Bugzilla bug #32184: added 'const' versions of hash table lookup

functions that don't reorder the hash entries.
Modified files: plhash.h, plhash.c
(NSPRPUB_CLIENT_BRANCH)

2 files changed, 52 insertions, 0 deletions

diff --git a/lib/ds/plhash.c b/lib/ds/plhash.c
index 30b46fdc..1adaac35 100644
--- a/lib/ds/plhash.c
+++ b/lib/ds/plhash.c
@@ -195,6 +195,34 @@ PL_HashTableRawLookup(PLHashTable *ht, PLHashNumber keyHash, const void *key)
     return hep;
 }
 
+/*
+** Same as PL_HashTableRawLookup but doesn't reorder the hash entries.
+*/
+PR_IMPLEMENT(PLHashEntry *const *)
+PL_HashTableRawLookupConst(const PLHashTable *ht, PLHashNumber keyHash,
+                           const void *key)
+{
+    PLHashEntry *he, *const *hep;
+    PLHashNumber h;
+
+#ifdef HASHMETER
+    ht->nlookups++;
+#endif
+    h = keyHash * GOLDEN_RATIO;
+    h >>= ht->shift;
+    hep = &ht->buckets[h];
+    while ((he = *hep) != 0) {
+        if (he->keyHash == keyHash && (*ht->keyCompare)(key, he->key)) {
+            break;
+        }
+        hep = &he->next;
+#ifdef HASHMETER
+        ht->nsteps++;
+#endif
+    }
+    return hep;
+}
+
 PR_IMPLEMENT(PLHashEntry *)
 PL_HashTableRawAdd(PLHashTable *ht, PLHashEntry **hep,
                    PLHashNumber keyHash, const void *key, void *value)
@@ -349,6 +377,23 @@ PL_HashTableLookup(PLHashTable *ht, const void *key)
 }
 
 /*
+** Same as PL_HashTableLookup but doesn't reorder the hash entries.
+*/
+PR_IMPLEMENT(void *)
+PL_HashTableLookupConst(const PLHashTable *ht, const void *key)
+{
+    PLHashNumber keyHash;
+    PLHashEntry *he, *const *hep;
+
+    keyHash = (*ht->keyHash)(key);
+    hep = PL_HashTableRawLookupConst(ht, keyHash, key);
+    if ((he = *hep) != 0) {
+        return he->value;
+    }
+    return 0;
+}
+
+/*
 ** Iterate over the entries in the hash table calling func for each
 ** entry found. Stop if "f" says to (return value & PR_ENUMERATE_STOP).
 ** Return a count of the number of elements scanned.
diff --git a/lib/ds/plhash.h b/lib/ds/plhash.h
index 3110d8ab..438dbd6a 100644
--- a/lib/ds/plhash.h
+++ b/lib/ds/plhash.h
@@ -104,6 +104,9 @@ PL_HashTableRemove(PLHashTable *ht, const void *key);
 PR_EXTERN(void *)
 PL_HashTableLookup(PLHashTable *ht, const void *key);
 
+PR_EXTERN(void *)
+PL_HashTableLookupConst(const PLHashTable *ht, const void *key);
+
 PR_EXTERN(PRIntn)
 PL_HashTableEnumerateEntries(PLHashTable *ht, PLHashEnumerator f, void *arg);
 
@@ -123,6 +126,10 @@ PL_CompareValues(const void *v1, const void *v2);
 PR_EXTERN(PLHashEntry **)
 PL_HashTableRawLookup(PLHashTable *ht, PLHashNumber keyHash, const void *key);
 
+PR_EXTERN(PLHashEntry *const *)
+PL_HashTableRawLookupConst(const PLHashTable *ht, PLHashNumber keyHash,
+                           const void *key);
+
 PR_EXTERN(PLHashEntry *)
 PL_HashTableRawAdd(PLHashTable *ht, PLHashEntry **hep, PLHashNumber keyHash,
                    const void *key, void *value);