[Resolved] Getting full name based on part

[webchef]

I have a problem with turning a page number into a full file name.

i have many pdf files that im trying to access... they are named as follows:

1_14.pdf
33_46.pdf
101_106.pdf
107_100.pdf
329_326.pdf
451_460.pdf

(always odd number, followed by underscore, followed by even number)

What happens is that i get a returned value that is a page number, such as 1, or 101, or 46, or 460. and using that value i want to get the full file name..

if the value is 101 then i want to get "101_106.pdf" into a string.

how can i go about doing this, taking into consideration odd and even numbers?

[laserlight]

hmm... basically

<pdf_filename> ::= <odd>_<even>.pdf
Given <odd> or <even>, obtain <pdf_filename>

Are the numbers guaranteed to be unique?
What is the signficance of the numbers?

[webchef]

the numbers are unique...

the pdf's were generated from eps's that were used to make a print A-Z map book.

basically, each pdf or file is an A3 spread. the book was printed in sections, 8 A3 sheets, back to front, that total 32 pages.

so for example

101_106.pdf has map page 101 and map page 106. they are named this way because odd numbers or odd pages are always on the left and even pages are on the right...

this is all for a flash/php/mysql CD based version of the A-Z map book. Its just in the test phases now, and i need to be able to open the pdf, and then zoom into the appropriate grid the user selected..

[laserlight]

hmm... perhaps try:

assume $dir is name of directory containing the pdf files
assume $page is page number returned

<?php
//let's see if $page is odd
$odd_flag = $page & 1;

$dh = opendir($dir)
	OR die("Directory '" . $dir . "' could not be opened!");
//loop through the listing of $dir
while (($file = readdir($dh)) !== false) {
	//let's see if this is a file or a directory
	if (is_file($file)) {
		//ok, we're dealing with a file
		if ($odd_flag) {
			//$page should precede the underscore
			if (preg_match('/' . $page . '\\_[02468]+\\.pdf/', $file)) {
				break;
			}
		} else {
			//$page should follow the underscore
			if (preg_match('/[13579]+\\_' . $page . '\\.pdf/', $file)) {
				break;
			}
		}
	}
}
closedir($dh);
//now if $file !== false, then $file contains the filename required
?>

[webchef]

thanks for the help!

i'll look over your code (looks tight!) and implement it as best i can...

thanks again..

mike

[Installer]

never mind

[webchef]

hey laserlight,

thaks for the code again.. but im having trouble with it.. it seems as though the variable $file is never being given a value. i can't work out why not...

here is my complete script:

<?php

// Function to determin left margin based on chosen grid
function left_margin ($getLeft) {
	switch ($getLeft) {
		case A:
			$left = 29.2;
			break;
		case B:
			$left = 113.2 + 29.2;
			break;
		case C:
			$left = (113.2 * 2) + 29.2;
			break;
		case D:
			$left = (113.2 * 3) + 29.2;
			break;
		case E:
			$left = (113.2 * 4) + 29.2;
			break;
		case F:
			$left = (113.2 * 5) + 29.2;
			break;
		case G:
			$left = (113.2 * 6) + 29.2;
			break;
		case H:
			$left = (113.2 * 7) + 29.2;
			break;
		case I:
			$left = (113.2 * 8) + 29.2;
			break;
		case J:
			$left = (113.2 * 9) + 29.2;
			break;
	}
	return $left;
}

// Function to determine top margin based on chosen grid
function top_margin ($getTop) {
	switch ($getTop) {
		case 1:
			$top = 23.6;
			break;
		case 2:
			$top = 113.2 + 23.6;
			break;
		case 3:
			$top = (113.2 * 2) + 23.6;
			break;
		case 4:
			$top = (113.2 * 3) + 23.6;
			break;
		case 5:
			$top = (113.2 * 4) + 23.6;
			break;
		case 6:
			$top = (113.2 * 5) + 23.6;
			break;
		case 7:
			$top = (113.2 * 6) + 23.6;
			break;
	}
	return $top;
}

//Connection information
$dbhost = "localhost";
$dbuser = "administrator";
$dbpass = "admin";
$dbname = "bahrainlocator";

// Connect to MySql
$connect = mysql_connect($dbhost, $dbuser, $dbpass)
	or die("Unable to connect to MySql");

// Connect to Database
$db = mysql_select_db($dbname, $connect)
	or die("Unable to connect to Database");

// SQL to retrieve pdf zoom location
$sql = "SELECT * FROM roads WHERE road = '$thisRoad'";

// Get sql result
$result = mysql_query($sql)
	or die("Unable to Road data");

while ($row = mysql_fetch_assoc($result)) {
  $road = $row['road'];
  $page = $row['start page'];
  $grid = $row['start grid'];
}

// Get Top and left margins based on returned $grid. i.e.: A-4
$left = left_margin ($grid[0]);
$top = top_margin ($grid[2]);

// Let's see if $page is odd
$odd_flag = $page & 1;

// Set location of pdf's and then open directory
$dir = "pdf";
$dh = opendir($dir)
	OR die("Directory '" . $dir . "' could not be opened!");

// Loop through the listing of $dir
while (($file = readdir($dh)) !== false) {
    // Let's see if this is a file or a directory
    if (is_file($file)) {
        // Check if $page is even or odd
        if ($odd_flag) {
            // $page should precede the underscore
            if (preg_match('/' . $page . '\_[02468]+\.pdf/', $file)) {
                $rString = "&link=".$file."#viewrect=".$left.",".$top.",113.2,113.2";
                echo "check 1 <br>";
            }
        } else {
            //$page should follow the underscore
            if (preg_match('/[13579]+\_' . $page . '\.pdf/', $file)) {
                $rString = "&link=".$file."#viewrect=".$left.",".$top.",113.2,113.2";	                
                echo "check 2 <br>";
            }
        }
    } else {
    	echo "NO GO! <br>";
    }
}
// Close the directory
closedir($dh);

// Send link back to flash
echo $rString."&";
// Check a few variables
echo "
	<br> page: $page 
	<br>grid: $top -- $left 
	<br> odd: $odd_flag 
	<br> file: $file 
	<br> road: $thisRoad
";

?>

the variable $thisRoad is obtained from the URL. The result i get is an empty rString (except for the ampersand at the very end) and one line of "no go!" for ever pdf file in the directory plus 2 more lines of "no go!" for some odd reason.

does the preg_match snippet where it says: [13579]+ actually allow more than one character on its side of the underscore? like wouldn't the above just find 1 characgter page numbers such 1_5.pdf. or 3_9. pdf?

thanks in advance for you help