pathops coincidence and security rewrite

src/pathops/SkIntersections.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkIntersections_DEFINE
 #define SkIntersections_DEFINE
 
 #include "SkPathOpsConic.h"
@@ skipping 94 matching lines @@
 
 #ifdef SK_DEBUG
     SkOpGlobalState* debugGlobalState() { return fDebugGlobalState; }
 #endif
 
     bool hasT(double t) const {
         SkASSERT(t == 0 || t == 1);
         return fUsed > 0 && (t == 0 ? fT[0][0] == 0 : fT[0][fUsed - 1] == 1);
     }
 
+    bool hasOppT(double t) const {
+        SkASSERT(t == 0 || t == 1);
+        return fUsed > 0 && (fT[1][0] == t || fT[1][fUsed - 1] == t);
+    }
+
     int insertSwap(double one, double two, const SkDPoint& pt) {
         if (fSwap) {
             return insert(two, one, pt);
         } else {
             return insert(one, two, pt);
         }
     }
 
     bool isCoincident(int index) {
         return (fIsCoincident[0] & 1 << index) != 0;
@@ skipping 48 matching lines @@
         quad.set(a);
         fMax = 2;
         return vertical(quad, top, bottom, x, flipped);
     }
 
     int quadLine(const SkPoint a[3], const SkPoint b[2]) {
         SkDQuad quad;
         quad.set(a);
         SkDLine line;
         line.set(b);
-        fMax = 3; // 2;  permit small coincident segment + non-coincident intersection
         return intersect(quad, line);
     }
 
     // leaves swap, max alone
     void reset() {
         fAllowNear = true;
         fUsed = 0;
         sk_bzero(fIsCoincident, sizeof(fIsCoincident));
     }
 
     void set(bool swap, int tIndex, double t) {
         fT[(int) swap][tIndex] = t;
     }
 
     void setMax(int max) {
         SkASSERT(max <= (int) SK_ARRAY_COUNT(fPt));
         fMax = max;
     }
 
     void swap() {
         fSwap ^= true;
     }
 
     bool swapped() const {
         return fSwap;
     }
-    
+
     int used() const {
         return fUsed;
     }
 
     void downDepth() {
         SkASSERT(--fDepth >= 0);
     }
 
     bool unBumpT(int index) {
         SkASSERT(fUsed == 1);
@@ skipping 95 matching lines @@
 #ifdef SK_DEBUG
     SkOpGlobalState* fDebugGlobalState;
     int fDepth;
 #endif
 #if DEBUG_T_SECT_LOOP_COUNT
     int fDebugLoopCount[3];
 #endif
 };
 
 #endif