Re: ICU4C API Addition Proposal: ucol_openFromBinary

See below.

Regards,
v.

Markus Scherer wrote:
> Vladimir Weinstein wrote:
> 
>> - binary image used in instantiation of the collator remains owned by 
>> the user and should stay around for the lifetime of the collator.
> 
> 
> Similarly, the base collator remains owned by the caller and must stay 
> around for the lifetime of the new collator. Right?
Yes.

> 
>> - For the purpose of creating a collator binary image, the following 
>> API is proposed:
>>
>> /**
>>  * Clones collator's  binary image. The image can be stored and
>>  * used for opening a collator using ucol_openBinary.
>>  *
>>  * @param coll The collator to get the image from
>>  * @param length returns the length of the data, in bytes.
>>  * @param status the error status
>>  * @return memory, owned by the caller, of size 'length' bytes.
>>  */
>> U_CAPI uint8_t* U_EXPORT2
>> ucol_cloneBinary(const UCollator *coll, int32_t *length, UErrorCode 
>> *status);
> 
> 
> Problematic: This would transfer ownership of an ICU-library-allocated 
> memory block to the application. Bad idea.
> 
> Better:
> U_CAPI int32_t U_EXPORT2
> ucol_cloneBinary(const UCollator *coll,
>                  uint8_t *dest, int32_t *destCapacity,
>                  UErrorCode *status);
> 
> returning the length (and doing the usual preflighting). This way, the 
> caller always owns the storage.
Not a big fan of preflighting etc. but I see the point. API amended.

> 
> markus
> 

-- 
Vladimir Weinstein, IBM GCoC-Unicode/ICU  San Jose, CA [email protected]