schiff

commit e6941a1da4a8516d3a822e24f9eec12f9bfcb462
parent d5517ae72e590f20ce302db9cdd19f5811571e91
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Tue,  9 Feb 2016 11:25:12 +0100

Fix the histogram sampling

The comparator of histogram values was wrongly defined leading to
invalid memory read.

Diffstat:
M
src/schiff_histogram.c
 | 
12
+++++++-----

1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/src/schiff_histogram.c b/src/schiff_histogram.c
@@ -78,11 +78,11 @@ parse_histogram_proba
 static INLINE int
 cmp_entry(const void* a, const void* b)
 {
-  double val;
+  const struct schiff_hentry* key = a;
   const struct schiff_hentry* entry = b;
   ASSERT(a && b);
-  val = *(const double*)a;
-  return val < entry->accum_proba ? -1 : val > entry->accum_proba ? 1 : 0;
+  return key->accum_proba < entry->accum_proba
+    ? -1 : key->accum_proba > entry->accum_proba ? 1 : 0;
 }
 
 static res_T
@@ -271,6 +271,7 @@ schiff_histogram_sample(const struct darray_hentry* histo, const double u)
 {
   const struct schiff_hentry* entries;
   const struct schiff_hentry* find;
+  struct schiff_hentry samp;
   size_t nentries;
   double v;
   ASSERT(histo && u >= 0.0 && u < 1.0);
@@ -279,8 +280,9 @@ schiff_histogram_sample(const struct darray_hentry* histo, const double u)
   nentries = darray_hentry_size_get(histo);
   ASSERT(nentries);
 
-  find = search_lower_bound
-    (&u, entries, nentries, sizeof(struct schiff_hentry), cmp_entry);
+  samp.accum_proba = u;
+  find = search_lower_bound(&samp, entries, nentries,
+    sizeof(struct schiff_hentry), cmp_entry);
 
   if(find == entries)
     return find->value;