Mercurial > zfc9000 / file revision

/*
	Copyright 2014 Teemu Piippo
	All rights reserved.

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions
	are met:

	1. Redistributions of source code must retain the above copyright
	   notice, this list of conditions and the following disclaimer.
	2. Redistributions in binary form must reproduce the above copyright
	   notice, this list of conditions and the following disclaimer in the
	   documentation and/or other materials provided with the distribution.
	3. Neither the name of the copyright holder nor the names of its
	   contributors may be used to endorse or promote products derived from
	   this software without specific prior written permission.

	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
	TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER
	OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
	LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
	NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <string.h>
#include "interface.h"
#include "network/rconsession.h"
#include "network/ipaddress.h"

enum
{
	RLINE_ON_BLACK = 256,
	RLINE_ON_RED,
	RLINE_ON_GREEN,
	RLINE_ON_YELLOW,
	RLINE_ON_BLUE,
	RLINE_ON_MAGENTA,
	RLINE_ON_CYAN,
	RLINE_ON_WHITE,
	RLINE_ON_BOLD,
	RLINE_OFF_BLACK,
	RLINE_OFF_RED,
	RLINE_OFF_GREEN,
	RLINE_OFF_YELLOW,
	RLINE_OFF_BLUE,
	RLINE_OFF_MAGENTA,
	RLINE_OFF_CYAN,
	RLINE_OFF_WHITE,
	RLINE_OFF_BOLD,
};

class RendererLine
{
public:
	RendererLine() {}

	METHOD data() const -> const Vector<int>& { return m_data; }
	METHOD length() const -> int { return m_length; }
	METHOD add_char (char ch) -> void;
	METHOD finalize() -> void;
	METHOD rows (int cols) const -> int;

private:
	METHOD set_color (Color a, bool on) -> void;

	Vector<int> m_data;
	int m_length = 0;
	bool m_final = false;
	Color m_activeColor = DEFAULT;
	bool m_boldActive = false;
	int m_colorCodeStage = 0;
	String m_string;
};

static const int g_pageSize = 10;

enum InputState
{
	INPUTSTATE_NORMAL,
	INPUTSTATE_ADDRESS,
	INPUTSTATE_PASSWORD,
	INPUTSTATE_CONFIRM_DISCONNECTION,
};

static StringList g_input;
static int g_inputCursor = 0;
static int g_cursor = 0;
static int g_pan = 0;
static bool g_needRefresh = false;
static bool g_needStatusBarRender = false;
static bool g_needInputRender = false;
static bool g_needOutputRender = false;
static struct { char ch; int x; } g_cursorChar;
static Vector<RendererLine> g_output;;
static int g_outputScroll = 0;
static String g_title;
static InputState g_inputState = INPUTSTATE_NORMAL;
static Function<void (void)> g_disconnectConfirmFunction = nullptr;
static IPAddress g_address;
static String g_statusBarText;

static const struct { Color color; bool bold; } g_colorCodes['v' - 'a' + 1] =
{
	{ RED,     true  }, // a - brick
	{ YELLOW,  true  }, // b - tan
	{ WHITE,   false }, // c - gray
	{ GREEN,   true  }, // d - light green
	{ YELLOW,  false }, // e - brown
	{ YELLOW,  true  }, // f - gold yellow
	{ RED,     true  }, // g - bright red
	{ BLUE,    false }, // h - dark blue
	{ YELLOW,  false }, // i - orange
	{ WHITE,   true  }, // j - white
	{ YELLOW,  true  }, // k - fire yellow
	{ DEFAULT, false }, // l - untranslated
	{ BLACK,   false }, // m - black
	{ BLUE,    true  }, // n - light blue
	{ YELLOW,  true  }, // o - cream
	{ GREEN,   true  }, // p - olive green
	{ GREEN,   false }, // q - dark green
	{ RED,     false }, // r - dark red
	{ YELLOW,  false }, // s - dark brown
	{ MAGENTA, false }, // t - purple
	{ BLACK,   true  }, // u - dark gray
	{ CYAN,    true  }, // v - cyan
};

// -------------------------------------------------------------------------------------------------
//
static FUNCTION
interface_color_pair (Color fg, Color bg) -> int
{
	return COLOR_PAIR ((int (fg) * NUM_COLORS) + int (bg));
}

// -------------------------------------------------------------------------------------------------
//
static FUNCTION
current_input() -> const String&
{
	return g_input[g_inputCursor];
}

// -------------------------------------------------------------------------------------------------
//
// Makes current_input() the lastmost input (so that we won't modify history)
//
static FUNCTION
detach_input() -> void
{
	if (g_inputCursor > 0)
	{
		g_input[0] = current_input();
		g_inputCursor = 0;
	}
}

// -------------------------------------------------------------------------------------------------
// A version of current_input() that allows changing the contents of it.
//
static FUNCTION
mutable_current_input() -> String&
{
	detach_input();
	return g_input[g_inputCursor];
}

// -------------------------------------------------------------------------------------------------
//
static FUNCTION
move_input_cursor (int delta) -> void
{
	// No input history when inputting addresses or passwords
	if (g_inputState != INPUTSTATE_NORMAL)
	{
		g_inputCursor = 0;
		return;
	}

	int oldcursor = g_inputCursor;
	g_inputCursor = clamp (g_inputCursor + delta, 0, g_input.size() - 1);

	if (g_inputCursor != oldcursor)
	{
		g_cursor = current_input().length();
		g_needInputRender = true;
	}
}

// -------------------------------------------------------------------------------------------------
//
static FUNCTION
interface_prompt_string() -> String
{
	String prompt;

	switch (g_inputState)
	{
	case INPUTSTATE_NORMAL: prompt = ">"; break;
	case INPUTSTATE_ADDRESS: prompt = "address:"; break;
	case INPUTSTATE_PASSWORD: prompt = "password:"; break;
	case INPUTSTATE_CONFIRM_DISCONNECTION: break;
	}

	return prompt;
}

// -------------------------------------------------------------------------------------------------
//
static FUNCTION
set_input_state (InputState newstate) -> void
{
	// Clear the input row (unless going to or from confirm state)
	if (newstate != INPUTSTATE_CONFIRM_DISCONNECTION
		and g_inputState != INPUTSTATE_CONFIRM_DISCONNECTION)
	{
		g_inputCursor = 0;
		mutable_current_input().clear();
	}

	switch (newstate)
	{
	case INPUTSTATE_ADDRESS:
		if (g_address.host != 0)
			mutable_current_input() = g_address.to_string (IP_WITH_PORT);
		break;

	default:
		break;
	}

	g_inputState = newstate;
	g_needInputRender = true;
}

// -------------------------------------------------------------------------------------------------
//
FUNCTION
Interface::initialize() -> void
{
	::initscr();
	::start_color();
	::raw();
	::keypad (stdscr, true);
	::noecho();
	::refresh();
	::timeout (0);
	::use_default_colors();
	g_input.clear();
	g_input << "";
	g_output.clear();
	g_output << RendererLine();
	g_title = format (APPNAME " %1 (%2)", full_version_string(), changeset_date_string());

	for (int i = 0; i < NUM_COLORS; ++i)
	for (int j = 0; j < NUM_COLORS; ++j)
	{
		init_pair ((i * NUM_COLORS + j),
			(i == DEFAULT) ? -1 : i,
			(j == DEFAULT) ? -1 : j);
	}

	render_full();
	refresh();
	g_needRefresh = false;
}

// -------------------------------------------------------------------------------------------------
//
static FUNCTION
interface_render_titlebar() -> void
{
	if (g_title.length() <= COLS)
	{
		int pair = interface_color_pair (WHITE, BLUE);
		int startx = (COLS - g_title.length()) / 2;
		int endx = startx + g_title.length();
		attron (pair);
		mvprintw (0, startx, "%s", g_title.chars());
		mvhline (0, 0, ' ', startx);
		mvhline (0, endx, ' ', COLS - endx);
		attroff (pair);
	}

	g_needRefresh = true;
}

// -------------------------------------------------------------------------------------------------
//
FUNCTION
Interface::set_title (const String& title) -> void
{
	g_title = title;
	interface_render_titlebar();
}

// -------------------------------------------------------------------------------------------------
//
static FUNCTION
safe_disconnect (Function<void()> afterwards) -> void
{
	if (RCONSession::get_session()->is_active())
	{
		g_disconnectConfirmFunction = afterwards;
		set_input_state (INPUTSTATE_CONFIRM_DISCONNECTION);
	}
	else
		afterwards();
}

// -------------------------------------------------------------------------------------------------
//
static FUNCTION
interface_render_output() -> void
{
	if (g_output.size() == 1)
		return;

	g_outputScroll = clamp (g_outputScroll, 0, g_output.size() - 1);

	int height = LINES - 3;
	int printOffset = 0;
	int end = g_output.size() - 1 - g_outputScroll;
	int start = end;
	int usedHeight = 0;
	int y = 1;
	bool tightFit = false;

	// Where to start?
	while (start > 0)
	{
		int rows = g_output[start - 1].rows (COLS);

		if (usedHeight + rows > height)
		{
			// This line won't fit anymore.
			tightFit = true;
			break;
		}

		start--;
		usedHeight += rows;
	}

	// See if there's any more rows to use (end may be too small)
	if (not tightFit)
	{
		while (end < g_output.size())
		{
			int rows = g_output[end].rows (COLS);

			if (usedHeight + rows > height)
			{
				tightFit = true;
				break;
			}

			end++;
			usedHeight += rows;
		}
	}

	if (start > 0)
		printOffset = height - usedHeight;

	g_outputScroll = g_output.size() - 1 - end;

	if (start < 0 or start == end or printOffset >= height)
		return;

	assert (start <= end and start - end <= height);

	// Clear the display
	for (int i = y; i < y + height; ++i)
		mvhline (i, 0, ' ', COLS);

	// Print the lines
	y += printOffset;

	for (int i = start; i < end; ++i)
	{
		int x = 0;

		for (int byte : g_output[i].data())
		{
			if (x == COLS)
			{
				x = 0;
				++y;
			}

			if (isprint (byte))
				mvaddch (y, x++, char (byte));
			else switch (byte)
			{
			case RLINE_ON_BLACK:
			case RLINE_ON_GREEN:
			case RLINE_ON_YELLOW:
			case RLINE_ON_BLUE:
			case RLINE_ON_MAGENTA:
			case RLINE_ON_CYAN:
			case RLINE_ON_WHITE:
				attron (interface_color_pair (Color (byte - RLINE_ON_BLACK), DEFAULT));
				break;

			case RLINE_OFF_BLACK:
			case RLINE_OFF_GREEN:
			case RLINE_OFF_YELLOW:
			case RLINE_OFF_BLUE:
			case RLINE_OFF_MAGENTA:
			case RLINE_OFF_CYAN:
			case RLINE_OFF_WHITE:
				attroff (interface_color_pair (Color (byte - RLINE_OFF_BLACK), DEFAULT));
				break;

			case RLINE_ON_BOLD:
				attron (A_BOLD);
				break;

			case RLINE_OFF_BOLD:
				attroff (A_BOLD);
				break;
			}
		}

		++y;
	}

	g_needOutputRender = false;
	g_needRefresh = true;
}

// -------------------------------------------------------------------------------------------------
//
static FUNCTION
interface_render_input() -> void
{
	int promptColor = interface_color_pair (WHITE, BLUE);

	// If we're asking the user if they want to disconnect, we don't render any input strings,
	// just the confirmation message.
	if (g_inputState == INPUTSTATE_CONFIRM_DISCONNECTION)
	{
		attron (promptColor);
		mvhline (LINES - 2, 0, ' ', COLS);
		mvprintw (LINES - 2, 0, "Are you sure you want to disconnect? y/n");
		attroff (promptColor);
		return;
	}

	String prompt = interface_prompt_string();
	int displayLength = COLS - prompt.length() - 2;
	String displayString = current_input();
	int y = LINES - 2;

	// If we're inputting a password, replace it with asterisks
	if (g_inputState == INPUTSTATE_PASSWORD)
	{
		for (char& ch : displayString)
			ch = '*';
	}

	// Ensure the cursor is within bounds
	g_cursor = clamp (g_cursor, 0, displayString.length());

	// Ensure that the cursor is always in view, adjust panning if this is not the case
	if (g_cursor > g_pan + displayLength)
		g_pan = g_cursor - displayLength; // cursor went too far right
	else if (g_cursor < g_pan)
		g_pan = g_cursor; // cursor went past the pan value to the left

	// What part of the string to draw?
	int start = g_pan;
	int end = min<int> (displayString.length(), start + displayLength);
	assert (g_cursor >= start and g_cursor <= end);

	// Render the input string
	mvhline (LINES - 2, 0, ' ', COLS);
	mvprintw (y, prompt.length() + 1, "%s", displayString.chars());

	// Render the prompt
	attron (promptColor);
	mvprintw (y, 0, "%s", prompt.chars());
	attroff (promptColor);

	// Store in memory where the cursor is now (so that we can re-draw it to position the terminal
	// cursor).
	g_cursorChar.ch = g_cursor != 0 ? displayString[g_cursor - 1] : '\0';
	g_cursorChar.x = prompt.length() + (g_cursor - g_pan);
	g_needRefresh = true;
	g_needInputRender = false;
}

// -------------------------------------------------------------------------------------------------
//
static FUNCTION
interface_render_statusbar() -> void
{
	int color = interface_color_pair (WHITE, BLUE);
	int y = LINES - 1;
	attron (color);
	mvhline (y, 0, ' ', COLS);
	mvprintw (y, 0, "%s", g_statusBarText.chars());
	attroff (color);
	g_needRefresh = true;
	g_needStatusBarRender = false;
}

// -------------------------------------------------------------------------------------------------
//
FUNCTION
Interface::update_statusbar() -> void
{
	String text;
	RCONSession* session = RCONSession::get_session();

	switch (session->state())
	{
	case RCON_DISCONNECTED:
		text = "Disconnected.";
		break;

	case RCON_CONNECTING:
	case RCON_AUTHENTICATING:
		text = "Connecting to " + session->address().to_string (IP_WITH_PORT) + "...";
		break;

	case RCON_CONNECTED:
		{
			String adminText = (session->num_admins() == 0) ? "No other admins"
				: format ("%1 other admin%s1", session->num_admins());
			text = format ("%1 | %2 | %3", session->address().to_string (IP_WITH_PORT),
				session->level(), adminText);
		}
		break;
	}

	if (not text.is_empty())
		text += " | ";

	text += "^N to connect, ^Q to quit";

	if (text != g_statusBarText)
	{
		g_statusBarText = text;
		g_needStatusBarRender = true;
	}
}

// -------------------------------------------------------------------------------------------------
//
FUNCTION
Interface::render_full() -> void
{
	update_statusbar();
	interface_render_titlebar();
	interface_render_output();
	interface_render_statusbar();
	interface_render_input();
}

// -------------------------------------------------------------------------------------------------
//
static FUNCTION
interface_position_cursor() -> void
{
	// This is only relevant if the input string is being drawn
	if (g_inputState == INPUTSTATE_CONFIRM_DISCONNECTION)
		return;

	int y = LINES - 2;

	if (g_cursorChar.ch != '\0')
		mvprintw (y, g_cursorChar.x, "%c", g_cursorChar.ch);
	else
		mvprintw (y, interface_prompt_string().length(), " ");
}

// -------------------------------------------------------------------------------------------------
//
FUNCTION
Interface::handle_input() -> void
{
	int ch = ::getch();

	if (ch == KEY_RESIZE)
	{
		::clear();
		render_full();
		return;
	}

	if (g_inputState == INPUTSTATE_CONFIRM_DISCONNECTION)
	{
		if (ch == 'y' or ch == 'Y')
		{
			RCONSession::get_session()->disconnect();
			g_disconnectConfirmFunction();
		}
		else if (ch == 'n' or ch == 'N')
			set_input_state (INPUTSTATE_NORMAL);

		return;
	}

	if (ch >= 0x20 and ch <= 0x7E)
	{
		mutable_current_input().insert (g_cursor++, char (ch));
		g_needInputRender = true;
	}
	else switch (ch)
	{
	case 'Q' - 'A' + 1: // ^Q
		switch (g_inputState)
		{
		case INPUTSTATE_CONFIRM_DISCONNECTION:
			break;

		case INPUTSTATE_NORMAL:
			safe_disconnect ([]()
			{
				RCONSession* session = RCONSession::get_session();

				if (session->is_active())
				{
					session->disconnect();
					set_input_state (INPUTSTATE_NORMAL);
				}
				else
				{
					endwin();
					throw Exitception();
				}
			});
			break;

		case INPUTSTATE_PASSWORD:
			set_input_state (INPUTSTATE_ADDRESS);
			break;

		case INPUTSTATE_ADDRESS:
			set_input_state (INPUTSTATE_NORMAL);
		}
		break;

	case '\e':
		if (g_inputState == INPUTSTATE_PASSWORD)
			set_input_state (INPUTSTATE_ADDRESS);
		else if (g_inputState == INPUTSTATE_ADDRESS)
			set_input_state (INPUTSTATE_NORMAL);
		break;

	case KEY_LEFT:
		if (g_cursor > 0)
		{
			g_cursor--;
			g_needInputRender = true;
		}
		break;

	case KEY_RIGHT:
		if (g_cursor < current_input().length())
		{
			g_cursor++;
			g_needInputRender = true;
		}
		break;

	case KEY_DOWN:
	case KEY_UP:
		move_input_cursor (ch == KEY_DOWN ? -1 : 1);
		break;

	case KEY_HOME:
		if (g_cursor != 0)
		{
			g_cursor = 0;
			g_needInputRender = true;
		}
		break;

	case KEY_END:
		if (g_cursor != current_input().length())
		{
			g_cursor = current_input().length();
			g_needInputRender = true;
		}
		break;

	case KEY_BACKSPACE:
		if (g_cursor > 0)
		{
			mutable_current_input().remove_at (--g_cursor);
			g_needInputRender = true;
		}
		break;

	case KEY_DC:
		if (g_cursor < current_input().length())
		{
			mutable_current_input().remove_at (g_cursor);
			g_needInputRender = true;
		}
		break;

	case KEY_PPAGE:
		g_outputScroll += min (g_pageSize, LINES / 2);
		g_needOutputRender = true;
		break;

	case KEY_NPAGE:
		g_outputScroll -= min (g_pageSize, LINES / 2);
		g_needOutputRender = true;
		break;

	case '\n':
	case KEY_ENTER:
		switch (g_inputState)
		{
		case INPUTSTATE_CONFIRM_DISCONNECTION:
			break; // handled above

		case INPUTSTATE_ADDRESS:
			try
			{
				g_address = IPAddress::from_string (current_input());
			}
			catch (std::exception& e)
			{
				print (e.what());
				return;
			}

			if (g_address.port == 0)
				g_address.port = 10666;

			set_input_state (INPUTSTATE_PASSWORD);
			break;

		case INPUTSTATE_PASSWORD:
			if (g_inputState == INPUTSTATE_PASSWORD and not current_input().is_empty())
			{
				RCONSession* session = RCONSession::new_session();
				session->set_password (current_input());
				session->connect (g_address);
				set_input_state (INPUTSTATE_NORMAL);
			}
			break;

		case INPUTSTATE_NORMAL:
			if (RCONSession::get_session()->send_command (current_input()))
			{
				g_input.insert (0, "");
				g_needInputRender = true;
			}
			break;
		}
		break;

	case 'N' - 'A' + 1: // ^N
		if (g_inputState == INPUTSTATE_NORMAL)
			safe_disconnect ([]() {set_input_state (INPUTSTATE_ADDRESS);});
		break;
	}
}

// -------------------------------------------------------------------------------------------------
//
FUNCTION
Interface::render() -> void
{
	if (g_needStatusBarRender) interface_render_statusbar();
	if (g_needInputRender) interface_render_input();
	if (g_needOutputRender) interface_render_output();

	if (g_needRefresh)
	{
		interface_position_cursor();
		refresh();
		g_needRefresh = false;
	}
}

// -------------------------------------------------------------------------------------------------
//
FUNCTION print_to_console (String a) -> void
{
	// Zandronum is retarded and SOMETIMES sends color codes as "\\c" and sometimes as "\x1C".
	// Let's correct that on our end and HOPE this won't cause conflicts.
	a.replace ("\\c", "\x1C");

	for (char ch : a)
	{
		if (ch == '\n')
		{
			g_output[g_output.size() - 1].finalize();
			g_output << RendererLine();
			continue;
		}

		g_output[g_output.size() - 1].add_char (ch);
	}

	g_needOutputRender = true;
}

// -------------------------------------------------------------------------------------------------
//
FUNCTION
Interface::connect (String address, String password) -> void
{
	try
	{
		g_address = IPAddress::from_string (address);
	}
	catch (std::exception& e)
	{
		print (e.what());
		return;
	}

	if (g_address.port == 0)
		g_address.port = 10666;

	RCONSession* session = RCONSession::new_session();
	session->set_password (password);
	session->connect (g_address);
}

// -------------------------------------------------------------------------------------------------
//
METHOD
RendererLine::finalize() -> void
{
	if (m_activeColor != DEFAULT)
		this->set_color (m_activeColor, false);

	if (m_boldActive)
		m_data << RLINE_OFF_BOLD;

	m_final = true;
}

// -------------------------------------------------------------------------------------------------
//
METHOD
RendererLine::add_char (char ch) -> void
{
	if (m_final)
		return; // Don't touch finalized lines.

	if (ch == '\x1C' and m_colorCodeStage == 0)
	{
		m_colorCodeStage = 1;
		return;
	}

	if (m_colorCodeStage == 1)
	{
		if (m_activeColor != DEFAULT)
			this->set_color (m_activeColor, false);

		if (m_boldActive)
			m_data << RLINE_OFF_BOLD;

		if (ch >= 'a' and ch <= 'v' and ch != 'l')
		{
			auto colorInfo = g_colorCodes[ch - 'a'];
			m_activeColor = colorInfo.color;
			m_boldActive = colorInfo.bold;
			assert (m_activeColor < 8);
			this->set_color (m_activeColor, true);

			if (m_boldActive)
				m_data << RLINE_ON_BOLD;
		}

		m_colorCodeStage = 0;
		return;
	}

	if (isprint (ch))
	{
		m_string += ch;
		m_data << int (ch);
		++m_length;
	}
}

// -------------------------------------------------------------------------------------------------
//
METHOD
RendererLine::set_color (Color a, bool on) -> void
{
	switch (a)
	{
	case BLACK:   m_data << (on ? RLINE_ON_BLACK   : RLINE_OFF_BLACK); break;
	case RED:     m_data << (on ? RLINE_ON_RED     : RLINE_OFF_RED); break;
	case GREEN:   m_data << (on ? RLINE_ON_GREEN   : RLINE_OFF_GREEN); break;
	case YELLOW:  m_data << (on ? RLINE_ON_YELLOW  : RLINE_OFF_YELLOW); break;
	case BLUE:    m_data << (on ? RLINE_ON_BLUE    : RLINE_OFF_BLUE); break;
	case MAGENTA: m_data << (on ? RLINE_ON_MAGENTA : RLINE_OFF_MAGENTA); break;
	case CYAN:    m_data << (on ? RLINE_ON_CYAN    : RLINE_OFF_CYAN); break;
	case WHITE:   m_data << (on ? RLINE_ON_WHITE   : RLINE_OFF_WHITE); break;
	case NUM_COLORS:
	case DEFAULT: assert (false); break;
	}
}

// -------------------------------------------------------------------------------------------------
// How many rows does this line take up?
//
METHOD
RendererLine::rows (int cols) const -> int
{
	int rows = length() / cols;

	if (length() % cols != 0)
		rows++;

	return max (rows, 1);
}