Smallhash: optimizations

- remove static array used only for copying (use alloca on resize)
- set SMSTACKSIZE to one of the values in 'hashsizes' since the full available size was never used.
- ensure ~1.5x as many buckets as entries, was 3x which caused malloc's quite early on.

1 files changed, 6 insertions, 7 deletions

diff --git a/source/blender/blenlib/BLI_smallhash.h b/source/blender/blenlib/BLI_smallhash.h
index 07bd9975467..f394a224ca1 100644
--- a/source/blender/blenlib/BLI_smallhash.h
+++ b/source/blender/blenlib/BLI_smallhash.h
@@ -39,17 +39,16 @@ typedef struct {
 	void *val;
 } SmallHashEntry;
 
-/*how much stack space to use before dynamically allocating memory*/
-#define SMSTACKSIZE 64
+/* how much stack space to use before dynamically allocating memory.
+ * set to match one of the values in 'hashsizes' to avoid too many mallocs  */
+#define SMSTACKSIZE 131
 typedef struct SmallHash {
-	SmallHashEntry *buckets;
-	SmallHashEntry *buckets_stack;
-	SmallHashEntry *buckets_copy;
-	SmallHashEntry _buckets_stack[SMSTACKSIZE];
-	SmallHashEntry _buckets_copy[SMSTACKSIZE];
 	unsigned int nbuckets;
 	unsigned int nentries;
 	unsigned int cursize;
+
+	SmallHashEntry *buckets;
+	SmallHashEntry  buckets_stack[SMSTACKSIZE];
 } SmallHash;
 
 typedef struct {