strverscmp

[Isaac Dunham <idunham@lavabit.com>]

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On Fri, 1 Feb 2013 21:38:33 -0500
Rich Felker <dalias@aerifal.cx> wrote:

> > Fix strverscmp (patch same as the last time I sent it)
> 
> I'm not sure whether we got it into a fully-working state or not; the
> conversation kinda died out last time. I'll review it again too. I
> remember it didn't look quite like the algorithm I described/proposed,
> but that doesn't mean it's wrong. It looked like it could at least use
> some streamlining though.

The last review was just before I got it working. Here's the final version.

Probably somewhere it could be optimized, though...
As long as it doesn't end up looking like the GNU one.

-- 
Isaac Dunham <idunham@lavabit.com>

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diff --git a/src/string/strverscmp.c b/src/string/strverscmp.c
index 7054967..8f3f11f 100644
--- a/src/string/strverscmp.c
+++ b/src/string/strverscmp.c
@@ -1,7 +1,41 @@
+#define _GNU_SOURCE
+#include <ctype.h>
 #include <string.h>
 
 int strverscmp(const char *l, const char *r)
 {
-	/* FIXME */
-	return strcmp(l, r);
+	int haszero=1;
+	while (*l && *r && l[0]==r[0]){
+		if (l[0]=='0'){
+			if (haszero==1) {
+				haszero=0;
+			}
+		} else if (isdigit(l[0])) {
+			if (haszero==1) {
+				haszero=2;
+			}
+		} else {
+			haszero=1;
+		}
+		l++; r++;
+	}
+	if (haszero==1 && (l[0]=='0' || r[0]=='0')) {
+		haszero=0;
+	}
+	if ((isdigit(l[0]) && isdigit(r[0]) ) && haszero) {
+		int lenl=0, lenr=0, firstl=l[0], firstr=r[0];
+		while (isdigit(l++[0]) ) {
+			lenl++;
+		}
+		while (isdigit(r++[0]) ) {
+			lenr++;
+		}
+		if (lenl==lenr) {
+			return (firstl -  firstr);
+		} else {
+			return (lenl - lenr);
+		}
+	} else {
+		return (l[0] -  r[0]);
+	}
 }