On 03/23/2015 01:03 PM, Pádraig Brady wrote:
> It just occurred to me that we could simplify from 3 to 2 loops,
> while also making the code more adaptive to the input,
> by simply determining the average line length per block.
great idea!
> I'll push the attached later.
just 2 minor, almost readability notes:
As you introduced the 'end' variable, why not using it
in the memchr() case, too?
@@ -290,7 +290,7 @@ wc (int fd, char const *file_x, struct fstatus *fstatus,
off_t current_pos)
else
{
/* memchr is more efficient with longer lines. */
- while ((p = memchr (p, '\n', (buf + bytes_read) - p)))
+ while ((p = memchr (p, '\n', end - p)))
{
++p;
++lines;
I'd favor multiplication by 15 on the other side, thus avoiding
to have to check for DIV-By-ZERO manually:
@@ -303,7 +303,7 @@ wc (int fd, char const *file_x, struct fstatus *fstatus,
off_t current_pos)
FIXME: This line length was determined in 2015, on both
x86_64 and ppc64, but it's worth re-evaluating in future with
newer compilers, CPUs, or memchr() implementations etc. */
- if (lines == plines || (bytes_read / (lines - plines) > 15))
+ if ((lines - plines) * 15 <= bytes_read)
long_lines = true;
else
long_lines = false;
Thanks & have a nice day,
Berny
