On 29.02.2016 17:06, Eric Blake wrote: > On 02/29/2016 08:46 AM, Max Reitz wrote: > >>>> Compressed Clusters Descriptor (x = 62 - (cluster_bits - 8)): >>>> >>>> - Bit 0 - x: Host cluster offset. This is usually _not_ aligned to >>>> a >>>> - cluster boundary! >>>> + Bit 0 - x: Bits 9-(x+9) of host cluster offset. This is >>> >>> I'd rather use one of "9..(x+9)", "[9, x+9]", "9 - (x+9)", "9—(x+9)" in >>> order to clarify that this is not a minus but a range. >> >> ...unless, of course, this is actually a byte offset, which it seems to >> be, judging from qcow2_get_cluster_offset() (and >> qcow2_decompress_cluster(), as Kevin said on IRC). > > Hmm, then I may be totally wrong. (Serves me right for trying to write a > spec patch without testing actual behavior). > > At the least, we may want to say that things are usually not aligned to > even a _sector_ boundary (not just cluster boundary), and also clarify > whether the sector length is truncated or rounded up (zlib doesn't care > about trailing garbage during decompression, but you DO need to know how > many sectors to read to ensure that you are supplying zlib with trailing > garbage, rather than a truncated stream).
Yes, I agree. Max
signature.asc
Description: OpenPGP digital signature
