From a3f391f5923305b5a612b329e4fef26bb3db0d6b Mon Sep 17 00:00:00 2001
From: Roland Haeder <roland@mxchange.org>
Date: Sat, 21 Mar 2015 21:58:26 +0100
Subject: [PATCH] Commented added switch to MHASH_SHA256 + 5-times hashing and
 some other improvements.
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

Signed-off-by: Roland Häder <roland@mxchange.org>
---
 contrib/chash/chash.php | 49 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 45 insertions(+), 4 deletions(-)

diff --git a/contrib/chash/chash.php b/contrib/chash/chash.php
index 408b4660..c37216ab 100644
--- a/contrib/chash/chash.php
+++ b/contrib/chash/chash.php
@@ -4,14 +4,24 @@ error_reporting(E_ALL | E_STRICT);
 define('START_TIME'            , microtime(TRUE));
 define('CHECK_POINT'           , 'chash.pos');
 
+// Hashes needed to complete a "block"
 $GLOBALS['block_size']          = 100;
 $GLOBALS['none_increment']      = (1 / pow(10, 20));
-$GLOBALS['hash_algo']           = MHASH_RIPEMD320;
+
+// Hashing algorythm
+$GLOBALS['hash_algo']           = MHASH_SHA256;
+
+// Automatic saving interval in seconds
 $GLOBALS['flush_file_time']     = 30;
+
+/*
+ * How long (in seconds) to try to find a proper hash until the best root hash
+ * is taken.
+ */
 $GLOBALS['restart_search_time'] = 1800;
 
 // Hashes per call
-$GLOBALS['hash_cycles'] = 3;
+$GLOBALS['hash_cycles'] = 5;
 
 // Total restarts
 $GLOBALS['total_restarts'] = 0;
@@ -73,6 +83,9 @@ function modulaHash ($hash1, $hash2) {
 	// Both must have same length
 	assert(strlen($hash1) === strlen($hash2));
 
+	// Init propability array with 256 zeros
+	$propability = array_fill(0, 256, 0);
+
 	// Init new hash
 	$modulaHash = '';
 
@@ -85,6 +98,9 @@ function modulaHash ($hash1, $hash2) {
 		$part1 = hexdec(substr($hash1, $idx, 2));
 		$part2 = hexdec(substr($hash2, $idx, 2));
 
+		// Debug message
+		//* NOISY-DEBUG: */ print 'part1=' . $part1 . ',part2=' . $part2 . PHP_EOL;
+
 		/*
 		 * If part1 is larget part2, part1 is divident and vise-versa. But don't do it
 		 * if one is zero
@@ -92,18 +108,43 @@ function modulaHash ($hash1, $hash2) {
 		if (($part1 > $part2) && ($part2 > 0)) {
 			// 'part1' is larger than 'part2'
 			$mod = $part1 % $part2;
-		} elseif (($part1 < $part2) && ($part1 > 0)) {
+		} elseif (($part2 > $part1) && ($part1 > 0)) {
 			// 'part2' is larger than 'part1'
 			$mod = $part2 % $part1;
 		}
 
-		// "Invert" the result against 255
+		// $mod is now mostly a small number so try to "improve" it
+		//* NOISY-DEBUG: */ print 'mod[' . gettype($mod) . ']=' . $mod . ' - BEFORE!' . PHP_EOL;
+		$mod = (int) round(sqrt($mod * ($part1 + $part2 + $mod ^ 7) / 3));
+		//* NOISY-DEBUG: */ print 'mod[' . gettype($mod) . ']=' . $mod . ' - AFTER!' . PHP_EOL;
+
+		// Make sure it is valid
+		assert($mod >= 0);
+		assert($mod <= 255);
+
+		// "Invert" the result against 255 as zeros are not good for later calculations
 		$mod = 255 - $mod;
 
+		// Add it to propability array for debugging
+		$propability[$mod]++;
+
 		// Encode to hex, pre-pad it with zeros and add to new hash
 		$modulaHash .= padHex($mod);
 	} // END - for
 
+	// Debug propability array
+	$cnt = 0;
+	foreach ($propability as $value) {
+		// Is the value larger than one, means the number has been found at least once?
+		if ($value > 0) {
+			// Then count it
+			$cnt++;
+		} // END - if
+	} // END - foreach
+
+	// Debug message
+	//* NOISY-DEBUG: */ print('cnt=' . $cnt . '/' . strlen($hash1) / 2 . PHP_EOL);
+
 	// Modula hash must have same length as input hash
 	assert(strlen($modulaHash) === strlen($hash1));
 
-- 
2.30.2