Reserve space upfront when possible, to avoid re-allocations.

src/dsc.h

@@ -162,9 +162,9 @@ public:
     int  n;
     int  elemsAllocated;
 
-    void AllocForOneMore() {
-        if(n >= elemsAllocated) {
-            elemsAllocated = (elemsAllocated + 32)*2;
+    void ReserveMore(int howMuch) {
+        if(n + howMuch > elemsAllocated) {
+            elemsAllocated = n + howMuch;
             T *newElem = (T *)MemAlloc((size_t)elemsAllocated*sizeof(elem[0]));
             for(int i = 0; i < n; i++) {
                 new(&newElem[i]) T(std::move(elem[i]));
@@ -175,6 +175,12 @@ public:
         }
     }
 
+    void AllocForOneMore() {
+        if(n >= elemsAllocated) {
+            ReserveMore((elemsAllocated + 32)*2 - n);
+        }
+    }
+
     void Add(const T *t) {
         AllocForOneMore();
         new(&elem[n++]) T(*t);
@@ -285,9 +291,9 @@ public:
         return t->h;
     }
 
-    void Add(T *t) {
-        if(n >= elemsAllocated) {
-            elemsAllocated = (elemsAllocated + 32)*2;
+    void ReserveMore(int howMuch) {
+        if(n + howMuch > elemsAllocated) {
+            elemsAllocated = n + howMuch;
             T *newElem = (T *)MemAlloc((size_t)elemsAllocated*sizeof(elem[0]));
             for(int i = 0; i < n; i++) {
                 new(&newElem[i]) T(std::move(elem[i]));
@@ -296,7 +302,13 @@ public:
             MemFree(elem);
             elem = newElem;
         }
+    }
 
+    void Add(T *t) {
+        if(n >= elemsAllocated) {
+            ReserveMore((elemsAllocated + 32)*2 - n);
+        }
+    
         int first = 0, last = n;
         // We know that we must insert within the closed interval [first,last]
         while(first != last) {

src/generate.cpp

@@ -217,7 +217,10 @@ void SolveSpaceUI::GenerateAll(Generate type, bool andFindFree, bool genForBBox)
     // Don't lose our numerical guesses when we regenerate.
     IdList<Param,hParam> prev = {};
     SK.param.MoveSelfInto(&prev);
+    SK.param.ReserveMore(prev.n);
+    int oldEntityCount = SK.entity.n;
     SK.entity.Clear();
+    SK.entity.ReserveMore(oldEntityCount);
 
     for(i = 0; i < SK.groupOrder.n; i++) {
         Group *g = SK.GetGroup(SK.groupOrder.elem[i]);

src/srf/boolean.cpp

@@ -664,6 +664,7 @@ void SShell::MakeFromAssemblyOf(SShell *a, SShell *b) {
 
     // First, copy over all the curves. Note which shell (a or b) each curve
     // came from, but assign it a new ID.
+    curve.ReserveMore(a->curve.n + b->curve.n);
     SCurve *c, cn;
     for(i = 0; i < 2; i++) {
         ab = (i == 0) ? a : b;
@@ -677,6 +678,7 @@ void SShell::MakeFromAssemblyOf(SShell *a, SShell *b) {
     }
 
     // Likewise copy over all the surfaces.
+    surface.ReserveMore(a->surface.n + b->surface.n);
     SSurface *s, sn;
     for(i = 0; i < 2; i++) {
         ab = (i == 0) ? a : b;

src/srf/curve.cpp

@@ -741,6 +741,7 @@ SCurve SCurve::FromTransformationOf(SCurve *a, Vector t,
     ret.surfB = a->surfB;
 
     SCurvePt *p;
+    ret.pts.ReserveMore(a->pts.n);
     for(p = a->pts.First(); p; p = a->pts.NextAfter(p)) {
         SCurvePt pp = *p;
         if(needScale) {

src/srf/surface.cpp

@@ -165,6 +165,7 @@ SSurface SSurface::FromTransformationOf(SSurface *a, Vector t, Quaternion q, dou
 
     if(includingTrims) {
         STrimBy *stb;
+        ret.trim.ReserveMore(a->trim.n);
         for(stb = a->trim.First(); stb; stb = a->trim.NextAfter(stb)) {
             STrimBy n = *stb;
             if(needScale) {
@@ -834,7 +835,7 @@ void SShell::MakeFromTransformationOf(SShell *a,
                                       Vector t, Quaternion q, double scale)
 {
     booleanFailed = false;
-
+    surface.ReserveMore(a->surface.n);
     SSurface *s;
     for(s = a->surface.First(); s; s = a->surface.NextAfter(s)) {
         SSurface n;
@@ -842,6 +843,7 @@ void SShell::MakeFromTransformationOf(SShell *a,
         surface.Add(&n); // keeping the old ID
     }
 
+    curve.ReserveMore(a->curve.n);
     SCurve *c;
     for(c = a->curve.First(); c; c = a->curve.NextAfter(c)) {
         SCurve n;

src/undoredo.cpp

@@ -47,6 +47,7 @@ void SolveSpaceUI::PushFromCurrentOnto(UndoStack *uk) {
 
     UndoState *ut = &(uk->d[uk->write]);
     *ut = {};
+    ut->group.ReserveMore(SK.group.n);
     for(i = 0; i < SK.group.n; i++) {
         Group *src = &(SK.group.elem[i]);
         Group dest = *src;
@@ -76,17 +77,21 @@ void SolveSpaceUI::PushFromCurrentOnto(UndoStack *uk) {
     for(i = 0; i < SK.groupOrder.n; i++) {
         ut->groupOrder.Add(&(SK.groupOrder.elem[i]));
     }
+    ut->request.ReserveMore(SK.request.n);
     for(i = 0; i < SK.request.n; i++) {
         ut->request.Add(&(SK.request.elem[i]));
     }
+    ut->constraint.ReserveMore(SK.constraint.n);
     for(i = 0; i < SK.constraint.n; i++) {
         Constraint *src = &(SK.constraint.elem[i]);
         Constraint dest = *src;
         ut->constraint.Add(&dest);
     }
+    ut->param.ReserveMore(SK.param.n);
     for(i = 0; i < SK.param.n; i++) {
         ut->param.Add(&(SK.param.elem[i]));
     }
+    ut->style.ReserveMore(SK.style.n);
     for(i = 0; i < SK.style.n; i++) {
         ut->style.Add(&(SK.style.elem[i]));
     }