add hash function BLI_ghash_assign, BLI_edgehash_assign

avoids remove,insert and only hashes the key once.

1 files changed, 71 insertions, 26 deletions

diff --git a/source/blender/blenlib/intern/BLI_ghash.c b/source/blender/blenlib/intern/BLI_ghash.c
index da886e59c21..8221393d4d5 100644
--- a/source/blender/blenlib/intern/BLI_ghash.c
+++ b/source/blender/blenlib/intern/BLI_ghash.c
@@ -84,30 +84,35 @@ typedef struct GHash {
 /* -------------------------------------------------------------------- */
 /* GHash API */
 
-GHash *BLI_ghash_new(GHashHashFP hashfp, GHashCmpFP cmpfp, const char *info)
-{
-	GHash *gh = MEM_mallocN(sizeof(*gh), info);
-	gh->hashfp = hashfp;
-	gh->cmpfp = cmpfp;
-	gh->entrypool = BLI_mempool_create(sizeof(Entry), 64, 64, 0);
+/* internal utility API */
 
-	gh->cursize = 0;
-	gh->nentries = 0;
-	gh->nbuckets = hashsizes[gh->cursize];
+BLI_INLINE unsigned int ghash_keyhash(GHash *gh, const void *key)
+{
+	return gh->hashfp(key) % gh->nbuckets;
+}
 
-	gh->buckets = MEM_callocN(gh->nbuckets * sizeof(*gh->buckets), "buckets");
+BLI_INLINE Entry *ghash_lookup_entry_ex(GHash *gh, const void *key,
+                                        const unsigned int hash)
+{
+	Entry *e;
 
-	return gh;
+	for (e = gh->buckets[hash]; e; e = e->next) {
+		if (gh->cmpfp(key, e->key) == 0) {
+			return e;
+		}
+	}
+	return NULL;
 }
 
-int BLI_ghash_size(GHash *gh)
+BLI_INLINE Entry *ghash_lookup_entry(GHash *gh, const void *key)
 {
-	return (int)gh->nentries;
+	const unsigned int hash = ghash_keyhash(gh, key);
+	return ghash_lookup_entry_ex(gh, key, hash);
 }
 
-void BLI_ghash_insert(GHash *gh, void *key, void *val)
+static void ghash_insert_ex(GHash *gh, void *key, void *val,
+                            unsigned int hash)
 {
-	unsigned int hash = gh->hashfp(key) % gh->nbuckets;
 	Entry *e = (Entry *)BLI_mempool_alloc(gh->entrypool);
 
 	BLI_assert((gh->flag & GHASH_FLAG_ALLOW_DUPES) || (BLI_ghash_haskey(gh, key) == 0));
@@ -129,7 +134,7 @@ void BLI_ghash_insert(GHash *gh, void *key, void *val)
 			Entry *e_next;
 			for (e = old[i]; e; e = e_next) {
 				e_next = e->next;
-				hash = gh->hashfp(e->key) % gh->nbuckets;
+				hash = ghash_keyhash(gh, e->key);
 				e->next = gh->buckets[hash];
 				gh->buckets[hash] = e;
 			}
@@ -139,17 +144,57 @@ void BLI_ghash_insert(GHash *gh, void *key, void *val)
 	}
 }
 
-BLI_INLINE Entry *ghash_lookup_entry(GHash *gh, const void *key)
+
+/* Public API */
+
+GHash *BLI_ghash_new(GHashHashFP hashfp, GHashCmpFP cmpfp, const char *info)
 {
-	const unsigned int hash = gh->hashfp(key) % gh->nbuckets;
-	Entry *e;
+	GHash *gh = MEM_mallocN(sizeof(*gh), info);
+	gh->hashfp = hashfp;
+	gh->cmpfp = cmpfp;
+	gh->entrypool = BLI_mempool_create(sizeof(Entry), 64, 64, 0);
 
-	for (e = gh->buckets[hash]; e; e = e->next) {
-		if (gh->cmpfp(key, e->key) == 0) {
-			return e;
-		}
+	gh->cursize = 0;
+	gh->nentries = 0;
+	gh->nbuckets = hashsizes[gh->cursize];
+
+	gh->buckets = MEM_callocN(gh->nbuckets * sizeof(*gh->buckets), "buckets");
+
+	return gh;
+}
+
+int BLI_ghash_size(GHash *gh)
+{
+	return (int)gh->nentries;
+}
+
+void BLI_ghash_insert(GHash *gh, void *key, void *val)
+{
+	const unsigned int hash = ghash_keyhash(gh, key);
+	ghash_insert_ex(gh, key, val, hash);
+}
+
+/**
+ * Assign a new value to a key that may already be in ghash.
+ * Avoids #BLI_ghash_remove, #BLI_ghash_insert calls (double lookups)
+ *
+ * \note We may want to have 'BLI_ghash_assign_ex' function that takes
+ * GHashKeyFreeFP & GHashValFreeFP args. for now aren't needed.
+ */
+void BLI_ghash_assign(GHash *gh, void *key, void *val, GHashKeyFreeFP keyfreefp, GHashValFreeFP valfreefp)
+{
+	const unsigned int hash = ghash_keyhash(gh, key);
+	Entry *e = ghash_lookup_entry_ex(gh, key, hash);
+	if (e) {
+		if (keyfreefp) keyfreefp(e->key);
+		if (valfreefp) valfreefp(e->val);
+
+		e->key = key;
+		e->val = val;
+	}
+	else {
+		ghash_insert_ex(gh, key, val, hash);
 	}
-	return NULL;
 }
 
 void *BLI_ghash_lookup(GHash *gh, const void *key)
@@ -166,7 +211,7 @@ void **BLI_ghash_lookup_p(GHash *gh, const void *key)
 
 bool BLI_ghash_remove(GHash *gh, void *key, GHashKeyFreeFP keyfreefp, GHashValFreeFP valfreefp)
 {
-	unsigned int hash = gh->hashfp(key) % gh->nbuckets;
+	const unsigned int hash = ghash_keyhash(gh, key);
 	Entry *e;
 	Entry *p = NULL;
 
@@ -196,7 +241,7 @@ bool BLI_ghash_remove(GHash *gh, void *key, GHashKeyFreeFP keyfreefp, GHashValFr
  * no free value argument since it will be returned */
 void *BLI_ghash_pop(GHash *gh, void *key, GHashKeyFreeFP keyfreefp)
 {
-	unsigned int hash = gh->hashfp(key) % gh->nbuckets;
+	const unsigned int hash = ghash_keyhash(gh, key);
 	Entry *e;
 	Entry *p = NULL;