<?php
/*
Self-programming client-side value converter script.
Define the conversions you need in simple PHP data structures,
and this script will generate the webpage and JavaScript for you.

Author: Peter R. Bloomfield (webmaster (at) avid-insight.co.uk)

This script is released under the terms of the GNU GPL v3.
This is provided as-is, under no warranty of any kind.

I cannot guarantee the accuracy of the conversion formulae!
Please feel free to contact me if you spot a mistake though.

*****

INSTRUCTIONS:

In the section which indicates "ADD YOUR CONVERTERS HERE", you define first of all a category of conversion
(such as 'Temperature' or 'Distance'). You then define the conversions which take place within that category.
NOTE: you MUST specify ALL conversions manually. Don't miss any out! (Maybe I'll change this in future).

The format is like this:

$categories['categoryname']->conversion['type1']['type2'] = "formula";

That defines a conversion from type1 to type2.
The category and type names must each be SINGLE WORDS, letters only. (You can include numbers too, but only if the number isn't the first character).

The formula should be expressed in terms of $str_inval.
For example, if your conversion from type1 to type2 needs you to double the input, then your formula would look like this:

"{$str_inval} * 2"

The $str_inval variable contains the name of the JavaScript variable which will appear later on.


Simple as that! Ok, so it's not *actually* all that simple, but it works. :-)
You can use my examples to get started with, and make your own.

*/

// Uncomment this for debugging:
//ini_set('display_errors', '1'); error_reporting(2047);

/// DO NOT CHANGE THIS BIT ///
// These variables will store the names of our input and output value variables
$str_inval = 'inval';
$str_outval = 'outval';
$categories = array();

// Define the strings for our temperature conversion
define('STR_TEMP', 'Temperature');
define('STR_TEMP_C', 'Celsius');
define('STR_TEMP_K', 'Kelvin');
define('STR_TEMP_F', 'Fahrenheit');


/// ADD YOUR CONVERTERS HERE ///

/// Temperature
// Define our temperature conversions from Celsius
$categories[STR_TEMP]->conversion[STR_TEMP_C][STR_TEMP_K] = "{$str_inval} + 273.15";
$categories[STR_TEMP]->conversion[STR_TEMP_C][STR_TEMP_F] = "({$str_inval} * (9.0 / 5.0)) + 32.0";
// Define our temperature conversions from Kelvin
$categories[STR_TEMP]->conversion[STR_TEMP_K][STR_TEMP_C] = "{$str_inval} - 273.15";
$categories[STR_TEMP]->conversion[STR_TEMP_K][STR_TEMP_F] = "({$str_inval} * (9.0 / 5.0)) - 459.67";
// Define our temperature conversions from Fahrenheit
$categories[STR_TEMP]->conversion[STR_TEMP_F][STR_TEMP_C] = "({$str_inval} - 32.0) * (5.0 / 9.0)";
$categories[STR_TEMP]->conversion[STR_TEMP_F][STR_TEMP_K] = "({$str_inval} + 459.67) * (5.0 / 9.0)";


/// Distance
// Define the strings for our distance conversion
define('STR_DIST', 'Distance');
define('STR_DIST_CM', 'Centimetres');
define('STR_DIST_IN', 'Inches');
define('STR_DIST_FT', 'Feet');
define('STR_DIST_KM', 'Kilometres');
define('STR_DIST_MT', 'Metres');
define('STR_DIST_MI', 'Miles');
define('STR_DIST_MM', 'Millimetres');
define('STR_DIST_YD', 'Yards');

// Define our distance conversions from Centimetres
$categories[STR_DIST]->conversion[STR_DIST_CM][STR_DIST_IN] = "{$str_inval} / 2.54";
$categories[STR_DIST]->conversion[STR_DIST_CM][STR_DIST_FT] = "{$str_inval} * 0.0328083";
$categories[STR_DIST]->conversion[STR_DIST_CM][STR_DIST_KM] = "{$str_inval} / 100000.0";
$categories[STR_DIST]->conversion[STR_DIST_CM][STR_DIST_MT] = "{$str_inval} / 100.0";
$categories[STR_DIST]->conversion[STR_DIST_CM][STR_DIST_MI] = "{$str_inval} / 160934.4";
$categories[STR_DIST]->conversion[STR_DIST_CM][STR_DIST_MM] = "{$str_inval} * 10.0";
$categories[STR_DIST]->conversion[STR_DIST_CM][STR_DIST_YD] = "{$str_inval} * 0.0109361";

// Define our distance conversions from Inches
$categories[STR_DIST]->conversion[STR_DIST_IN][STR_DIST_CM] = "{$str_inval} * 2.54";
$categories[STR_DIST]->conversion[STR_DIST_IN][STR_DIST_FT] = "{$str_inval} / 12.0";
$categories[STR_DIST]->conversion[STR_DIST_IN][STR_DIST_KM] = "{$str_inval} * 0.0000254";
$categories[STR_DIST]->conversion[STR_DIST_IN][STR_DIST_MT] = "{$str_inval} * 0.0254";
$categories[STR_DIST]->conversion[STR_DIST_IN][STR_DIST_MI] = "{$str_inval} / 63360";
$categories[STR_DIST]->conversion[STR_DIST_IN][STR_DIST_MM] = "{$str_inval} * 25.4";
$categories[STR_DIST]->conversion[STR_DIST_IN][STR_DIST_YD] = "{$str_inval} / 36.0";

// Define our distance conversions from Feet
$categories[STR_DIST]->conversion[STR_DIST_FT][STR_DIST_CM] = "{$str_inval} / 0.0328083";
$categories[STR_DIST]->conversion[STR_DIST_FT][STR_DIST_IN] = "{$str_inval} * 12.0";
$categories[STR_DIST]->conversion[STR_DIST_FT][STR_DIST_KM] = "{$str_inval} / 3280.83";
$categories[STR_DIST]->conversion[STR_DIST_FT][STR_DIST_MT] = "{$str_inval} / 3.28083";
$categories[STR_DIST]->conversion[STR_DIST_FT][STR_DIST_MI] = "{$str_inval} / 5280";
$categories[STR_DIST]->conversion[STR_DIST_FT][STR_DIST_MM] = "{$str_inval} / 0.00328083";
$categories[STR_DIST]->conversion[STR_DIST_FT][STR_DIST_YD] = "{$str_inval} / 3.0";

// Define our distance conversions from Kilometres
$categories[STR_DIST]->conversion[STR_DIST_KM][STR_DIST_CM] = "{$str_inval} * 100000.0";
$categories[STR_DIST]->conversion[STR_DIST_KM][STR_DIST_IN] = "{$str_inval} / 0.0000254";
$categories[STR_DIST]->conversion[STR_DIST_KM][STR_DIST_FT] = "{$str_inval} * 3280.83";
$categories[STR_DIST]->conversion[STR_DIST_KM][STR_DIST_MT] = "{$str_inval} * 1000.0";
$categories[STR_DIST]->conversion[STR_DIST_KM][STR_DIST_MI] = "{$str_inval} / 1.609344";
$categories[STR_DIST]->conversion[STR_DIST_KM][STR_DIST_MM] = "{$str_inval} * 1000000.0";
$categories[STR_DIST]->conversion[STR_DIST_KM][STR_DIST_YD] = "{$str_inval}";

// Define our distance conversions from Metres
$categories[STR_DIST]->conversion[STR_DIST_MT][STR_DIST_CM] = "{$str_inval} * 100.0";
$categories[STR_DIST]->conversion[STR_DIST_MT][STR_DIST_IN] = "{$str_inval} * 39.37";
$categories[STR_DIST]->conversion[STR_DIST_MT][STR_DIST_FT] = "{$str_inval} * 3.28083";
$categories[STR_DIST]->conversion[STR_DIST_MT][STR_DIST_KM] = "{$str_inval} / 1000.0";
$categories[STR_DIST]->conversion[STR_DIST_MT][STR_DIST_MI] = "{$str_inval} / 1609.344";
$categories[STR_DIST]->conversion[STR_DIST_MT][STR_DIST_MM] = "{$str_inval} * 1000.0";
$categories[STR_DIST]->conversion[STR_DIST_MT][STR_DIST_YD] = "{$str_inval} * 1.09361";

// Define our distance conversions from Miles
$categories[STR_DIST]->conversion[STR_DIST_MI][STR_DIST_CM] = "{$str_inval} * 160934.4";
$categories[STR_DIST]->conversion[STR_DIST_MI][STR_DIST_IN] = "{$str_inval} * 63360";
$categories[STR_DIST]->conversion[STR_DIST_MI][STR_DIST_FT] = "{$str_inval} * 5280";
$categories[STR_DIST]->conversion[STR_DIST_MI][STR_DIST_KM] = "{$str_inval} * 1.609344";
$categories[STR_DIST]->conversion[STR_DIST_MI][STR_DIST_MT] = "{$str_inval} * 1609.344";
$categories[STR_DIST]->conversion[STR_DIST_MI][STR_DIST_MM] = "{$str_inval} * 1609344.0";
$categories[STR_DIST]->conversion[STR_DIST_MI][STR_DIST_YD] = "{$str_inval} * 1760";

// Define our distance conversions from Millimetres
$categories[STR_DIST]->conversion[STR_DIST_MM][STR_DIST_CM] = "{$str_inval} / 10.0";
$categories[STR_DIST]->conversion[STR_DIST_MM][STR_DIST_IN] = "{$str_inval} * 0.03937";
$categories[STR_DIST]->conversion[STR_DIST_MM][STR_DIST_FT] = "{$str_inval} * 0.00328083";
$categories[STR_DIST]->conversion[STR_DIST_MM][STR_DIST_KM] = "{$str_inval} / 1000000.0";
$categories[STR_DIST]->conversion[STR_DIST_MM][STR_DIST_MT] = "{$str_inval} / 1000.0";
$categories[STR_DIST]->conversion[STR_DIST_MM][STR_DIST_MI] = "{$str_inval} / 1609344.0";
$categories[STR_DIST]->conversion[STR_DIST_MM][STR_DIST_YD] = "{$str_inval} * 0.00109361";

// Define our distance conversions from Yards
$categories[STR_DIST]->conversion[STR_DIST_YD][STR_DIST_CM] = "{$str_inval} / 109.361";
$categories[STR_DIST]->conversion[STR_DIST_YD][STR_DIST_IN] = "{$str_inval} * 36.0";
$categories[STR_DIST]->conversion[STR_DIST_YD][STR_DIST_FT] = "{$str_inval} * 3.0";
$categories[STR_DIST]->conversion[STR_DIST_YD][STR_DIST_KM] = "{$str_inval} / 0.00109361";
$categories[STR_DIST]->conversion[STR_DIST_YD][STR_DIST_MT] = "{$str_inval} / 1.09361";
$categories[STR_DIST]->conversion[STR_DIST_YD][STR_DIST_MI] = "{$str_inval} / 1760";
$categories[STR_DIST]->conversion[STR_DIST_YD][STR_DIST_MM] = "{$str_inval} / 1093.61";


/// Time
// Define the strings for our time conversion
define('STR_TIME', 'Time');
define('STR_TIME_S', 'Seconds');
define('STR_TIME_M', 'Minutes');
define('STR_TIME_H', 'Hours');
define('STR_TIME_D', 'Days');
define('STR_TIME_W', 'Weeks');

// Define our distance conversions from Seconds
$categories[STR_TIME]->conversion[STR_TIME_S][STR_TIME_M] = "{$str_inval} / 60.0";
$categories[STR_TIME]->conversion[STR_TIME_S][STR_TIME_H] = "{$str_inval} / 3600.0";
$categories[STR_TIME]->conversion[STR_TIME_S][STR_TIME_D] = "{$str_inval} / 86400.0";
$categories[STR_TIME]->conversion[STR_TIME_S][STR_TIME_W] = "{$str_inval} / 604800.0";

// Define our distance conversions from Minutes
$categories[STR_TIME]->conversion[STR_TIME_M][STR_TIME_S] = "{$str_inval} * 60.0";
$categories[STR_TIME]->conversion[STR_TIME_M][STR_TIME_H] = "{$str_inval} / 60.0";
$categories[STR_TIME]->conversion[STR_TIME_M][STR_TIME_D] = "{$str_inval} / 1440.0";
$categories[STR_TIME]->conversion[STR_TIME_M][STR_TIME_W] = "{$str_inval} / 10080.0";

// Define our distance conversions from Hours
$categories[STR_TIME]->conversion[STR_TIME_H][STR_TIME_S] = "{$str_inval} * 3600.0";
$categories[STR_TIME]->conversion[STR_TIME_H][STR_TIME_M] = "{$str_inval} * 60.0";
$categories[STR_TIME]->conversion[STR_TIME_H][STR_TIME_D] = "{$str_inval} / 24.0";
$categories[STR_TIME]->conversion[STR_TIME_H][STR_TIME_M] = "{$str_inval} / 168.0";

// Define our distance conversions from Days
$categories[STR_TIME]->conversion[STR_TIME_D][STR_TIME_S] = "{$str_inval} * 86400.0";
$categories[STR_TIME]->conversion[STR_TIME_D][STR_TIME_M] = "{$str_inval} * 1440.0";
$categories[STR_TIME]->conversion[STR_TIME_D][STR_TIME_H] = "{$str_inval} * 24.0";
$categories[STR_TIME]->conversion[STR_TIME_D][STR_TIME_W] = "{$str_inval} / 7.0";

// Define our distance conversions from Weeks
$categories[STR_TIME]->conversion[STR_TIME_W][STR_TIME_S] = "{$str_inval} * 604800.0";
$categories[STR_TIME]->conversion[STR_TIME_W][STR_TIME_M] = "{$str_inval} * 10080.0";
$categories[STR_TIME]->conversion[STR_TIME_W][STR_TIME_H] = "{$str_inval} * 168.0";
$categories[STR_TIME]->conversion[STR_TIME_W][STR_TIME_D] = "{$str_inval} * 7.0";


/// END CONVERTERS ///


?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"  dir="ltr" lang="en-US">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Avid Insight - Converters</title>

<script type="text/javascript">

<?php
// Go through each category of conversion
foreach ($categories as $catname => $cat) {
    // Output the header of the function
    echo "function convert_{$catname}()\n{\n";
    
    // Get all the form elements
    ?>
    var elem_input_value;
    var elem_output_value;
    var elem_input_type;
    var elem_output_type;
    try {
        elem_input_value = document.getElementById('<?php echo "{$catname}_input"; ?>');
        elem_output_value = document.getElementById('<?php echo "{$catname}_output"; ?>');
        elem_input_type = document.getElementById('<?php echo "{$catname}_input_type"; ?>');
        elem_output_type = document.getElementById('<?php echo "{$catname}_output_type"; ?>');
    } catch (e) {
        alert("Failed to locate form elements.");
        return;
    }
    
    var <?php echo $str_inval; ?> = parseFloat(elem_input_value.value);
    var <?php echo $str_outval; ?> = 0.0;

    switch (elem_input_type.value) {
        <?php
        // Go through each input type available to us
        foreach ($cat->conversion as $srctypename => $conversions) {
            echo "      case \"{$srctypename}\":\n";
            echo "      switch (elem_output_type.value) {\n";
            
            // Add a conversion to self if necessary
            if (!isset($conversions[$srctypename])) echo "          case \"{$srctypename}\": {$str_outval} = {$str_inval}; break\n";
                        
            // Go through each destination type
            foreach ($conversions as $desttypename => $formula) {
                echo "          case \"{$desttypename}\": {$str_outval} = {$formula}; break;\n";
            }
            
            echo "          default:\n";
            echo "          alert(\"Unrecognised conversion requested: \" + elem_input_type.value + \" -> \" + elem_input_type.value);\n";
            echo "          break;\n";
            
            echo "      }\n";
            echo "      break;\n\n";
        }
        ?>
        
        default:
            alert("Unrecognised input type: " + elem_input_type.value);
            break;
    }
    
    <?php
    // Function is finished
    echo "  elem_output_value.value = {$str_outval};\n";
    echo "}\n\n";
}
?>

</script>

</head>
<body>

<?php
foreach ($categories as $catname => $cat) {
    // Pre-construct the units options for a selection box
    $str_unitsoptions = '';
    foreach ($cat->conversion as $srctypename => $conversions) {
        $str_unitsoptions .= "          <option value=\"{$srctypename}\">{$srctypename}</option>\n";
    }
    
    // Output the form elements for this category
    echo <<<XXXEODXXX
<form action="" method="get" onsubmit="return false;">
    <fieldset>
        <h3>{$catname}</h3>
        
        <label for="{$catname}_input">&nbsp;&nbsp;Input: </label>
        <input type="text" name="{$catname}_input" id="{$catname}_input" value="0.0" size="16" maxlength="24" />
        <select name="{$catname}_input_type" id="{$catname}_input_type" size="1">
{$str_unitsoptions}
        </select>
        
        <br/>
        
        <label for="{$catname}_output">Output: </label>
        <input type="text" name="{$catname}_output" id="{$catname}_output" value="" size="16" maxlength="14" readonly="readonly" />
        <select name="{$catname}_output_type" id="{$catname}_output_type" size="1">
{$str_unitsoptions}
        </select>
        
        <br/>
        
        <input type="submit" value="Convert" onclick="convert_{$catname}();" />
        
    </fieldset>
</form>
<br/>

XXXEODXXX;
}
?>

</body>
</html>