From 4eefaf421bfeddf040d96a3dafb12e09673423d7 Mon Sep 17 00:00:00 2001
From: Antonin Kral <a.kral@bobek.cz>
Date: Sun, 31 Jan 2010 08:32:52 +0100
Subject: Imported Upstream version 1.3.1

---
 shell/mr.js | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 shell/mr.js

(limited to 'shell/mr.js')

diff --git a/shell/mr.js b/shell/mr.js
new file mode 100644
index 0000000..7b0814d
--- /dev/null
+++ b/shell/mr.js
@@ -0,0 +1,95 @@
+// mr.js
+
+MR = {};
+
+MR.init = function(){
+    $max = 0;
+    $arr = [];
+    emit = MR.emit;
+    $numEmits = 0;
+    $numReduces = 0;
+    $numReducesToDB = 0;
+    gc(); // this is just so that keep memory size sane
+}
+
+MR.cleanup = function(){
+    MR.init();
+    gc();
+}
+
+MR.emit = function(k,v){
+    $numEmits++;
+    var num = nativeHelper.apply( get_num_ , [ k ] );
+    var data = $arr[num];
+    if ( ! data ){
+        data = { key : k , values : new Array(1000) , count : 0 };
+        $arr[num] = data;
+    }
+    data.values[data.count++] = v;
+    $max = Math.max( $max , data.count );
+}
+
+MR.doReduce = function( useDB ){
+    $numReduces++;
+    if ( useDB )
+        $numReducesToDB++;
+    $max = 0;
+    for ( var i=0; i<$arr.length; i++){
+        var data = $arr[i];
+        if ( ! data ) 
+            continue;
+        
+        if ( useDB ){
+            var x = tempcoll.findOne( { _id : data.key } );
+            if ( x ){
+                data.values[data.count++] = x.value;
+            }
+        }
+
+        var r = $reduce( data.key , data.values.slice( 0 , data.count ) );
+        if ( r && r.length && r[0] ){ 
+            data.values = r; 
+            data.count = r.length;
+        }
+        else{ 
+            data.values[0] = r;
+            data.count = 1;
+        }
+        
+        $max = Math.max( $max , data.count ); 
+        
+        if ( useDB ){
+            if ( data.count == 1 ){
+                tempcoll.save( { _id : data.key , value : data.values[0] } );
+            }
+            else {
+                tempcoll.save( { _id : data.key , value : data.values.slice( 0 , data.count ) } );
+            }
+        }
+    }
+}
+
+MR.check = function(){                        
+    if ( $max < 2000 && $arr.length < 1000 ){ 
+        return 0; 
+    }
+    MR.doReduce();
+    if ( $max < 2000 && $arr.length < 1000 ){ 
+        return 1;
+    }
+    MR.doReduce( true );
+    $arr = []; 
+    $max = 0; 
+    reset_num();
+    gc();
+    return 2;
+}
+
+MR.finalize = function(){
+    tempcoll.find().forEach( 
+        function(z){
+            z.value = $finalize( z._id , z.value );
+            tempcoll.save( z );
+        }
+    );
+}
-- 
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