Re: [U-Boot] [PATCH 1/1] efi_loader: MAX_UTF8_PER_UTF16 = 3

[Heinrich Schuchardt]

On 10/09/2017 08:43 PM, Alexander Graf wrote:
> 
> 
>> Am 09.10.2017 um 20:39 schrieb Heinrich Schuchardt :
>>
>> A code point encoded by one UTF-16 symbol is converted to a
>> maximum of three UTF-8 symbols.
>>
>> 0x could be encoded as 0xef 0xbf 0xbf.
>> The first byte carries four bits, the second and third byte
>> carry six bits each.
>>
>> A code point encoded by two UTF-16 symbols is converted to four
>> UTF-8 symbols.
> 
> Yes, so why do you set it to 3?

The constant is not bytes per code point but bytes per UTF-16.

4 / 2 = 2 < 3

Cheers

Heinrich

> 
> Please also explain what exactly this actually fixes :).
> 
> 
> Alex
> 
>>
>> Fixes: 78178bb0c9d lib: add some utf16 handling helpers
>> Signed-off-by: Heinrich Schuchardt 
>> ---
>> The code is only used by efi_loader.
>> So this patch should go via efi-next.
>> ---
>> include/charset.h | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/charset.h b/include/charset.h
>> index 9c2866bbe6..2f7f7eacc9 100644
>> --- a/include/charset.h
>> +++ b/include/charset.h
>> @@ -9,7 +9,7 @@
>> #ifndef __CHARSET_H_
>> #define __CHARSET_H_
>>
>> -#define MAX_UTF8_PER_UTF16 4
>> +#define MAX_UTF8_PER_UTF16 3
>>
>> /**
>>  * utf16_strlen() - Get the length of an utf16 string
>> @@ -52,7 +52,7 @@ uint16_t *utf16_strdup(const uint16_t *s);
>>  * Converts 'size' characters of the utf16 string 'src' to utf8
>>  * written to the 'dest' buffer.
>>  *
>> - * NOTE that a single utf16 character can generate up to 4 utf8
>> + * NOTE that a single utf16 character can generate up to 3 utf8
>>  * characters.  See MAX_UTF8_PER_UTF16.
>>  *
>>  * @dest   the destination buffer to write the utf8 characters
>> -- 
>> 2.14.1
>>
> 

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Re: [U-Boot] [PATCH 1/1] efi_loader: MAX_UTF8_PER_UTF16 = 3

[Alexander Graf]

> Am 09.10.2017 um 20:39 schrieb Heinrich Schuchardt :
> 
> A code point encoded by one UTF-16 symbol is converted to a
> maximum of three UTF-8 symbols.
> 
> 0x could be encoded as 0xef 0xbf 0xbf.
> The first byte carries four bits, the second and third byte
> carry six bits each.
> 
> A code point encoded by two UTF-16 symbols is converted to four
> UTF-8 symbols.

Yes, so why do you set it to 3?

Please also explain what exactly this actually fixes :).


Alex

> 
> Fixes: 78178bb0c9d lib: add some utf16 handling helpers
> Signed-off-by: Heinrich Schuchardt 
> ---
> The code is only used by efi_loader.
> So this patch should go via efi-next.
> ---
> include/charset.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/charset.h b/include/charset.h
> index 9c2866bbe6..2f7f7eacc9 100644
> --- a/include/charset.h
> +++ b/include/charset.h
> @@ -9,7 +9,7 @@
> #ifndef __CHARSET_H_
> #define __CHARSET_H_
> 
> -#define MAX_UTF8_PER_UTF16 4
> +#define MAX_UTF8_PER_UTF16 3
> 
> /**
>  * utf16_strlen() - Get the length of an utf16 string
> @@ -52,7 +52,7 @@ uint16_t *utf16_strdup(const uint16_t *s);
>  * Converts 'size' characters of the utf16 string 'src' to utf8
>  * written to the 'dest' buffer.
>  *
> - * NOTE that a single utf16 character can generate up to 4 utf8
> + * NOTE that a single utf16 character can generate up to 3 utf8
>  * characters.  See MAX_UTF8_PER_UTF16.
>  *
>  * @dest   the destination buffer to write the utf8 characters
> -- 
> 2.14.1
> 
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[U-Boot] [PATCH 1/1] efi_loader: MAX_UTF8_PER_UTF16 = 3

[Heinrich Schuchardt]

A code point encoded by one UTF-16 symbol is converted to a
maximum of three UTF-8 symbols.

0x could be encoded as 0xef 0xbf 0xbf.
The first byte carries four bits, the second and third byte
carry six bits each.

A code point encoded by two UTF-16 symbols is converted to four
UTF-8 symbols.

Fixes: 78178bb0c9d lib: add some utf16 handling helpers
Signed-off-by: Heinrich Schuchardt 
---
The code is only used by efi_loader.
So this patch should go via efi-next.
---
 include/charset.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/charset.h b/include/charset.h
index 9c2866bbe6..2f7f7eacc9 100644
--- a/include/charset.h
+++ b/include/charset.h
@@ -9,7 +9,7 @@
 #ifndef __CHARSET_H_
 #define __CHARSET_H_
 
-#define MAX_UTF8_PER_UTF16 4
+#define MAX_UTF8_PER_UTF16 3
 
 /**
  * utf16_strlen() - Get the length of an utf16 string
@@ -52,7 +52,7 @@ uint16_t *utf16_strdup(const uint16_t *s);
  * Converts 'size' characters of the utf16 string 'src' to utf8
  * written to the 'dest' buffer.
  *
- * NOTE that a single utf16 character can generate up to 4 utf8
+ * NOTE that a single utf16 character can generate up to 3 utf8
  * characters.  See MAX_UTF8_PER_UTF16.
  *
  * @dest   the destination buffer to write the utf8 characters
-- 
2.14.1

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