PHP - How Is The Loop Algorithm?

Hey all. I am racking my brain trying to figure out the best way to handle a certain process my company needs me to do. First I will give a general description of the issue, then I will get into specifics.

Basically I have a file that contains a bunch of data. The data stored in the file is consistant, each entry has X number of elements with a total character size of Y. Element 1 in each entry will always take up the same amount of characters.

So if I have 2 elements in each data entry, each 5 characters long, then each data entry is 10 characters. Whcih means to access the 2nd element of the 3rd entry I would grab characters 15-20.

I would want to be able to search this data for a number of things. Basically id want to be able to say, "give me all results where element 1 = 'pancakes'. Or where element 2 >8. Or more substaintial searches such as element 1>10 AND element 2<5.

Is there a good way to do this?

My first line of thought would be to run through the file, grabbing every element that can be searched on. So lets say if elements 2 and 4 can be searched on, and I have 10 entries, I would run through and grab an array holding  the values for entry 2 and 4.

array(
 array('index=>0', 'element2'=>10, 'element4'=>12),
 array('index=>1', 'element2'=>11, 'element4'=>-2),
 array('index=>2', 'element2'=>0, 'element4'=>7)
)

Then, depending on the search,  I would reorder the array and search through it. So if I wanted to see if element2 was greater then 8, id reorder by element2 and then search. As if this wasnt difficult enough, the issue would be on complex searches such as 'element1>10 OR (element2=6 AND element3=0)'

I suppose i could store the result array of each individual search result and then merge/union/intersect based on the AND/OR.

To make things ever CRAZIER, the flat files can have other flat files as children. So if I have element1 in file 1 and element1 in file 2, all of file2 data would be part of the corrisponding data in file1.

So, id basically need to be able to "join" files. I have thought of a number of solutions, but im not sure how they will pan out.

Ugh.

In case your wondering WHY I need to do this. My company runs a lot of data off an old database called filepro which uses flat files with index and map files. Right now we have a few systems which weve "synched" with mysql which runs batch updates between the two databases to keep data consistant.

We wont be coming "off" of filepro for a long, long time. But a lot of my php/mysql apps need access to the data on filepro. So, Im trying to find a way to quickly be able to search and pull data from filepro into php. Basically, i want to run search queries on the flat files.

Basically id like your input on a number of things:

Is this even a reasonable attempt?

Is the idea of pulling the searched elements into php to actually run the search, then collecting the correct rows and getting the data directly from them a smart move?

Once I have the searchable elements and index, what algorithms are good for actually running the search?

I'm decoding some strings that were encoded by someone else, I have the key and already made a decoder in C++ and it is working but I want to avoid call "exec".

For now I've tried to use mcrypt_decrypt (mcrypt Version 2.5.8) with all possible options but none gives correct results, compared to the correct c++ .exe results.

I tried to "convert" the function to PHP around 6 times but none worked, I'm sure there is something I'm missing or I don't know about.

This is the working decoder function in c++:
Code: [Select]
void XTEADecode(LPCVOID lpBuffer, int dwSize, DWORD *lpXteaKey) {
    LPDWORD lpPtr = (LPDWORD)lpBuffer;
    int j;
    for(j=0; j<dwSize; j=j+8){
        unsigned long v0=*lpPtr, v1=*(lpPtr+1), i;
        unsigned long delta=0x9E3779B9, sum=delta*32;
        for(i=0; i<32; i++) {
            v1 -= ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + lpXteaKey[sum>>11 & 3]);
            sum -= delta;
            v0 -= ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + lpXteaKey[sum & 3]);
        }
        *lpPtr=v0; *(lpPtr+1)=v1;
        lpPtr+=2;
    }
}
Any suggestions would be appreciated.

I am trying to find a tutorial on how to perform a depth first search. I've seen pseudocodes and sources in other languages, but I just can't implement it in PHP no matter what I try. Can anyone show me how or where I can read up on it or how to do it?

I am trying to write a PHP script that implements the MD5 algorithm just so that I can better understand MD5's inner-workings. For those of you already familiar with how MD5 works, could you help me figure out why my script is not producing the correct output?

<?php
$string = "";

$a = "01100111010001010010001100000001"; // 0x67452301
$b = "11101111110011011010101110001001"; // 0xEFCDAB89
$c = "10011000101110101101110011111110"; // 0x98BADCFE
$d = "00010000001100100101010001110110"; // 0x10325476

$aa = $a;
$bb = $b;
$cc = $c;
$dd = $d;

// PADDED BINARY FOR NULL STRING, I.E.: ""
$binary_md5 = "10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000";
$binary_md5_words = strlen($binary_md5) / 32;

// SPLIT BINARY INTO 16 32-BIT WORDS
for($i = 1; $i <= $binary_md5_words; $i++) {
    $m[] = substr($binary_md5, ($i - 1) * 32, 32);
}

// GENERATE T-VALUES
for($i = 0; $i < 64; $i++) {
    $T[] = Pad(decbin(floor(4294967296 * abs(sin($i+1)))), 32);
}

/*
// PRINT THE M[K] ARRAY
echo "<h1>m[k] Array</h1><br>";
print_r($m);
echo "<br><br>";

// PRINT THE T[t] ARRAY
echo "<h1>T[t] Array</h1><br>";
print_r($T);
echo "<br><br>";

// TEST ANDxy
echo "<h1>Test ANDxy</h1><br>";
echo "$m[0]<br>$T[0]<br>";
echo ANDxy($m[0], $T[0]);
echo "<br><br>";

// TEST ORxy
echo "<h1>Test ORxy</h1><br>";
echo "$m[0]<br>$T[0]<br>";
echo ORxy($m[0], $T[0]);
echo "<br><br>";

// TEST ADDxy
echo "<h1>Test ADDxy</h1><br>";
echo "$m[0]<br>$T[0]<br>";
echo ADDxy($m[0], $T[0]);
echo "<br><br>";

// TEST XORxy
echo "<h1>Test XORxy</h1><br>";
echo "$m[0]<br>$T[0]<br>";
echo XORxy($m[0], $T[0]);
echo "<br><br>";

// TEST NOTx
echo "<h1>Test NOTx</h1><br>";
echo "$m[0]<br>";
echo NOTx($m[0]);
echo "<br><br>";

// TEST SHIFTleft
echo "<h1>Test SHIFTleft</h1><br>";
echo "$m[0]<br>";
echo SHIFTleft($m[0], 1);
echo "<br><br>";

// TEST F
echo "<h1>Test F</h1><br>";
echo "X = $m[0]<br>Y = $m[1]<br>Z = $m[2]<br>F = ";
echo F($m[0], $m[1], $m[2]);
$step1 = ANDxy($m[0], $m[1]);
$step2 = ANDxy(NOTx($m[0]), $m[2]);
$step3 = ORxy($step1, $step2);
echo "<br>F = $step3";
echo "<br><br>";

// TEST H
echo "<h1>Test H</h1><br>";
echo "X = $m[0]<br>Y = $m[1]<br>Z = $m[2]<br>F = ";
echo H($m[0], $m[1], $m[2]);
echo "<br><br>";
*/

// ROUND 1
$a = ff($a, $b, $c, $d, $m, 0, 7, $T[0]);
$d = ff($d, $a, $b, $c, $m, 1, 12, $T[1]);
$c = ff($c, $d, $a, $b, $m, 2, 17, $T[2]);
$b = ff($b, $c, $d, $a, $m, 3, 22, $T[3]);

$a = ff($a, $b, $c, $d, $m, 4, 7, $T[4]);
$d = ff($d, $a, $b, $c, $m, 5, 12, $T[5]);
$c = ff($c, $d, $a, $b, $m, 6, 17, $T[6]);
$b = ff($b, $c, $d, $a, $m, 7, 22, $T[7]);

$a = ff($a, $b, $c, $d, $m, 8, 7, $T[8]);
$d = ff($d, $a, $b, $c, $m, 9, 12, $T[9]);
$c = ff($c, $d, $a, $b, $m, 10, 17, $T[10]);
$b = ff($b, $c, $d, $a, $m, 11, 22, $T[11]);

$a = ff($a, $b, $c, $d, $m, 12, 17, $T[12]);
$d = ff($d, $a, $b, $c, $m, 13, 12, $T[13]);
$c = ff($c, $d, $a, $b, $m, 14, 17, $T[14]);
$b = ff($b, $c, $d, $a, $m, 15, 22, $T[15]);

// ROUND 2
$a = gg($a, $b, $c, $d, $m, 1, 5, $T[16]);
$d = gg($d, $a, $b, $c, $m, 6, 9, $T[17]);
$c = gg($c, $d, $a, $b, $m, 11, 14, $T[18]);
$b = gg($b, $c, $d, $a, $m, 0, 20, $T[19]);

$a = gg($a, $b, $c, $d, $m, 5, 5, $T[20]);
$d = gg($d, $a, $b, $c, $m, 10, 9, $T[21]);
$c = gg($c, $d, $a, $b, $m, 15, 14, $T[22]);
$b = gg($b, $c, $d, $a, $m, 4, 20, $T[23]);

$a = gg($a, $b, $c, $d, $m, 9, 5, $T[24]);
$d = gg($d, $a, $b, $c, $m, 14, 9, $T[25]);
$c = gg($c, $d, $a, $b, $m, 3, 14, $T[26]);
$b = gg($b, $c, $d, $a, $m, 8, 20, $T[27]);

$a = gg($a, $b, $c, $d, $m, 13, 5, $T[28]);
$d = gg($d, $a, $b, $c, $m, 2, 9, $T[29]);
$c = gg($c, $d, $a, $b, $m, 7, 14, $T[30]);
$b = gg($b, $c, $d, $a, $m, 12, 20, $T[31]);

// ROUND 3
$a = hh($a, $b, $c, $d, $m, 5, 4, $T[32]);
$d = hh($d, $a, $b, $c, $m, 8, 11, $T[33]);
$c = hh($c, $d, $a, $b, $m, 11, 16, $T[34]);
$b = hh($b, $c, $d, $a, $m, 14, 23, $T[35]);

$a = hh($a, $b, $c, $d, $m, 1, 4, $T[36]);
$d = hh($d, $a, $b, $c, $m, 4, 11, $T[37]);
$c = hh($c, $d, $a, $b, $m, 7, 16, $T[38]);
$b = hh($b, $c, $d, $a, $m, 10, 23, $T[39]);

$a = hh($a, $b, $c, $d, $m, 13, 4, $T[40]);
$d = hh($d, $a, $b, $c, $m, 0, 11, $T[41]);
$c = hh($c, $d, $a, $b, $m, 3, 16, $T[42]);
$b = hh($b, $c, $d, $a, $m, 6, 23, $T[43]);

$a = hh($a, $b, $c, $d, $m, 9, 4, $T[44]);
$d = hh($d, $a, $b, $c, $m, 12, 11, $T[45]);
$c = hh($c, $d, $a, $b, $m, 15, 16, $T[46]);
$b = hh($b, $c, $d, $a, $m, 2, 23, $T[47]);

// ROUND 4
$a = ii($a, $b, $c, $d, $m, 0, 6, $T[48]);
$d = ii($d, $a, $b, $c, $m, 7, 10, $T[49]);
$c = ii($c, $d, $a, $b, $m, 14, 15, $T[50]);
$b = ii($b, $c, $d, $a, $m, 5, 21, $T[51]);

$a = ii($a, $b, $c, $d, $m, 12, 6, $T[52]);
$d = ii($d, $a, $b, $c, $m, 3, 10, $T[53]);
$c = ii($c, $d, $a, $b, $m, 10, 15, $T[54]);
$b = ii($b, $c, $d, $a, $m, 1, 21, $T[55]);

$a = ii($a, $b, $c, $d, $m, 8, 6, $T[56]);
$d = ii($d, $a, $b, $c, $m, 15, 10, $T[57]);
$c = ii($c, $d, $a, $b, $m, 6, 15, $T[58]);
$b = ii($b, $c, $d, $a, $m, 13, 21, $T[59]);

$a = ii($a, $b, $c, $d, $m, 4, 6, $T[60]);
$d = ii($d, $a, $b, $c, $m, 11, 10, $T[61]);
$c = ii($c, $d, $a, $b, $m, 2, 15, $T[62]);
$b = ii($b, $c, $d, $a, $m, 9, 21, $T[63]);

$a = ADDxy($a, $aa);
$b = ADDxy($b, $bb);
$c = ADDxy($c, $cc);
$d = ADDxy($d, $dd);

// ECHO RESULTS
echo "<h1>String</h1><br>";
echo "String: '$string'<br>";
$md5 = md5($string);
echo "MD5: $md5<br><br>";
$md5_1 = substr($md5, 0, 8);
$md5_2 = substr($md5, 8, 8);
$md5_3 = substr($md5, 16, 8);
$md5_4 = substr($md5, 24, 8);
echo "A = $md5_1<br>B = $md5_2<br>C = $md5_3<br>D = $md5_4<br><br>";
$md5_bin_a = Pad(decbin(hexdec($md5_1)), 32); 
$md5_bin_b = Pad(decbin(hexdec($md5_2)), 32); 
$md5_bin_c = Pad(decbin(hexdec($md5_3)), 32); 
$md5_bin_d = Pad(decbin(hexdec($md5_4)), 32); 
echo "A = $md5_bin_a<br>B = $md5_bin_b<br>C = $md5_bin_c<br>D = $md5_bin_d<br><br>";
echo "<h1>Results</h1><br>";
echo "A = $a<br>B = $b<br>C = $c<br>D = $d<br><br>";
$a_dec = bindec($a);
$b_dec = bindec($b);
$c_dec = bindec($c);
$d_dec = bindec($d);
$a_hex = dechex($a_dec);
$b_hex = dechex($b_dec);
$c_hex = dechex($c_dec);
$d_hex = dechex($d_dec);
echo "A = $a_hex<br>B = $b_hex<br>C = $c_hex<br>D = $d_hex<br><br>";

// FUNCTIONS
function ff($a, $b, $c, $d, $m, $k, $s, $t) {
    //a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s)
    return ADDxy($b, SHIFTleft(ADDxy(ADDxy(ADDxy($a, F($b, $c, $d)), $m[$k]), $t), $s));
}

function gg($a, $b, $c, $d, $m, $k, $s, $t) {
    //a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s)
    return ADDxy($b, SHIFTleft(ADDxy(ADDxy(ADDxy($a, G($b, $c, $d)), $m[$k]), $t), $s));
}

function hh($a, $b, $c, $d, $m, $k, $s, $t) {
    //a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s)
    return ADDxy($b, SHIFTleft(ADDxy(ADDxy(ADDxy($a, H($b, $c, $d)), $m[$k]), $t), $s));
}

function ii($a, $b, $c, $d, $m, $k, $s, $t) {
    //a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s)
    return ADDxy($b, SHIFTleft(ADDxy(ADDxy(ADDxy($a, I($b, $c, $d)), $m[$k]), $t), $s));
}

function F($X, $Y, $Z) {
    //return ($X & $Y) | ((~$X) & $Z);
    return ORxy(ANDxy($X, $Y), ANDxy(NOTx($X), $Z));
}

function G($X, $Y, $Z) {
    //return ($X & $Z) | ($Y & (~$Z));
    return ORxy(ANDxy($X, $Z), ANDxy($Y, NOTx($Z)));
}

function H($X, $Y, $Z) {
    //return $X ^ $Y ^ $Z;
    return XORxy(XORxy($X, $Y), $Z);
}

function I($X, $Y, $Z) {
    //return $Y ^ ($X | (~$Z));
    return XORxy($Y, ORxy($X, NOTx($Z)));
}

function Pad($binary, $pad_length) {
    $pad_length = $pad_length - strlen($binary);
    for($i = 0; $i < $pad_length; $i++) {
        $padding .= '0';
    }
    return $padding . $binary;
}

function mod($val, $div) {
    $r = $val - (floor($val/$div)*$div);
    return $r;
}
function ANDxy($x, $y) {
    $x_dec = bindec($x);
    $y_dec = bindec($y);
    
    $result = $x_dec & $y_dec;
    $result = Pad(decbin($result), strlen($x));
    
    return $result;   
}

function ORxy($x, $y) {
    $x_dec = bindec($x);
    $y_dec = bindec($y);
    
    $result = $x_dec | $y_dec;
    $result = Pad(decbin($result), strlen($x));
    
    return $result;   
}

function ADDxy($x, $y) {
    $x_dec = bindec($x);
    $y_dec = bindec($y);
    
    $result = mod($x_dec + $y_dec, pow(2, 32));
    $result = Pad(decbin($result), strlen($x));
    
    return $result;   
}

function XORxy($x, $y) {
    $x_dec = bindec($x);
    $y_dec = bindec($y);
    
    $result = $x_dec ^ $y_dec;
    $result = Pad(decbin($result), strlen($x));
    
    return $result;   
}

function NOTx($x) {
    $x_dec = bindec($x);
    
    $result = ~$x_dec;
    $result = Pad(decbin($result), strlen($x));
    
    return $result;
}

function SHIFTleft($x, $y) {
    $x_dec = bindec($x);
    
    $result = $x_dec << $y;
    $result = Pad(decbin($result), strlen($x));
    
    return $result;   
}

function SHIFTright($x, $y) {
    $x_dec = bindec($x);
    
    $result = $x_dec >> $y;
    $result = Pad(decbin($result), strlen($x));
    
    return $result;   
}
?>

Alright, so I have 100 user ids which I need sorted in a very specific way. Right now, they're organized in a 1-100 format. Let's think of each ID as ID#1, ID#2, ID#3 etc all the way up to ID#100. I need to code a script to echo them out in the following order:
$ID2.'<br/>';
$ID1.'<br/>';
$ID4.'<br/>';
$ID3.'<br/>';
$ID6.'<br/>';
$ID5.'<br/>';
//etc up to
$ID100.'<br/>';
$ID99.'<br/>';

Is there any special algorithm or trick with an array to do this? I will attach a file with each ID seperated by a semi-colon. And also here is the script I have right now which echo's them out in order:
<?PHP
$File = "IDs.txt";
$Login = file($File);
$String = file_get_contents($File);
$Logins = explode(";", $String);
foreach($Logins as $Login)

{

echo $Login.'<br/>';

}
?>