addDictionary error checking improvements, a=chris

diff --git a/src/library/IndexDictionary.php b/src/library/IndexDictionary.php
index 23d4f15ce..dcdecea25 100644
--- a/src/library/IndexDictionary.php
+++ b/src/library/IndexDictionary.php
@@ -228,7 +228,7 @@ class IndexDictionary implements CrawlConstants
                 $rec_num = ($i << 8) + $j;
                 $prefix_info = $this->extractPrefixRecord($prefix_string,
                         $rec_num);
-                if ($prefix_info !== false) {
+                if (isset($prefix_info[1])) {
                     list($offset, $count) = $prefix_info;
                     if ($first_offset_flag) {
                         $first_offset = $offset;
diff --git a/src/library/IndexShard.php b/src/library/IndexShard.php
index 655fdd899..6e9d0adcf 100644
--- a/src/library/IndexShard.php
+++ b/src/library/IndexShard.php
@@ -1566,7 +1566,7 @@ class IndexShard extends PersistentStructure implements
      * @param int $offset byte offset to start reading from
      * @param int $len number of bytes to read
      * @param bool $cache whether to cache disk blocks read from disk
-     * @return string data fromthat location  in the shard
+     * @return string data from that location  in the shard
      */
     public function getShardSubstring($offset, $len, $cache = true)
     {
@@ -1580,13 +1580,17 @@ class IndexShard extends PersistentStructure implements
         }
         // otherwise, this loop is slower, but handles general case
         $data = $this->readBlockShardAtOffset($block_offset, $cache);
-        if ($data === false) {return "";}
+        if ($data === false) {
+            return "";
+        }
         $substring = substr($data, $start_loc);
         $block_size = self::SHARD_BLOCK_SIZE;
         $block_offset += $block_size;
         while (strlen($substring) < $len) {
             $data = $this->readBlockShardAtOffset($block_offset, $cache);
-            if ($data === false) {return $substring;}
+            if ($data === false) {
+                return $substring;
+            }
             $block_offset += $block_size;
             $substring .= $data;
         }
diff --git a/src/library/Utility.php b/src/library/Utility.php
index cbaada7ee..8fcb9c66d 100755
--- a/src/library/Utility.php
+++ b/src/library/Utility.php
@@ -230,6 +230,9 @@ function charCopy($source, &$destination, $start, $length, $timeout_msg = "")
     $endk = intval($length - 1);
     $end = intval($start + $endk);
     $start = intval($start);
+    if (strlen($destination) <= $endk) {
+        return;
+    }
     if ($timeout_msg == "") {
         for ($j = $end, $k = $endk; $j >= $start; $j--, $k--) {
             $destination[$j] = $source[$k];