In the front only, if you want to call it that way. Say, I want to just modify the TTL or TOS values of IP header of a network packet (accessed using evbuffer API) passing through my box: don't want to use pullup() which is costly, since, the IP header could be a few headers away from the beginning (MAC + other enapsulations).
I don't understand how add_reference() would meet the need: I want to modify the bytes in the packet headers, from less than a byte upto 16 bytes max. Regards, -devi On Tue, Nov 15, 2016 at 11:35 AM, Philip Prindeville < [email protected]> wrote: > Where in the buffer is the data? Is it near the front or not? > > If it’s near the front, then use evbuffer_pullup(). Otherwise, you could > provide your own underlying storage with evbuffer_add_reference(). > > > > On Nov 15, 2016, at 11:58 AM, Devi Prasad Ivaturi <[email protected]> > wrote: > > And I get the impression that these API are to insert data rather than > modify existing data. > > On Nov 15, 2016 10:43 AM, "Devi Prasad Ivaturi" <[email protected]> > wrote: > > BTW, I did consider reserve/commit space API, but, thought they might be > an overkill. I prefer peeking the byte location and modifying it. > > On Nov 15, 2016 10:12 AM, "Devi Prasad Ivaturi" <[email protected]> > wrote: > > How can I modify a byte or two directly in evbuffer data? > > > > >
