[Python-Dev] Type of range object members (original) (raw)

Guido van Rossum guido at python.org
Wed Aug 16 00:29:13 CEST 2006

On 8/15/06, "Martin v. Löwis" <martin at v.loewis.de> wrote:

Guido van Rossum schrieb: > From the Python user's perspective, yes, as much as possible. But > I'm still playing with the thought of having two implementation types, > since otherwise we'd have to devote 4 bytes (8 on a 64-bit platform) > to the single bit telling the difference between the two internal > representations.

We had this discussion before; if you use obsize==0 to indicate that it's an int, this space isn't needed in a long int. On a 32-bit platform, the size of an int would go up from 12 to 16; if we stop using a special-cased allocator (which we should (*)), there isn't any space increase on such a platform. On a 64-bit platform, the size of an int would go up from 24 bytes to 32 bytes. Regards, Martin (*) people have complained that the memory allocated for a large number of ints isn't ever reused. They consumed it by passing range() some large argument.

Since range() won't return a real list any more, this no longer is the case. I worry that dropping the special allocator will be too slow. And the space increase on 64-bit platforms is too much IMO. But clearly these issues can only be addressed by careful benchmarking. Perhaps we should do some of that to settle the issue.

-- --Guido van Rossum (home page: http://www.python.org/~guido/)

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