4 files changed, 42 insertions, 4 deletions

diff --git a/source/blender/blenlib/BLI_edgehash.h b/source/blender/blenlib/BLI_edgehash.h
index 1962201c8d2..f961d73cd79 100644
--- a/source/blender/blenlib/BLI_edgehash.h
+++ b/source/blender/blenlib/BLI_edgehash.h
@@ -40,6 +40,7 @@ enum {
 	EDGEHASH_FLAG_ALLOW_DUPES = (1 << 0),  /* only checked for in debug mode */
 };
 
+EdgeHash       *BLI_edgehash_new_ex(const unsigned int nentries_reserve);
 EdgeHash       *BLI_edgehash_new(void);
 void            BLI_edgehash_free(EdgeHash *eh, EdgeHashFreeFP valfreefp);
 void            BLI_edgehash_insert(EdgeHash *eh, unsigned int v0, unsigned int v1, void *val);
diff --git a/source/blender/blenlib/BLI_ghash.h b/source/blender/blenlib/BLI_ghash.h
index 4688c6e3831..5f748fcaecd 100644
--- a/source/blender/blenlib/BLI_ghash.h
+++ b/source/blender/blenlib/BLI_ghash.h
@@ -58,6 +58,8 @@ enum {
 
 /* *** */
 
+GHash *BLI_ghash_new_ex(GHashHashFP hashfp, GHashCmpFP cmpfp, const char *info,
+                        const unsigned int nentries_reserve);
 GHash *BLI_ghash_new(GHashHashFP hashfp, GHashCmpFP cmpfp, const char *info);
 void   BLI_ghash_free(GHash *gh, GHashKeyFreeFP keyfreefp, GHashValFreeFP valfreefp);
 void   BLI_ghash_insert(GHash *gh, void *key, void *val);
diff --git a/source/blender/blenlib/intern/BLI_ghash.c b/source/blender/blenlib/intern/BLI_ghash.c
index 10a425ca12c..a1cbf8a5ce0 100644
--- a/source/blender/blenlib/intern/BLI_ghash.c
+++ b/source/blender/blenlib/intern/BLI_ghash.c
@@ -86,6 +86,11 @@ struct GHash {
 
 /* internal utility API */
 
+BLI_INLINE bool ghash_test_expand_buckets(const unsigned int nentries, const unsigned int nbuckets)
+{
+	return (nentries > nbuckets / 2);
+}
+
 BLI_INLINE unsigned int ghash_keyhash(GHash *gh, const void *key)
 {
 	return gh->hashfp(key) % gh->nbuckets;
@@ -122,7 +127,7 @@ static void ghash_insert_ex(GHash *gh, void *key, void *val,
 	e->val = val;
 	gh->buckets[hash] = e;
 
-	if (UNLIKELY(++gh->nentries > gh->nbuckets / 2)) {
+	if (UNLIKELY(ghash_test_expand_buckets(++gh->nentries, gh->nbuckets))) {
 		Entry **old = gh->buckets;
 		const unsigned nold = gh->nbuckets;
 		unsigned int i;
@@ -147,7 +152,8 @@ static void ghash_insert_ex(GHash *gh, void *key, void *val,
 
 /* Public API */
 
-GHash *BLI_ghash_new(GHashHashFP hashfp, GHashCmpFP cmpfp, const char *info)
+GHash *BLI_ghash_new_ex(GHashHashFP hashfp, GHashCmpFP cmpfp, const char *info,
+                        const unsigned int nentries_reserve)
 {
 	GHash *gh = MEM_mallocN(sizeof(*gh), info);
 
@@ -159,12 +165,24 @@ GHash *BLI_ghash_new(GHashHashFP hashfp, GHashCmpFP cmpfp, const char *info)
 	gh->cursize = 0;
 	gh->flag = 0;
 
+	/* if we have reserved the number of elements that this hash will contain */
+	if (nentries_reserve) {
+		while (ghash_test_expand_buckets(nentries_reserve, gh->nbuckets)) {
+			gh->nbuckets = hashsizes[++gh->cursize];
+		}
+	}
+
 	gh->buckets = MEM_callocN(gh->nbuckets * sizeof(*gh->buckets), "buckets");
 	gh->entrypool = BLI_mempool_create(sizeof(Entry), 64, 64, 0);
 
 	return gh;
 }
 
+GHash *BLI_ghash_new(GHashHashFP hashfp, GHashCmpFP cmpfp, const char *info)
+{
+	return BLI_ghash_new_ex(hashfp, cmpfp, info, 0);
+}
+
 int BLI_ghash_size(GHash *gh)
 {
 	return (int)gh->nentries;
diff --git a/source/blender/blenlib/intern/edgehash.c b/source/blender/blenlib/intern/edgehash.c
index 3263c69ee6a..738f1f0c7a1 100644
--- a/source/blender/blenlib/intern/edgehash.c
+++ b/source/blender/blenlib/intern/edgehash.c
@@ -86,6 +86,11 @@ struct EdgeHash {
 
 #define EDGE_HASH(v0, v1)  ((v0 * 39) ^ (v1 * 31))
 
+BLI_INLINE bool edgehash_test_expand_buckets(const unsigned int nentries, const unsigned int nbuckets)
+{
+	return (nentries > nbuckets / 2);
+}
+
 BLI_INLINE unsigned int edgehash_keyhash(EdgeHash *eh, unsigned int v0, unsigned int v1)
 {
 	BLI_assert(v0 < v1);
@@ -130,7 +135,7 @@ static void edgehash_insert_ex(EdgeHash *eh, unsigned int v0, unsigned int v1, v
 	e->val = val;
 	eh->buckets[hash] = e;
 
-	if (UNLIKELY(++eh->nentries > eh->nbuckets / 2)) {
+	if (UNLIKELY(edgehash_test_expand_buckets(++eh->nentries, eh->nbuckets))) {
 		EdgeEntry **old = eh->buckets;
 		const unsigned int nold = eh->nbuckets;
 		unsigned int i;
@@ -157,7 +162,7 @@ static void edgehash_insert_ex(EdgeHash *eh, unsigned int v0, unsigned int v1, v
 
 /* Public API */
 
-EdgeHash *BLI_edgehash_new(void)
+EdgeHash *BLI_edgehash_new_ex(const unsigned int nentries_reserve)
 {
 	EdgeHash *eh = MEM_callocN(sizeof(*eh), "EdgeHash");
 
@@ -166,12 +171,24 @@ EdgeHash *BLI_edgehash_new(void)
 	eh->cursize = 0;
 	eh->flag = 0;
 
+	/* if we have reserved the number of elements that this hash will contain */
+	if (nentries_reserve) {
+		while (edgehash_test_expand_buckets(nentries_reserve, eh->nbuckets)) {
+			eh->nbuckets = _ehash_hashsizes[++eh->cursize];
+		}
+	}
+
 	eh->buckets = MEM_callocN(eh->nbuckets * sizeof(*eh->buckets), "eh buckets 2");
 	eh->epool = BLI_mempool_create(sizeof(EdgeEntry), 512, 512, BLI_MEMPOOL_SYSMALLOC);
 
 	return eh;
 }
 
+EdgeHash *BLI_edgehash_new(void)
+{
+	return BLI_edgehash_new_ex(0);
+}
+
 /**
  * Insert edge (\a v0, \a v1) into hash with given value, does
  * not check for duplicates.