documentation including example

Signed-off-by: Peter Radisson <--show-origin>
---
 man3/mbrtoc32.3 | 154 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 154 insertions(+)
 create mode 100644 man3/mbrtoc32.3

diff --git a/man3/mbrtoc32.3 b/man3/mbrtoc32.3
new file mode 100644
index 000000000..8d0c33de1
--- /dev/null
+++ b/man3/mbrtoc32.3
@@ -0,0 +1,154 @@
+.TH  MBRTOC32  3 "2021-06-02" Linux "Linux Programmer's Manual"
+.SH NAME
+mbrtoc32, c32rtomb \- convert between multibyte sequence and 32-bit wide character
+.SH SYNOPSIS
+.nf
+.B #include <uchar.h>
+.PP
+.BI "size_t t mbrtoc32 (char32_t * restrict "c32 " ,"
+.BI"                          const char *" restrict s " , size_t " n " ,"
+.BI "                         mbstate_t * restrict " p ");"
+.PP
+.BI "size_t c32rtomb (char * restrict " s ", char32_t  " c32 " ,"
+.BI "                     mbstate_t * restrict " p " );"
+.fi
+.SH DESCRIPTION
+The
+.BR mbrtoc32  ()
+function inspects at most
+.I n
+bytes of the UTF-8 multibyte string starting at
+.IR s .
+If a multibyte is identified as valid the corresponding UCS-32
+32-bit wide character is stored in
+.IR c32 .
+If  the  multibyte  character is the null wide character, it
+resets the shift state
+.I *p
+to the initial state and returns 0.
+If
+.I p
+is  NULL,  a  static anonymous state known only to the
+function is used instead.
+.PP
+The
+.BR c32rtomb ()
+function converts the 32-bit wide character stored in
+.I c32
+into a mutability sequence  into the memory
+.IR s .
+.SH "RETURN VALUES"
+The
+.BR mbrtoc32  ()
+function returns
+0 for the nul character.
+\-1 for invalid input,
+\-2 for a truncated input,
+\-3 for multibyte 32-bit wide character sequence that is
+written to
+.IR *c32 .
+No bytes are processed from the input
+.PP
+Otherwise the number of bytes in the multibyte sequence is returned.
+.PP
+The
+.BR c32tombr  ()
+function returns \-1 on error otherwise the number of bytes used
+for the multibytes sequence.
+.SH EXAMPLE
+The input sequence is written as byte sequence to allow a proper
+display. Note that the input is UTF-8 and UTF-32 , it may not possible
+to convert every code.
+.EX
+.nf.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <locale.h>
+#include <uchar.h>
+#include <wchar.h>
+
+void toc32( char *in,  int in_len, char32_t **outbuf, int *len)
+{
+    char *p_in , *end ;
+    char32_t *p_out,*out;
+    size_t rc;
+
+    out=malloc(in_len*sizeof(*out));
+    p_out = out;
+    p_in = in;
+    end = in + in_len;
+    while((rc = mbrtoc32(p_out, p_in, end - p_in, NULL)))
+    {
+        if(rc ==  -1)      // invalid input
+            break;
+        else if(rc == (size_t)-2) // truncated input
+	  break;
+        else if(rc == (size_t)-3) // UTF-32 high surrogate
+            p_out += 1;
+        else {
+            p_in += rc;
+            p_out += 1;
+        };
+    }
+    // out_sz = p_out - out + 1;
+  *len=p_out - out + 1;
+  *outbuf=out;
+}
+
+void fromc32(char32_t *in, int in_len, char **outbuf, int *len)
+{
+  char *out,*p;
+  int i;
+   size_t rc;
+  p=out=malloc(MB_CUR_MAX * in_len);
+  for(i=0;i<in_len;i++) {
+    rc=c32rtomb(p, in[i], NULL);
+    if(rc == (size_t)-1) break;
+    p += rc;
+    }
+  *outbuf=out;
+  *len=p-out+1;
+}
+
+void dump_u8(char *in, int len)
+{
+    int i;
+    printf("Processing %d UTF-8 code units: [ ", len);
+    for(i = 0; i <len ; ++i) printf("%#x ", (unsigned char)in[i]);
+    puts("]");
+}
+
+void dump_u32(char32_t *in, int len)
+{
+    int i;
+    printf("Processing %d UTF-32 code units: [ ", len);
+    for(i = 0; i < len; ++i) printf("0x%04x ", in[i]);
+    puts("]");
+
+}
+
+int main(void){
+  char in[] = "z\u00df\u6c34\U0001F34C";
+  char32_t *out;
+  int out_len,len;
+  char *p;
+  // make sure we have utf8
+  setlocale(LC_ALL, "de_DE.utf8");
+  dump_u8(in,sizeof in / sizeof *in);
+  toc32(in,sizeof in / sizeof *in,&out,&out_len);
+  dump_u32(out,out_len);
+  fromc32(out,out_len,&p,&len);
+  dump_u8(p,len);
+  return 0;
+}
+
+.fi
+.EE
+This is a simple example and not production ready.
+.SH "CONFORMING TO"
+C11
+.SH "SEE ALSO"
+.BR mbrtoc16 (),
+.BR c16tocmbr (),
+.BR mbsrtowcs ()
--
2.26.2