replace some qsort calls with std::sort

This is safer and has the potential to be more efficient. Note that this
required rewriting the involved comparator to judge less-than instead of a
three-outcome comparison.

diff --git a/lib/vpsc/generate-constraints.cpp b/lib/vpsc/generate-constraints.cpp
index 459f7f55ef35912ca9ef9d76d396e412a8a50581..bee95cb1c143382ad254b58ce90e9fd0dcf94a31 100644 (file)
--- a/lib/vpsc/generate-constraints.cpp
+++ b/lib/vpsc/generate-constraints.cpp
@@ -16,6 +16,7 @@
  * Adaptagrams repository.
  */
 
+#include <algorithm>
 #include <set>
 #include <cassert>
 #include <cstdlib>
@@ -124,20 +125,18 @@ struct Event {
        Event(EventType t, Node *v, double p) : type(t),v(v),pos(p) {};
 };
 
-int compare_events(const void *a, const void *b) {
-       Event *ea=*(Event**)a;
-       Event *eb=*(Event**)b;
+static bool compare_events(const Event *ea, const Event *eb) {
        if(ea->v->r==eb->v->r) {
                // when comparing opening and closing from the same rect
                // open must come first
-               if(ea->type==Open) return -1;
-               return 1;
+               if(ea->type == Open && eb->type != Open) return true;
+               return false;
        } else if(ea->pos > eb->pos) {
-               return 1;
+               return false;
        } else if(ea->pos < eb->pos) {
-               return -1;
+               return true;
        }
-       return 0;
+       return false;
 }
 
 /**
@@ -154,7 +153,7 @@ int generateXConstraints(const int n, Rectangle** rs, Variable** vars, Constrain
                events[ctr++]=new Event(Open,v,rs[i]->getMinY());
                events[ctr++]=new Event(Close,v,rs[i]->getMaxY());
        }
-       qsort((Event*)events.data(), (size_t)2*n, sizeof(Event*), compare_events );
+       std::sort(events.begin(), events.end(), compare_events);
 
        NodeSet scanline;
        vector<Constraint*> constraints;
@@ -237,7 +236,7 @@ int generateYConstraints(const int n, Rectangle** rs, Variable** vars, Constrain
                events[ctr++]=new Event(Open,v,rs[i]->getMinX());
                events[ctr++]=new Event(Close,v,rs[i]->getMaxX());
        }
-       qsort((Event*)events.data(), (size_t)2*n, sizeof(Event*), compare_events );
+       std::sort(events.begin(), events.end(), compare_events);
        NodeSet scanline;
        vector<Constraint*> constraints;
        for(i=0;i<2*n;i++) {