Added starting/ending columns to source mapping entries.

slither/core/source_mapping/source_mapping.py

@@ -15,7 +15,9 @@ class SourceMapping(Context):
     @staticmethod
     def _compute_line(source_code, start, length):
         """
-            Compute line(s) number from a start/end offset
+            Compute line(s) numbers and starting/ending columns
+            from a start/end offset. All results start from 0.
+
             Not done in an efficient way
         """
         total_length = len(source_code)
@@ -23,14 +25,29 @@ class SourceMapping(Context):
         counter = 0
         i = 0
         lines = []
+        starting_column = None
+        ending_column = None
         while counter < total_length:
-            counter += len(source_code[i])
-            i = i+1
+            # Determine the length of the line, and advance the line number
+            lineLength = len(source_code[i])
+            i = i + 1
+
+            # Determine our column numbers.
+            if starting_column is None and counter + lineLength > start:
+                starting_column = (start - counter) + 1
+            if starting_column is not None and ending_column is None and counter + lineLength > start + length:
+                ending_column = ((start + length) - counter) + 1
+
+            # Advance the current position counter, and determine line numbers.
+            counter += lineLength
             if counter > start:
                 lines.append(i)
-            if counter > start+length:
+
+            # If our advanced position for the next line is out of range, stop.
+            if counter > start + length:
                 break
-        return lines
+
+        return (lines, starting_column, ending_column)
 
     @staticmethod
     def _convert_source_mapping(offset, slither):
@@ -55,12 +72,13 @@ class SourceMapping(Context):
             return {'start':s, 'length':l}
         filename = sourceUnits[f]
 
-        lines = []
-
         if filename in slither.source_code:
-            lines = SourceMapping._compute_line(slither.source_code[filename], s, l)
+            (lines, starting_column, ending_column) = SourceMapping._compute_line(slither.source_code[filename], s, l)
+        else:
+            (lines, starting_column, ending_column) = ([], None, None)
 
-        return {'start':s, 'length':l, 'filename': filename, 'lines' : lines }
+        return {'start': s, 'length': l, 'filename': filename, 'lines': lines,
+                'starting_column': starting_column, 'ending_column': ending_column}
 
     def set_offset(self, offset, slither):
         if isinstance(offset, dict):