PDO_SQLSRV wrapper for legacy MSSQL PHP database functions

mssql_helper.php

<?php

if (! extension_loaded('mssql') && extension_loaded('pdo_sqlsrv')) {
	//Return an associative array. Used on mssql_fetch_array()'s result_type parameter.
	define('MSSQL_ASSOC', '1');

	//Return an array with numeric keys. Used on mssql_fetch_array()'s result_type parameter.
	define('MSSQL_NUM', '2');

	//Return an array with both numeric keys and keys with their field name. This is the default value for mssql_fetch_array()'s result_type parameter.
	define('MSSQL_BOTH', '3');

	//Indicates the 'TEXT' type in MSSQL, used by mssql_bind()'s type parameter.
	define('SQLTEXT', '35');

	//Indicates the 'VARCHAR' type in MSSQL, used by mssql_bind()'s type parameter.
	define('SQLVARCHAR', '39');

	//Indicates the 'CHAR' type in MSSQL, used by mssql_bind()'s type parameter.
	define('SQLCHAR', '47');

	//Represents one byte, with a range of -128 to 127.
	define('SQLINT1', '48');

	//Represents two bytes, with a range of -32768 to 32767.
	define('SQLINT2', '52');

	//Represents four bytes, with a range of -2147483648 to 2147483647.
	define('SQLINT4', '56');

	//Indicates the 'BIT' type in MSSQL, used by mssql_bind()'s type parameter.
	define('SQLBIT', '50');

	//Represents an four byte float.
	define('SQLFLT4', '59');

	//Represents an eight byte float.
	define('SQLFLT8', '62');

	class MSSQL_PDO extends PDO {
		public function __construct($dsn, $username="", $password="", $driver_options=array()) {
			parent::__construct($dsn,$username,$password, $driver_options);
			if (empty($driver_options[PDO::ATTR_STATEMENT_CLASS])) {
				$this->setAttribute(PDO::ATTR_STATEMENT_CLASS, array('MSSQL_PDOStatement', array($this)));
			}
		}
	}
	class MSSQL_PDOStatement extends PDOStatement {
		//public $_all = null;
		public $dbh;
		protected function __construct($dbh) {
			$this->dbh = $dbh;
		}

	}

	function mssql_last_link($link_identifier = null) {
		static $last = null;
		if ($link_identifier) {
			$last = $link_identifier;
		}
		return $last;
	}

	function mssql_bind($stmt, $param_name, &$var, $type, $is_output = false, $is_null = false, $maxlen = -1) {
		$mssql_type_map = array(
				SQLTEXT => PDO::PARAM_LOB,
				SQLVARCHAR => PDO::PARAM_STR,
				SQLCHAR => PDO::PARAM_STR,
				SQLINT1 => PDO::PARAM_INT,
				SQLINT2 => PDO::PARAM_INT,
				SQLINT4 => PDO::PARAM_INT,
				SQLBIT =>  PDO::PARAM_BOOL,
				SQLFLT4 => PDO::PARAM_INT,
				SQLFLT8 => PDO::PARAM_INT,
		);
		$var = $is_null?null:$var;
		$ret = $stmt->bindParam($param_name, $var, $mssql_type_map[$type], $is_output?$maxlen:($maxlen<0?null:$maxlen));
		return $ret;
	}


	function mssql_close() {

	}

	function mssql_connect($servername, $username, $password, $new_link = false) {
		$pdo = new MSSQL_PDO('sqlsrv:Server='.$servername, $username, $password);
		$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
				$pdo->setAttribute(PDO::ATTR_STATEMENT_CLASS, array('MSSQL_PDOStatement', array($pdo)));
		mssql_last_link($pdo);

		return $pdo;
	}

	function mssql_pconnect($servername, $username, $password, $new_link = false) {
		$pdo = mssql_connect($servername, $username, $password, $new_link);

		// @todo this may not work except at connection time.
		// this wont work in fast-cgi or pdo_sqlsrv in anycase.
		// left here as a woulda-shoulda-cant
		//$pdo->setAttribute(PDO::ATTR_PERSISTENT, true);
		return $pdo;
	}

	function mssql_execute($stmt, $skip_results = false) {
		return $stmt->execute();
	}


	function mssql_fetch_array($result, $result_type = MSSQL_BOTH) {
		$mssql_result_type = array(
				MSSQL_ASSOC => PDO::FETCH_ASSOC,
				MSSQL_NUM =>PDO::FETCH_NUM,
				MSSQL_BOTH => PDO::FETCH_BOTH
		);
		return $result->fetch($mssql_result_type[$result_type]);
	}

	function mssql_fetch_assoc($result) {
		return $result->fetch(PDO::FETCH_ASSOC);
	}

	function mssql_fetch_object($result) {
		return $result->fetch(PDO::FETCH_OBJ);
	}

	function mssql_fetch_row($result) {
		return $result->fetch();
	}

	function mssql_free_result($result) {
		return $stmt->closeCursor();
	}

	function mssql_free_statement($stmt) {
		return $stmt->closeCursor();
	}

	function mssql_get_last_message() {
		$link_identifier = mssql_last_link();

		$errors = $link_identifier->errorInfo();
		return $errors[2];
	}

	function mssql_init($sp_name, $link_identifier = null) {
		if (is_null($link_identifier)) {
			$link_identifier = mssql_last_link();
		}

		return $link_identifier->prepare('exec '.$sp_name);

	}

	function mssql_next_result($result_id) {
		return $result_id->nextRowset();
	}

	function mssql_num_fields($result) {
		return $result->columnCount();
	}

	function mssql_num_rows($result) {
		return $result->rowCount();
	}

	function mssql_query($query, $link_identifier = null, $batch_size = 0) {
		if (is_null($link_identifier)) {
			$link_identifier = mssql_last_link();
		}

		// $stmt = $link_identifier->query($query);
		$driver_options = array(
				PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL,
				PDO::SQLSRV_ATTR_CURSOR_SCROLL_TYPE => PDO::SQLSRV_CURSOR_BUFFERED
		);
		$stmt = $link_identifier->prepare($query, $driver_options);
		$return = $stmt->execute();

		// Match mssql_query behavior
		if ($return) {
			$rows = $stmt->rowCount();
			$link_identifier->lastAffected = $rows;

			if (is_null($rows)) {
				$return = true;
			} else {
				$return = $stmt;
			}
		}
		return $return;

	}

	function mssql_data_seek($result_identifier, $row_number) {
		/*
		if (is_null($result_identifier->_all)) {
			$result_identifier->_all = $result_identifier->fetchAll(PDO::FETCH_BOTH);
		}
		$row = $result_identifier->_all[$row_number];
		*/
		$row = $result_identifier->fetch(PDO::FETCH_BOTH, PDO::FETCH_ORI_ABS, $row_number);

		// Rewind - CI always does a data_seek(0) as a rewind, but that offsets the cursor,
		// we have to move to -1 so the next fetch will return the first piece of data
		// @todo rather than resetting, it would be better to restore the old position
		// if we can't fetch that data somehow then track the position in the statement class
		$row = $result_identifier->fetch(PDO::FETCH_BOTH, PDO::FETCH_ORI_ABS, -1);

		return $row;
	}

	function mssql_result($resource, $row, $field) {
		$data_row = mssql_data_seek($resource, $row);
		return $data_row[$field];
	}


	function mssql_rows_affected($link_identifier = null) {
		if (is_null($link_identifier)) {
			$link_identifier = mssql_last_link();
		}
		return 	$link_identifier->lastAffected;

	}

	// @todo try/catch return false on failure
	function mssql_select_db($database_name, $link_identifier = null) {
		if (is_null($link_identifier)) {
			$link_identifier = mssql_last_link();
		}
		$affected = $link_identifier->exec('USE '.$database_name);
		$link_identifier->lastAffected = $affected;

		return true;
	}
}

@christracey @vwmoose
I've moved this code to https://github.com/displague/mssql_helper - feel free to open issues or PRs against it. I don't have PHP or MSSQL running anywhere (haven't in years), so you may also feel free to fork the project and keep your changes in forks.