From b8d516fc52296d3971c46e7cdbd473d3866b7143 Mon Sep 17 00:00:00 2001
From: Yusuke Shinyama <yusuke@cs.nyu.edu>
Date: Sat, 14 May 2011 14:16:40 +0900
Subject: [PATCH] extended Plane class.

---
 pdfminer/utils.py | 37 +++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/pdfminer/utils.py b/pdfminer/utils.py
index 0d531c3..2892963 100644
--- a/pdfminer/utils.py
+++ b/pdfminer/utils.py
@@ -196,7 +196,7 @@ class ObjIdRange(object):
 
 ##  Plane
 ##
-##  A data structure for objects placed on a plane.
+##  A set-like data structure for objects placed on a plane.
 ##  Can efficiently find objects in a certain rectangular area.
 ##  It maintains two parallel lists of objects, each of
 ##  which is sorted by its x or y coordinate.
@@ -204,7 +204,8 @@ class ObjIdRange(object):
 class Plane(object):
 
     def __init__(self, objs=None, gridsize=50):
-        self._objs = {}
+        self._objs = set()
+        self._grid = {}
         self.gridsize = gridsize
         if objs is not None:
             for obj in objs:
@@ -214,6 +215,15 @@ class Plane(object):
     def __repr__(self):
         return ('<Plane objs=%r>' % list(self))
 
+    def __iter__(self):
+        return iter(self._objs)
+
+    def __len__(self):
+        return len(self._objs)
+
+    def __contains__(self, obj):
+        return obj in self._objs
+
     def _getrange(self, (x0,y0,x1,y1)):
         for y in drange(y0, y1, self.gridsize):
             for x in drange(x0, x1, self.gridsize):
@@ -223,35 +233,38 @@ class Plane(object):
     # add(obj): place an object.
     def add(self, obj):
         for k in self._getrange((obj.x0, obj.y0, obj.x1, obj.y1)):
-            if k not in self._objs:
+            if k not in self._grid:
                 r = []
-                self._objs[k] = r
+                self._grid[k] = r
             else:
-                r = self._objs[k]
+                r = self._grid[k]
             r.append(obj)
+        self._objs.add(obj)
         return
 
     # remove(obj): displace an object.
     def remove(self, obj):
         for k in self._getrange((obj.x0, obj.y0, obj.x1, obj.y1)):
             try:
-                self._objs[k].remove(obj)
+                self._grid[k].remove(obj)
             except (KeyError, ValueError):
                 pass
+        self._objs.remove(obj)
         return
 
     # find(): finds objects that are in a certain area.
     def find(self, (x0,y0,x1,y1)):
         r = set()
+        done = set()
         for k in self._getrange((x0,y0,x1,y1)):
-            if k not in self._objs: continue
-            for obj in self._objs[k]:
-                if obj in r: continue
-                r.add(obj)
+            if k not in self._grid: continue
+            for obj in self._grid[k]:
+                if obj in done: continue
+                done.add(obj)
                 if (obj.x1 <= x0 or x1 <= obj.x0 or
                     obj.y1 <= y0 or y1 <= obj.y0): continue
-                yield obj
-        return
+                r.add(obj)
+        return r
 
 
 # create_bmp