summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--src/string/strverscmp.c57
1 files changed, 25 insertions, 32 deletions
diff --git a/src/string/strverscmp.c b/src/string/strverscmp.c
index 6f37cc68..4daf276d 100644
--- a/src/string/strverscmp.c
+++ b/src/string/strverscmp.c
@@ -2,40 +2,33 @@
#include <ctype.h>
#include <string.h>
-int strverscmp(const char *l, const char *r)
+int strverscmp(const char *l0, const char *r0)
{
- int haszero=1;
- while (*l==*r) {
- if (!*l) return 0;
+ const unsigned char *l = (const void *)l0;
+ const unsigned char *r = (const void *)r0;
+ size_t i, dp, j;
+ int z = 1;
- if (*l=='0') {
- if (haszero==1) {
- haszero=0;
- }
- } else if (isdigit(*l)) {
- if (haszero==1) {
- haszero=2;
- }
- } else {
- haszero=1;
- }
- l++; r++;
+ /* Find maximal matching prefix and track its maximal digit
+ * suffix and whether those digits are all zeros. */
+ for (dp=i=0; l[i]==r[i]; i++) {
+ int c = l[i];
+ if (!c) return 0;
+ if (!isdigit(c)) dp=i+1, z=1;
+ else if (c!='0') z=0;
}
- if (haszero==1 && (*l=='0' || *r=='0')) {
- haszero=0;
- }
- if ((isdigit(*l) && isdigit(*r) ) && haszero) {
- size_t lenl=0, lenr=0;
- while (isdigit(l[lenl]) ) lenl++;
- while (isdigit(r[lenr]) ) lenr++;
- if (lenl==lenr) {
- return (*l - *r);
- } else if (lenl>lenr) {
- return 1;
- } else {
- return -1;
- }
- } else {
- return (*l - *r);
+
+ if (l[dp]!='0' && r[dp]!='0') {
+ /* If we're not looking at a digit sequence that began
+ * with a zero, longest digit string is greater. */
+ for (j=i; isdigit(l[j]); j++)
+ if (!isdigit(r[j])) return 1;
+ if (isdigit(r[j])) return -1;
+ } else if (z && dp<i && (isdigit(l[i]) || isdigit(r[i]))) {
+ /* Otherwise, if common prefix of digit sequence is
+ * all zeros, digits order less than non-digits. */
+ return (unsigned char)(l[i]-'0') - (unsigned char)(r[i]-'0');
}
+
+ return l[i] - r[i];
}