On 08/05, Junio C Hamano wrote:
> Thomas Gummerer <t.gummerer@xxxxxxxxx> writes:
>
> > +static struct directory_entry *read_directories_v5(unsigned int *dir_offset,
> > + unsigned int *dir_table_offset,
> > + void *mmap,
> > + int mmap_size)
> > +{
> > + int i, ondisk_directory_size;
> > + uint32_t *filecrc, *beginning, *end;
> > + struct directory_entry *current = NULL;
> > + struct ondisk_directory_entry *disk_de;
> > + struct directory_entry *de;
> > + unsigned int data_len, len;
> > + char *name;
> > +
> > + ondisk_directory_size = sizeof(disk_de->flags)
> > + + sizeof(disk_de->foffset)
> > + + sizeof(disk_de->cr)
> > + + sizeof(disk_de->ncr)
> > + + sizeof(disk_de->nsubtrees)
> > + + sizeof(disk_de->nfiles)
> > + + sizeof(disk_de->nentries)
> > + + sizeof(disk_de->sha1);
> > + name = (char *)mmap + *dir_offset;
> > + beginning = mmap + *dir_table_offset;
>
> Notice how you computed name with pointer arithmetic by first
> casting mmap (which is "void *") and when computing beginning, you
> forgot to cast mmap and attempted pointer arithmetic with "void *".
> The latter does not work and breaks compilation.
>
> The pointer-arith with "void *" is not limited to this function.
Sorry for not noticing this, it always compiled fine for me. Guess
I should use -pedantic more often ;-)
> Please check the a band-aid (I wouldn't call it a fix-up) patch I
> added on top of the series before queuing the topic to 'pu'; it is
> primarily to illustrate the places I noticed that have this issue.
>
> I do not necessarily suggest that the way the band-aid patch makes
> it compile is the best approach. It might be cleaner to use a saner
> type like "char *" (or perhaps "const char *") as the type to point
> at a piece of memory you read from the disk. I haven't formed an
> opinion.
>
> Thanks.
I've used the type of the respective assignment for now. e.g. i have
struct cache_header *hdr, so I'm using
hdr = (struct cache_header *)mmap + x;
read-cache-v5.c compiles with -pedantic without warnings.
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