2 files changed, 34 insertions, 8 deletions

diff --git a/src/object.c b/src/object.c
index 2554656a3..58668da5b 100644
--- a/src/object.c
+++ b/src/object.c
@@ -332,35 +332,60 @@ robj *getDecodedObject(robj *o) {
     }
 }
 
-/* Compare two string objects via strcmp() or alike.
+/* Compare two string objects via strcmp() or strcoll() depending on flags.
  * Note that the objects may be integer-encoded. In such a case we
  * use ll2string() to get a string representation of the numbers on the stack
  * and compare the strings, it's much faster than calling getDecodedObject().
  *
- * Important note: if objects are not integer encoded, but binary-safe strings,
- * sdscmp() from sds.c will apply memcmp() so this function ca be considered
- * binary safe. */
-int compareStringObjects(robj *a, robj *b) {
+ * Important note: when REDIS_COMPARE_BINARY is used a binary-safe comparison
+ * is used. */
+
+#define REDIS_COMPARE_BINARY (1<<0)
+#define REDIS_COMPARE_COLL (1<<1)
+
+int compareStringObjectsWithFlags(robj *a, robj *b, int flags) {
     redisAssertWithInfo(NULL,a,a->type == REDIS_STRING && b->type == REDIS_STRING);
     char bufa[128], bufb[128], *astr, *bstr;
+    size_t alen, blen, minlen;
     int bothsds = 1;
 
     if (a == b) return 0;
     if (a->encoding != REDIS_ENCODING_RAW) {
-        ll2string(bufa,sizeof(bufa),(long) a->ptr);
+        alen = ll2string(bufa,sizeof(bufa),(long) a->ptr);
         astr = bufa;
         bothsds = 0;
     } else {
         astr = a->ptr;
+        alen = sdslen(astr);
     }
     if (b->encoding != REDIS_ENCODING_RAW) {
-        ll2string(bufb,sizeof(bufb),(long) b->ptr);
+        blen = ll2string(bufb,sizeof(bufb),(long) b->ptr);
         bstr = bufb;
         bothsds = 0;
     } else {
         bstr = b->ptr;
+        blen = sdslen(bstr);
+    }
+    if (flags & REDIS_COMPARE_COLL) {
+        return strcoll(astr,bstr);
+    } else {
+        int cmp;
+
+        minlen = (alen < blen) ? alen : blen;
+        cmp = memcmp(astr,bstr,minlen);
+        if (cmp == 0) return alen-blen;
+        return cmp;
     }
-    return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
+}
+
+/* Wrapper for compareStringObjectsWithFlags() using binary comparison. */
+int compareStringObjects(robj *a, robj *b) {
+    return compareStringObjectsWithFlags(a,b,REDIS_COMPARE_BINARY);
+}
+
+/* Wrapper for compareStringObjectsWithFlags() using collation. */
+int collateStringObjects(robj *a, robj *b) {
+    return compareStringObjectsWithFlags(a,b,REDIS_COMPARE_COLL);
 }
 
 /* Equal string objects return 1 if the two objects are the same from the
diff --git a/src/redis.h b/src/redis.h
index 2fbd930bc..043d64c01 100644
--- a/src/redis.h
+++ b/src/redis.h
@@ -995,6 +995,7 @@ int getLongDoubleFromObject(robj *o, long double *target);
 int getLongDoubleFromObjectOrReply(redisClient *c, robj *o, long double *target, const char *msg);
 char *strEncoding(int encoding);
 int compareStringObjects(robj *a, robj *b);
+int collateStringObjects(robj *a, robj *b);
 int equalStringObjects(robj *a, robj *b);
 unsigned long estimateObjectIdleTime(robj *o);