feat: #369: bloomUtil exposes addressOf and filterOf methods to build…

… from ExpandedBlockDetail
vechain · Apr 15, 2024 · 4f235e5 · 4f235e5
1 parent 942f647
commit 4f235e5
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Showing 2 changed files with 6 additions and 3 deletions.
diff --git a/packages/core/src/bloom/bloom.ts b/packages/core/src/bloom/bloom.ts
@@ -41,8 +41,8 @@ function addWithUInt32Wrap(a: number, b: number): number {
  * @return {number} - The number of bits per key.
  */
 function calculateBitsPerKey(k: number): number {
-    if (k < 1) return 2;
-    return k > 30 ? 44 : Math.ceil(k / 0.69);
+    if (k <= 1) return 2;
+    return k >= 30 ? 44 : Math.ceil(k / 0.69);
 }
 
 /**

diff --git a/packages/core/src/utils/bloom/bloom.ts b/packages/core/src/utils/bloom/bloom.ts
@@ -21,7 +21,10 @@ const BLOOM_REGEX = /^(0x)?[0-9a-f]{16,}$/i;
 /**
  * Bloom Filter *k* parameter set to 5 (hence 5 hashes functions are
  * used in filter generation) is computed supposing to express the
- * 20 bytes long address in 1 byte, hence k =
+ * 20 bytes long address in 1 byte, hence k = 8 * ln(2) approximated to 5,
+ * leading to a Bloom Filter size of between 8 and 16 bytes to encode
+ * the addresses of a Thor block with a probability of false positives much
+ * smaller than 1%.
  */
 const BLOOM_DEFAULT_K = 5;