get rid of getSnippet offset notice, a=chris

diff --git a/lib/btree.php b/lib/btree.php
index 3554c5128..682768d3f 100644
--- a/lib/btree.php
+++ b/lib/btree.php
@@ -116,7 +116,8 @@ class BTree
             $node = unserialize(file_get_contents($node_file));
             return $node;
         } else {
-            exit("Could not read node $id from disk");
+            crawlLog("Btree could not read node $id from disk");
+            return false;
         }
     }

@@ -149,7 +150,9 @@ class BTree
         $node_file = $this->dir."/$id.txt";
         if(file_exists($node_file)) {
             unlink($node_file);
-        } else exit("Could not delete node $id from disk");
+        } else {
+            crawlLog("Could not delete node $id from disk");
+        }
     }

     /**
diff --git a/models/model.php b/models/model.php
index 719f960ea..7cef97826 100755
--- a/models/model.php
+++ b/models/model.php
@@ -281,14 +281,12 @@ class Model implements CrawlConstants
             sort($word_locations);
             foreach($word_locations as $pos) {
                 if($pos < $high) continue;
-                $pre_low = ($pos >= SNIPPET_LENGTH_LEFT) ?
-                    $pos - SNIPPET_LENGTH_LEFT: 0;
+                $pre_low = max($pos - SNIPPET_LENGTH_LEFT, 0);
                 $low = mb_stripos($text_source, " ", $pre_low);
                 if($low > $pos) {
                     $low = $pre_low;
                 }
-                $pre_high = ($pos + SNIPPET_LENGTH_RIGHT <= $len ) ?
-                    $pos + SNIPPET_LENGTH_RIGHT: $len;
+                $pre_high = min($pos + SNIPPET_LENGTH_RIGHT, $len);
                 $high = mb_stripos($text_source, " ",
                     max(min($pre_high - 10, 0), min($pos, $len)));
                 if($high > $pre_high + 10){