revise DHT hashing functions, add test logic

1 files changed, 30 insertions, 38 deletions

diff --git a/src/include/gnunet_crypto_lib.h b/src/include/gnunet_crypto_lib.h
index bd318ab84..4e26429c9 100644
--- a/src/include/gnunet_crypto_lib.h
+++ b/src/include/gnunet_crypto_lib.h
@@ -1038,61 +1038,53 @@ GNUNET_CRYPTO_hash_xor (const struct GNUNET_HashCode *a,
 
 
 /**
- * @ingroup hash
- * Convert a hashcode into a key.
+ * Count the number of leading 0 bits in @a h.
  *
- * @param hc hash code that serves to generate the key
- * @param skey set to a valid session key
- * @param iv set to a valid initialization vector
+ * @param h a hash
+ * @return number of leading 0 bits in @a h
  */
-void
-GNUNET_CRYPTO_hash_to_aes_key (
-  const struct GNUNET_HashCode *hc,
-  struct GNUNET_CRYPTO_SymmetricSessionKey *skey,
-  struct GNUNET_CRYPTO_SymmetricInitializationVector *iv);
+unsigned int
+GNUNET_CRYPTO_hash_count_leading_zeros (const struct GNUNET_HashCode *h);
 
 
 /**
- * @ingroup hash
- * Obtain a bit from a hashcode.
+ * Count the number of tailing 0 bits in @a h.
  *
- * @param code the `struct GNUNET_HashCode` to index bit-wise
- * @param bit index into the hashcode, [0...159] where 0 is the leftmost bit
- *        (bytes in code interpreted big endian)
- * @return Bit \a bit from hashcode \a code, -1 for invalid index
+ * @param h a hash
+ * @return number of tailing 0 bits in @a h
  */
-int
-GNUNET_CRYPTO_hash_get_bit_ltr (const struct GNUNET_HashCode *code,
-                                unsigned int bit);
+unsigned int
+GNUNET_CRYPTO_hash_count_tailing_zeros (const struct GNUNET_HashCode *h);
 
 
 /**
- * Obtain a bit from a hashcode.
- * @param code the GNUNET_CRYPTO_hash to index bit-wise
- * @param bit index into the hashcode, [0...511] where 0 is the rightmost bit
- *        (bytes in code interpreted little endian)
- * @return Bit \a bit from hashcode \a code, -1 for invalid index
+ * Compute the distance between have and target as a 64-bit value.
+ * Differences in the lower bits must count stronger than differences
+ * in the higher bits.
+ *
+ * @param xor input hash
+ * @param bucket up to which offset we are to ignore @a xor
+ * @return the subsequent 64 bits after @a bucket from @a xor, in
+ *  host byte order.
  */
-int
-GNUNET_CRYPTO_hash_get_bit_rtl (const struct GNUNET_HashCode *code,
-                                unsigned int bit);
+uint64_t
+GNUNET_CRYPTO_hash_bucket_distance (const struct GNUNET_HashCode *xor,
+                                    unsigned int bucket);
 
 
 /**
  * @ingroup hash
- * Determine how many low order bits match in two
- * `struct GNUNET_HashCodes`.  e.g. - 010011 and 011111 share
- * the first two lowest order bits, and therefore the
- * return value is two (NOT XOR distance, nor how many
- * bits match absolutely!).
+ * Convert a hashcode into a key.
  *
- * @param first the first hashcode
- * @param second the hashcode to compare first to
- * @return the number of bits that match
+ * @param hc hash code that serves to generate the key
+ * @param skey set to a valid session key
+ * @param iv set to a valid initialization vector
  */
-unsigned int
-GNUNET_CRYPTO_hash_matching_bits (const struct GNUNET_HashCode *first,
-                                  const struct GNUNET_HashCode *second);
+void
+GNUNET_CRYPTO_hash_to_aes_key (
+  const struct GNUNET_HashCode *hc,
+  struct GNUNET_CRYPTO_SymmetricSessionKey *skey,
+  struct GNUNET_CRYPTO_SymmetricInitializationVector *iv);
 
 
 /**