-/* --- @versioncmp@ --- *
- *
- * Arguments: @const char *va, *vb@ = two version strings
- *
- * Returns: Less than, equal to, or greater than zero, according to
- * whether @va@ is less than, equal to, or greater than @vb@.
- *
- * Use: Compares version number strings.
- *
- * The algorithm is an extension of the Debian version
- * comparison algorithm. A version number consists of three
- * components:
- *
- * [EPOCH :] MAIN [- SUB]
- *
- * The MAIN part may contain colons or hyphens if there is an
- * EPOCH or SUB, respectively. Version strings are compared
- * componentwise: first epochs, then main parts, and finally
- * subparts.
- *
- * The component comparison is done as follows. First, the
- * initial subsequence of nondigit characters is extracted from
- * each string, and these are compared lexicographically, using
- * ASCII ordering, except that letters precede non-letters. If
- * both are the same, an initial sequence of digits is extracted
- * from the remaining parts of the version strings, and these
- * are compared numerically (an empty sequence being considered
- * to have the value zero). This process is repeated until we
- * have a winner or until both strings are exhausted.
- */
-
-struct vinfo {
- const char *e, *el;
- const char *m, *ml;
- const char *s, *sl;
-};
-
-static int vint(const char **vv, const char *vl)
-{
- int n = 0;
- const char *v = *vv;
- int ch;
-
- while (v < vl) {
- ch = *v;
- if (!isdigit((unsigned char)ch))
- break;
- v++;
- n = n * 10 + (ch - '0');
- }
- *vv = v;
- return (n);
-}
-
-static const char *vchr(const char **vv, const char *vl)
-{
- const char *v = *vv;
- const char *b = v;
- int ch;
-
- while (v < vl) {
- ch = *v;
- if (isdigit((unsigned char)ch))
- break;
- v++;
- }
- *vv = v;
- return (b);
-}
-
-#define CMP(x, y) ((x) < (y) ? -1 : +1)
-
-static int vcmp(const char *va, const char *val,
- const char *vb, const char *vbl)
-{
- const char *pa, *pb;
- int ia, ib;
-
- for (;;) {
-
- /* --- See if we're done --- */
-
- if (va == val && vb == vbl)
- return (0);
-
- /* --- Compare nondigit portions --- */
-
- pa = vchr(&va, val); pb = vchr(&vb, vbl);
- for (;;) {
- if (pa == va && pb == vb)
- break;
- else if (pa == va)
- return (-1);
- else if (pb == vb)
- return (+1);
- else if (*pa == *pb) {
- pa++; pb++;
- continue;
- } else if (isalpha((unsigned char)*pa) == isalpha((unsigned char)*pb))
- return (CMP(*pa, *pb));
- else if (isalpha((unsigned char)*pa))
- return (-1);
- else
- return (+1);
- }
-
- /* --- Compare digit portions --- */
-
- ia = vint(&va, val); ib = vint(&vb, vbl);
- if (ia != ib)
- return (CMP(ia, ib));
- }
-}
-
-static void vsplit(const char *v, struct vinfo *vi)
-{
- const char *p;
- size_t n;
-
- if ((p = strchr(v, ':')) == 0)
- vi->e = vi->el = 0;
- else {
- vi->e = v;
- vi->el = p;
- v = p + 1;
- }
-
- n = strlen(v);
- if ((p = strrchr(v, '-')) == 0)
- vi->s = vi->sl = 0;
- else {
- vi->s = p + 1;
- vi->sl = v + n;
- n = p - v;
- }
-
- vi->m = v;
- vi->ml = v + n;
-}
-
-int versioncmp(const char *va, const char *vb)
-{
- struct vinfo via, vib;
- int rc;
-
- vsplit(va, &via); vsplit(vb, &vib);
- if ((rc = vcmp(via.e, via.el, vib.e, vib.el)) != 0 ||
- (rc = vcmp(via.m, via.ml, vib.m, vib.ml)) != 0 ||
- (rc = vcmp(via.s, via.sl, vib.s, vib.sl)) != 0)
- return (rc);
- return (0);
-}
-