[PATCH 2/3] read-cache: use get_be32 instead of hand-rolled ntoh_l

Commit d60c49c (read-cache.c: allow unaligned mapping of the index file, 2012-04-03) introduced helpers to access unaligned data. However, we already have get_be32, which has a few advantages: 1. It's already written, so we avoid duplication. 2. It's probably faster, since it does the endian

Re: [PATCH 2/3] read-cache: use get_be32 instead of hand-rolled ntoh_l

Jeff King wrote: This _might_ still suffer from the issue fixed in 5f6a112 (block-sha1: avoid pointer conversion that violates alignment constraints, 2012-07-22), as we are taking the pointer of a uint32 in a struct. No conversion, so no issue there. Line 1484 looks more problematic:

Re: [PATCH 2/3] read-cache: use get_be32 instead of hand-rolled ntoh_l

On Thu, Jan 23, 2014 at 03:34:16PM -0800, Jonathan Nieder wrote: Line 1484 looks more problematic: disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset); In v4 indexes, src_offset doesn't have any particular alignment so this conversion has undefined behavior.