1 files changed, 17 insertions, 15 deletions
diff --git a/lib/sourcemap.js b/lib/sourcemap.js
index 6cbce5e1..da4ab4fe 100644
--- a/lib/sourcemap.js
+++ b/lib/sourcemap.js
@@ -45,16 +45,30 @@
 function SourceMap(options) {
     options = defaults(options, {
         file : null,
-        root : null
+        root : null,
+        orig : null,
     });
     var generator = new MOZ_SourceMap.SourceMapGenerator({
         file       : options.file,
         sourceRoot : options.root
     });
+    var orig_map = options.orig && new MOZ_SourceMap.SourceMapConsumer(options.orig);
     function add(source, gen_line, gen_col, orig_line, orig_col, name) {
+        orig_line++;
+        gen_line++;
+        if (orig_map) {
+            var info = orig_map.originalPositionFor({
+                line: orig_line,
+                column: orig_col
+            });
+            source = info.source;
+            orig_line = info.line;
+            orig_col = info.column;
+            name = info.name;
+        }
         generator.addMapping({
-            generated : { line: gen_line + 1, column: gen_col },
-            original  : { line: orig_line + 1, column: orig_col },
+            generated : { line: gen_line, column: gen_col },
+            original  : { line: orig_line, column: orig_col },
             source    : source,
             name      : name
         });
@@ -65,15 +79,3 @@ function SourceMap(options) {
         toString   : function() { return generator.toString() }
     };
 };
-
-function SourceMapInput(map) {
-    map = new MOZ_SourceMap.SourceMapConsumer(map);
-    return {
-        info: function(line, col) {
-            return map.originalPositionFor({
-                line: line,
-                column: col
-            });
-        }
-    };
-};