diff --git a/include/forarray.h b/include/forarray.h
index 867fc10f..14f0e20e 100644
--- a/include/forarray.h
+++ b/include/forarray.h
@@ -19,8 +19,9 @@ private:
     uint32_t max = std::numeric_limits<uint32_t>::min();
 public:
     forarray(const uint32_t n=2) {
-        size_bytes = n * FOR_ELE_SIZE;
+        size_bytes = METADATA_OVERHEAD + (n * FOR_ELE_SIZE);
         in = new uint8_t[size_bytes];
+        memset(in, 0, size_bytes);
     }
 
     static inline uint32_t required_bits(const uint32_t v) {
@@ -28,8 +29,9 @@ public:
     }
 
     uint32_t inline sorted_append_size_required(uint32_t value) {
-        uint32_t m = *(uint32_t *)(in + 0);
-        uint32_t bnew = required_bits(value - m);
+        uint32_t m = std::min(min, value);
+        uint32_t M = std::max(max, value);
+        uint32_t bnew = required_bits(M - m);
         return METADATA_OVERHEAD + for_compressed_size_bits(length+1, bnew);
     }
 
@@ -37,11 +39,13 @@ public:
     bool append_sorted(uint32_t value) {
         uint32_t size_required = sorted_append_size_required(value);
 
-        if(size_required > size_bytes) {
+        if(size_required+4 > size_bytes) {
             // grow the array first
             size_t new_size = (size_t) (size_required * FOR_GROWTH_FACTOR);
             uint8_t *new_location = (uint8_t *) realloc(in, new_size);
-            if(new_location == NULL) return false;
+            if(new_location == NULL) {
+                abort();
+            }
             in = new_location;
             size_bytes = (uint32_t) new_size;
         }
@@ -68,13 +72,12 @@ public:
     bool append_unsorted(uint32_t value) {
       uint32_t size_required = unsorted_append_size_required(value);
 
-      if(size_required > size_bytes) {
+      if(size_required+4 > size_bytes) {
           // grow the array first
           size_t new_size = (size_t) (size_required * FOR_GROWTH_FACTOR);
           uint8_t *new_location = (uint8_t *) realloc(in, new_size);
           if(new_location == NULL) {
               abort();
-              return false;
           }
           in = new_location;
           size_bytes = (uint32_t) new_size;
@@ -83,11 +86,10 @@ public:
       uint32_t new_length_bytes = for_append_unsorted(in, length, value);
       if(new_length_bytes == 0) {
           abort();
-          return false;
       }
 
-      if (in[length] < min) min = in[length];
-      if (in[length] > max) max = in[length];
+      if(value < min) min = value;
+      if(value > max) max = value;
 
       length_bytes = new_length_bytes;
       length++;
diff --git a/src/art.cpp b/src/art.cpp
index b0877047..8110bdca 100644
--- a/src/art.cpp
+++ b/src/art.cpp
@@ -283,6 +283,8 @@ void* art_search(const art_tree *t, const unsigned char *key, int key_len) {
             if (prefix_len != min(MAX_PREFIX_LEN, n->partial_len))
                 return NULL;
             depth = depth + n->partial_len;
+            if(depth > key_len-1)
+                return NULL;
         }
 
         // Recursively search
diff --git a/src/collection.cpp b/src/collection.cpp
index 956c6ea6..1a6a6f80 100644
--- a/src/collection.cpp
+++ b/src/collection.cpp
@@ -36,10 +36,12 @@ void Collection::add(std::vector<std::string> tokens, uint16_t score) {
         document.offsets = new uint32_t[kv.second.size()];
 
         uint32_t num_hits = 0;
-        const unsigned char *key = (const unsigned char *) kv.first.c_str();
-        int key_len = (int) kv.first.length() + 1;  // for the terminating \0 char
 
-        art_leaf* leaf = (art_leaf *) art_search(&t, key, key_len);
+        int key_len = (int) kv.first.length() + 1;  // for the terminating \0 char
+        char *key = new char[key_len];
+        strcpy(key, kv.first.c_str());
+
+        art_leaf* leaf = (art_leaf *) art_search(&t, (const unsigned char *) key, key_len);
         if(leaf != NULL) {
             num_hits = leaf->values->ids.getLength();
         }
@@ -50,7 +52,7 @@ void Collection::add(std::vector<std::string> tokens, uint16_t score) {
             document.offsets[i] = kv.second[i];
         }
 
-        art_insert(&t, key, key_len, &document, num_hits);
+        art_insert(&t, (const unsigned char *) key, key_len, &document, num_hits);
         delete document.offsets;
     }