Le 08/04/2012 16:52, Andrei Alexandrescu a écrit :
On 4/8/12 4:54 AM, Manu wrote:
On 8 April 2012 12:46, Vladimir Panteleev <vladi...@thecybershadow.net
<mailto:vladi...@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.
Andrei
As it is a flag, why not limit the string size to 2GB instead of 512MB ?
