/************************************************

  pg.c -

  Author: matz 
  created at: Tue May 13 20:07:35 JST 1997

  Author: ematsu
  modified at: Wed Jan 20 16:41:51 1999

  $Author: jdavis $
  $Date: 2008-10-05 12:43:27 -0700 (Sun, 05 Oct 2008) $
************************************************/

#include "pg.h"

#define rb_define_singleton_alias(klass,new,old) rb_define_alias(rb_singleton_class(klass),new,old)

static VALUE rb_cPGconn;
static VALUE rb_cPGresult;
static VALUE rb_ePGError;

/* The following functions are part of libpq, but not
 * available from ruby-pg, because they are deprecated,
 * obsolete, or generally not useful:
 *
 * * PQfreemem -- unnecessary: copied to ruby object, then
 *                freed. Ruby object's memory is freed when
 *                it is garbage collected.
 * * PQbinaryTuples -- better to use PQfformat
 * * PQprint -- not very useful
 * * PQsetdb -- not very useful
 * * PQoidStatus -- deprecated, use PQoidValue
 * * PQrequestCancel -- deprecated, use PQcancel
 * * PQfn -- use a prepared statement instead
 * * PQgetline -- deprecated, use PQgetCopyData
 * * PQgetlineAsync -- deprecated, use PQgetCopyData
 * * PQputline -- deprecated, use PQputCopyData
 * * PQputnbytes -- deprecated, use PQputCopyData
 * * PQendcopy -- deprecated, use PQputCopyEnd
 */

/***************************************************************************
 * UTILITY FUNCTIONS
 **************************************************************************/

static void free_pgconn(PGconn *);
static void pgresult_check(VALUE, VALUE);

static PGconn *get_pgconn(VALUE self);
static VALUE pgconn_finish(VALUE self);
static VALUE pgresult_clear(VALUE self);
static VALUE pgresult_aref(VALUE self, VALUE index);

static PQnoticeReceiver default_notice_receiver = NULL;
static PQnoticeProcessor default_notice_processor = NULL;

/*
 * Used to quote the values passed in a Hash to PGconn.init
 * when building the connection string.
 */
static VALUE
pgconn_s_quote_connstr(VALUE string)
{
	char *str,*ptr;
	int i,j=0,len;
	VALUE result;

	Check_Type(string, T_STRING);

	ptr = RSTRING_PTR(string);
	len = RSTRING_LEN(string);
	str = ALLOC_N(char, len * 2 + 2 + 1);
	str[j++] = '\'';
	for(i = 0; i < len; i++) {
		if(ptr[i] == '\'' || ptr[i] == '\\')
			str[j++] = '\\';
		str[j++] = ptr[i];	
	}
	str[j++] = '\'';
	result = rb_str_new(str, j);
	free(str);
	return result;
}

static char *
value_as_cstring(VALUE in_str)
{
	VALUE rstring = rb_obj_as_string(in_str);
	return StringValuePtr(rstring);
}

static void
free_pgconn(PGconn *conn)
{
	if(conn != NULL)
		PQfinish(conn);
}

static void
free_pgresult(PGresult *result)
{
	if(result != NULL)
		PQclear(result);
}

static PGconn*
get_pgconn(VALUE self)
{
	PGconn *conn;
	Data_Get_Struct(self, PGconn, conn);
	if (conn == NULL) rb_raise(rb_ePGError, "not connected");
	return conn;
}

static PGresult*
get_pgresult(VALUE self)
{
	PGresult *result;
	Data_Get_Struct(self, PGresult, result);
	if (result == NULL) rb_raise(rb_ePGError, "result has been cleared");
	return result;
}

static VALUE
new_pgresult(PGresult *result)
{
	return Data_Wrap_Struct(rb_cPGresult, NULL, free_pgresult, result);
}

/*
 * Raises appropriate exception if PGresult is
 * in a bad state.
 */
static void
pgresult_check(VALUE rb_pgconn, VALUE rb_pgresult)
{
	VALUE error;
	PGconn *conn = get_pgconn(rb_pgconn);
	PGresult *result;
	Data_Get_Struct(rb_pgresult, PGresult, result);

	if(result == NULL)
	{
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
	}
	else
	{
		switch (PQresultStatus(result))
		{
		case PGRES_TUPLES_OK:
		case PGRES_COPY_OUT:
		case PGRES_COPY_IN:
		case PGRES_EMPTY_QUERY:
		case PGRES_COMMAND_OK:
			return;
		case PGRES_BAD_RESPONSE:
		case PGRES_FATAL_ERROR:
		case PGRES_NONFATAL_ERROR:
			error = rb_exc_new2(rb_ePGError, PQresultErrorMessage(result));
			break;
		default:
			error = rb_exc_new2(rb_ePGError,
				"internal error : unknown result status.");
		}
	}

	rb_iv_set(error, "@connection", rb_pgconn);
	rb_iv_set(error, "@result", rb_pgresult);
	rb_exc_raise(error);
	return;
}

static VALUE
yield_pgresult(VALUE rb_pgresult)
{
	int i;
	PGresult *result = get_pgresult(rb_pgresult);
	for(i = 0; i < PQntuples(result); i++) {
		return rb_yield(pgresult_aref(rb_pgresult, INT2NUM(i)));
	}
	return Qnil;
}

static void
notice_receiver_proxy(void *arg, const PGresult *result)
{
	VALUE proc;
	VALUE self = (VALUE)arg;

	if ((proc = rb_iv_get(self, "@notice_receiver")) != Qnil) {
		rb_funcall(proc, rb_intern("call"), 1, 
			Data_Wrap_Struct(rb_cPGresult, NULL, NULL, (PGresult*)result));
	}
	return;
}

static void
notice_processor_proxy(void *arg, const char *message)
{
	VALUE proc;
	VALUE self = (VALUE)arg;

	if ((proc = rb_iv_get(self, "@notice_processor")) != Qnil) {
		rb_funcall(proc, rb_intern("call"), 1, rb_tainted_str_new2(message));
	}
	return;
}

/*
 * Appends key='val' to conninfo_rstr
 */
static void
build_key_value_string(VALUE conninfo_rstr, char *key, VALUE val)
{
	if(val != Qnil) {
		if(RSTRING_LEN(conninfo_rstr) > 0)
			rb_str_cat2(conninfo_rstr, " ");
		rb_str_cat2(conninfo_rstr, key);
		rb_str_cat2(conninfo_rstr, "=");
		rb_str_concat(conninfo_rstr, 
			pgconn_s_quote_connstr(rb_obj_as_string(val)));
	}
	return;
}

static VALUE
parse_connect_args(int argc, VALUE *argv, VALUE self)
{
	VALUE args,arg;
	PGconn *conn = NULL;
	VALUE conninfo_rstr = rb_str_new("",0);
	VALUE error;
	char *host, *port, *opt, *tty, *dbname, *login, *pwd;
	host=port=opt=tty=dbname=login=pwd=NULL;

	rb_scan_args(argc, argv, "0*", &args); 
	if (RARRAY_LEN(args) == 1) { 
		arg = rb_ary_entry(args,0);
		if(TYPE(arg) == T_HASH) {
			build_key_value_string(conninfo_rstr, "host", 
				rb_hash_aref(arg, ID2SYM(rb_intern("host"))));
			build_key_value_string(conninfo_rstr, "hostaddr", 
				rb_hash_aref(arg, ID2SYM(rb_intern("hostaddr"))));
			build_key_value_string(conninfo_rstr, "port", 
				rb_hash_aref(arg, ID2SYM(rb_intern("port"))));
			build_key_value_string(conninfo_rstr, "dbname", 
				rb_hash_aref(arg, ID2SYM(rb_intern("dbname"))));
			build_key_value_string(conninfo_rstr, "user", 
				rb_hash_aref(arg, ID2SYM(rb_intern("user"))));
			build_key_value_string(conninfo_rstr, "password", 
				rb_hash_aref(arg, ID2SYM(rb_intern("password"))));
			build_key_value_string(conninfo_rstr, "connect_timeout", 
				rb_hash_aref(arg, ID2SYM(rb_intern("connect_timeout"))));
			build_key_value_string(conninfo_rstr, "options", 
				rb_hash_aref(arg, ID2SYM(rb_intern("options"))));
			build_key_value_string(conninfo_rstr, "tty", 
				rb_hash_aref(arg, ID2SYM(rb_intern("tty"))));
			build_key_value_string(conninfo_rstr, "sslmode", 
				rb_hash_aref(arg, ID2SYM(rb_intern("sslmode"))));
			build_key_value_string(conninfo_rstr, "krbsrvname", 
				rb_hash_aref(arg, ID2SYM(rb_intern("krbsrvname"))));
			build_key_value_string(conninfo_rstr, "gsslib", 
				rb_hash_aref(arg, ID2SYM(rb_intern("gsslib"))));
			build_key_value_string(conninfo_rstr, "service", 
				rb_hash_aref(arg, ID2SYM(rb_intern("service"))));
		}
		else if(TYPE(arg) == T_STRING) {
			conninfo_rstr = arg;
		}
		else {
			rb_raise(rb_eArgError, 
				"Expecting String or Hash as single argument");
		}
	}
	else if (RARRAY_LEN(args) == 7) {
		build_key_value_string(conninfo_rstr, "host", rb_ary_entry(args,0));
		build_key_value_string(conninfo_rstr, "port", rb_ary_entry(args,1));
		build_key_value_string(conninfo_rstr, "options", rb_ary_entry(args,2));
		build_key_value_string(conninfo_rstr, "tty", rb_ary_entry(args,3));
		build_key_value_string(conninfo_rstr, "dbname", rb_ary_entry(args,4));
		build_key_value_string(conninfo_rstr, "user", rb_ary_entry(args,5));
		build_key_value_string(conninfo_rstr, "password", rb_ary_entry(args,6));
	}
	else {
		rb_raise(rb_eArgError, 
			"Expected connection info string, hash, or 7 separate arguments.");
	}

	return conninfo_rstr;
}

/********************************************************************
 *
 * Document-class: PGError
 *
 * This is the exception class raised when an error is returned from
 * a libpq API call.
 * 
 * The attributes +connection+ and +result+ are set to the connection
 * object and result set object, respectively.
 *
 * If the connection object or result set object is not available from
 * the context in which the error was encountered, it is +nil+.
 */

/********************************************************************
 * 
 * Document-class: PGconn
 *
 * The class to access PostgreSQL RDBMS, based on the libpq interface, 
 * provides convenient OO methods to interact with PostgreSQL.
 *
 * For example, to send query to the database on the localhost:
 *    require 'pg'
 *    conn = PGconn.open(:dbname => 'test')
 *    res = conn.exec('SELECT $1 AS a, $2 AS b, $3 AS c',[1, 2, nil])
 *    # Equivalent to:
 *    #  res  = conn.exec('SELECT 1 AS a, 2 AS b, NULL AS c')
 *
 * See the PGresult class for information on working with the results of a query.
 *
 */

static VALUE
pgconn_alloc(VALUE klass)
{
	return Data_Wrap_Struct(klass, NULL, free_pgconn, NULL);
}

/**************************************************************************
 * PGconn SINGLETON METHODS
 **************************************************************************/

/*
 * Document-method: new
 *
 * call-seq:
 *    PGconn.new(connection_hash) -> PGconn
 *    PGconn.new(connection_string) -> PGconn
 *    PGconn.new(host, port, options, tty, dbname, login, password) ->  PGconn
 *
 * * +host+ - server hostname
 * * +hostaddr+ - server address (avoids hostname lookup, overrides +host+)
 * * +port+ - server port number
 * * +dbname+ - connecting database name
 * * +user+ - login user name
 * * +password+ - login password
 * * +connect_timeout+ - maximum time to wait for connection to succeed
 * * +options+ - backend options
 * * +tty+ - (ignored in newer versions of PostgreSQL)
 * * +sslmode+ - (disable|allow|prefer|require)
 * * +krbsrvname+ - kerberos service name
 * * +gsslib+ - GSS library to use for GSSAPI authentication
 * * +service+ - service name to use for additional parameters
 *
 * _connection_hash_ example: +PGconn.connect(:dbname=>'test', :port=>5432)
 * _connection_string_ example: +PGconn.connect("dbname=test port=5432")
 * _connection_hash_ example: +PGconn.connect(nil,5432,nil,nil,'test',nil,nil)
 *  
 *  On failure, it raises a PGError exception.
 */
static VALUE
pgconn_init(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = NULL;
	VALUE conninfo;
	VALUE error;

	conninfo = parse_connect_args(argc, argv, self);
	conn = PQconnectdb(StringValuePtr(conninfo));

	if(conn == NULL)
		rb_raise(rb_ePGError, "PQconnectStart() unable to allocate structure");
	if (PQstatus(conn) == CONNECTION_BAD) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}

	Check_Type(self, T_DATA);
	DATA_PTR(self) = conn;
	
	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, self, pgconn_finish, self);
	}
	return self;
}

/*
 * call-seq:
 *    PGconn.connect_start(connection_hash) -> PGconn
 *    PGconn.connect_start(connection_string) -> PGconn
 *    PGconn.connect_start(host, port, options, tty, dbname, login, password) ->  PGconn
 *
 * This is an asynchronous version of PGconn.connect().
 *
 * Use PGconn#connect_poll to poll the status of the connection.
 */
static VALUE
pgconn_s_connect_start(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = NULL;
	VALUE rb_conn;
	VALUE conninfo;
	VALUE error;

	/*
	 * PGconn.connect_start must act as both alloc() and initialize()
	 * because it is not invoked by calling new().
	 */
	rb_conn = pgconn_alloc(rb_cPGconn);

	conninfo = parse_connect_args(argc, argv, self);
	conn = PQconnectdb(StringValuePtr(conninfo));

	if(conn == NULL)
		rb_raise(rb_ePGError, "PQconnectStart() unable to allocate structure");
	if (PQstatus(conn) == CONNECTION_BAD) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}

	Check_Type(rb_conn, T_DATA);
	DATA_PTR(rb_conn) = conn;

	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, self, pgconn_finish, self);
	}
	return rb_conn;
}

/*
 * call-seq:
 *    PGconn.conndefaults() -> Array
 *
 * Returns an array of hashes. Each hash has the keys:
 * * +:keyword+ - the name of the option
 * * +:envvar+ - the environment variable to fall back to
 * * +:compiled+ - the compiled in option as a secondary fallback
 * * +:val+ - the option's current value, or +nil+ if not known
 * * +:label+ - the label for the field
 * * +:dispchar+ - "" for normal, "D" for debug, and "*" for password
 * * +:dispsize+ - field size
 */
static VALUE
pgconn_s_conndefaults(VALUE self)
{
	PQconninfoOption *options = PQconndefaults();
	VALUE ary = rb_ary_new();
	VALUE hash;
	int i = 0;
	
	for(i = 0; options[i].keyword != NULL; i++) {
		hash = rb_hash_new();
		if(options[i].keyword)
			rb_hash_aset(hash, ID2SYM(rb_intern("keyword")), 
				rb_str_new2(options[i].keyword));
		if(options[i].envvar)
			rb_hash_aset(hash, ID2SYM(rb_intern("envvar")), 
				rb_str_new2(options[i].envvar));
		if(options[i].compiled)
			rb_hash_aset(hash, ID2SYM(rb_intern("compiled")), 
				rb_str_new2(options[i].compiled));
		if(options[i].val)
			rb_hash_aset(hash, ID2SYM(rb_intern("val")), 
				rb_str_new2(options[i].val));
		if(options[i].label)
			rb_hash_aset(hash, ID2SYM(rb_intern("label")), 
				rb_str_new2(options[i].label));
		if(options[i].dispchar)
			rb_hash_aset(hash, ID2SYM(rb_intern("dispchar")), 
				rb_str_new2(options[i].dispchar));
		rb_hash_aset(hash, ID2SYM(rb_intern("dispsize")), 
			INT2NUM(options[i].dispsize));
		rb_ary_push(ary, hash);
	}
	PQconninfoFree(options);
	return ary;
}


/*
 * call-seq:
 *    PGconn.encrypt_password( password, username ) -> String
 *
 * This function is intended to be used by client applications that
 * send commands like: +ALTER USER joe PASSWORD 'pwd'+.
 * The arguments are the cleartext password, and the SQL name 
 * of the user it is for.
 *
 * Return value is the encrypted password.
 */
static VALUE
pgconn_s_encrypt_password(VALUE self, VALUE password, VALUE username)
{
	char *ret;
	Check_Type(password, T_STRING);
	Check_Type(username, T_STRING);
	ret = PQencryptPassword(StringValuePtr(password),
		StringValuePtr(username));
	return rb_tainted_str_new2(ret);
}

/*
 * call-seq:
 *    PGconn.isthreadsafe() -> Boolean
 *
 * Returns +true+ if libpq is thread safe, +false+ otherwise.
 */
static VALUE
pgconn_s_isthreadsafe(VALUE self)
{
	return PQisthreadsafe() ? Qtrue : Qfalse;
}

/**************************************************************************
 * PGconn INSTANCE METHODS
 **************************************************************************/

/*
 * call-seq:
 *    conn.connect_poll() -> Fixnum
 *
 * Returns one of:
 * * +PGRES_POLLING_READING+ - wait until the socket is ready to read
 * * +PGRES_POLLING_WRITING+ - wait until the socket is ready to write
 * * +PGRES_POLLING_FAILED+ - the asynchronous connection has failed
 * * +PGRES_POLLING_OK+ - the asynchronous connection is ready
 *
 * Example:
 *   conn = PGconn.connect_start("dbname=mydatabase")
 *   socket = IO.for_fd(conn.socket)
 *   status = conn.connect_poll
 *   while(status != PGconn::PGRES_POLLING_OK) do
 *     # do some work while waiting for the connection to complete
 *     if(status == PGconn::PGRES_POLLING_READING)
 *       if(not select([socket], [], [], 10.0))
 *         raise "Asynchronous connection timed out!"
 *       end
 *     elsif(status == PGconn::PGRES_POLLING_WRITING)
 *       if(not select([], [socket], [], 10.0))
 *         raise "Asynchronous connection timed out!"
 *       end
 *     end
 *     status = conn.connect_poll
 *   end
 *   # now conn.status == CONNECTION_OK, and connection
 *   # is ready.
 */
static VALUE
pgconn_connect_poll(VALUE self)
{
	PostgresPollingStatusType status;
	status = PQconnectPoll(get_pgconn(self));
	return INT2FIX((int)status);
}

/*
 * call-seq:
 *    conn.finish()
 *
 * Closes the backend connection.
 */
static VALUE
pgconn_finish(VALUE self)
{
	PQfinish(get_pgconn(self));
	DATA_PTR(self) = NULL;
	return Qnil;
}

/*
 * call-seq:
 *    conn.reset()
 *
 * Resets the backend connection. This method closes the 
 * backend connection and tries to re-connect.
 */
static VALUE
pgconn_reset(VALUE self)
{
	PQreset(get_pgconn(self));
	return self;
}

/*
 * call-seq:
 *    conn.reset_start() -> nil
 *
 * Initiate a connection reset in a nonblocking manner.
 * This will close the current connection and attempt to
 * reconnect using the same connection parameters.
 * Use PGconn#reset_poll to check the status of the 
 * connection reset.
 */
static VALUE
pgconn_reset_start(VALUE self)
{
	if(PQresetStart(get_pgconn(self)) == 0)
		rb_raise(rb_ePGError, "reset has failed");
	return Qnil;
}

/*
 * call-seq:
 *    conn.reset_poll -> Fixnum
 *
 * Checks the status of a connection reset operation.
 * See PGconn#connect_start and PGconn#connect_poll for
 * usage information and return values.
 */
static VALUE
pgconn_reset_poll(VALUE self)
{
	PostgresPollingStatusType status;
	status = PQresetPoll(get_pgconn(self));
	return INT2FIX((int)status);
}

/*
 * call-seq:
 *    conn.db()
 *
 * Returns the connected database name.
 */
static VALUE
pgconn_db(VALUE self)
{
	char *db = PQdb(get_pgconn(self));
	if (!db) return Qnil;
	return rb_tainted_str_new2(db);
}

/*
 * call-seq:
 *    conn.user()
 *
 * Returns the authenticated user name.
 */
static VALUE
pgconn_user(VALUE self)
{
	char *user = PQuser(get_pgconn(self));
	if (!user) return Qnil;
	return rb_tainted_str_new2(user);
}

/*
 * call-seq:
 *    conn.pass()
 *
 * Returns the authenticated user name.
 */
static VALUE
pgconn_pass(VALUE self)
{
	char *user = PQpass(get_pgconn(self));
	if (!user) return Qnil;
	return rb_tainted_str_new2(user);
}

/*
 * call-seq:
 *    conn.host()
 *
 * Returns the connected server name.
 */
static VALUE
pgconn_host(VALUE self)
{
	char *host = PQhost(get_pgconn(self));
	if (!host) return Qnil;
	return rb_tainted_str_new2(host);
}

/*
 * call-seq:
 *    conn.port()
 *
 * Returns the connected server port number.
 */
static VALUE
pgconn_port(VALUE self)
{
	char* port = PQport(get_pgconn(self));
	return INT2NUM(atol(port));
}

/*
 * call-seq:
 *    conn.tty()
 *
 * Returns the connected pgtty. (Obsolete)
 */
static VALUE
pgconn_tty(VALUE self)
{
	char *tty = PQtty(get_pgconn(self));
	if (!tty) return Qnil;
	return rb_tainted_str_new2(tty);
}

/*
 * call-seq:
 *    conn.options()
 *
 * Returns backend option string.
 */
static VALUE
pgconn_options(VALUE self)
{
	char *options = PQoptions(get_pgconn(self));
	if (!options) return Qnil;
	return rb_tainted_str_new2(options);
}

/*
 * call-seq:
 *    conn.status()
 *
 * Returns status of connection : CONNECTION_OK or CONNECTION_BAD
 */
static VALUE
pgconn_status(VALUE self)
{
	return INT2NUM(PQstatus(get_pgconn(self)));
}

/*
 * call-seq:
 *    conn.transaction_status()
 *
 * returns one of the following statuses:
 *   PQTRANS_IDLE    = 0 (connection idle)
 *   PQTRANS_ACTIVE  = 1 (command in progress)
 *   PQTRANS_INTRANS = 2 (idle, within transaction block)
 *   PQTRANS_INERROR = 3 (idle, within failed transaction)
 *   PQTRANS_UNKNOWN = 4 (cannot determine status)
 */
static VALUE
pgconn_transaction_status(VALUE self)
{
	return INT2NUM(PQtransactionStatus(get_pgconn(self)));
}

/*
 * call-seq:
 *    conn.parameter_status( param_name ) -> String
 *
 * Returns the setting of parameter _param_name_, where
 * _param_name_ is one of
 * * +server_version+
 * * +server_encoding+
 * * +client_encoding+ 
 * * +is_superuser+
 * * +session_authorization+
 * * +DateStyle+
 * * +TimeZone+
 * * +integer_datetimes+
 * * +standard_conforming_strings+
 * 
 * Returns nil if the value of the parameter is not known.
 */
static VALUE
pgconn_parameter_status(VALUE self, VALUE param_name)
{
	const char *ret = PQparameterStatus(get_pgconn(self), 
			StringValuePtr(param_name));
	if(ret == NULL)
		return Qnil;
	else
		return rb_tainted_str_new2(ret);
}

/*
 * call-seq:
 *  conn.protocol_version -> Integer
 *
 * The 3.0 protocol will normally be used when communicating with PostgreSQL 7.4 
 * or later servers; pre-7.4 servers support only protocol 2.0. (Protocol 1.0 is 
 * obsolete and not supported by libpq.)
 */
static VALUE
pgconn_protocol_version(VALUE self)
{
	return INT2NUM(PQprotocolVersion(get_pgconn(self)));
}

/*
 * call-seq:
 *   conn.server_version -> Integer
 *
 * The number is formed by converting the major, minor, and revision numbers into two-decimal-digit numbers and appending them together. For example, version 7.4.2 will be returned as 70402, and version 8.1 will be returned as 80100 (leading zeroes are not shown). Zero is returned if the connection is bad.
 */
static VALUE
pgconn_server_version(VALUE self)
{
	return INT2NUM(PQserverVersion(get_pgconn(self)));
}

/*
 * call-seq:
 *    conn.error() -> String
 *
 * Returns the error message about connection.
 */
static VALUE
pgconn_error_message(VALUE self)
{
	char *error = PQerrorMessage(get_pgconn(self));
	if (!error) return Qnil;
	return rb_tainted_str_new2(error);
}

/*
 * call-seq:
 *    conn.socket() -> Fixnum
 *
 * Returns the socket's file descriptor for this connection.
 */
static VALUE
pgconn_socket(VALUE self)
{
	int sd;
	if( (sd = PQsocket(get_pgconn(self))) < 0)
		rb_raise(rb_ePGError, "Can't get socket descriptor");
	return INT2NUM(sd);
}


/*
 * call-seq:
 *    conn.backend_pid() -> Fixnum
 *
 * Returns the process ID of the backend server
 * process for this connection.
 * Note that this is a PID on database server host.
 */
static VALUE
pgconn_backend_pid(VALUE self)
{
	return INT2NUM(PQbackendPID(get_pgconn(self)));
}

/*
 * call-seq:
 *    conn.connection_needs_password() -> Boolean
 *
 * Returns +true+ if the authentication method required a
 * password, but none was available. +false+ otherwise.
 */
static VALUE
pgconn_connection_needs_password(VALUE self)
{
	return PQconnectionNeedsPassword(get_pgconn(self)) ? Qtrue : Qfalse;
}

/*
 * call-seq:
 *    conn.connection_used_password() -> Boolean
 *
 * Returns +true+ if the authentication method used
 * a caller-supplied password, +false+ otherwise.
 */
static VALUE
pgconn_connection_used_password(VALUE self)
{
	return PQconnectionUsedPassword(get_pgconn(self)) ? Qtrue : Qfalse;
}


//TODO get_ssl


/*
 * call-seq:
 *    conn.exec(sql [, params, result_format ] ) -> PGresult
 *
 * Sends SQL query request specified by _sql_ to PostgreSQL.
 * Returns a PGresult instance on success.
 * On failure, it raises a PGError exception.
 *
 * +params+ is an optional array of the bind parameters for the SQL query.
 * Each element of the +params+ array may be either:
 *   a hash of the form:
 *     {:value  => String (value of bind parameter)
 *      :type   => Fixnum (oid of type of bind parameter)
 *      :format => Fixnum (0 for text, 1 for binary)
 *     }
 *   or, it may be a String. If it is a string, that is equivalent to the hash:
 *     { :value => <string value>, :type => 0, :format => 0 }
 * 
 * PostgreSQL bind parameters are represented as $1, $1, $2, etc.,
 * inside the SQL query. The 0th element of the +params+ array is bound
 * to $1, the 1st element is bound to $2, etc. +nil+ is treated as +NULL+.
 * 
 * If the types are not specified, they will be inferred by PostgreSQL.
 * Instead of specifying type oids, it's recommended to simply add
 * explicit casts in the query to ensure that the right type is used.
 *
 * For example: "SELECT $1::int"
 *
 * The optional +result_format+ should be 0 for text results, 1
 * for binary.
 */
static VALUE
pgconn_exec(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE command, params, in_res_fmt;
	VALUE param, param_type, param_value, param_format;
	VALUE param_value_tmp;
	VALUE sym_type, sym_value, sym_format;
	VALUE gc_array;
	int i=0;
	int nParams;
	Oid *paramTypes;
	char ** paramValues;
	int *paramLengths;
	int *paramFormats;
	int resultFormat;

	rb_scan_args(argc, argv, "12", &command, &params, &in_res_fmt);

	Check_Type(command, T_STRING);

	/* If called with no parameters, use PQexec */
	if(NIL_P(params)) {
		result = PQexec(conn, StringValuePtr(command));
		rb_pgresult = new_pgresult(result);
		pgresult_check(self, rb_pgresult);
		if (rb_block_given_p()) {
			return rb_ensure(yield_pgresult, rb_pgresult, 
				pgresult_clear, rb_pgresult);
		}
		return rb_pgresult;
	}

	/* If called with parameters, and optionally result_format,
	 * use PQexecParams
	 */
	Check_Type(params, T_ARRAY);

	if(NIL_P(in_res_fmt)) {
		resultFormat = 0;
	}
	else {
		resultFormat = NUM2INT(in_res_fmt);
	}

	gc_array = rb_ary_new();
	rb_gc_register_address(&gc_array);
	sym_type = ID2SYM(rb_intern("type"));
	sym_value = ID2SYM(rb_intern("value"));
	sym_format = ID2SYM(rb_intern("format"));
	nParams = RARRAY(params)->len;
	paramTypes = ALLOC_N(Oid, nParams); 
	paramValues = ALLOC_N(char *, nParams);
	paramLengths = ALLOC_N(int, nParams);
	paramFormats = ALLOC_N(int, nParams);
	for(i = 0; i < nParams; i++) {
		param = rb_ary_entry(params, i);
		if (TYPE(param) == T_HASH) {
			param_type = rb_hash_aref(param, sym_type);
			param_value_tmp = rb_hash_aref(param, sym_value);
			if(param_value_tmp == Qnil)
				param_value = param_value_tmp;
			else
				param_value = rb_obj_as_string(param_value_tmp);
			param_format = rb_hash_aref(param, sym_format);
		}
		else {
			param_type = Qnil;
			if(param == Qnil)
				param_value = param;
			else
				param_value = rb_obj_as_string(param);
			param_format = Qnil;
		}

		if(param_type == Qnil)
			paramTypes[i] = 0;
		else
			paramTypes[i] = NUM2INT(param_type);

		if(param_value == Qnil) {
			paramValues[i] = NULL;
			paramLengths[i] = 0;
		}
		else {
			Check_Type(param_value, T_STRING);
			/* make sure param_value doesn't get freed by the GC */
			rb_ary_push(gc_array, param_value);
			paramValues[i] = StringValuePtr(param_value);
			paramLengths[i] = RSTRING_LEN(param_value);
		}

		if(param_format == Qnil)
			paramFormats[i] = 0;
		else
			paramFormats[i] = NUM2INT(param_format);
	}
	
	result = PQexecParams(conn, StringValuePtr(command), nParams, paramTypes, 
		(const char * const *)paramValues, paramLengths, paramFormats, resultFormat);

	rb_gc_unregister_address(&gc_array);

	free(paramTypes);
	free(paramValues);
	free(paramLengths);
	free(paramFormats);

	rb_pgresult = new_pgresult(result);
	pgresult_check(self, rb_pgresult);
	if (rb_block_given_p()) {
		return rb_ensure(yield_pgresult, rb_pgresult, 
			pgresult_clear, rb_pgresult);
	}
	return rb_pgresult;
}

/*
 * call-seq:
 *    conn.prepare(stmt_name, sql [, param_types ] ) -> PGresult
 *
 * Prepares statement _sql_ with name _name_ to be executed later.
 * Returns a PGresult instance on success.
 * On failure, it raises a PGError exception.
 *
 * +param_types+ is an optional parameter to specify the Oids of the 
 * types of the parameters.
 *
 * If the types are not specified, they will be inferred by PostgreSQL.
 * Instead of specifying type oids, it's recommended to simply add
 * explicit casts in the query to ensure that the right type is used.
 *
 * For example: "SELECT $1::int"
 * 
 * PostgreSQL bind parameters are represented as $1, $1, $2, etc.,
 * inside the SQL query.
 */
static VALUE
pgconn_prepare(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE name, command, in_paramtypes;
	VALUE param;
	int i = 0;
	int nParams = 0;
	Oid *paramTypes = NULL;

	rb_scan_args(argc, argv, "21", &name, &command, &in_paramtypes);
	Check_Type(name, T_STRING);
	Check_Type(command, T_STRING);

	if(! NIL_P(in_paramtypes)) {
		Check_Type(in_paramtypes, T_ARRAY);
		nParams = RARRAY(in_paramtypes)->len;
		paramTypes = ALLOC_N(Oid, nParams); 
		for(i = 0; i < nParams; i++) {
			param = rb_ary_entry(in_paramtypes, i);
			Check_Type(param, T_FIXNUM);
			if(param == Qnil)
				paramTypes[i] = 0;
			else
				paramTypes[i] = NUM2INT(param);
		}
	}
	result = PQprepare(conn, StringValuePtr(name), StringValuePtr(command),
			nParams, paramTypes);

	free(paramTypes);

	rb_pgresult = new_pgresult(result);
	pgresult_check(self, rb_pgresult);
	return rb_pgresult;
}

/*
 * call-seq:
 *    conn.exec_prepared(statement_name [, params, result_format ] ) -> PGresult
 *
 * Execute prepared named statement specified by _statement_name_.
 * Returns a PGresult instance on success.
 * On failure, it raises a PGError exception.
 *
 * +params+ is an array of the optional bind parameters for the 
 * SQL query. Each element of the +params+ array may be either:
 *   a hash of the form:
 *     {:value  => String (value of bind parameter)
 *      :format => Fixnum (0 for text, 1 for binary)
 *     }
 *   or, it may be a String. If it is a string, that is equivalent to the hash:
 *     { :value => <string value>, :format => 0 }
 * 
 * PostgreSQL bind parameters are represented as $1, $1, $2, etc.,
 * inside the SQL query. The 0th element of the +params+ array is bound
 * to $1, the 1st element is bound to $2, etc. +nil+ is treated as +NULL+.
 *
 * The optional +result_format+ should be 0 for text results, 1
 * for binary.
 */
static VALUE
pgconn_exec_prepared(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE name, params, in_res_fmt;
	VALUE param, param_value, param_format;
	VALUE param_value_tmp;
	VALUE sym_value, sym_format;
	VALUE gc_array;
	int i = 0;
	int nParams;
	char ** paramValues;
	int *paramLengths;
	int *paramFormats;
	int resultFormat;


	rb_scan_args(argc, argv, "12", &name, &params, &in_res_fmt);
	Check_Type(name, T_STRING);

	if(NIL_P(params)) {
		params = rb_ary_new2(0);
		resultFormat = 0;
	}
	else {
		Check_Type(params, T_ARRAY);
	}

	if(NIL_P(in_res_fmt)) {
		resultFormat = 0;
	}
	else {
		resultFormat = NUM2INT(in_res_fmt);
	}

	gc_array = rb_ary_new();
	rb_gc_register_address(&gc_array);
	sym_value = ID2SYM(rb_intern("value"));
	sym_format = ID2SYM(rb_intern("format"));
	nParams = RARRAY(params)->len;
	paramValues = ALLOC_N(char *, nParams);
	paramLengths = ALLOC_N(int, nParams);
	paramFormats = ALLOC_N(int, nParams);
	for(i = 0; i < nParams; i++) {
		param = rb_ary_entry(params, i);
		if (TYPE(param) == T_HASH) {
			param_value_tmp = rb_hash_aref(param, sym_value);
			if(param_value_tmp == Qnil)
				param_value = param_value_tmp;
			else
				param_value = rb_obj_as_string(param_value_tmp);
			param_format = rb_hash_aref(param, sym_format);
		}
		else {
			if(param == Qnil)
				param_value = param;
			else
				param_value = rb_obj_as_string(param);
			param_format = INT2NUM(0);
		}
		if(param_value == Qnil) {
			paramValues[i] = NULL;
			paramLengths[i] = 0;
		}
		else {
			Check_Type(param_value, T_STRING);
			/* make sure param_value doesn't get freed by the GC */
			rb_ary_push(gc_array, param_value);
			paramValues[i] = StringValuePtr(param_value);
			paramLengths[i] = RSTRING_LEN(param_value);
		}

		if(param_format == Qnil)
			paramFormats[i] = 0;
		else
			paramFormats[i] = NUM2INT(param_format);
	}
	
	result = PQexecPrepared(conn, StringValuePtr(name), nParams, 
		(const char * const *)paramValues, paramLengths, paramFormats, 
		resultFormat);

	rb_gc_unregister_address(&gc_array);

	free(paramValues);
	free(paramLengths);
	free(paramFormats);

	rb_pgresult = new_pgresult(result);
	pgresult_check(self, rb_pgresult);
	if (rb_block_given_p()) {
		return rb_ensure(yield_pgresult, rb_pgresult, 
			pgresult_clear, rb_pgresult);
	}
	return rb_pgresult;
}

/*
 * call-seq:
 *    conn.describe_prepared( statement_name ) -> PGresult
 *
 * Retrieve information about the prepared statement
 * _statement_name_.
 */
static VALUE
pgconn_describe_prepared(VALUE self, VALUE stmt_name)
{
	PGresult *result;
	VALUE rb_pgresult;
	PGconn *conn = get_pgconn(self);
	char *stmt;
	if(stmt_name == Qnil) {
		stmt = NULL;
	}
	else {
		Check_Type(stmt_name, T_STRING);
		stmt = StringValuePtr(stmt_name);
	}
	result = PQdescribePrepared(conn, stmt);
	rb_pgresult = new_pgresult(result);
	pgresult_check(self, rb_pgresult);
	return rb_pgresult;
}


/*
 * call-seq:
 *    conn.describe_portal( portal_name ) -> PGresult
 *
 * Retrieve information about the portal _portal_name_.
 */
static VALUE
pgconn_describe_portal(self, stmt_name)
	VALUE self, stmt_name;
{
	PGresult *result;
	VALUE rb_pgresult;
	PGconn *conn = get_pgconn(self);
	char *stmt;
	if(stmt_name == Qnil) {
		stmt = NULL;
	}
	else {
		Check_Type(stmt_name, T_STRING);
		stmt = StringValuePtr(stmt_name);
	}
	result = PQdescribePortal(conn, stmt);
	rb_pgresult = new_pgresult(result);
	pgresult_check(self, rb_pgresult);
	return rb_pgresult;
}


/*
 * call-seq:
 *    conn.make_empty_pgresult( status ) -> PGresult
 *
 * Constructs and empty PGresult with status _status_.
 * _status_ may be one of:
 * * +PGRES_EMPTY_QUERY+
 * * +PGRES_COMMAND_OK+
 * * +PGRES_TUPLES_OK+
 * * +PGRES_COPY_OUT+
 * * +PGRES_COPY_IN+
 * * +PGRES_BAD_RESPONSE+
 * * +PGRES_NONFATAL_ERROR+
 * * +PGRES_FATAL_ERROR+
 */
static VALUE
pgconn_make_empty_pgresult(VALUE self, VALUE status)
{
	PGresult *result;
	VALUE rb_pgresult;
	PGconn *conn = get_pgconn(self);
	result = PQmakeEmptyPGresult(conn, NUM2INT(status));
	rb_pgresult = new_pgresult(result);
	pgresult_check(self, rb_pgresult);
	return rb_pgresult;
}


/*
 * call-seq:
 *    conn.escape_string( str ) -> String
 *    PGconn.escape_string( str ) -> String  # DEPRECATED
 *
 * Connection instance method for versions of 8.1 and higher of libpq
 * uses PQescapeStringConn, which is safer. Avoid calling as a class method,
 * the class method uses the deprecated PQescapeString() API function.
 * 
 * Returns a SQL-safe version of the String _str_.
 * This is the preferred way to make strings safe for inclusion in 
 * SQL queries.
 * 
 * Consider using exec_params, which avoids the need for passing values 
 * inside of SQL commands.
 */
static VALUE
pgconn_s_escape(VALUE self, VALUE string)
{
	char *escaped;
	int size,error;
	VALUE result;

	Check_Type(string, T_STRING);

	escaped = ALLOC_N(char, RSTRING_LEN(string) * 2 + 1);
	if(CLASS_OF(self) == rb_cPGconn) {
		size = PQescapeStringConn(get_pgconn(self), escaped, 
			RSTRING_PTR(string), RSTRING_LEN(string), &error);
		if(error) {
			rb_raise(rb_ePGError, PQerrorMessage(get_pgconn(self)));
		}
	} else {
		size = PQescapeString(escaped, RSTRING_PTR(string),
			RSTRING_LEN(string));
	}
	result = rb_str_new(escaped, size);
	free(escaped);
	OBJ_INFECT(result, string);
	return result;
}

/*
 * call-seq:
 *   conn.escape_bytea( string ) -> String 
 *   PGconn.escape_bytea( string ) -> String # DEPRECATED
 *
 * Connection instance method for versions of 8.1 and higher of libpq
 * uses PQescapeByteaConn, which is safer. Avoid calling as a class method,
 * the class method uses the deprecated PQescapeBytea() API function.
 *
 * Use the instance method version of this function, it is safer than the
 * class method.
 *
 * Escapes binary data for use within an SQL command with the type +bytea+.
 * 
 * Certain byte values must be escaped (but all byte values may be escaped)
 * when used as part of a +bytea+ literal in an SQL statement. In general, to
 * escape a byte, it is converted into the three digit octal number equal to
 * the octet value, and preceded by two backslashes. The single quote (') and
 * backslash (\) characters have special alternative escape sequences.
 * #escape_bytea performs this operation, escaping only the minimally required 
 * bytes.
 * 
 * Consider using exec_params, which avoids the need for passing values inside of 
 * SQL commands.
 */
static VALUE
pgconn_s_escape_bytea(VALUE self, VALUE str)
{
	unsigned char *from, *to;
	size_t from_len, to_len;
	VALUE ret;

	Check_Type(str, T_STRING);
	from      = (unsigned char*)RSTRING_PTR(str);
	from_len  = RSTRING_LEN(str);

	if(CLASS_OF(self) == rb_cPGconn) {
		to = PQescapeByteaConn(get_pgconn(self), from, from_len, &to_len);
	} else {
		to = PQescapeBytea( from, from_len, &to_len);
	}

	ret = rb_str_new((char*)to, to_len - 1);
	OBJ_INFECT(ret, str);
	PQfreemem(to);
	return ret;
}


/*
 * call-seq:
 *   PGconn.unescape_bytea( string )
 *
 * Converts an escaped string representation of binary data into binary data --- the
 * reverse of #escape_bytea. This is needed when retrieving +bytea+ data in text format,
 * but not when retrieving it in binary format.
 *
 */
static VALUE
pgconn_s_unescape_bytea(VALUE self, VALUE str)
{
	unsigned char *from, *to;
	size_t to_len;
	VALUE ret;

	Check_Type(str, T_STRING);
	from = (unsigned char*)StringValuePtr(str);

	to = PQunescapeBytea(from, &to_len);

	ret = rb_str_new((char*)to, to_len);
	OBJ_INFECT(ret, str);
	PQfreemem(to);
	return ret;
}

/*
 * call-seq:
 *    conn.send_query(sql [, params, result_format ] ) -> nil
 *
 * Sends SQL query request specified by _sql_ to PostgreSQL for
 * asynchronous processing, and immediately returns.
 * On failure, it raises a PGError exception.
 *
 * +params+ is an optional array of the bind parameters for the SQL query.
 * Each element of the +params+ array may be either:
 *   a hash of the form:
 *     {:value  => String (value of bind parameter)
 *      :type   => Fixnum (oid of type of bind parameter)
 *      :format => Fixnum (0 for text, 1 for binary)
 *     }
 *   or, it may be a String. If it is a string, that is equivalent to the hash:
 *     { :value => <string value>, :type => 0, :format => 0 }
 * 
 * PostgreSQL bind parameters are represented as $1, $1, $2, etc.,
 * inside the SQL query. The 0th element of the +params+ array is bound
 * to $1, the 1st element is bound to $2, etc. +nil+ is treated as +NULL+.
 * 
 * If the types are not specified, they will be inferred by PostgreSQL.
 * Instead of specifying type oids, it's recommended to simply add
 * explicit casts in the query to ensure that the right type is used.
 *
 * For example: "SELECT $1::int"
 *
 * The optional +result_format+ should be 0 for text results, 1
 * for binary.
 */
static VALUE
pgconn_send_query(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	int result;
	VALUE command, params, in_res_fmt;
	VALUE param, param_type, param_value, param_format;
	VALUE param_value_tmp;
	VALUE sym_type, sym_value, sym_format;
	VALUE gc_array;
	VALUE error;
	int i=0;
	int nParams;
	Oid *paramTypes;
	char ** paramValues;
	int *paramLengths;
	int *paramFormats;
	int resultFormat;

	rb_scan_args(argc, argv, "12", &command, &params, &in_res_fmt);
	Check_Type(command, T_STRING);

	/* If called with no parameters, use PQsendQuery */
	if(NIL_P(params)) {
		if(PQsendQuery(conn,StringValuePtr(command)) == 0) {
			error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
			rb_iv_set(error, "@connection", self);
			rb_exc_raise(error);
		}
		return Qnil;
	}

	/* If called with parameters, and optionally result_format,
	 * use PQsendQueryParams
	 */
	Check_Type(params, T_ARRAY);

	if(NIL_P(in_res_fmt)) {
		resultFormat = 0;
	}
	else {
		resultFormat = NUM2INT(in_res_fmt);
	}

	gc_array = rb_ary_new();
	rb_gc_register_address(&gc_array);
	sym_type = ID2SYM(rb_intern("type"));
	sym_value = ID2SYM(rb_intern("value"));
	sym_format = ID2SYM(rb_intern("format"));
	nParams = RARRAY(params)->len;
	paramTypes = ALLOC_N(Oid, nParams); 
	paramValues = ALLOC_N(char *, nParams);
	paramLengths = ALLOC_N(int, nParams);
	paramFormats = ALLOC_N(int, nParams);
	for(i = 0; i < nParams; i++) {
		param = rb_ary_entry(params, i);
		if (TYPE(param) == T_HASH) {
			param_type = rb_hash_aref(param, sym_type);
			param_value_tmp = rb_hash_aref(param, sym_value);
			if(param_value_tmp == Qnil)
				param_value = param_value_tmp;
			else
				param_value = rb_obj_as_string(param_value_tmp);
			param_format = rb_hash_aref(param, sym_format);
		}
		else {
			param_type = INT2NUM(0);
			if(param == Qnil)
				param_value = param;
			else
				param_value = rb_obj_as_string(param);
			param_format = INT2NUM(0);
		}

		if(param_type == Qnil)
			paramTypes[i] = 0;
		else
			paramTypes[i] = NUM2INT(param_type);

		if(param_value == Qnil) {
			paramValues[i] = NULL;
			paramLengths[i] = 0;
		}
		else {
			Check_Type(param_value, T_STRING);
			/* make sure param_value doesn't get freed by the GC */
			rb_ary_push(gc_array, param_value);
			paramValues[i] = StringValuePtr(param_value);
			paramLengths[i] = RSTRING_LEN(param_value);
		}

		if(param_format == Qnil)
			paramFormats[i] = 0;
		else
			paramFormats[i] = NUM2INT(param_format);
	}
	
	result = PQsendQueryParams(conn, StringValuePtr(command), nParams, paramTypes, 
		(const char * const *)paramValues, paramLengths, paramFormats, resultFormat);

	rb_gc_unregister_address(&gc_array);	

	free(paramTypes);
	free(paramValues);
	free(paramLengths);
	free(paramFormats);

	if(result == 0) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}

/*
 * call-seq:
 *    conn.send_prepare( stmt_name, sql [, param_types ] ) -> nil
 *
 * Prepares statement _sql_ with name _name_ to be executed later.
 * Sends prepare command asynchronously, and returns immediately.
 * On failure, it raises a PGError exception.
 *
 * +param_types+ is an optional parameter to specify the Oids of the 
 * types of the parameters.
 *
 * If the types are not specified, they will be inferred by PostgreSQL.
 * Instead of specifying type oids, it's recommended to simply add
 * explicit casts in the query to ensure that the right type is used.
 *
 * For example: "SELECT $1::int"
 * 
 * PostgreSQL bind parameters are represented as $1, $1, $2, etc.,
 * inside the SQL query.
 */
static VALUE
pgconn_send_prepare(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	int result;
	VALUE name, command, in_paramtypes;
	VALUE param;
	VALUE error;
	int i = 0;
	int nParams = 0;
	Oid *paramTypes = NULL;

	rb_scan_args(argc, argv, "21", &name, &command, &in_paramtypes);
	Check_Type(name, T_STRING);
	Check_Type(command, T_STRING);

	if(! NIL_P(in_paramtypes)) {
		Check_Type(in_paramtypes, T_ARRAY);
		nParams = RARRAY(in_paramtypes)->len;
		paramTypes = ALLOC_N(Oid, nParams); 
		for(i = 0; i < nParams; i++) {
			param = rb_ary_entry(in_paramtypes, i);
			Check_Type(param, T_FIXNUM);
			if(param == Qnil)
				paramTypes[i] = 0;
			else
				paramTypes[i] = NUM2INT(param);
		}
	}
	result = PQsendPrepare(conn, StringValuePtr(name), StringValuePtr(command),
			nParams, paramTypes);

	free(paramTypes);

	if(result == 0) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}

/*
 * call-seq:
 *    conn.send_query_prepared( statement_name [, params, result_format ] )
 *      -> nil
 *
 * Execute prepared named statement specified by _statement_name_
 * asynchronously, and returns immediately.
 * On failure, it raises a PGError exception.
 *
 * +params+ is an array of the optional bind parameters for the 
 * SQL query. Each element of the +params+ array may be either:
 *   a hash of the form:
 *     {:value  => String (value of bind parameter)
 *      :format => Fixnum (0 for text, 1 for binary)
 *     }
 *   or, it may be a String. If it is a string, that is equivalent to the hash:
 *     { :value => <string value>, :format => 0 }
 * 
 * PostgreSQL bind parameters are represented as $1, $1, $2, etc.,
 * inside the SQL query. The 0th element of the +params+ array is bound
 * to $1, the 1st element is bound to $2, etc. +nil+ is treated as +NULL+.
 *
 * The optional +result_format+ should be 0 for text results, 1
 * for binary.
 */
static VALUE
pgconn_send_query_prepared(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	int result;
	VALUE name, params, in_res_fmt;
	VALUE param, param_value, param_format;
	VALUE param_value_tmp;
	VALUE sym_value, sym_format;
	VALUE gc_array;
	VALUE error;
	int i = 0;
	int nParams;
	char ** paramValues;
	int *paramLengths;
	int *paramFormats;
	int resultFormat;

	rb_scan_args(argc, argv, "12", &name, &params, &in_res_fmt);
	Check_Type(name, T_STRING);

	if(NIL_P(params)) {
		params = rb_ary_new2(0);
		resultFormat = 0;
	}
	else {
		Check_Type(params, T_ARRAY);
	}

	if(NIL_P(in_res_fmt)) {
		resultFormat = 0;
	}
	else {
		resultFormat = NUM2INT(in_res_fmt);
	}

	gc_array = rb_ary_new();
	rb_gc_register_address(&gc_array);
	sym_value = ID2SYM(rb_intern("value"));
	sym_format = ID2SYM(rb_intern("format"));
	nParams = RARRAY(params)->len;
	paramValues = ALLOC_N(char *, nParams);
	paramLengths = ALLOC_N(int, nParams);
	paramFormats = ALLOC_N(int, nParams);
	for(i = 0; i < nParams; i++) {
		param = rb_ary_entry(params, i);
		if (TYPE(param) == T_HASH) {
			param_value_tmp = rb_hash_aref(param, sym_value);
			if(param_value_tmp == Qnil)
				param_value = param_value_tmp;
			else
				param_value = rb_obj_as_string(param_value_tmp);
			param_format = rb_hash_aref(param, sym_format);
		}
		else {
			if(param == Qnil)
				param_value = param;
			else
				param_value = rb_obj_as_string(param);
			param_format = INT2NUM(0);
		}

		if(param_value == Qnil) {
			paramValues[i] = NULL;
			paramLengths[i] = 0;
		}
		else {
			Check_Type(param_value, T_STRING);
			/* make sure param_value doesn't get freed by the GC */
			rb_ary_push(gc_array, param_value);
			paramValues[i] = StringValuePtr(param_value);
			paramLengths[i] = RSTRING_LEN(param_value);
		}

		if(param_format == Qnil)
			paramFormats[i] = 0;
		else
			paramFormats[i] = NUM2INT(param_format);
	}
	
	result = PQsendQueryPrepared(conn, StringValuePtr(name), nParams, 
		(const char * const *)paramValues, paramLengths, paramFormats, 
		resultFormat);

	rb_gc_unregister_address(&gc_array);

	free(paramValues);
	free(paramLengths);
	free(paramFormats);

	if(result == 0) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}

/*
 * call-seq:
 *    conn.send_describe_prepared( statement_name ) -> nil
 *
 * Asynchronously send _command_ to the server. Does not block. 
 * Use in combination with +conn.get_result+.
 */
static VALUE
pgconn_send_describe_prepared(VALUE self, VALUE stmt_name)
{
	VALUE error;
	PGconn *conn = get_pgconn(self);
	/* returns 0 on failure */
	if(PQsendDescribePrepared(conn,StringValuePtr(stmt_name)) == 0) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}


/*
 * call-seq:
 *    conn.send_describe_portal( portal_name ) -> nil
 *
 * Asynchronously send _command_ to the server. Does not block. 
 * Use in combination with +conn.get_result+.
 */
static VALUE
pgconn_send_describe_portal(VALUE self, VALUE portal)
{
	VALUE error;
	PGconn *conn = get_pgconn(self);
	/* returns 0 on failure */
	if(PQsendDescribePortal(conn,StringValuePtr(portal)) == 0) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}


/*
 * call-seq:
 *    conn.get_result() -> PGresult
 *
 * Blocks waiting for the next result from a call to
 * +PGconn#send_query+ (or another asynchronous command), and returns
 * it. Returns +nil+ if no more results are available.
 *
 * Note: call this function repeatedly until it returns +nil+, or else
 * you will not be able to issue further commands.
 */
static VALUE
pgconn_get_result(VALUE self)
{
	PGconn *conn = get_pgconn(self);
	PGresult *result;
	VALUE rb_pgresult;

	result = PQgetResult(conn);
	if(result == NULL)
		return Qnil;
	rb_pgresult = new_pgresult(result);
	if (rb_block_given_p()) {
		return rb_ensure(yield_pgresult, rb_pgresult,
			pgresult_clear, rb_pgresult);
	}
	return rb_pgresult;
}

/*
 * call-seq:
 *    conn.consume_input()
 *
 * If input is available from the server, consume it.
 * After calling +consume_input+, you can check +is_busy+
 * or *notifies* to see if the state has changed.
 */
static VALUE
pgconn_consume_input(self)
	VALUE self;
{
	VALUE error;
	PGconn *conn = get_pgconn(self);
	/* returns 0 on error */
	if(PQconsumeInput(conn) == 0) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}

/*
 * call-seq:
 *    conn.is_busy() -> Boolean
 *
 * Returns +true+ if a command is busy, that is, if
 * PQgetResult would block. Otherwise returns +false+.
 */
static VALUE
pgconn_is_busy(self)
	VALUE self;
{
	return PQisBusy(get_pgconn(self)) ? Qtrue : Qfalse;
}

/*
 * call-seq:
 *    conn.setnonblocking(Boolean) -> nil
 *
 * Sets the nonblocking status of the connection. 
 * In the blocking state, calls to PGconn#send_query
 * will block until the message is sent to the server,
 * but will not wait for the query results.
 * In the nonblocking state, calls to PGconn#send_query
 * will return an error if the socket is not ready for
 * writing.
 * Note: This function does not affect PGconn#exec, because
 * that function doesn't return until the server has 
 * processed the query and returned the results.
 * Returns +nil+.
 */
static VALUE
pgconn_setnonblocking(self, state)
	VALUE self, state;
{
	int arg;
	VALUE error;
	PGconn *conn = get_pgconn(self);
	if(state == Qtrue)
		arg = 1;
	else if (state == Qfalse)
		arg = 0;
	else
		rb_raise(rb_eArgError, "Boolean value expected");

	if(PQsetnonblocking(conn, arg) == -1) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return Qnil;
}


/*
 * call-seq:
 *    conn.isnonblocking() -> Boolean
 *
 * Returns +true+ if a command is busy, that is, if
 * PQgetResult would block. Otherwise returns +false+.
 */
static VALUE
pgconn_isnonblocking(self)
	VALUE self;
{
	return PQisnonblocking(get_pgconn(self)) ? Qtrue : Qfalse;
}

/*
 * call-seq:
 *    conn.flush() -> Boolean
 *
 * Attempts to flush any queued output data to the server.
 * Returns +true+ if data is successfully flushed, +false+
 * if not (can only return +false+ if connection is
 * nonblocking.
 * Raises PGError exception if some other failure occurred.
 */
static VALUE
pgconn_flush(self)
	VALUE self;
{
	PGconn *conn = get_pgconn(self);
	int ret;
	VALUE error;
	ret = PQflush(conn);
	if(ret == -1) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return (ret) ? Qfalse : Qtrue;
}

/*
 * call-seq:
 *    conn.cancel() -> String
 *
 * Requests cancellation of the command currently being
 * processed.
 *
 * Returns +nil+ on success, or a string containing the
 * error message if a failure occurs.
 */
static VALUE
pgconn_cancel(VALUE self)
{
	char errbuf[256];
	PGcancel *cancel;
	VALUE retval;
	int ret;

	cancel = PQgetCancel(get_pgconn(self));
	if(cancel == NULL)
		rb_raise(rb_ePGError,"Invalid connection!");

	ret = PQcancel(cancel, errbuf, 256);
	if(ret == 1) 
		retval = Qnil;
	else
		retval = rb_str_new2(errbuf);

	PQfreeCancel(cancel);
	return retval;
}

/*
 * call-seq:
 *    conn.notifies()
 *
 * Returns an array of the unprocessed notifiers.
 * If there is no unprocessed notifier, it returns +nil+.
 */
static VALUE
pgconn_notifies(VALUE self)
{
	PGconn* conn = get_pgconn(self);
	PGnotify *notify;
	VALUE hash;
	VALUE sym_relname, sym_be_pid, sym_extra;
	VALUE relname, be_pid, extra;

	sym_relname = ID2SYM(rb_intern("relname"));
	sym_be_pid = ID2SYM(rb_intern("be_pid"));
	sym_extra = ID2SYM(rb_intern("extra"));

	notify = PQnotifies(conn);
	if (notify == NULL) {
		return Qnil;
	}
	
	hash = rb_hash_new();
	relname = rb_tainted_str_new2(notify->relname);
	be_pid = INT2NUM(notify->be_pid);
	extra = rb_tainted_str_new2(PGNOTIFY_EXTRA(notify));
	
	rb_hash_aset(hash, sym_relname, relname);
	rb_hash_aset(hash, sym_be_pid, be_pid);
	rb_hash_aset(hash, sym_extra, extra);

	PQfreemem(notify);
	return hash;
}


/*
 * call-seq:
 *    conn.put_copy_data( buffer ) -> Boolean
 *
 * Transmits _buffer_ as copy data to the server.
 * Returns true if the data was sent, false if it was
 * not sent (false is only possible if the connection
 * is in nonblocking mode, and this command would block).
 *
 * Raises an exception if an error occurs.
 */
static VALUE
pgconn_put_copy_data(self, buffer)
	VALUE self, buffer;
{
	int ret;
	VALUE error;
	PGconn *conn = get_pgconn(self);
	Check_Type(buffer, T_STRING);

	ret = PQputCopyData(conn, RSTRING_PTR(buffer),
			RSTRING_LEN(buffer));
	if(ret == -1) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return (ret) ? Qtrue : Qfalse;
}

/*
 * call-seq:
 *    conn.put_copy_end( [ error_message ] ) -> Boolean
 *
 * Sends end-of-data indication to the server.
 *
 * _error_message_ is an optional parameter, and if set,
 * forces the COPY command to fail with the string
 * _error_message_.
 *
 * Returns true if the end-of-data was sent, false if it was
 * not sent (false is only possible if the connection
 * is in nonblocking mode, and this command would block).
 */ 
static VALUE
pgconn_put_copy_end(int argc, VALUE *argv, VALUE self)
{
	VALUE str;
	VALUE error;
	int ret;
	char *error_message = NULL;
	PGconn *conn = get_pgconn(self);

	if (rb_scan_args(argc, argv, "01", &str) == 0)
		error_message = NULL;
	else
		error_message = StringValuePtr(str);

	ret = PQputCopyEnd(conn, error_message);
	if(ret == -1) {
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	return (ret) ? Qtrue : Qfalse;
}

/*
 * call-seq:
 *    conn.get_copy_data( [ async = false ] ) -> String
 *
 * Return a string containing one row of data, +nil+
 * if the copy is done, or +false+ if the call would 
 * block (only possible if _async_ is true).
 *
 */
static VALUE
pgconn_get_copy_data(int argc, VALUE *argv, VALUE self )
{
	VALUE async_in;
	VALUE error;
	VALUE result_str;
	int ret;
	int async;
	char *buffer;
	PGconn *conn = get_pgconn(self);

	if (rb_scan_args(argc, argv, "01", &async_in) == 0)
		async = 0;
	else
		async = (async_in == Qfalse || async_in == Qnil) ? 0 : 1;

	ret = PQgetCopyData(conn, &buffer, async);
	if(ret == -2) { // error
		error = rb_exc_new2(rb_ePGError, PQerrorMessage(conn));
		rb_iv_set(error, "@connection", self);
		rb_exc_raise(error);
	}
	if(ret == -1) { // No data left
		return Qnil;
	}
	if(ret == 0) { // would block
		return Qfalse;
	}
	result_str = rb_tainted_str_new(buffer, ret);
	PQfreemem(buffer);
	return result_str;
}

/*
 * call-seq:
 *    conn.set_error_verbosity( verbosity ) -> Fixnum
 *
 * Sets connection's verbosity to _verbosity_ and returns
 * the previous setting. Available settings are:
 * * PQERRORS_TERSE
 * * PQERRORS_DEFAULT
 * * PQERRORS_VERBOSE
 */
static VALUE
pgconn_set_error_verbosity(VALUE self, VALUE in_verbosity)
{
	PGconn *conn = get_pgconn(self);
	PGVerbosity verbosity = NUM2INT(in_verbosity);
	return INT2FIX(PQsetErrorVerbosity(conn, verbosity));
}

/*
 * call-seq:
 *    conn.trace( stream ) -> nil
 * 
 * Enables tracing message passing between backend. The 
 * trace message will be written to the stream _stream_,
 * which must implement a method +fileno+ that returns
 * a writable file descriptor.
 */
static VALUE
pgconn_trace(VALUE self, VALUE stream)
{
	FILE *fp;
	VALUE fileno;
	FILE *new_fp;
	int old_fd, new_fd;
	VALUE new_file;

	if(rb_respond_to(stream,rb_intern("fileno")) == Qfalse)
		rb_raise(rb_eArgError, "stream does not respond to method: fileno");

	fileno = rb_funcall(stream, rb_intern("fileno"), 0);
	if(fileno == Qnil)
		rb_raise(rb_eArgError, "can't get file descriptor from stream");

	/* Duplicate the file descriptor and re-open
	 * it. Then, make it into a ruby File object
	 * and assign it to an instance variable.
	 * This prevents a problem when the File
	 * object passed to this function is closed
	 * before the connection object is. */
	old_fd = NUM2INT(fileno);
	new_fd = dup(old_fd);
	new_fp = fdopen(new_fd, "w");

	if(new_fp == NULL)
		rb_raise(rb_eArgError, "stream is not writable");

	new_file = rb_funcall(rb_cIO, rb_intern("new"), 1, INT2NUM(new_fd));
	rb_iv_set(self, "@trace_stream", new_file);

	PQtrace(get_pgconn(self), new_fp);
	return Qnil;
}

/*
 * call-seq:
 *    conn.untrace() -> nil
 * 
 * Disables the message tracing.
 */
static VALUE
pgconn_untrace(VALUE self)
{
	VALUE trace_stream;
	PQuntrace(get_pgconn(self));
	trace_stream = rb_iv_get(self, "@trace_stream");
	rb_funcall(trace_stream, rb_intern("close"), 0);
	rb_iv_set(self, "@trace_stream", Qnil);
	return Qnil;
}

/*
 * call-seq:
 *   conn.set_notice_receiver {|result| ... } -> Proc
 *
 * Notice and warning messages generated by the server are not returned
 * by the query execution functions, since they do not imply failure of
 * the query. Instead they are passed to a notice handling function, and
 * execution continues normally after the handler returns. The default
 * notice handling function prints the message on <tt>stderr</tt>, but the
 * application can override this behavior by supplying its own handling
 * function.
 *
 * This function takes a new block to act as the handler, which should
 * accept a single parameter that will be a PGresult object, and returns 
 * the Proc object previously set, or +nil+ if it was previously the default.
 *
 * If you pass no arguments, it will reset the handler to the default.
 */
static VALUE
pgconn_set_notice_receiver(VALUE self)
{
	VALUE proc, old_proc;
	PGconn *conn = get_pgconn(self);

	/* If default_notice_receiver is unset, assume that the current 
	 * notice receiver is the default, and save it to a global variable. 
	 * This should not be a problem because the default receiver is
	 * always the same, so won't vary among connections.
	 */
	if(default_notice_receiver == NULL)
		default_notice_receiver = PQsetNoticeReceiver(conn, NULL, NULL);

	old_proc = rb_iv_get(self, "@notice_receiver");
	if( rb_block_given_p() ) {
		proc = rb_block_proc();
		PQsetNoticeReceiver(conn, notice_receiver_proxy, (void *)self);
	} else {
		/* if no block is given, set back to default */
		proc = Qnil;
		PQsetNoticeReceiver(conn, default_notice_receiver, NULL);
	}

	rb_iv_set(self, "@notice_receiver", proc);
	return old_proc;
}

/*
 * call-seq:
 *   conn.set_notice_processor {|message| ... } -> Proc
 *
 * Notice and warning messages generated by the server are not returned
 * by the query execution functions, since they do not imply failure of
 * the query. Instead they are passed to a notice handling function, and
 * execution continues normally after the handler returns. The default
 * notice handling function prints the message on <tt>stderr</tt>, but the
 * application can override this behavior by supplying its own handling
 * function.
 *
 * This function takes a new block to act as the handler, which should
 * accept a single parameter that will be a PGresult object, and returns 
 * the Proc object previously set, or +nil+ if it was previously the default.
 *
 * If you pass no arguments, it will reset the handler to the default.
 */
static VALUE
pgconn_set_notice_processor(VALUE self)
{
	VALUE proc, old_proc;
	PGconn *conn = get_pgconn(self);

	/* If default_notice_processor is unset, assume that the current 
	 * notice processor is the default, and save it to a global variable. 
	 * This should not be a problem because the default processor is
	 * always the same, so won't vary among connections.
	 */
	if(default_notice_processor == NULL)
		default_notice_processor = PQsetNoticeProcessor(conn, NULL, NULL);

	old_proc = rb_iv_get(self, "@notice_processor");
	if( rb_block_given_p() ) {
		proc = rb_block_proc();
		PQsetNoticeProcessor(conn, notice_processor_proxy, (void *)self);
	} else {
		/* if no block is given, set back to default */
		proc = Qnil;
		PQsetNoticeProcessor(conn, default_notice_processor, NULL);
	}

	rb_iv_set(self, "@notice_processor", proc);
	return old_proc;
}
/*
 * call-seq:
 *    conn.get_client_encoding() -> String
 * 
 * Returns the client encoding as a String.
 */
static VALUE
pgconn_get_client_encoding(VALUE self)
{
	char *encoding = (char *)pg_encoding_to_char(PQclientEncoding(get_pgconn(self)));
	return rb_tainted_str_new2(encoding);
}

/*
 * call-seq:
 *    conn.set_client_encoding( encoding )
 * 
 * Sets the client encoding to the _encoding_ String.
 */
static VALUE
pgconn_set_client_encoding(VALUE self, VALUE str)
{
	Check_Type(str, T_STRING);
	if ((PQsetClientEncoding(get_pgconn(self), StringValuePtr(str))) == -1){
		rb_raise(rb_ePGError, "invalid encoding name: %s",StringValuePtr(str));
	}
	return Qnil;
}

/*
 * call-seq:
 *    conn.transaction { |conn| ... } -> nil
 *
 * Executes a +BEGIN+ at the start of the block,
 * and a +COMMIT+ at the end of the block, or 
 * +ROLLBACK+ if any exception occurs.
 */
static VALUE
pgconn_transaction(VALUE self)
{
	PGconn *conn = get_pgconn(self);
	PGresult *result;
	VALUE rb_pgresult;
	int status;
	
	if (rb_block_given_p()) {
		result = PQexec(conn, "BEGIN");
		rb_pgresult = new_pgresult(result);
		pgresult_check(self, rb_pgresult);
		rb_protect(rb_yield, self, &status);
		if(status == 0) {
			result = PQexec(conn, "COMMIT");
			rb_pgresult = new_pgresult(result);
			pgresult_check(self, rb_pgresult);
		}
		else {
			/* exception occurred, ROLLBACK and re-raise */
			result = PQexec(conn, "ROLLBACK");
			rb_pgresult = new_pgresult(result);
			pgresult_check(self, rb_pgresult);
			rb_jump_tag(status);
		}
			
	}
	else {
		/* no block supplied? */
		rb_raise(rb_eArgError, "Must supply block for PGconn#transaction");
	}
	return Qnil;
}

/*
 * call-seq:
 *    PGconn.quote_ident( str ) -> String
 *    conn.quote_ident( str ) -> String
 *
 * Returns a string that is safe for inclusion in a SQL query
 * as an identifier. Note: this is not a quote function for values,
 * but for identifiers.
 * 
 * For example, in a typical SQL query: +SELECT FOO FROM MYTABLE+
 * The identifier +FOO+ is folded to lower case, so it actually means
 * +foo+. If you really want to access the case-sensitive field name
 * +FOO+, use this function like +PGconn.quote_ident('FOO')+, which
 * will return +"FOO"+ (with double-quotes). PostgreSQL will see the
 * double-quotes, and it will not fold to lower case.
 *
 * Similarly, this function also protects against special characters,
 * and other things that might allow SQL injection if the identifier
 * comes from an untrusted source.
 */
static VALUE
pgconn_s_quote_ident(VALUE self, VALUE in_str)
{
	VALUE ret;
	char *str = StringValuePtr(in_str);
	/* result size at most NAMEDATALEN*2 plus surrounding
	 * double-quotes. */
	char buffer[NAMEDATALEN*2+2];
	unsigned int i=0,j=0;
	
	if(strlen(str) >= NAMEDATALEN) {
		rb_raise(rb_eArgError, 
			"Input string is longer than NAMEDATALEN-1 (%d)",
			NAMEDATALEN-1);
	}
	buffer[j++] = '"';
	for(i = 0; i < strlen(str) && str[i]; i++) {
		if(str[i] == '"') 
			buffer[j++] = '"';
		buffer[j++] = str[i];
	}
	buffer[j++] = '"';
	ret = rb_str_new(buffer,j);
	OBJ_INFECT(ret, in_str);
	return ret;
}


/*
 * call-seq:
 *    conn.block( [ timeout ] ) -> Boolean
 *
 * Blocks until the server is no longer busy, or until the 
 * optional _timeout_ is reached, whichever comes first.
 * _timeout_ is measured in seconds and can be fractional.
 * 
 * Returns +false+ if _timeout_ is reached, +true+ otherwise.
 * 
 * If +true+ is returned, +conn.is_busy+ will return +false+
 * and +conn.get_result+ will not block.
 */
static VALUE
pgconn_block(int argc, VALUE *argv, VALUE self)
{
	PGconn *conn = get_pgconn(self);
	int sd = PQsocket(conn);
	int ret;
	struct timeval timeout;
	struct timeval *ptimeout = NULL;
	VALUE timeout_in;
	double timeout_sec;
	fd_set sd_rset;

	if (rb_scan_args(argc, argv, "01", &timeout_in) == 1) {
		timeout_sec = NUM2DBL(timeout_in);
		timeout.tv_sec = (long)timeout_sec;
		timeout.tv_usec = (long)((timeout_sec - (long)timeout_sec) * 1e6);
		ptimeout = &timeout;
	}

	PQconsumeInput(conn);
	while(PQisBusy(conn)) {
		FD_ZERO(&sd_rset);
		FD_SET(sd, &sd_rset);
		ret = rb_thread_select(sd+1, &sd_rset, NULL, NULL, ptimeout);
		/* if select() times out, return false */
		if(ret == 0) 
			return Qfalse;
		PQconsumeInput(conn);
	} 

	return Qtrue;
}

/*
 * call-seq:
 *    conn.get_last_result( ) -> PGresult
 *
 * This function retrieves all available results
 * on the current connection (from previously issued
 * asynchronous commands like +send_query()+) and
 * returns the last non-NULL result, or +nil+ if no
 * results are available.
 *
 * This function is similar to +PGconn#get_result+
 * except that it is designed to get one and only
 * one result.
 */
static VALUE
pgconn_get_last_result(VALUE self)
{
	VALUE ret, result;
	ret = Qnil;
	while((result = pgconn_get_result(self)) != Qnil) {
		ret = result;
	}
	pgresult_check(self, ret);
	return ret;
}


/*
 * call-seq:
 *    conn.async_exec(sql [, params, result_format ] ) -> PGresult
 *
 * This function has the same behavior as +PGconn#exec+,
 * except that it's implemented using asynchronous command 
 * processing and ruby's +rb_thread_select+ in order to 
 * allow other threads to process while waiting for the
 * server to complete the request.
 */
static VALUE
pgconn_async_exec(int argc, VALUE *argv, VALUE self)
{
	pgconn_send_query(argc, argv, self);
	pgconn_block(0, NULL, self);
	return pgconn_get_last_result(self);
}

/**************************************************************************
 * LARGE OBJECT SUPPORT
 **************************************************************************/

/*
 * call-seq:
 *    conn.lo_creat( [mode] ) -> Fixnum
 *
 * Creates a large object with mode _mode_. Returns a large object Oid.
 * On failure, it raises PGError exception.
 */
static VALUE
pgconn_locreat(int argc, VALUE *argv, VALUE self)
{
	Oid lo_oid;
	int mode;
	VALUE nmode;
	PGconn *conn = get_pgconn(self);

	if (rb_scan_args(argc, argv, "01", &nmode) == 0)
		mode = INV_READ;
	else
		mode = NUM2INT(nmode);

	lo_oid = lo_creat(conn, mode);
	if (lo_oid == 0)
		rb_raise(rb_ePGError, "lo_creat failed");

	return INT2FIX(lo_oid);
}

/*
 * call-seq:
 *    conn.lo_create( oid ) -> Fixnum
 *
 * Creates a large object with oid _oid_. Returns the large object Oid.
 * On failure, it raises PGError exception.
 */
static VALUE
pgconn_locreate(VALUE self, VALUE in_lo_oid)
{
	Oid ret, lo_oid;
	PGconn *conn = get_pgconn(self);
	lo_oid = NUM2INT(in_lo_oid);

	ret = lo_create(conn, in_lo_oid);
	if (ret == InvalidOid)
		rb_raise(rb_ePGError, "lo_create failed");

	return INT2FIX(ret);
}

/*
 * call-seq:
 *    conn.lo_import(file) -> Fixnum
 *
 * Import a file to a large object. Returns a large object Oid.
 *
 * On failure, it raises a PGError exception.
 */
static VALUE
pgconn_loimport(VALUE self, VALUE filename)
{
	Oid lo_oid;

	PGconn *conn = get_pgconn(self);

	Check_Type(filename, T_STRING);

	lo_oid = lo_import(conn, StringValuePtr(filename));
	if (lo_oid == 0) {
		rb_raise(rb_ePGError, PQerrorMessage(conn));
	}
	return INT2FIX(lo_oid);
}

/*
 * call-seq:
 *    conn.lo_export( oid, file ) -> nil
 *
 * Saves a large object of _oid_ to a _file_.
 */
static VALUE
pgconn_loexport(VALUE self, VALUE lo_oid, VALUE filename)
{
	PGconn *conn = get_pgconn(self);
	int oid;
	Check_Type(filename, T_STRING);

	oid = NUM2INT(lo_oid);
	if (oid < 0) {
		rb_raise(rb_ePGError, "invalid large object oid %d",oid);
	}

	if (lo_export(conn, oid, StringValuePtr(filename)) < 0) {
		rb_raise(rb_ePGError, PQerrorMessage(conn));
	}
	return Qnil;
}

/*
 * call-seq:
 *    conn.lo_open( oid, [mode] ) -> Fixnum
 *
 * Open a large object of _oid_. Returns a large object descriptor 
 * instance on success. The _mode_ argument specifies the mode for
 * the opened large object,which is either +INV_READ+, or +INV_WRITE+.
 *
 * If _mode_ is omitted, the default is +INV_READ+.
 */
static VALUE
pgconn_loopen(int argc, VALUE *argv, VALUE self)
{
	Oid lo_oid;
	int fd, mode;
	VALUE nmode, selfid;
	PGconn *conn = get_pgconn(self);

	rb_scan_args(argc, argv, "11", &selfid, &nmode);
	lo_oid = NUM2INT(selfid);
	if(NIL_P(nmode))
		mode = INV_READ;
	else
		mode = NUM2INT(nmode);

	if((fd = lo_open(conn, lo_oid, mode)) < 0) {
		rb_raise(rb_ePGError, "can't open large object");
	}
	return INT2FIX(fd);
}

/*
 * call-seq:
 *    conn.lo_write( lo_desc, buffer ) -> Fixnum
 *
 * Writes the string _buffer_ to the large object _lo_desc_.
 * Returns the number of bytes written.
 */
static VALUE
pgconn_lowrite(VALUE self, VALUE in_lo_desc, VALUE buffer)
{
	int n;
	PGconn *conn = get_pgconn(self);
	int fd = NUM2INT(in_lo_desc);

	Check_Type(buffer, T_STRING);

	if( RSTRING_LEN(buffer) < 0) {
		rb_raise(rb_ePGError, "write buffer zero string");
	}
	if((n = lo_write(conn, fd, StringValuePtr(buffer), 
				RSTRING_LEN(buffer))) < 0) {
		rb_raise(rb_ePGError, "lo_write failed");
	}

	return INT2FIX(n);
}

/*
 * call-seq:
 *    conn.lo_read( lo_desc, len ) -> String
 *
 * Attempts to read _len_ bytes from large object _lo_desc_,
 * returns resulting data.
 */
static VALUE
pgconn_loread(VALUE self, VALUE in_lo_desc, VALUE in_len)
{
	int ret;
	PGconn *conn = get_pgconn(self);
	int len = NUM2INT(in_len);
	int lo_desc = NUM2INT(in_lo_desc);
	VALUE str;
	char *buffer;

	buffer = malloc(len);
	if(buffer == NULL)
		rb_raise(rb_eNoMemError, "Malloc failed!");

	if (len < 0){
		rb_raise(rb_ePGError,"nagative length %d given", len);
	}

	if((ret = lo_read(conn, lo_desc, buffer, len)) < 0)
		rb_raise(rb_ePGError, "lo_read failed");

	if(ret == 0) {
		free(buffer);
		return Qnil;
	}

	str = rb_tainted_str_new(buffer, len);
	free(buffer);

	return str;
}


/*
 * call-seq
 *    conn.lo_lseek( lo_desc, offset, whence ) -> Fixnum
 *
 * Move the large object pointer _lo_desc_ to offset _offset_.
 * Valid values for _whence_ are +SEEK_SET+, +SEEK_CUR+, and +SEEK_END+.
 * (Or 0, 1, or 2.)
 */
static VALUE
pgconn_lolseek(VALUE self, VALUE in_lo_desc, VALUE offset, VALUE whence)
{
	PGconn *conn = get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);
	int ret;

	if((ret = lo_lseek(conn, lo_desc, NUM2INT(offset), NUM2INT(whence))) < 0) {
		rb_raise(rb_ePGError, "lo_lseek failed");
	}

	return INT2FIX(ret);
}

/*
 * call-seq:
 *    conn.lo_tell( lo_desc ) -> Fixnum
 *
 * Returns the current position of the large object _lo_desc_.
 */
static VALUE
pgconn_lotell(VALUE self, VALUE in_lo_desc)
{
	int position;
	PGconn *conn = get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);

	if((position = lo_tell(conn, lo_desc)) < 0)
		rb_raise(rb_ePGError,"lo_tell failed");

	return INT2FIX(position);
}

/*
 * call-seq:
 *    conn.lo_truncate( lo_desc, len ) -> nil
 *
 * Truncates the large object _lo_desc_ to size _len_.
 */
static VALUE
pgconn_lotruncate(VALUE self, VALUE in_lo_desc, VALUE in_len)
{
	PGconn *conn = get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);
	size_t len = NUM2INT(in_len);

	if(lo_truncate(conn,lo_desc,len) < 0)
		rb_raise(rb_ePGError,"lo_truncate failed");

	return Qnil;
}

/*
 * call-seq:
 *    conn.lo_close( lo_desc ) -> nil
 *
 * Closes the postgres large object of _lo_desc_.
 */
static VALUE
pgconn_loclose(VALUE self, VALUE in_lo_desc)
{
	PGconn *conn = get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);

	if(lo_unlink(conn,lo_desc) < 0)
		rb_raise(rb_ePGError,"lo_close failed");

	return Qnil;
}

/*
 * call-seq:
 *    conn.lo_unlink( oid ) -> nil
 *
 * Unlinks (deletes) the postgres large object of _oid_.
 */
static VALUE
pgconn_lounlink(VALUE self, VALUE in_oid)
{
	PGconn *conn = get_pgconn(self);
	int oid = NUM2INT(in_oid);

	if (oid < 0)
		rb_raise(rb_ePGError, "invalid oid %d",oid);

	if(lo_unlink(conn,oid) < 0)
		rb_raise(rb_ePGError,"lo_unlink failed");

	return Qnil;
}

/********************************************************************
 * 
 * Document-class: PGresult
 *
 * The class to represent the query result tuples (rows). 
 * An instance of this class is created as the result of every query.
 * You may need to invoke the #clear method of the instance when finished with
 * the result for better memory performance.
 *
 * Example:
 *    require 'pg'
 *    conn = PGconn.open(:dbname => 'test')
 *    res  = conn.exec('SELECT 1 AS a, 2 AS b, NULL AS c')
 *    res.getvalue(0,0) # '1'
 *    res[0]['b']       # '2'
 *    res[0]['c']       # nil
 *  
 */

/**************************************************************************
 * PGresult INSTANCE METHODS
 **************************************************************************/

/*
 * call-seq:
 *    res.result_status() -> Fixnum
 *
 * Returns the status of the query. The status value is one of:
 * * +PGRES_EMPTY_QUERY+
 * * +PGRES_COMMAND_OK+
 * * +PGRES_TUPLES_OK+
 * * +PGRES_COPY_OUT+
 * * +PGRES_COPY_IN+
 * * +PGRES_BAD_RESPONSE+
 * * +PGRES_NONFATAL_ERROR+
 * * +PGRES_FATAL_ERROR+
 */
static VALUE
pgresult_result_status(VALUE self)
{
	return INT2FIX(PQresultStatus(get_pgresult(self)));
}

/*
 * call-seq:
 *    res.res_status( status ) -> String
 *
 * Returns the string representation of status +status+.
 *
*/
static VALUE
pgresult_res_status(VALUE self, VALUE status)
{
	return rb_tainted_str_new2(PQresStatus(NUM2INT(status)));
}

/*
 * call-seq:
 *    res.result_error_message() -> String
 *
 * Returns the error message of the command as a string. 
 */
static VALUE
pgresult_result_error_message(VALUE self)
{
	return rb_tainted_str_new2(PQresultErrorMessage(get_pgresult(self)));
}

/*
 * call-seq:
 *    res.result_error_field(fieldcode) -> String
 *
 * Returns the individual field of an error.
 *
 * +fieldcode+ is one of:
 * * +PG_DIAG_SEVERITY+
 * * +PG_DIAG_SQLSTATE+
 * * +PG_DIAG_MESSAGE_PRIMARY+
 * * +PG_DIAG_MESSAGE_DETAIL+
 * * +PG_DIAG_MESSAGE_HINT+
 * * +PG_DIAG_STATEMENT_POSITION+
 * * +PG_DIAG_INTERNAL_POSITION+
 * * +PG_DIAG_INTERNAL_QUERY+
 * * +PG_DIAG_CONTEXT+
 * * +PG_DIAG_SOURCE_FILE+
 * * +PG_DIAG_SOURCE_LINE+
 * * +PG_DIAG_SOURCE_FUNCTION+
 */
static VALUE
pgresult_result_error_field(VALUE self, VALUE field)
{
	PGresult *result = get_pgresult(self);
	int fieldcode = NUM2INT(field);
	return rb_tainted_str_new2(PQresultErrorField(result,fieldcode));
}

/*
 * call-seq:
 *    res.clear() -> nil
 *
 * Clears the PGresult object as the result of the query.
 */
static VALUE
pgresult_clear(VALUE self)
{
	PQclear(get_pgresult(self));
	DATA_PTR(self) = NULL;
	return Qnil;
}

/*
 * call-seq:
 *    res.ntuples() -> Fixnum
 *
 * Returns the number of tuples in the query result.
 */
static VALUE
pgresult_ntuples(VALUE self)
{
	return INT2FIX(PQntuples(get_pgresult(self)));
}

/*
 * call-seq:
 *    res.nfields() -> Fixnum
 *
 * Returns the number of columns in the query result.
 */
static VALUE
pgresult_nfields(VALUE self)
{
	return INT2NUM(PQnfields(get_pgresult(self)));
}

/*
 * call-seq:
 *    res.fname( index ) -> String
 *
 * Returns the name of the column corresponding to _index_.
 */
static VALUE
pgresult_fname(VALUE self, VALUE index)
{
	PGresult *result;
	int i = NUM2INT(index);

	result = get_pgresult(self);
	if (i < 0 || i >= PQnfields(result)) {
		rb_raise(rb_eArgError,"invalid field number %d", i);
	}
	return rb_tainted_str_new2(PQfname(result, i));
}

/*
 * call-seq:
 *    res.fnumber( name ) -> Fixnum
 *
 * Returns the index of the field specified by the string _name_.
 *
 * Raises an ArgumentError if the specified _name_ isn't one of the field names;
 * raises a TypeError if _name_ is not a String.
 */
static VALUE
pgresult_fnumber(VALUE self, VALUE name)
{
	int n;

	Check_Type(name, T_STRING);

	n = PQfnumber(get_pgresult(self), StringValuePtr(name));
	if (n == -1) {
		rb_raise(rb_eArgError,"Unknown field: %s", StringValuePtr(name));
	}
	return INT2FIX(n);
}

/*
 * call-seq:
 *    res.ftable( column_number ) -> Fixnum
 *
 * Returns the Oid of the table from which the column _column_number_
 * was fetched.
 *
 * Raises ArgumentError if _column_number_ is out of range or if
 * the Oid is undefined for that column.
 */
static VALUE
pgresult_ftable(VALUE self, VALUE column_number)
{
	Oid n = PQftable(get_pgresult(self), NUM2INT(column_number));
	if (n == InvalidOid) {
		rb_raise(rb_eArgError,"Oid is undefined for column: %d", 
			NUM2INT(column_number));
	}
	return INT2FIX(n);
}

/*
 * call-seq:
 *    res.ftablecol( column_number ) -> Fixnum
 *
 * Returns the column number (within its table) of the table from 
 * which the column _column_number_ is made up.
 *
 * Raises ArgumentError if _column_number_ is out of range or if
 * the column number from its table is undefined for that column.
 */
static VALUE
pgresult_ftablecol(VALUE self, VALUE column_number)
{
	int n = PQftablecol(get_pgresult(self), NUM2INT(column_number));
	if (n == 0) {
		rb_raise(rb_eArgError,
			"Column number from table is undefined for column: %d", 
			NUM2INT(column_number));
	}
	return INT2FIX(n);
}

/*
 * call-seq:
 *    res.fformat( column_number ) -> Fixnum
 *
 * Returns the format (0 for text, 1 for binary) of column
 * _column_number_.
 * 
 * Raises ArgumentError if _column_number_ is out of range.
 */
static VALUE
pgresult_fformat(VALUE self, VALUE column_number)
{
	PGresult *result = get_pgresult(self);
	int fnumber = NUM2INT(column_number);
	if (fnumber >= PQnfields(result)) {
		rb_raise(rb_eArgError, "Column number is out of range: %d", 
			fnumber);
	}
	return INT2FIX(PQfformat(result, fnumber));
}

/*
 * call-seq:
 *    res.ftype( column_number )
 *
 * Returns the data type associated with _column_number_.
 *
 * The integer returned is the internal +OID+ number (in PostgreSQL) of the type.
 */
static VALUE
pgresult_ftype(VALUE self, VALUE index)
{
	PGresult* result = get_pgresult(self);
	int i = NUM2INT(index);
	if (i < 0 || i >= PQnfields(result)) {
		rb_raise(rb_eArgError, "invalid field number %d", i);
	}
	return INT2NUM(PQftype(result, i));
}

/*
 * call-seq:
 *    res.fmod( column_number )
 *
 * Returns the type modifier associated with column _column_number_.
 * 
 * Raises ArgumentError if _column_number_ is out of range.
 */
static VALUE
pgresult_fmod(VALUE self, VALUE column_number)
{
	PGresult *result = get_pgresult(self);
	int fnumber = NUM2INT(column_number);
	int modifier;
	if (fnumber >= PQnfields(result)) {
		rb_raise(rb_eArgError, "Column number is out of range: %d", 
			fnumber);
	}
	if((modifier = PQfmod(result,fnumber)) == -1)
		rb_raise(rb_eArgError, 
			"No modifier information available for column: %d", 
			fnumber);
	return INT2NUM(modifier);
}

/*
 * call-seq:
 *    res.fsize( index )
 *
 * Returns the size of the field type in bytes.  Returns <tt>-1</tt> if the field is variable sized.
 *
 *   res = conn.exec("SELECT myInt, myVarChar50 FROM foo")
 *   res.size(0) => 4
 *   res.size(1) => -1
 */
static VALUE
pgresult_fsize(VALUE self, VALUE index)
{
	PGresult *result;
	int i = NUM2INT(index);

	result = get_pgresult(self);
	if (i < 0 || i >= PQnfields(result)) {
		rb_raise(rb_eArgError,"invalid field number %d", i);
	}
	return INT2NUM(PQfsize(result, i));
}

/*
 * call-seq:
 *    res.getvalue( tup_num, field_num )
 *
 * Returns the value in tuple number _tup_num_, field _field_num_,
 * or +nil+ if the field is +NULL+.
 */
static VALUE
pgresult_getvalue(VALUE self, VALUE tup_num, VALUE field_num)
{
	PGresult *result;
	int i = NUM2INT(tup_num);
	int j = NUM2INT(field_num);

	result = get_pgresult(self);
	if(i < 0 || i >= PQntuples(result)) {
		rb_raise(rb_eArgError,"invalid tuple number %d", i);
	}
	if(j < 0 || j >= PQnfields(result)) {
		rb_raise(rb_eArgError,"invalid field number %d", j);
	}
	if(PQgetisnull(result, i, j))
		return Qnil;
	return rb_tainted_str_new(PQgetvalue(result, i, j), 
				PQgetlength(result, i, j));
}

/*
 * call-seq:
 *    res.getisnull(tuple_position, field_position) -> boolean
 *
 * Returns +true+ if the specified value is +nil+; +false+ otherwise.
 */
static VALUE
pgresult_getisnull(VALUE self, VALUE tup_num, VALUE field_num)
{
	PGresult *result;
	int i = NUM2INT(tup_num);
	int j = NUM2INT(field_num);

	result = get_pgresult(self);
	if (i < 0 || i >= PQntuples(result)) {
		rb_raise(rb_eArgError,"invalid tuple number %d", i);
	}
	if (j < 0 || j >= PQnfields(result)) {
		rb_raise(rb_eArgError,"invalid field number %d", j);
	}
	return PQgetisnull(result, i, j) ? Qtrue : Qfalse;
}

/*
 * call-seq:
 *    res.getlength( tup_num, field_num ) -> Fixnum
 *
 * Returns the (String) length of the field in bytes.
 *
 * Equivalent to <tt>res.value(<i>tup_num</i>,<i>field_num</i>).length</tt>.
 */
static VALUE
pgresult_getlength(VALUE self, VALUE tup_num, VALUE field_num)
{
	PGresult *result;
	int i = NUM2INT(tup_num);
	int j = NUM2INT(field_num);

	result = get_pgresult(self);
	if (i < 0 || i >= PQntuples(result)) {
		rb_raise(rb_eArgError,"invalid tuple number %d", i);
	}
	if (j < 0 || j >= PQnfields(result)) {
		rb_raise(rb_eArgError,"invalid field number %d", j);
	}
	return INT2FIX(PQgetlength(result, i, j));
}

/*
 * call-seq:
 *    res.nparams() -> Fixnum
 *
 * Returns the number of parameters of a prepared statement.
 * Only useful for the result returned by conn.describePrepared
 */
static VALUE
pgresult_nparams(VALUE self)
{
	PGresult *result;

	result = get_pgresult(self);
	return INT2FIX(PQnparams(result));
}

/*
 * call-seq:
 *    res.paramtype( param_number ) -> Oid
 *
 * Returns the Oid of the data type of parameter _param_number_.
 * Only useful for the result returned by conn.describePrepared
 */
static VALUE
pgresult_paramtype(VALUE self, VALUE param_number)
{
	PGresult *result;

	result = get_pgresult(self);
	return INT2FIX(PQparamtype(result,NUM2INT(param_number)));
}

/*
 * call-seq:
 *    res.cmd_status() -> String
 *
 * Returns the status string of the last query command.
 */
static VALUE
pgresult_cmd_status(VALUE self)
{
	return rb_tainted_str_new2(PQcmdStatus(get_pgresult(self)));
}

/*
 * call-seq:
 *    res.cmd_tuples() -> Fixnum
 *
 * Returns the number of tuples (rows) affected by the SQL command.
 *
 * If the SQL command that generated the PGresult was not one of:
 * * +INSERT+
 * * +UPDATE+
 * * +DELETE+
 * * +MOVE+
 * * +FETCH+
 * or if no tuples were affected, <tt>0</tt> is returned.
 */
static VALUE
pgresult_cmd_tuples(VALUE self)
{
	long n;
	n = strtol(PQcmdTuples(get_pgresult(self)),NULL, 10);
	return INT2NUM(n);
}

/*
 * call-seq:
 *    res.oid_value() -> Fixnum
 *
 * Returns the +oid+ of the inserted row if applicable,
 * otherwise +nil+.
 */
static VALUE
pgresult_oid_value(VALUE self)
{
	Oid n = PQoidValue(get_pgresult(self));
	if (n == InvalidOid)
		return Qnil;
	else
		return INT2FIX(n);
}

/* Utility methods not in libpq */

/*
 * call-seq:
 *    res[ n ] -> Hash
 *
 * Returns tuple _n_ as a hash. 
 */
static VALUE
pgresult_aref(VALUE self, VALUE index)
{
	PGresult *result = get_pgresult(self);
	int tuple_num = NUM2INT(index);
	int field_num;
	VALUE fname,val;
	VALUE tuple;

	if(tuple_num >= PQntuples(result))
		rb_raise(rb_eIndexError, "Index %d is out of range", tuple_num);
	tuple = rb_hash_new();
	for(field_num = 0; field_num < PQnfields(result); field_num++) {
		fname = rb_tainted_str_new2(PQfname(result,field_num));
		if(PQgetisnull(result, tuple_num, field_num)) {
			rb_hash_aset(tuple, fname, Qnil);
		}
		else {
			val = rb_tainted_str_new(PQgetvalue(result, tuple_num, field_num),
				PQgetlength(result, tuple_num, field_num));
			rb_hash_aset(tuple, fname, val);
		}
	}
	return tuple;
}

/*
 * call-seq:
 *    res.each{ |tuple| ... }
 *
 * Invokes block for each tuple in the result set.
 */
static VALUE
pgresult_each(VALUE self)
{
	PGresult *result = get_pgresult(self);
	int tuple_num;

	for(tuple_num = 0; tuple_num < PQntuples(result); tuple_num++) {
		rb_yield(pgresult_aref(self, INT2NUM(tuple_num)));
	}
	return self;
}

/*
 * call-seq:
 *    res.fields() -> Array
 *
 * Returns an array of Strings representing the names of the fields in the result.
 */
static VALUE
pgresult_fields(VALUE self)
{
	PGresult *result;
	VALUE ary;
	int n, i;

	result = get_pgresult(self);
	n = PQnfields(result);
	ary = rb_ary_new2(n);
	for (i=0;i<n;i++) {
		rb_ary_push(ary, rb_tainted_str_new2(PQfname(result, i)));
	}
	return ary;
}

/**************************************************************************/

void
Init_pg()
{
	rb_ePGError = rb_define_class("PGError", rb_eStandardError);
	rb_cPGconn = rb_define_class("PGconn", rb_cObject);
	rb_cPGresult = rb_define_class("PGresult", rb_cObject);


	/*************************
	 *  PGError 
	 *************************/
	rb_define_alias(rb_ePGError, "error", "message");
	rb_define_attr(rb_ePGError, "connection", 1, 0);
	rb_define_attr(rb_ePGError, "result", 1, 0);

	/*************************
	 *  PGconn 
	 *************************/

	/******     PGconn CLASS METHODS     ******/
	rb_define_alloc_func(rb_cPGconn, pgconn_alloc);
	rb_define_singleton_alias(rb_cPGconn, "connect", "new");
	rb_define_singleton_alias(rb_cPGconn, "open", "new");
	rb_define_singleton_alias(rb_cPGconn, "setdb", "new");
	rb_define_singleton_alias(rb_cPGconn, "setdblogin", "new");
	rb_define_singleton_method(rb_cPGconn, "escape_string", pgconn_s_escape, 1);
	rb_define_singleton_alias(rb_cPGconn, "escape", "escape_string");
	rb_define_singleton_method(rb_cPGconn, "escape_bytea", pgconn_s_escape_bytea, 1);
	rb_define_singleton_method(rb_cPGconn, "unescape_bytea", pgconn_s_unescape_bytea, 1);
	rb_define_singleton_method(rb_cPGconn, "isthreadsafe", pgconn_s_isthreadsafe, 0);
	rb_define_singleton_method(rb_cPGconn, "encrypt_password", pgconn_s_encrypt_password, 0);
	rb_define_singleton_method(rb_cPGconn, "quote_ident", pgconn_s_quote_ident, 1);
	rb_define_singleton_method(rb_cPGconn, "connect_start", pgconn_s_connect_start, -1);
	rb_define_singleton_method(rb_cPGconn, "conndefaults", pgconn_s_conndefaults, 0);

	/******     PGconn CLASS CONSTANTS: Connection Status     ******/
	rb_define_const(rb_cPGconn, "CONNECTION_OK", INT2FIX(CONNECTION_OK));
	rb_define_const(rb_cPGconn, "CONNECTION_BAD", INT2FIX(CONNECTION_BAD));

	/******     PGconn CLASS CONSTANTS: Nonblocking connection status     ******/
	rb_define_const(rb_cPGconn, "CONNECTION_STARTED", INT2FIX(CONNECTION_STARTED));
	rb_define_const(rb_cPGconn, "CONNECTION_MADE", INT2FIX(CONNECTION_MADE));
	rb_define_const(rb_cPGconn, "CONNECTION_AWAITING_RESPONSE", INT2FIX(CONNECTION_AWAITING_RESPONSE));
	rb_define_const(rb_cPGconn, "CONNECTION_AUTH_OK", INT2FIX(CONNECTION_AUTH_OK));
	rb_define_const(rb_cPGconn, "CONNECTION_SSL_STARTUP", INT2FIX(CONNECTION_SSL_STARTUP));
	rb_define_const(rb_cPGconn, "CONNECTION_SETENV", INT2FIX(CONNECTION_SETENV));

	/******     PGconn CLASS CONSTANTS: Nonblocking connection polling status     ******/
	rb_define_const(rb_cPGconn, "PGRES_POLLING_READING", INT2FIX(PGRES_POLLING_READING));
	rb_define_const(rb_cPGconn, "PGRES_POLLING_WRITING", INT2FIX(PGRES_POLLING_WRITING));
	rb_define_const(rb_cPGconn, "PGRES_POLLING_FAILED", INT2FIX(PGRES_POLLING_FAILED));
	rb_define_const(rb_cPGconn, "PGRES_POLLING_OK", INT2FIX(PGRES_POLLING_OK));

	/******     PGconn CLASS CONSTANTS: Transaction Status     ******/
	rb_define_const(rb_cPGconn, "PQTRANS_IDLE", INT2FIX(PQTRANS_IDLE));
	rb_define_const(rb_cPGconn, "PQTRANS_ACTIVE", INT2FIX(PQTRANS_ACTIVE));
	rb_define_const(rb_cPGconn, "PQTRANS_INTRANS", INT2FIX(PQTRANS_INTRANS));
	rb_define_const(rb_cPGconn, "PQTRANS_INERROR", INT2FIX(PQTRANS_INERROR));
	rb_define_const(rb_cPGconn, "PQTRANS_UNKNOWN", INT2FIX(PQTRANS_UNKNOWN));

	/******     PGconn CLASS CONSTANTS: Error Verbosity     ******/
	rb_define_const(rb_cPGconn, "PQERRORS_TERSE", INT2FIX(PQERRORS_TERSE));
	rb_define_const(rb_cPGconn, "PQERRORS_DEFAULT", INT2FIX(PQERRORS_DEFAULT));
	rb_define_const(rb_cPGconn, "PQERRORS_VERBOSE", INT2FIX(PQERRORS_VERBOSE));

	/******     PGconn CLASS CONSTANTS: Large Objects     ******/
	rb_define_const(rb_cPGconn, "INV_WRITE", INT2FIX(INV_WRITE));
	rb_define_const(rb_cPGconn, "INV_READ", INT2FIX(INV_READ));
	rb_define_const(rb_cPGconn, "SEEK_SET", INT2FIX(SEEK_SET));
	rb_define_const(rb_cPGconn, "SEEK_CUR", INT2FIX(SEEK_CUR));
	rb_define_const(rb_cPGconn, "SEEK_END", INT2FIX(SEEK_END));

	/******     PGconn INSTANCE METHODS: Connection Control     ******/
	rb_define_method(rb_cPGconn, "initialize", pgconn_init, -1);
	rb_define_method(rb_cPGconn, "connect_poll", pgconn_connect_poll, 0);
	rb_define_method(rb_cPGconn, "finish", pgconn_finish, 0);
	rb_define_method(rb_cPGconn, "reset", pgconn_reset, 0);
	rb_define_method(rb_cPGconn, "reset_start", pgconn_reset_start, 0);
	rb_define_method(rb_cPGconn, "reset_poll", pgconn_reset_poll, 0);
	rb_define_method(rb_cPGconn, "conndefaults", pgconn_s_conndefaults, 0);
	rb_define_alias(rb_cPGconn, "close", "finish");

	/******     PGconn INSTANCE METHODS: Connection Status     ******/
	rb_define_method(rb_cPGconn, "db", pgconn_db, 0);
	rb_define_method(rb_cPGconn, "user", pgconn_user, 0);
	rb_define_method(rb_cPGconn, "pass", pgconn_pass, 0);
	rb_define_method(rb_cPGconn, "host", pgconn_host, 0);
	rb_define_method(rb_cPGconn, "port", pgconn_port, 0);
	rb_define_method(rb_cPGconn, "tty", pgconn_tty, 0);
	rb_define_method(rb_cPGconn, "options", pgconn_options, 0);
	rb_define_method(rb_cPGconn, "status", pgconn_status, 0);
	rb_define_method(rb_cPGconn, "transaction_status", pgconn_transaction_status, 0);
	rb_define_method(rb_cPGconn, "parameter_status", pgconn_parameter_status, 1);
	rb_define_method(rb_cPGconn, "protocol_version", pgconn_protocol_version, 0);
	rb_define_method(rb_cPGconn, "server_version", pgconn_server_version, 0);
	rb_define_method(rb_cPGconn, "error_message", pgconn_error_message, 0);
	rb_define_method(rb_cPGconn, "socket", pgconn_socket, 0);
	rb_define_method(rb_cPGconn, "backend_pid", pgconn_backend_pid, 0);
	rb_define_method(rb_cPGconn, "connection_needs_password", pgconn_connection_needs_password, 0);
	rb_define_method(rb_cPGconn, "connection_used_password", pgconn_connection_used_password, 0);
	//rb_define_method(rb_cPGconn, "getssl", pgconn_getssl, 0);

	/******     PGconn INSTANCE METHODS: Command Execution     ******/
	rb_define_method(rb_cPGconn, "exec", pgconn_exec, -1);
	rb_define_alias(rb_cPGconn, "query", "exec");
	rb_define_method(rb_cPGconn, "prepare", pgconn_prepare, -1);
	rb_define_method(rb_cPGconn, "exec_prepared", pgconn_exec_prepared, -1);
	rb_define_method(rb_cPGconn, "describe_prepared", pgconn_describe_prepared, 1);
	rb_define_method(rb_cPGconn, "describe_portal", pgconn_describe_portal, 1);
	rb_define_method(rb_cPGconn, "make_empty_pgresult", pgconn_make_empty_pgresult, 1);
	rb_define_method(rb_cPGconn, "escape_string", pgconn_s_escape, 1);
	rb_define_alias(rb_cPGconn, "escape", "escape_string");
	rb_define_method(rb_cPGconn, "escape_bytea", pgconn_s_escape_bytea, 1);
	rb_define_method(rb_cPGconn, "unescape_bytea", pgconn_s_unescape_bytea, 1);

	/******     PGconn INSTANCE METHODS: Asynchronous Command Processing     ******/
	rb_define_method(rb_cPGconn, "send_query", pgconn_send_query, -1);
	rb_define_method(rb_cPGconn, "send_prepare", pgconn_send_prepare, -1);
	rb_define_method(rb_cPGconn, "send_query_prepared", pgconn_send_query_prepared, -1);
	rb_define_method(rb_cPGconn, "send_describe_prepared", pgconn_send_describe_prepared, 1);
	rb_define_method(rb_cPGconn, "send_describe_portal", pgconn_send_describe_portal, 1);
	rb_define_method(rb_cPGconn, "get_result", pgconn_get_result, 0);
	rb_define_method(rb_cPGconn, "consume_input", pgconn_consume_input, 0);
	rb_define_method(rb_cPGconn, "is_busy", pgconn_is_busy, 0);
	rb_define_method(rb_cPGconn, "setnonblocking", pgconn_setnonblocking, 1);
	rb_define_method(rb_cPGconn, "isnonblocking", pgconn_isnonblocking, 0);
	rb_define_method(rb_cPGconn, "flush", pgconn_flush, 0);

	/******     PGconn INSTANCE METHODS: Cancelling Queries in Progress     ******/
	rb_define_method(rb_cPGconn, "cancel", pgconn_cancel, 0);

	/******     PGconn INSTANCE METHODS: NOTIFY     ******/
	rb_define_method(rb_cPGconn, "notifies", pgconn_notifies, 0);

	/******     PGconn INSTANCE METHODS: COPY     ******/
	rb_define_method(rb_cPGconn, "put_copy_data", pgconn_put_copy_data, 1);
	rb_define_method(rb_cPGconn, "put_copy_end", pgconn_put_copy_end, -1);
	rb_define_method(rb_cPGconn, "get_copy_data", pgconn_get_copy_data, -1);

	/******     PGconn INSTANCE METHODS: Control Functions     ******/
	rb_define_method(rb_cPGconn, "set_error_verbosity", pgconn_set_error_verbosity, 1);
	rb_define_method(rb_cPGconn, "trace", pgconn_trace, 1);
	rb_define_method(rb_cPGconn, "untrace", pgconn_untrace, 0);

	/******     PGconn INSTANCE METHODS: Notice Processing     ******/
	rb_define_method(rb_cPGconn, "set_notice_receiver", pgconn_set_notice_receiver, 0);
	rb_define_method(rb_cPGconn, "set_notice_processor", pgconn_set_notice_processor, 0);

	/******     PGconn INSTANCE METHODS: Other    ******/
	rb_define_method(rb_cPGconn, "get_client_encoding", pgconn_get_client_encoding, 0);
	rb_define_method(rb_cPGconn, "set_client_encoding", pgconn_set_client_encoding, 1);
	rb_define_method(rb_cPGconn, "transaction", pgconn_transaction, 0);
	rb_define_method(rb_cPGconn, "block", pgconn_block, -1);
	rb_define_method(rb_cPGconn, "quote_ident", pgconn_s_quote_ident, 1);
	rb_define_method(rb_cPGconn, "async_exec", pgconn_async_exec, -1);
	rb_define_alias(rb_cPGconn, "async_query", "async_exec");
	rb_define_method(rb_cPGconn, "get_last_result", pgconn_get_last_result, 0);

	/******     PGconn INSTANCE METHODS: Large Object Support     ******/
	rb_define_method(rb_cPGconn, "lo_creat", pgconn_locreat, -1);
	rb_define_alias(rb_cPGconn, "locreat", "lo_creat");
	rb_define_method(rb_cPGconn, "lo_create", pgconn_locreate, 1);
	rb_define_alias(rb_cPGconn, "locreate", "lo_create");
	rb_define_method(rb_cPGconn, "lo_import", pgconn_loimport, 1);
	rb_define_alias(rb_cPGconn, "loimport", "lo_import");
	rb_define_method(rb_cPGconn, "lo_export", pgconn_loexport, 2);
	rb_define_alias(rb_cPGconn, "loexport", "lo_export");
	rb_define_method(rb_cPGconn, "lo_open", pgconn_loopen, -1);
	rb_define_alias(rb_cPGconn, "loopen", "lo_open");
	rb_define_method(rb_cPGconn, "lo_write",pgconn_lowrite, 2);
	rb_define_alias(rb_cPGconn, "lowrite", "lo_write");
	rb_define_method(rb_cPGconn, "lo_read",pgconn_loread, 2);
	rb_define_alias(rb_cPGconn, "loread", "lo_read");
	rb_define_method(rb_cPGconn, "lo_lseek",pgconn_lolseek, 3);
	rb_define_alias(rb_cPGconn, "lolseek", "lo_lseek");
	rb_define_alias(rb_cPGconn, "lo_seek", "lo_lseek");
	rb_define_alias(rb_cPGconn, "loseek", "lo_lseek");
	rb_define_method(rb_cPGconn, "lo_tell",pgconn_lotell, 1);
	rb_define_alias(rb_cPGconn, "lotell", "lo_tell");
	rb_define_method(rb_cPGconn, "lo_truncate", pgconn_lotruncate, 2);
	rb_define_alias(rb_cPGconn, "lotruncate", "lo_truncate");
	rb_define_method(rb_cPGconn, "lo_close",pgconn_loclose, 1);
	rb_define_alias(rb_cPGconn, "loclose", "lo_close");
	rb_define_method(rb_cPGconn, "lo_unlink", pgconn_lounlink, 1);
	rb_define_alias(rb_cPGconn, "lounlink", "lo_unlink");

	/*************************
	 *  PGresult 
	 *************************/
	rb_include_module(rb_cPGresult, rb_mEnumerable);

	/******     PGresult CONSTANTS: result status      ******/
	rb_define_const(rb_cPGresult, "PGRES_EMPTY_QUERY", INT2FIX(PGRES_EMPTY_QUERY));
	rb_define_const(rb_cPGresult, "PGRES_COMMAND_OK", INT2FIX(PGRES_COMMAND_OK));
	rb_define_const(rb_cPGresult, "PGRES_TUPLES_OK", INT2FIX(PGRES_TUPLES_OK));
	rb_define_const(rb_cPGresult, "PGRES_COPY_OUT", INT2FIX(PGRES_COPY_OUT));
	rb_define_const(rb_cPGresult, "PGRES_COPY_IN", INT2FIX(PGRES_COPY_IN));
	rb_define_const(rb_cPGresult, "PGRES_BAD_RESPONSE", INT2FIX(PGRES_BAD_RESPONSE));
	rb_define_const(rb_cPGresult, "PGRES_NONFATAL_ERROR",INT2FIX(PGRES_NONFATAL_ERROR));
	rb_define_const(rb_cPGresult, "PGRES_FATAL_ERROR", INT2FIX(PGRES_FATAL_ERROR));

	/******     PGresult CONSTANTS: result error field codes      ******/
	rb_define_const(rb_cPGresult, "PG_DIAG_SEVERITY", INT2FIX(PG_DIAG_SEVERITY));
	rb_define_const(rb_cPGresult, "PG_DIAG_SQLSTATE", INT2FIX(PG_DIAG_SQLSTATE));
	rb_define_const(rb_cPGresult, "PG_DIAG_MESSAGE_PRIMARY", INT2FIX(PG_DIAG_MESSAGE_PRIMARY));
	rb_define_const(rb_cPGresult, "PG_DIAG_MESSAGE_DETAIL", INT2FIX(PG_DIAG_MESSAGE_DETAIL));
	rb_define_const(rb_cPGresult, "PG_DIAG_MESSAGE_HINT", INT2FIX(PG_DIAG_MESSAGE_HINT));
	rb_define_const(rb_cPGresult, "PG_DIAG_STATEMENT_POSITION", INT2FIX(PG_DIAG_STATEMENT_POSITION));
	rb_define_const(rb_cPGresult, "PG_DIAG_INTERNAL_POSITION", INT2FIX(PG_DIAG_INTERNAL_POSITION));
	rb_define_const(rb_cPGresult, "PG_DIAG_INTERNAL_QUERY", INT2FIX(PG_DIAG_INTERNAL_QUERY));
	rb_define_const(rb_cPGresult, "PG_DIAG_CONTEXT", INT2FIX(PG_DIAG_CONTEXT));
	rb_define_const(rb_cPGresult, "PG_DIAG_SOURCE_FILE", INT2FIX(PG_DIAG_SOURCE_FILE));
	rb_define_const(rb_cPGresult, "PG_DIAG_SOURCE_LINE", INT2FIX(PG_DIAG_SOURCE_LINE));
	rb_define_const(rb_cPGresult, "PG_DIAG_SOURCE_FUNCTION", INT2FIX(PG_DIAG_SOURCE_FUNCTION));

	/******     PGresult INSTANCE METHODS: libpq     ******/
	rb_define_method(rb_cPGresult, "result_status", pgresult_result_status, 0);
	rb_define_method(rb_cPGresult, "res_status", pgresult_res_status, 1);
	rb_define_method(rb_cPGresult, "result_error_message", pgresult_result_error_message, 0);
	rb_define_method(rb_cPGresult, "result_error_field", pgresult_result_error_field, 1);
	rb_define_method(rb_cPGresult, "clear", pgresult_clear, 0);
	rb_define_method(rb_cPGresult, "ntuples", pgresult_ntuples, 0);
	rb_define_alias(rb_cPGresult, "num_tuples", "ntuples");
	rb_define_method(rb_cPGresult, "nfields", pgresult_nfields, 0);
	rb_define_alias(rb_cPGresult, "num_fields", "nfields");
	rb_define_method(rb_cPGresult, "fname", pgresult_fname, 1);
	rb_define_method(rb_cPGresult, "fnumber", pgresult_fnumber, 1);
	rb_define_method(rb_cPGresult, "ftable", pgresult_ftable, 1);
	rb_define_method(rb_cPGresult, "ftablecol", pgresult_ftablecol, 1);
	rb_define_method(rb_cPGresult, "fformat", pgresult_fformat, 1);
	rb_define_method(rb_cPGresult, "ftype", pgresult_ftype, 1);
	rb_define_method(rb_cPGresult, "fmod", pgresult_fmod, 1);
	rb_define_method(rb_cPGresult, "fsize", pgresult_fsize, 1);
	rb_define_method(rb_cPGresult, "getvalue", pgresult_getvalue, 2);
	rb_define_method(rb_cPGresult, "getisnull", pgresult_getisnull, 2);
	rb_define_method(rb_cPGresult, "getlength", pgresult_getlength, 2);
	rb_define_method(rb_cPGresult, "nparams", pgresult_nparams, 0);
	rb_define_method(rb_cPGresult, "paramtype", pgresult_paramtype, 0);
	rb_define_method(rb_cPGresult, "cmd_status", pgresult_cmd_status, 0);
	rb_define_method(rb_cPGresult, "cmd_tuples", pgresult_cmd_tuples, 0);
	rb_define_alias(rb_cPGresult, "cmdtuples", "cmd_tuples");
	rb_define_method(rb_cPGresult, "oid_value", pgresult_oid_value, 0);

	/******     PGresult INSTANCE METHODS: other     ******/
	rb_define_method(rb_cPGresult, "[]", pgresult_aref, 1);
	rb_define_method(rb_cPGresult, "each", pgresult_each, 0);
	rb_define_method(rb_cPGresult, "fields", pgresult_fields, 0);

}
