2Geom: update to r2422.

Fixes LP #1482806: crash on Pattern along Path with horizontal segments.
This was caused by empty SBasis objects. After the changes in 2Geom,
empty SBasis objects should no longer be created.

Fixed bugs:
  - https://launchpad.net/bugs/1482806

(bzr r14299)

6 files changed, 51 insertions, 55 deletions

diff --git a/src/2geom/d2-sbasis.cpp b/src/2geom/d2-sbasis.cpp
index ebec16fdd..4f00ff6a5 100644
--- a/src/2geom/d2-sbasis.cpp
+++ b/src/2geom/d2-sbasis.cpp
@@ -147,12 +147,12 @@ Piecewise<D2<SBasis> > force_continuity(Piecewise<D2<SBasis> > const &f, double
                 SBasis &prev_sb=result.segs[prev][dim];
                 SBasis &cur_sb =result.segs[cur][dim];
                 Coord const c=pt0[dim];
-                if (prev_sb.empty()) {
+                if (prev_sb.isZero(0)) {
                   prev_sb = SBasis(Linear(0.0, c));
                 } else {
                   prev_sb[0][1] = c;
                 }
-                if (cur_sb.empty()) {
+                if (cur_sb.isZero(0)) {
                   cur_sb = SBasis(Linear(c, 0.0));
                 } else {
                   cur_sb[0][0] = c;
@@ -198,30 +198,22 @@ Point unitTangentAt(D2<SBasis> const & a, Coord t, unsigned n)
     return Point (0,0);
 }
 
-static void set_first_point(Piecewise<D2<SBasis> > &f, Point a){
+static void set_first_point(Piecewise<D2<SBasis> > &f, Point const &a){
     if ( f.empty() ){
         f.concat(Piecewise<D2<SBasis> >(D2<SBasis>(SBasis(Linear(a[X])), SBasis(Linear(a[Y])))));
         return;
     }
     for (unsigned dim=0; dim<2; dim++){
-        if (f.segs.front()[dim].size() == 0){
-            f.segs.front()[dim] = SBasis(Linear(a[dim],0));
-        }else{
-            f.segs.front()[dim][0][0] = a[dim];
-        }
+        f.segs.front()[dim][0][0] = a[dim];
     }
 }
-static void set_last_point(Piecewise<D2<SBasis> > &f, Point a){
+static void set_last_point(Piecewise<D2<SBasis> > &f, Point const &a){
     if ( f.empty() ){
         f.concat(Piecewise<D2<SBasis> >(D2<SBasis>(SBasis(Linear(a[X])), SBasis(Linear(a[Y])))));
         return;
     }
     for (unsigned dim=0; dim<2; dim++){
-        if (f.segs.back()[dim].size() == 0){
-            f.segs.back()[dim] = SBasis(Linear(0,a[dim]));
-        }else{
-            f.segs.back()[dim][0][1] = a[dim];
-        }
+        f.segs.back()[dim][0][1] = a[dim];
     }
 }
 
diff --git a/src/2geom/numeric/fitting-model.h b/src/2geom/numeric/fitting-model.h
index fb96d1d2a..b2ca92ad8 100644
--- a/src/2geom/numeric/fitting-model.h
+++ b/src/2geom/numeric/fitting-model.h
@@ -372,7 +372,6 @@ class LFMSBasis
 
     void instance(SBasis & sb, ConstVectorView const& raw_data) const
     {
-        sb.clear();
         sb.resize(m_order+1);
         for (unsigned int i = 0, k = 0; i < raw_data.size(); i+=2, ++k)
         {
diff --git a/src/2geom/sbasis-geometric.cpp b/src/2geom/sbasis-geometric.cpp
index 4c474f7f0..8aaa15144 100644
--- a/src/2geom/sbasis-geometric.cpp
+++ b/src/2geom/sbasis-geometric.cpp
@@ -228,7 +228,7 @@ Geom::unitVector(D2<SBasis> const &V_in, double tol, unsigned order){
     // -This done, unitVector will have jumps at zeros: fill the gaps with arcs of circles.
     D2<SBasis> V = RescaleForNonVanishingEnds(V_in);
 
-    if (V[0].empty() && V[1].empty())
+    if (V[0].isZero(0) && V[1].isZero(0))
         return Piecewise<D2<SBasis> >(D2<SBasis>(Linear(1),SBasis()));
     SBasis x = V[0], y = V[1];
     SBasis r_eqn1, r_eqn2;
diff --git a/src/2geom/sbasis-roots.cpp b/src/2geom/sbasis-roots.cpp
index 57bef4c0f..e3e5e4441 100644
--- a/src/2geom/sbasis-roots.cpp
+++ b/src/2geom/sbasis-roots.cpp
@@ -222,7 +222,7 @@ static void multi_roots_internal(SBasis const &f,
 				 double b,
 				 double fb){
 
-    if (f.size()==0){
+    if (f.isZero(0)){
         int idx;
         idx=upper_level(levels,0,vtol);
         if (idx<(int)levels.size()&&fabs(levels.at(idx))<=vtol){
@@ -414,7 +414,7 @@ static void level_sets_internal(SBasis const &f,
 				 double fb,
 				 double tol=1e-5){
 
-    if (f.size()==0){
+    if (f.isZero(0)){
         unsigned idx;
         idx=upper_level( levels, 0. );
         if (idx<levels.size() && levels[idx].contains(0.)){
@@ -614,6 +614,7 @@ std::vector<double> roots1(SBasis const & s, Interval const ivl) {
 std::vector<double> roots(SBasis const & s) {
     switch(s.size()) {
         case 0:
+            assert(false);
             return std::vector<double>();
         case 1:
             return roots1(s);
@@ -628,6 +629,7 @@ std::vector<double> roots(SBasis const & s) {
 std::vector<double> roots(SBasis const & s, Interval const ivl) {
     switch(s.size()) {
         case 0:
+        	assert(false);
             return std::vector<double>();
         case 1:
             return roots1(s, ivl);
diff --git a/src/2geom/sbasis-to-bezier.cpp b/src/2geom/sbasis-to-bezier.cpp
index 09fbb03ef..d9a90aace 100644
--- a/src/2geom/sbasis-to-bezier.cpp
+++ b/src/2geom/sbasis-to-bezier.cpp
@@ -100,9 +100,7 @@ int sgn(unsigned int j, unsigned int k)
 */
 void sbasis_to_bezier (Bezier & bz, SBasis const& sb, size_t sz)
 {
-    if (sb.size() == 0) {
-        THROW_RANGEERROR("size of sb is too small");
-    }
+    assert(sb.size() > 0);
 
     size_t q, n;
     bool even;
diff --git a/src/2geom/sbasis.h b/src/2geom/sbasis.h
index 787e8b722..6923017be 100644
--- a/src/2geom/sbasis.h
+++ b/src/2geom/sbasis.h
@@ -83,49 +83,52 @@ public:
     const_iterator end() const { return d.end();}
     iterator begin() { return d.begin();}
     iterator end() { return d.end();}
-    bool empty() const {return d.empty();}
+    bool empty() const { return d.size() == 1 && d[0][0] == 0 && d[0][1] == 0; }
     Linear &back() {return d.back();}
     Linear const &back() const {return d.back();}
-    void pop_back() { d.pop_back();}
-    void resize(unsigned n) { d.resize(n);}
-    void resize(unsigned n, Linear const& l) { d.resize(n, l);}
+    void pop_back() {
+		if (d.size() > 1) {
+			d.pop_back();
+		} else {
+			d[0][0] = 0;
+			d[0][1] = 0;
+		}
+	}
+    void resize(unsigned n) { d.resize(std::max<unsigned>(n, 1));}
+    void resize(unsigned n, Linear const& l) { d.resize(std::max<unsigned>(n, 1), l);}
     void reserve(unsigned n) { d.reserve(n);}
-    void clear() {d.clear();}
+    void clear() {
+    	d.resize(1);
+    	d[0][0] = 0;
+    	d[0][1] = 0;
+    }
     void insert(iterator before, const_iterator src_begin, const_iterator src_end) { d.insert(before, src_begin, src_end);}
     Linear& at(unsigned i) { return d.at(i);}
     //void insert(Linear* before, int& n, Linear const &l) { d.insert(std::vector<Linear>::iterator(before), n, l);}
     bool operator==(SBasis const&B) const { return d == B.d;}
     bool operator!=(SBasis const&B) const { return d != B.d;}
-    operator std::vector<Linear>() { return d;}
-
     
-    SBasis() {}
+    SBasis()
+		: d(1, Linear(0, 0))
+	{}
     explicit SBasis(double a)
-        : d(1)
-    {
-        d[0][0] = a;
-        d[0][1] = a;
-    }
+        : d(1, Linear(a, a))
+    {}
     explicit SBasis(double a, double b)
-        : d(1)
-    {
-        d[0][0] = a;
-        d[0][1] = b;
-    }
-    SBasis(SBasis const & a) :
-        d(a.d)
+        : d(1, Linear(a, b))
     {}
-    SBasis(std::vector<Linear> const & ls) :
-        d(ls)
+    SBasis(SBasis const &a)
+        : d(a.d)
+    {}
+    SBasis(std::vector<Linear> const &ls)
+        : d(ls)
+    {}
+    SBasis(Linear const &bo)
+		: d(1, bo)
+	{}
+    SBasis(Linear* bo)
+		: d(1, bo ? *bo : Linear(0, 0))
     {}
-    SBasis(Linear const & bo) {
-        push_back(bo);
-    }
-    SBasis(Linear* bo) {
-        if (bo) {
-            push_back(*bo);
-        }
-    }
     explicit SBasis(size_t n, Linear const&l) : d(n, l) {}
 
     SBasis(Coord c0, Coord c1, Coord c2, Coord c3)
@@ -179,6 +182,7 @@ public:
     template <typename Iter>
     SBasis(Iter first, Iter last) {
         assert(std::distance(first, last) % 2 == 0);
+        assert(std::distance(first, last) >= 2);
         for (; first != last; ++first) {
             --last;
             push_back(Linear(*first, *last));
@@ -188,14 +192,14 @@ public:
     //IMPL: FragmentConcept
     typedef double output_type;
     inline bool isZero(double eps=EPSILON) const {
-        if(empty()) return true;
+    	assert(size() > 0);
         for(unsigned i = 0; i < size(); i++) {
             if(!(*this)[i].isZero(eps)) return false;
         }
         return true;
     }
     inline bool isConstant(double eps=EPSILON) const {
-        if (empty()) return true;
+    	assert(size() > 0);
         if(!(*this)[0].isConstant(eps)) return false;
         for (unsigned i = 1; i < size(); i++) {
             if(!(*this)[i].isZero(eps)) return false;
@@ -212,6 +216,7 @@ public:
     int degreesOfFreedom() const { return size()*2;}
 
     double valueAt(double t) const {
+    	assert(size() > 0);
         double s = t*(1-t);
         double p0 = 0, p1 = 0;
         for(unsigned k = size(); k > 0; k--) {
@@ -239,11 +244,11 @@ public:
 //MUTATOR PRISON
     //remove extra zeros
     void normalize() {
-        while(!empty() && 0 == back()[0] && 0 == back()[1])
+        while(size() > 1 && back().isZero(0))
             pop_back();
     }
 
-    void truncate(unsigned k) { if(k < size()) resize(k); }
+    void truncate(unsigned k) { if(k < size()) resize(std::max<size_t>(k, 1)); }
 private:
     void derive(); // in place version
 };