replace NearPoint with a more generic context object

[nominatim.git] / lib / SearchContext.php

diff --git a/lib/SearchContext.php b/lib/SearchContext.php
new file mode 100644 (file)
index 0000000..a6b6358
--- /dev/null
+++ b/lib/SearchContext.php
@@ -0,0 +1,73 @@
+<?php
+
+namespace Nominatim;
+
+require_once(CONST_BasePath.'/lib/lib.php');
+
+
+/**
+ * Collects search constraints that are independent of the
+ * actual interpretation of the search query.
+ *
+ * The search context is shared between all SearchDescriptions. This
+ * object mainly serves as context provider for the database queries.
+ * Therefore most data is directly cached as SQL statements.
+ */
+class SearchContext
+{
+    private $fNearRadius = false;
+
+    // cached SQL
+
+    public $sqlNear = '';
+
+    public function hasNearPoint()
+    {
+        return $this->fNearRadius !== false;
+    }
+
+    public function nearRadius()
+    {
+        return $this->fNearRadius;
+    }
+
+    public function setNearPoint($fLat, $fLon, $fRadius = 0.1)
+    {
+        $this->fNearRadius = $fRadius;
+        $this->sqlNear = 'ST_SetSRID(ST_Point('.$fLon.','.$fLat.'),4326)';
+    }
+
+    /**
+     * Extract a coordinate point from a query string.
+     *
+     * @param string $sQuery Query to scan.
+     *
+     * @return The remaining query string.
+     */
+    public function setNearPointFromQuery($sQuery)
+    {
+        $aResult = parseLatLon($sQuery);
+
+        if ($aResult !== false
+            && $aResult[1] <= 90.1
+            && $aResult[1] >= -90.1
+            && $aResult[2] <= 180.1
+            && $aResult[2] >= -180.1
+        ) {
+            $this->setNearPoint($aResult[1], $aResult[2]);
+            $sQuery = trim(str_replace($aResult[0], ' ', $sQuery));
+        }
+
+        return $sQuery;
+    }
+
+    public function distanceSQL($sObj)
+    {
+        return 'ST_Distance('.$this->sqlNear.", $sObj)";
+    }
+
+    public function withinSQL($sObj)
+    {
+        return sprintf('ST_DWithin(%s, %s, %F)', $sObj, $this->sqlNear, $this->fNearRadius);
+    }
+}