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[GNUnet-SVN] r19056 - gnunet/src/util
From: |
gnunet |
Subject: |
[GNUnet-SVN] r19056 - gnunet/src/util |
Date: |
Sat, 7 Jan 2012 21:15:45 +0100 |
Author: grothoff
Date: 2012-01-07 21:15:45 +0100 (Sat, 07 Jan 2012)
New Revision: 19056
Modified:
gnunet/src/util/crypto_hash.c
Log:
-add missing comments, expand error checking
Modified: gnunet/src/util/crypto_hash.c
===================================================================
--- gnunet/src/util/crypto_hash.c 2012-01-07 19:54:12 UTC (rev 19055)
+++ gnunet/src/util/crypto_hash.c 2012-01-07 20:15:45 UTC (rev 19056)
@@ -244,6 +244,12 @@
/* ***************** binary-ASCII encoding *************** */
+/**
+ * Get the numeric value corresponding to a character.
+ *
+ * @param a a character
+ * @return corresponding numeric value
+ */
static unsigned int
getValue__ (unsigned char a)
{
@@ -254,6 +260,7 @@
return -1;
}
+
/**
* Convert GNUNET_CRYPTO_hash to ASCII encoding. The ASCII encoding is rather
* GNUnet specific. It was chosen such that it only uses characters
@@ -306,6 +313,7 @@
result->encoding[wpos] = '\0';
}
+
/**
* Convert ASCII encoding back to GNUNET_CRYPTO_hash
*
@@ -320,6 +328,7 @@
unsigned int wpos;
unsigned int bits;
unsigned int vbit;
+ int ret;
if (strlen (enc) != sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1)
return GNUNET_SYSERR;
@@ -327,11 +336,15 @@
vbit = 2; /* padding! */
wpos = sizeof (GNUNET_HashCode);
rpos = sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1;
- bits = getValue__ (enc[--rpos]) >> 3;
+ bits = (ret = getValue__ (enc[--rpos])) >> 3;
+ if (-1 == ret)
+ return GNUNET_SYSERR;
while (wpos > 0)
{
GNUNET_assert (rpos > 0);
- bits = (getValue__ (enc[--rpos]) << vbit) | bits;
+ bits = ((ret = getValue__ (enc[--rpos])) << vbit) | bits;
+ if (-1 == ret)
+ return GNUNET_SYSERR;
vbit += 5;
if (vbit >= 8)
{
@@ -345,6 +358,7 @@
return GNUNET_OK;
}
+
/**
* Compute the distance between 2 hashcodes. The computation must be
* fast, not involve bits[0] or bits[4] (they're used elsewhere), and be
@@ -366,6 +380,13 @@
return (x1 * x2);
}
+
+/**
+ * Create a random hash code.
+ *
+ * @param mode desired quality level
+ * @param result hash code that is randomized
+ */
void
GNUNET_CRYPTO_hash_create_random (enum GNUNET_CRYPTO_Quality mode,
GNUNET_HashCode * result)
@@ -376,6 +397,14 @@
result->bits[i] = GNUNET_CRYPTO_random_u32 (mode, UINT32_MAX);
}
+
+/**
+ * compute result(delta) = b - a
+ *
+ * @param a some hash code
+ * @param b some hash code
+ * @param result set to b - a
+ */
void
GNUNET_CRYPTO_hash_difference (const GNUNET_HashCode * a,
const GNUNET_HashCode * b,
@@ -387,6 +416,14 @@
result->bits[i] = b->bits[i] - a->bits[i];
}
+
+/**
+ * compute result(b) = a + delta
+ *
+ * @param a some hash code
+ * @param delta some hash code
+ * @param result set to a + delta
+ */
void
GNUNET_CRYPTO_hash_sum (const GNUNET_HashCode * a,
const GNUNET_HashCode * delta, GNUNET_HashCode *
result)
@@ -398,6 +435,13 @@
}
+/**
+ * compute result = a ^ b
+ *
+ * @param a some hash code
+ * @param b some hash code
+ * @param result set to a ^ b
+ */
void
GNUNET_CRYPTO_hash_xor (const GNUNET_HashCode * a, const GNUNET_HashCode * b,
GNUNET_HashCode * result)
@@ -411,6 +455,10 @@
/**
* Convert a hashcode into a key.
+ *
+ * @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
*/
void
GNUNET_CRYPTO_hash_to_aes_key (const GNUNET_HashCode * hc,
@@ -441,6 +489,7 @@
return (((unsigned char *) code)[bit >> 3] & (1 << (bit & 7))) > 0;
}
+
/**
* Determine how many low order bits match in two
* GNUNET_HashCodes. i.e. - 010011 and 011111 share
@@ -470,6 +519,9 @@
/**
* Compare function for HashCodes, producing a total ordering
* of all hashcodes.
+ *
+ * @param h1 some hash code
+ * @param h2 some hash code
* @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
*/
int
@@ -495,6 +547,10 @@
/**
* Find out which of the two GNUNET_CRYPTO_hash codes is closer to target
* in the XOR metric (Kademlia).
+ *
+ * @param h1 some hash code
+ * @param h2 some hash code
+ * @param target some hash code
* @return -1 if h1 is closer, 1 if h2 is closer and 0 if h1==h2.
*/
int
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