On 4/8/12 4:54 AM, Manu wrote:

On 8 April 2012 12:46, Vladimir Panteleev <vladimir@thecybershadow.net

<mailto:vladimir@thecybershadow.net>> wrote:

   On Sunday, 8 April 2012 at 05:56:36 UTC, Andrei Alexandrescu wrote:

       Walter and I discussed today about using the small string
       optimization in string and other arrays of immutable small objects.

       On 64 bit machines, string occupies 16 bytes. We could use the
       first byte as discriminator, which means that all strings under
       16 chars need no memory allocation at all.


   Don't use the first byte. Use the last byte.

   The last byte is the highest-order byte of the length. Limiting
   arrays to 18.37 exabytes, as opposed to 18.45 exabytes, is a much
   nicer limitation than making assumptions about the memory layout.

What is the plan for 32bit?

We can experiment with making strings shorter than 8 chars in-situ. The drawback will be that length will be limited to 29 bits, i.e. 512MB.