[9fans] bufreset deletes b->nbl-1 blocks?

I'm reading the sam source (very educational) and I've stumbled across a piece I don't understand, in buff.c:^bufreset: for(i=b->nbl-1; --i>=0; ) delblock(b, i); Doesn't this delete b-nbl-1 blocks? Also delblock would always call memmove, moving 1 block at the end, if I read it correctly.

Re: [9fans] bufreset deletes b->nbl-1 blocks?

On Fri, Aug 12, 2016 at 8:32 AM Costin Chirvasuta wrote: > > So isn't the memmove just to cover the case where you are > > deleting a block that isn't at the very end? > > Yes, but from what I understand i is always lower. > > Say b->nbl starts at 10. i=b->nbl-1 so i=9. --i so

Re: [9fans] bufreset deletes b->nbl-1 blocks?

But delblock only calls memmove if i is less then b->nbl, which was just decremented, correct? So isn't the memmove just to cover the case where you are deleting a block that isn't at the very end? Jim

Re: [9fans] bufreset deletes b->nbl-1 blocks?

Sorry, you're right, delblock(b, 0) is called. delblock(b, 9) isn't called. It's called for the sequence 8..0, as you stated. So is this correct? Doesn't this mean one block will never get released back to the temporary disc? On Fri, Aug 12, 2016 at 6:48 PM, James A. Robinson

Re: [9fans] bufreset deletes b->nbl-1 blocks?

Have you checked whether or not that final block is special in some way? For example only mapped to memory and not to disk blocks? Jim

Re: [9fans] bufreset deletes b->nbl-1 blocks?

I believe bufreset can be called at any time and b->cbi (the current cached block) can point to anything. Either way, that block is never returned to the Disc's free list so that file address won't be reused from that point on. On Fri, Aug 12, 2016 at 7:16 PM, James A. Robinson