docs(fnv1a): documents fnv1a

Author: daprahamian

Diff for: lib/bson/fnv1a.js

@@ -11,6 +11,11 @@ const FNV_PRIME = new Long(16777619, 0);
 const OFFSET_BASIS = new Long(2166136261, 0);
 const FNV_MASK = new Long(MASK_32, 0);
 
+/**
+ * Implementation of the FNV-1a hash for a 32-bit hash value
+ * Algorithm can be found here: http://www.isthe.com/chongo/tech/comp/fnv/#FNV-1a
+ * @ignore
+ */
 function fnv1a32(input, encoding) {
   encoding = encoding || 'utf8';
   const octets = Buffer.from(input, encoding);
@@ -24,6 +29,12 @@ function fnv1a32(input, encoding) {
   return hash.getLowBitsUnsigned();
 }
 
+/**
+ * Implements FNV-1a to generate 32-bit hash, then uses xor-folding
+ * to convert to a 24-bit hash. See here for more info:
+ * http://www.isthe.com/chongo/tech/comp/fnv/#xor-fold
+ * @ignore
+ */
 function fnv1a24(input, encoding) {
   const _32bit = fnv1a32(input, encoding);
   const base = _32bit & MASK_24;