<?php

/**

* Flattens a text file structure.

*

* This function reads a text file, interprets its structure

* (assuming a specific format), and outputs a flattened string.

* Supports older PHP versions.

*

* @param string $filePath The path to the text file.

* @param string $delimiter The delimiter separating key-value pairs.

* @param string $newline The newline character.

* @return string The flattened string.

*/

function flattenTextFile(string $filePath, string $delimiter = '=', string $newline = "\n"): string

{

$flattenedString = '';

if (!file_exists($filePath)) {

return "Error: File not found at $filePath";

}

$file = fopen($filePath, 'r');

if ($file === false) {

return "Error: Could not open file at $filePath";

}

while (($line = fgets($file)) !== false) {

// Trim whitespace

$line = trim($line);

// Skip empty lines and comments

if (empty($line) || strpos($line, '#') === 0) {

continue;

}

// Split the line into key and value

$parts = explode($delimiter, $line, 2);

if (count($parts) === 2) {

$key = trim($parts[0]);

$value = trim($parts[1]);

// Escape special characters in the key for safe output

$key = htmlspecialchars($key);

// Append the flattened key-value pair to the string

$flattenedString .= "$key: $value$newline";

}

}

fclose($file);

return $flattenedString;

}

//Example usage (for testing)

/*

$filePath = 'data.txt'; // Replace with your file path

// Create a sample file for testing

$testData = "name=John Doe\n# This is a comment\nage=30\ncity=New York\nemail=john.doe@example.com";

file_put_contents($filePath, $testData);

$flattenedData = flattenTextFile($filePath);

echo $flattenedData;

//Clean up the test file

unlink($filePath);

*/

?>