Commented added switch to MHASH_SHA256 + 5-times hashing and some other improvements.

[core.git] / contrib / chash / chash.php

diff --git a/contrib/chash/chash.php b/contrib/chash/chash.php
index 408b4660e553b50152a6044df95e8ed0f7acac4a..c37216ab3bb3826443e2a9ae03496c2da1db9cef 100644 (file)
--- 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));