INTERNAL: Add get_shard_key for hash_ketama

Author: namsic

cluster_config.c

@@ -84,6 +84,28 @@ struct cluster_config {
 };
 
 
+#ifdef SHARD_KEY
+static const char *get_shard_key(const char *key, uint32_t nkey, uint32_t *nshardkey)
+{
+    const char *left = memchr(key, '{', nkey);
+    if (left == NULL) {
+        return NULL;
+    }
+
+    const char *right = memchr(left + 1, '}', nkey - (left - key) - 1);
+    if (right == NULL) {
+        return NULL;
+    }
+
+    *nshardkey = right - left - 1;
+    if (*nshardkey == 0) {
+        return NULL;
+    }
+
+    return left + 1;
+}
+#endif
+
 static void hash_md5(const char *key, uint32_t nkey, unsigned char *result)
 {
     MD5_CTX ctx;
@@ -97,6 +119,15 @@ static uint32_t hash_ketama(const char *key, uint32_t nkey)
 {
     unsigned char digest[16];
 
+#ifdef SHARD_KEY
+    uint32_t nshardkey;
+    const char *shardkey = get_shard_key(key, nkey, &nshardkey);
+    if (shardkey) {
+        key = shardkey;
+        nkey = nshardkey;
+    }
+#endif
+
     hash_md5(key, nkey, digest);
     return (uint32_t)((digest[3] << 24)
                      |(digest[2] << 16)