Add CountIf method to IdList to simplify some call sites. NFC.

This also changes GetNumConstraints to return size_t.

src/dsc.h

@@ -400,6 +400,11 @@ public:
     const T *begin() const { return &elem[0]; }
     const T *end() const { return &elem[n]; }
 
+    template<typename F>
+    size_t CountIf(F &&predicate) const {
+        return std::count_if(begin(), end(), std::forward<F&&>(predicate));
+    }
+
     void ClearTags() {
         int i;
         for(i = 0; i < n; i++) {

src/group.cpp

@@ -49,14 +49,8 @@ bool Group::IsVisible() {
     return true;
 }
 
-int Group::GetNumConstraints(void) {
-    int num = 0;
-    for(int i = 0; i < SK.constraint.n; i++) {
-        Constraint *c = &SK.constraint.elem[i];
-        if(c->group.v != h.v) continue;
-        num++;
-    }
-    return num;
+size_t Group::GetNumConstraints(void) {
+    return SK.constraint.CountIf([&](Constraint const & c) { return c.group.v == h.v; });
 }
 
 Vector Group::ExtrusionGetVector() {

src/sketch.h

@@ -264,7 +264,7 @@ public:
     void AddEq(IdList<Equation,hEquation> *l, Expr *expr, int index);
     void GenerateEquations(IdList<Equation,hEquation> *l);
     bool IsVisible();
-    int GetNumConstraints();
+    size_t GetNumConstraints();
     Vector ExtrusionGetVector();
     void ExtrusionForceVectorTo(const Vector &v);
 

src/textscreens.cpp

@@ -698,16 +698,12 @@ void TextWindow::EditControlDone(std::string s) {
                 g->valA = ev;
 
                 if(g->type == Group::Type::ROTATE) {
-                    int i, c = 0;
-                    for(i = 0; i < SK.constraint.n; i++) {
-                        if(SK.constraint.elem[i].group.v == g->h.v) c++;
-                    }
                     // If the group does not contain any constraints, then
                     // set the numerical guess to space the copies uniformly
                     // over one rotation. Don't touch the guess if we're
                     // already constrained, because that would break
                     // convergence.
-                    if(c == 0) {
+                    if(g->GetNumConstraints() == 0) {
                         double copies = (g->skipFirst) ? (ev + 1) : ev;
                         SK.GetParam(g->h.param(3))->val = PI/(2*copies);
                     }