Date: Wed, 15 Feb 2006 16:02:37 +0100 From: Ulrich Spoerlein <q@galgenberg.net> To: Peter Jeremy <peterjeremy@optushome.com.au> Cc: hackers@freebsd.org Subject: Re: Naive implementation of strverscmp(3) Message-ID: <20060215150237.GA1123@galgenberg.net> In-Reply-To: <20060215080532.GB684@turion.vk2pj.dyndns.org> References: <20060214212503.GE1107@galgenberg.net> <20060215080532.GB684@turion.vk2pj.dyndns.org>
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Peter Jeremy wrote:
> >Is there a chance this might get included into libc? Or is it considered=
=20
> >bloat?
>I don't think it belongs in libc. Maybe libutil.
This would require patching the gqview configure script, but I can live=20
with that.
>For the first point, consider
> strverscmp("jan25", "janx25");
This fell victim to a rearranging of the while loop. Thanks for pointing=20
that out!
Attached is an updated version, which now also takes leading zeros into=20
account. It still differs from the GNU version, because
strverscmp("foo.009", "foo.0") > 0
In my book, '009' is just greater than zero, no matter what. If someone=20
could explain to me, why the GNU folks do it the other way round, I=20
could try implementing that too.
Also, what do people think about the commented out while construct? It=20
saves a call to strcspn(s2) if s1 has no digits, but it's rather ugly.
Ulrich Spoerlein
--=20
PGP Key ID: 20FEE9DD Encrypted mail welcome!
Fingerprint: AEC9 AF5E 01AC 4EE1 8F70 6CBD E76E 2227 20FE E9DD
Which is worse: ignorance or apathy?
Don't know. Don't care.
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#ifdef __FreeBSD__
int
strverscmp(const char *s1, const char *s2);
int
strverscmp(const char *s1, const char *s2)
{
static const char *digits =3D "0123456789";
char *t1, *t2;
int ret;
long n1, n2;
size_t p1, p2;
p1 =3D strcspn(s1, digits);
p2 =3D strcspn(s2, digits);
//while ((p1=3Dstrcspn(s1, digits)) !=3D 0 && p1 =3D=3D (p2=3Dstrcspn(s2,=
digits))) {
while (p1 =3D=3D p2 && p1 !=3D 0) {
=20
/* Different prefix */
if ((ret =3D strncmp(s1, s2, p1)) !=3D 0)
return ret;
s1 +=3D p1;
s2 +=3D p2;
n1 =3D strtol(s1, &t1, 10);
n2 =3D strtol(s2, &t2, 10);
=20
if (n1 < n2)
return -1;
else if (n1 > n2)
return 1;
/* One number is "shorter", e.g., "07" vs "007" */
if (t1-s1 < t2-s2)
return 1;
else if (t1-s1 > t2-s2)
return -1;
/* Numbers are equal or not present, try with next ones. */
s1 =3D t1;
s2 =3D t2;
p1 =3D strcspn(s1, digits);
p2 =3D strcspn(s2, digits);
}
=20
return strcmp(s1, s2);
}
#endif
int
main(int argc, char **argv)
{
char **array, *temp;
int i, j, n =3D 10;
array =3D (char **) calloc(n, sizeof(char *));
array[0] =3D strdup("jan009");
array[1] =3D strdup("jan10");
array[2] =3D strdup("jan09");
array[3] =3D strdup("jan0a");
array[4] =3D strdup("jan17b");
array[5] =3D strdup("jan17a");
array[6] =3D strdup("janx25");
array[7] =3D strdup("jan25");
array[8] =3D strdup("jan17x");
array[9] =3D strdup("jan9");
/* Bubble sort */
for (i=3D0; i<n; ++i) {
for (j=3Di; j<n; ++j) {
if (strverscmp(array[i], array[j]) > 0) {
temp =3D array[j];
array[j] =3D array[i];
array[i] =3D temp;
}
}
}
for (i=3D0; i<n; ++i) {
printf("%s\n", array[i]);
}
printf("%d =3D 0\n", strverscmp("a", "a"));
printf("%d < 0\n", strverscmp("item#99", "item#100"));
printf("%d > 0\n", strverscmp("alpha1", "alpha001"));
printf("%d > 0\n", strverscmp("part1_f012", "part1_f01"));
printf("%d < 0\n", strverscmp("foo.009", "foo.0"));
printf("%d\n", strcmp("jan25", "janx25"));
printf("%d\n", strverscmp("jan25", "janx25"));
return 0;
}
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