Adding a JSON string formatter to the JsonFile class

src/Composer/Json/JsonFormatter.php

@@ -0,0 +1,88 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Json;
+
+/**
+ * Format JSON output
+ *
+ * @author Justin Rainbow <justin.rainbow@gmail.com>
+ */
+class JsonFormatter
+{
+	private $indent = '    ';
+
+	private $level = 1;
+
+	/**
+	 * Indents a flat JSON string to make it more human-readable
+	 *
+	 * Original code for this function can be found at:
+	 *  http://recursive-design.com/blog/2008/03/11/format-json-with-php/
+	 *
+	 * @param string $json The original JSON string to process
+	 * @return string Indented version of the original JSON string
+	 */
+	public function format($json)
+	{
+		if (!is_string($json)) {
+			$json = json_encode($json);
+		}
+
+		$result = '';
+		$pos = 0;
+		$strLen = strlen($json);
+		$indentStr = $this->indent;
+		$newLine = "\n";
+		$prevChar = '';
+		$outOfQuotes = true;
+
+		for ($i = 0; $i <= $strLen; $i++) {
+			// Grab the next character in the string
+			$char = substr($json, $i, 1);
+
+			// Are we inside a quoted string?
+			if ($char == '"' && $prevChar != '\\') {
+				$outOfQuotes = !$outOfQuotes;
+			} else if (($char == '}' || $char == ']') && $outOfQuotes) {
+				// If this character is the end of an element,
+				// output a new line and indent the next line
+				$result .= $newLine;
+				$pos --;
+				for ($j=0; $j<$pos; $j++) {
+					$result .= $indentStr;
+				}
+			}
+
+			// Add the character to the result string
+			$result .= $char;
+
+			// If the last character was the beginning of an element,
+			// output a new line and indent the next line
+			if (($char == ',' || $char == '{' || $char == '[') && $outOfQuotes) {
+				$result .= $newLine;
+
+				if ($char == '{' || $char == '[') {
+					$pos ++;
+				}
+
+				for ($j = 0; $j < $pos; $j++) {
+					$result .= $indentStr;
+				}
+			}
+
+			$prevChar = $char;
+		}
+
+		return $result;
+	}
+}