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Screen Updating and Cursor Movement Optimization: A Library Package _✓K_✓e_✓n_✓n_✓e_✓t_✓h _✓C. _✓R. _✓C. _✓A_✓r_✓n_✓o_✓l_✓d Computer Science Division Department of Electrical Engineering and Computer Science University of California, Berkeley Berkeley, California 94720 _✓A_✓B_✓S_✓T_✓R_✓A_✓C_✓T This document describes a package of C library functions which allow the user to: 1) update a screen with reasonable optimization, 2) get input from the terminal in a screen-oriented fashion, and 3) independent from the above, move the cursor op- timally from one point to another. These routines all use the _✓t_✓e_✓r_✓m_✓c_✓a_✓p(5) database to describe the capabilities of the terminal. _✓A_✓c_✓k_✓n_✓o_✓w_✓l_✓e_✓d_✓g_✓e_✓m_✓e_✓n_✓t_✓s This package would not exist without the work of Bill Joy, who, in writing his editor, created the capability to generally describe terminals, wrote the routines which read this database, and, most importantly, those which implement optimal cursor movement, which routines I have simply lifted nearly intact. Doug Merritt and Kurt Shoens also were ex- tremely important, as were both willing to waste time listening to me rant and rave. The help and/or support of Ken Abrams, Alan Char, Mark Horton, and Joe Kalash, was, and is, also greatly appreciated. Revised 16 April 1986 Screen Package PS1:18-3 _✓1. _✓O_✓v_✓e_✓r_✓v_✓i_✓e_✓w In making available the generalized terminal descrip- tions in _✓t_✓e_✓r_✓m_✓c_✓a_✓p(5), much information was made available to the programmer, but little work was taken out of one's hands. The purpose of this package is to allow the C pro- grammer to do the most common type of terminal dependent functions, those of movement optimization and optimal screen updating, without doing any of the dirty work, and (hopeful- ly) with nearly as much ease as is necessary to simply print or read things. The package is split into three parts: (1) Screen up- dating; (2) Screen updating with user input; and (3) Cursor motion optimization. It is possible to use the motion optimization without using either of the other two, and screen updating and input can be done without any programmer knowledge of the motion optimization, or indeed the database itself. _✓1._✓1. _✓T_✓e_✓r_✓m_✓i_✓n_✓o_✓l_✓o_✓g_✓y (_✓o_✓r, _✓W_✓o_✓r_✓d_✓s _✓Y_✓o_✓u _✓C_✓a_✓n _✓S_✓a_✓y _✓t_✓o _✓S_✓o_✓u_✓n_✓d _✓B_✓r_✓i_✓l_✓l_✓i_✓- _✓a_✓n_✓t) In this document, the following terminology is kept to with reasonable consistency: _✓w_✓i_✓n_✓d_✓o_✓w: An internal representation containing an image of what a section of the terminal screen may look like at some point in time. This subsection can either encom- pass the entire terminal screen, or any smaller portion down to a single character within that screen. _✓t_✓e_✓r_✓m_✓i_✓n_✓a_✓l: Sometimes called _✓t_✓e_✓r_✓m_✓i_✓n_✓a_✓l _✓s_✓c_✓r_✓e_✓e_✓n. The package's idea of what the terminal's screen currently looks like, _✓i._✓e., what the user sees now. This is a special _✓s_✓c_✓r_✓e_✓e_✓n: _✓s_✓c_✓r_✓e_✓e_✓n: This is a subset of windows which are as large as the terminal screen, _✓i._✓e., they start at the upper left hand corner and encompass the lower right hand corner. One of these, _✓s_✓t_✓d_✓s_✓c_✓r, is automatically provided for the programmer. _✓1._✓2. _✓C_✓o_✓m_✓p_✓i_✓l_✓i_✓n_✓g _✓T_✓h_✓i_✓n_✓g_✓s In order to use the library, it is necessary to have certain types and variables defined. Therefore, the pro- grammer must have a line: #_✓i_✓n_✓c_✓l_✓u_✓d_✓e <_✓c_✓u_✓r_✓s_✓e_✓s._✓h> at the top of the program source. The header file PS1:18-4 Screen Package <_✓c_✓u_✓r_✓s_✓e_✓s._✓h> needs to include <_✓s_✓g_✓t_✓t_✓y._✓h>, so the one should not do so oneself[1]. Also, compilations should have the fol- lowing form: _✓c_✓c [ flags ] file ... -_✓l_✓c_✓u_✓r_✓s_✓e_✓s -_✓l_✓t_✓e_✓r_✓m_✓c_✓a_✓p _✓1._✓3. _✓S_✓c_✓r_✓e_✓e_✓n _✓U_✓p_✓d_✓a_✓t_✓i_✓n_✓g In order to update the screen optimally, it is neces- sary for the routines to know what the screen currently looks like and what the programmer wants it to look like next. For this purpose, a data type (structure) named _✓W_✓I_✓N_✓- _✓D_✓O_✓W is defined which describes a window image to the rou- tines, including its starting position on the screen (the (y, x) co-ordinates of the upper left hand corner) and its size. One of these (called _✓c_✓u_✓r_✓s_✓c_✓r for _✓c_✓u_✓r_✓r_✓e_✓n_✓t _✓s_✓c_✓r_✓e_✓e_✓n) is a screen image of what the terminal currently looks like. Another screen (called _✓s_✓t_✓d_✓s_✓c_✓r, for _✓s_✓t_✓a_✓n_✓d_✓a_✓r_✓d _✓s_✓c_✓r_✓e_✓e_✓n) is pro- vided by default to make changes on. A window is a purely internal representation. It is used to build and store a potential image of a portion of the terminal. It doesn't bear any necessary relation to what is really on the terminal screen. It is more like an array of characters on which to make changes. When one has a window which describes what some part the terminal should look like, the routine _✓r_✓e_✓f_✓r_✓e_✓s_✓h() (or _✓w_✓r_✓e_✓f_✓r_✓e_✓s_✓h() if the window is not _✓s_✓t_✓d_✓s_✓c_✓r) is called. _✓r_✓e_✓- _✓f_✓r_✓e_✓s_✓h() makes the terminal, in the area covered by the win- dow, look like that window. Note, therefore, that changing something on a window _✓d_✓o_✓e_✓s _✓n_✓o_✓t _✓c_✓h_✓a_✓n_✓g_✓e _✓t_✓h_✓e _✓t_✓e_✓r_✓m_✓i_✓n_✓a_✓l. Actual updates to the terminal screen are made only by calling _✓r_✓e_✓- _✓f_✓r_✓e_✓s_✓h() or _✓w_✓r_✓e_✓f_✓r_✓e_✓s_✓h(). This allows the programmer to main- tain several different ideas of what a portion of the termi- nal screen should look like. Also, changes can be made to windows in any order, without regard to motion efficiency. Then, at will, the programmer can effectively say "make it look like this", and let the package worry about the best way to do this. _✓1._✓4. _✓N_✓a_✓m_✓i_✓n_✓g _✓C_✓o_✓n_✓v_✓e_✓n_✓t_✓i_✓o_✓n_✓s As hinted above, the routines can use several windows, but two are automatically given: _✓c_✓u_✓r_✓s_✓c_✓r, which knows what the terminal looks like, and _✓s_✓t_✓d_✓s_✓c_✓r, which is what the pro- ____________________ [1] The screen package also uses the Standard I/O li- brary, so <_✓c_✓u_✓r_✓s_✓e_✓s._✓h> includes <_✓s_✓t_✓d_✓i_✓o._✓h>. It is redundant (but harmless) for the programmer to do it, too. Screen Package PS1:18-5 grammer wants the terminal to look like next. The user should never really access _✓c_✓u_✓r_✓s_✓c_✓r directly. Changes should be made to the appropriate screen, and then the routine _✓r_✓e_✓- _✓f_✓r_✓e_✓s_✓h() (or _✓w_✓r_✓e_✓f_✓r_✓e_✓s_✓h()) should be called. Many functions are set up to deal with _✓s_✓t_✓d_✓s_✓c_✓r as a de- fault screen. For example, to add a character to _✓s_✓t_✓d_✓s_✓c_✓r, one calls _✓a_✓d_✓d_✓c_✓h() with the desired character. If a dif- ferent window is to be used, the routine _✓w_✓a_✓d_✓d_✓c_✓h() (for _✓window-specific _✓a_✓d_✓d_✓c_✓h()) is provided[2]. This convention of prepending function names with a "_✓w" when they are to be ap- plied to specific windows is consistent. The only routines which do _✓n_✓o_✓t do this are those to which a window must always be specified. In order to move the current (y, x) co-ordinates from one point to another, the routines _✓m_✓o_✓v_✓e() and _✓w_✓m_✓o_✓v_✓e() are provided. However, it is often desirable to first move and then perform some I/O operation. In order to avoid clumsy- ness, most I/O routines can be preceded by the prefix "_✓m_✓v" and the desired (y, x) co-ordinates then can be added to the arguments to the function. For example, the calls move(y, x); addch(ch); can be replaced by mvaddch(y, x, ch); and wmove(win, y, x); waddch(win, ch); can be replaced by mvwaddch(win, y, x, ch); Note that the window description pointer (_✓w_✓i_✓n) comes before the added (y, x) co-ordinates. If such pointers are need, they are always the first parameters passed. _✓2. _✓V_✓a_✓r_✓i_✓a_✓b_✓l_✓e_✓s Many variables which are used to describe the terminal environment are available to the programmer. They are: ____________________ [2] Actually, _✓a_✓d_✓d_✓c_✓h() is really a "#define" macro with arguments, as are most of the "functions" which deal with _✓s_✓t_✓d_✓s_✓c_✓r as a default. PS1:18-6 Screen Package type name description ________________________________________________________________________ WINDOW * curscr current version of the screen (terminal screen). WINDOW * stdscr standard screen. Most updates are usually done here. char * Def_term default terminal type if type cannot be determined bool My_term use the terminal specification in _✓D_✓e_✓f__✓t_✓e_✓r_✓m as ter- minal, irrelevant of real terminal type char * ttytype full name of the current terminal. int LINES number of lines on the terminal int COLS number of columns on the terminal int ERR error flag returned by routines on a fail. int OK error flag returned by routines when things go right. There are also several "#define" constants and types which are of general usefulness: reg storage class ``register'' (_✓e._✓g., _✓r_✓e_✓g _✓i_✓n_✓t _✓i;) bool boolean type, actually a ``char'' (_✓e._✓g., _✓b_✓o_✓o_✓l _✓d_✓o_✓n_✓e_✓i_✓t;) TRUE boolean ``true'' flag (1). FALSE boolean ``false'' flag (0). _✓3. _✓U_✓s_✓a_✓g_✓e This is a description of how to actually use the screen package. In it, we assume all updating, reading, etc. is applied to _✓s_✓t_✓d_✓s_✓c_✓r. All instructions will work on any win- dow, with changing the function name and parameters as men- tioned above. _✓3._✓1. _✓S_✓t_✓a_✓r_✓t_✓i_✓n_✓g _✓u_✓p In order to use the screen package, the routines must know about terminal characteristics, and the space for _✓c_✓u_✓r_✓s_✓c_✓r and _✓s_✓t_✓d_✓s_✓c_✓r must be allocated. These functions are performed by _✓i_✓n_✓i_✓t_✓s_✓c_✓r(). Since it must allocate space for the windows, it can overflow core when attempting to do so. On this rather rare occasion, _✓i_✓n_✓i_✓t_✓s_✓c_✓r() returns ERR. _✓i_✓n_✓- _✓i_✓t_✓s_✓c_✓r() must _✓a_✓l_✓w_✓a_✓y_✓s be called before any of the routines which affect windows are used. If it is not, the program will core dump as soon as either _✓c_✓u_✓r_✓s_✓c_✓r or _✓s_✓t_✓d_✓s_✓c_✓r are refer- enced. However, it is usually best to wait to call it until after you are sure you will need it, like after checking for startup errors. Terminal status changing routines like _✓n_✓l() and _✓c_✓b_✓r_✓e_✓a_✓k() should be called after _✓i_✓n_✓i_✓t_✓s_✓c_✓r(). Now that the screen windows have been allocated, you can set them up for the run. If you want to, say, allow the window to scroll, use _✓s_✓c_✓r_✓o_✓l_✓l_✓o_✓k(). If you want the cursor to Screen Package PS1:18-7 be left after the last change, use _✓l_✓e_✓a_✓v_✓e_✓o_✓k(). If this isn't done, _✓r_✓e_✓f_✓r_✓e_✓s_✓h() will move the cursor to the window's current (y, x) co-ordinates after updating it. New windows of your own can be created, too, by using the functions _✓n_✓e_✓w_✓w_✓i_✓n() and _✓s_✓u_✓b_✓w_✓i_✓n(). _✓d_✓e_✓l_✓w_✓i_✓n() will allow you to get rid of old win- dows. If you wish to change the official size of the termi- nal by hand, just set the variables _✓L_✓I_✓N_✓E_✓S and _✓C_✓O_✓L_✓S to be what you want, and then call _✓i_✓n_✓i_✓t_✓s_✓c_✓r(). This is best done before, but can be done either before or after, the first call to _✓i_✓n_✓i_✓t_✓s_✓c_✓r(), as it will always delete any existing _✓s_✓t_✓d_✓s_✓c_✓r and/or _✓c_✓u_✓r_✓s_✓c_✓r before creating new ones. _✓3._✓2. _✓T_✓h_✓e _✓N_✓i_✓t_✓t_✓y-_✓G_✓r_✓i_✓t_✓t_✓y _✓3._✓2._✓1. _✓O_✓u_✓t_✓p_✓u_✓t Now that we have set things up, we will want to actual- ly update the terminal. The basic functions used to change what will go on a window are _✓a_✓d_✓d_✓c_✓h() and _✓m_✓o_✓v_✓e(). _✓a_✓d_✓d_✓c_✓h() adds a character at the current (y, x) co-ordinates, return- ing ERR if it would cause the window to illegally scroll, _✓i._✓e., printing a character in the lower right-hand corner of a terminal which automatically scrolls if scrolling is not allowed. _✓m_✓o_✓v_✓e() changes the current (y, x) co-ordinates to whatever you want them to be. It returns ERR if you try to move off the window when scrolling is not allowed. As men- tioned above, you can combine the two into _✓m_✓v_✓a_✓d_✓d_✓c_✓h() to do both things in one fell swoop. The other output functions, such as _✓a_✓d_✓d_✓s_✓t_✓r() and _✓p_✓r_✓i_✓n_✓t_✓w(), all call _✓a_✓d_✓d_✓c_✓h() to add characters to the window. After you have put on the window what you want there, when you want the portion of the terminal covered by the window to be made to look like it, you must call _✓r_✓e_✓f_✓r_✓e_✓s_✓h(). In order to optimize finding changes, _✓r_✓e_✓f_✓r_✓e_✓s_✓h() assumes that any part of the window not changed since the last _✓r_✓e_✓f_✓r_✓e_✓s_✓h() of that window has not been changed on the terminal, _✓i._✓e., that you have not refreshed a portion of the terminal with an overlapping window. If this is not the case, the rou- tines _✓t_✓o_✓u_✓c_✓h_✓w_✓i_✓n(), _✓t_✓o_✓u_✓c_✓h_✓l_✓i_✓n_✓e(), and _✓t_✓o_✓u_✓c_✓h_✓o_✓v_✓e_✓r_✓l_✓a_✓p() are pro- vided to make it look like a desired part of window has been changed, thus forcing _✓r_✓e_✓f_✓r_✓e_✓s_✓h() check that whole subsection of the terminal for changes. If you call _✓w_✓r_✓e_✓f_✓r_✓e_✓s_✓h() with _✓c_✓u_✓r_✓s_✓c_✓r, it will make the screen look like _✓c_✓u_✓r_✓s_✓c_✓r thinks it looks like. This is use- ful for implementing a command which would redraw the screen in case it get messed up. PS1:18-8 Screen Package _✓3._✓2._✓2. _✓I_✓n_✓p_✓u_✓t Input is essentially a mirror image of output. The complementary function to _✓a_✓d_✓d_✓c_✓h() is _✓g_✓e_✓t_✓c_✓h() which, if echo is set, will call _✓a_✓d_✓d_✓c_✓h() to echo the character. Since the screen package needs to know what is on the terminal at all times, if characters are to be echoed, the tty must be in raw or cbreak mode. If it is not, _✓g_✓e_✓t_✓c_✓h() sets it to be cbreak, and then reads in the character. _✓3._✓2._✓3. _✓M_✓i_✓s_✓c_✓e_✓l_✓l_✓a_✓n_✓e_✓o_✓u_✓s All sorts of fun functions exists for maintaining and changing information about the windows. For the most part, the descriptions in section 5.4. should suffice. _✓3._✓3. _✓F_✓i_✓n_✓i_✓s_✓h_✓i_✓n_✓g _✓u_✓p In order to do certain optimizations, and, on some ter- minals, to work at all, some things must be done before the screen routines start up. These functions are performed in _✓g_✓e_✓t_✓t_✓t_✓m_✓o_✓d_✓e() and _✓s_✓e_✓t_✓t_✓e_✓r_✓m(), which are called by _✓i_✓n_✓i_✓t_✓s_✓c_✓r(). In order to clean up after the routines, the routine _✓e_✓n_✓d_✓w_✓i_✓n() is provided. It restores tty modes to what they were when _✓i_✓n_✓i_✓t_✓s_✓c_✓r() was first called. Thus, anytime after the call to initscr, _✓e_✓n_✓d_✓w_✓i_✓n() should be called before exit- ing. _✓4. _✓C_✓u_✓r_✓s_✓o_✓r _✓M_✓o_✓t_✓i_✓o_✓n _✓O_✓p_✓t_✓i_✓m_✓i_✓z_✓a_✓t_✓i_✓o_✓n: _✓S_✓t_✓a_✓n_✓d_✓i_✓n_✓g _✓A_✓l_✓o_✓n_✓e It is possible to use the cursor optimization functions of this screen package without the overhead and additional size of the screen updating functions. The screen updating functions are designed for uses where parts of the screen are changed, but the overall image remains the same. This includes such programs as _✓r_✓o_✓g_✓u_✓e and _✓v_✓i[3]. Certain other programs will find it difficult to use these functions in this manner without considerable unnecessary program over- head. For such applications, such as some "_✓c_✓r_✓t _✓h_✓a_✓c_✓k_✓s"[4] and optimizing _✓m_✓o_✓r_✓e(1)-type programs, all that is needed is the motion optimizations. This, therefore, is a description of what some of what goes on at the lower levels of this screen package. The descriptions assume a certain amount of familiarity with programming problems and some finer points of C. None of it is terribly difficult, but you should be ____________________ [3] _✓r_✓o_✓g_✓u_✓e actually uses these functions, _✓v_✓i does not. [4] Graphics programs designed to run on character- oriented terminals. I could name many, but they come and go, so the list would be quickly out of date. Recently, there have been programs such as _✓r_✓a_✓i_✓n, _✓r_✓o_✓c_✓k_✓e_✓t, and _✓g_✓u_✓n. Screen Package PS1:18-9 forewarned. _✓4._✓1. _✓T_✓e_✓r_✓m_✓i_✓n_✓a_✓l _✓I_✓n_✓f_✓o_✓r_✓m_✓a_✓t_✓i_✓o_✓n In order to use a terminal's features to the best of a program's abilities, it must first know what they are[5]. The _✓t_✓e_✓r_✓m_✓c_✓a_✓p(5) database describes these, but a certain amount of decoding is necessary, and there are, of course, both efficient and inefficient ways of reading them in. The algorithm that the uses is taken from _✓v_✓i and is hideously efficient. It reads them in a tight loop into a set of variables whose names are two uppercase letters with some mnemonic value. For example, _✓H_✓O is a string which moves the cursor to the "home" position[6]. As there are two types of variables involving ttys, there are two routines. The first, _✓g_✓e_✓t_✓t_✓m_✓o_✓d_✓e(), sets some variables based upon the tty modes accessed by _✓g_✓t_✓t_✓y(2) and _✓s_✓t_✓t_✓y(2) The second, _✓s_✓e_✓t_✓t_✓e_✓r_✓m(), a larger task by reading in the descriptions from the _✓t_✓e_✓r_✓m_✓c_✓a_✓p(5) database. This is the way these routines are used by _✓i_✓n_✓i_✓t_✓s_✓c_✓r(): _✓i_✓f (isatty(0)) { gettmode(); _✓i_✓f ((sp=getenv("TERM")) != NULL) setterm(sp); _✓e_✓l_✓s_✓e setterm(Def_term); } _✓e_✓l_✓s_✓e setterm(Def_term); _puts(TI); _puts(VS); _✓i_✓s_✓a_✓t_✓t_✓y() checks to see if file descriptor 0 is a termi- nal[7]. If it is, _✓g_✓e_✓t_✓t_✓m_✓o_✓d_✓e() sets the terminal description modes from a _✓g_✓t_✓t_✓y(2) _✓g_✓e_✓t_✓e_✓n_✓v() is then called to get the name of the terminal, and that value (if there is one) is passed ____________________ [5] If this comes as any surprise to you, there's this tower in Paris they're thinking of junking that I can let you have for a song. [6] These names are identical to those variables used in the _✓t_✓e_✓r_✓m_✓c_✓a_✓p(5) database to describe each capability. See Appendix A for a complete list of those read, and the _✓t_✓e_✓r_✓m_✓c_✓a_✓p(5) manual page for a full description. [7] _✓i_✓s_✓a_✓t_✓t_✓y() is defined in the default C library function routines. It does a _✓g_✓t_✓t_✓y(2) on the descriptor and checks the return value. PS1:18-10 Screen Package to _✓s_✓e_✓t_✓t_✓e_✓r_✓m(), which reads in the variables from _✓t_✓e_✓r_✓m_✓c_✓a_✓p(5) associated with that terminal. (_✓g_✓e_✓t_✓e_✓n_✓v() returns a pointer to a string containing the name of the terminal, which we save in the character pointer _✓s_✓p.) If _✓i_✓s_✓a_✓t_✓t_✓y() returns false, the default terminal _✓D_✓e_✓f__✓t_✓e_✓r_✓m is used. The _✓T_✓I and _✓V_✓S sequences initialize the terminal (__✓p_✓u_✓t_✓s() is a macro which uses _✓t_✓p_✓u_✓t_✓s() (see _✓t_✓e_✓r_✓m_✓c_✓a_✓p(3)) and __✓p_✓u_✓t_✓c_✓h_✓a_✓r() to put out a string). _✓e_✓n_✓d_✓w_✓i_✓n() undoes these things. _✓4._✓2. _✓M_✓o_✓v_✓e_✓m_✓e_✓n_✓t _✓O_✓p_✓t_✓i_✓m_✓i_✓z_✓a_✓t_✓i_✓o_✓n_✓s, _✓o_✓r, _✓G_✓e_✓t_✓t_✓i_✓n_✓g _✓O_✓v_✓e_✓r _✓Y_✓o_✓n_✓d_✓e_✓r Now that we have all this useful information, it would be nice to do something with it[8]. The most difficult thing to do properly is motion optimization. When you con- sider how many different features various terminals have (tabs, backtabs, non-destructive space, home sequences, ab- solute tabs, .....) you can see that deciding how to get from here to there can be a decidedly non-trivial task. The editor _✓v_✓i uses many of these features, and the routines it uses to do this take up many pages of code. Fortunately, I was able to liberate them with the author's permission, and use them here. After using _✓g_✓e_✓t_✓t_✓m_✓o_✓d_✓e() and _✓s_✓e_✓t_✓t_✓e_✓r_✓m() to get the termi- nal descriptions, the function _✓m_✓v_✓c_✓u_✓r() deals with this task. It usage is simple: you simply tell it where you are now and where you want to go. For example mvcur(0, 0, LINES/2, COLS/2) would move the cursor from the home position (0, 0) to the middle of the screen. If you wish to force absolute ad- dressing, you can use the function _✓t_✓g_✓o_✓t_✓o() from the _✓t_✓e_✓r_✓m_✓- _✓l_✓i_✓b(7) routines, or you can tell _✓m_✓v_✓c_✓u_✓r() that you are impos- sibly far away, like Cleveland. For example, to absolutely address the lower left hand corner of the screen from any- where just claim that you are in the upper right hand corner: mvcur(0, COLS-1, LINES-1, 0) _✓5. _✓T_✓h_✓e _✓F_✓u_✓n_✓c_✓t_✓i_✓o_✓n_✓s In the following definitions, "[*]" means that the "function" is really a "#define" macro with arguments. This ____________________ [8] Actually, it _✓c_✓a_✓n be emotionally fulfilling just to get the information. This is usually only true, however, if you have the social life of a kumquat. Screen Package PS1:18-11 means that it will not show up in stack traces in the de- bugger, or, in the case of such functions as _✓a_✓d_✓d_✓c_✓h(), it will show up as it's "_✓w" counterpart. The arguments are given to show the order and type of each. Their names are not mandatory, just suggestive. _✓5._✓1. _✓O_✓u_✓t_✓p_✓u_✓t _✓F_✓u_✓n_✓c_✓t_✓i_✓o_✓n_✓s _✓a_✓d_✓d_✓c_✓h(_✓c_✓h) [*] _✓c_✓h_✓a_✓r _✓c_✓h; _✓w_✓a_✓d_✓d_✓c_✓h(_✓w_✓i_✓n, _✓c_✓h) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓c_✓h_✓a_✓r _✓c_✓h; Add the character _✓c_✓h on the window at the current (y, x) co-ordinates. If the character is a newline ('\n') the line will be cleared to the end, and the current (y, x) co-ordinates will be changed to the be- ginning off the next line if newline mapping is on, or to the next line at the same x co-ordinate if it is off. A return ('\r') will move to the beginning of the line on the window. Tabs ('\t') will be expanded into spaces in the normal tabstop positions of every eight characters. This returns ERR if it would cause the screen to scroll illegally. _✓a_✓d_✓d_✓s_✓t_✓r(_✓s_✓t_✓r) [*] _✓c_✓h_✓a_✓r *_✓s_✓t_✓r; _✓w_✓a_✓d_✓d_✓s_✓t_✓r(_✓w_✓i_✓n, _✓s_✓t_✓r) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓c_✓h_✓a_✓r *_✓s_✓t_✓r; Add the string pointed to by _✓s_✓t_✓r on the window at the current (y, x) co-ordinates. This returns ERR if it would cause the screen to scroll illegally. In this case, it will put on as much as it can. _✓b_✓o_✓x(_✓w_✓i_✓n, _✓v_✓e_✓r_✓t, _✓h_✓o_✓r) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓c_✓h_✓a_✓r _✓v_✓e_✓r_✓t, _✓h_✓o_✓r; Draws a box around the window using _✓v_✓e_✓r_✓t as the charac- ter for drawing the vertical sides, and _✓h_✓o_✓r for drawing the horizontal lines. If scrolling is not allowed, and the window encompasses the lower right-hand corner of PS1:18-12 Screen Package the terminal, the corners are left blank to avoid a scroll. _✓c_✓l_✓e_✓a_✓r() [*] _✓w_✓c_✓l_✓e_✓a_✓r(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Resets the entire window to blanks. If _✓w_✓i_✓n is a screen, this sets the clear flag, which will cause a clear-screen sequence to be sent on the next _✓r_✓e_✓f_✓r_✓e_✓s_✓h() call. This also moves the current (y, x) co-ordinates to (0, 0). _✓c_✓l_✓e_✓a_✓r_✓o_✓k(_✓s_✓c_✓r, _✓b_✓o_✓o_✓l_✓f) [*] _✓W_✓I_✓N_✓D_✓O_✓W *_✓s_✓c_✓r; _✓b_✓o_✓o_✓l _✓b_✓o_✓o_✓l_✓f; Sets the clear flag for the screen _✓s_✓c_✓r. If _✓b_✓o_✓o_✓l_✓f is TRUE, this will force a clear-screen to be printed on the next _✓r_✓e_✓f_✓r_✓e_✓s_✓h(), or stop it from doing so if _✓b_✓o_✓o_✓l_✓f is FALSE. This only works on screens, and, unlike _✓c_✓l_✓e_✓a_✓r(), does not alter the contents of the screen. If _✓s_✓c_✓r is _✓c_✓u_✓r_✓s_✓c_✓r, the next _✓r_✓e_✓f_✓r_✓e_✓s_✓h() call will cause a clear-screen, even if the window passed to _✓r_✓e_✓f_✓r_✓e_✓s_✓h() is not a screen. _✓c_✓l_✓r_✓t_✓o_✓b_✓o_✓t() [*] _✓w_✓c_✓l_✓r_✓t_✓o_✓b_✓o_✓t(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Wipes the window clear from the current (y, x) co- ordinates to the bottom. This does not force a clear- screen sequence on the next refresh under any cir- cumstances. This has no associated "mv" command. _✓c_✓l_✓r_✓t_✓o_✓e_✓o_✓l() [*] _✓w_✓c_✓l_✓r_✓t_✓o_✓e_✓o_✓l(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Wipes the window clear from the current (y, x) co- ordinates to the end of the line. This has no associ- ated "mv" command. Screen Package PS1:18-13 _✓d_✓e_✓l_✓c_✓h() _✓w_✓d_✓e_✓l_✓c_✓h(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Delete the character at the current (y, x) co- ordinates. Each character after it on the line shifts to the left, and the last character becomes blank. _✓d_✓e_✓l_✓e_✓t_✓e_✓l_✓n() _✓w_✓d_✓e_✓l_✓e_✓t_✓e_✓l_✓n(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Delete the current line. Every line below the current one will move up, and the bottom line will become blank. The current (y, x) co-ordinates will remain un- changed. _✓e_✓r_✓a_✓s_✓e() [*] _✓w_✓e_✓r_✓a_✓s_✓e(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Erases the window to blanks without setting the clear flag. This is analagous to _✓c_✓l_✓e_✓a_✓r(), except that it never causes a clear-screen sequence to be generated on a _✓r_✓e_✓f_✓r_✓e_✓s_✓h(). This has no associated "mv" command. _✓f_✓l_✓u_✓s_✓h_✓o_✓k(_✓w_✓i_✓n, _✓b_✓o_✓o_✓l_✓f) [*] _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓b_✓o_✓o_✓l _✓b_✓o_✓o_✓l_✓f; Normally, _✓r_✓e_✓f_✓r_✓e_✓s_✓h() _✓f_✓f_✓l_✓u_✓s_✓h()'s _✓s_✓t_✓d_✓o_✓u_✓t when it is fin- ished. _✓f_✓l_✓u_✓s_✓h_✓o_✓k() allows you to control this. if _✓b_✓o_✓o_✓l_✓f is TRUE (_✓i._✓e., non-zero) it will do the _✓f_✓f_✓l_✓u_✓s_✓h(); if it is FALSE. it will not. _✓i_✓d_✓l_✓o_✓k(_✓w_✓i_✓n, _✓b_✓o_✓o_✓l_✓f) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓b_✓o_✓o_✓l _✓b_✓o_✓o_✓l_✓f; Reserved for future use. This will eventually signal to _✓r_✓e_✓f_✓r_✓e_✓s_✓h() that it is all right to use the insert and PS1:18-14 Screen Package delete line sequences when updating the window. _✓i_✓n_✓s_✓c_✓h(_✓c) _✓c_✓h_✓a_✓r _✓c; _✓w_✓i_✓n_✓s_✓c_✓h(_✓w_✓i_✓n, _✓c) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓c_✓h_✓a_✓r _✓c; Insert _✓c at the current (y, x) co-ordinates Each char- acter after it shifts to the right, and the last char- acter disappears. This returns ERR if it would cause the screen to scroll illegally. _✓i_✓n_✓s_✓e_✓r_✓t_✓l_✓n() _✓w_✓i_✓n_✓s_✓e_✓r_✓t_✓l_✓n(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Insert a line above the current one. Every line below the current line will be shifted down, and the bottom line will disappear. The current line will become blank, and the current (y, x) co-ordinates will remain unchanged. _✓m_✓o_✓v_✓e(_✓y, _✓x) [*] _✓i_✓n_✓t _✓y, _✓x; _✓w_✓m_✓o_✓v_✓e(_✓w_✓i_✓n, _✓y, _✓x) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓i_✓n_✓t _✓y, _✓x; Change the current (y, x) co-ordinates of the window to (_✓y, _✓x). This returns ERR if it would cause the screen to scroll illegally. _✓o_✓v_✓e_✓r_✓l_✓a_✓y(_✓w_✓i_✓n_✓1, _✓w_✓i_✓n_✓2) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n_✓1, *_✓w_✓i_✓n_✓2; Overlay _✓w_✓i_✓n_✓1 on _✓w_✓i_✓n_✓2. The contents of _✓w_✓i_✓n_✓1, insofar as they fit, are placed on _✓w_✓i_✓n_✓2 at their starting (y, x) co-ordinates. This is done non-destructively, i.e., blanks on _✓w_✓i_✓n_✓1 leave the contents of the space on _✓w_✓i_✓n_✓2 untouched. Screen Package PS1:18-15 _✓o_✓v_✓e_✓r_✓w_✓r_✓i_✓t_✓e(_✓w_✓i_✓n_✓1, _✓w_✓i_✓n_✓2) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n_✓1, *_✓w_✓i_✓n_✓2; Overwrite _✓w_✓i_✓n_✓1 on _✓w_✓i_✓n_✓2. The contents of _✓w_✓i_✓n_✓1, insofar as they fit, are placed on _✓w_✓i_✓n_✓2 at their starting (y, x) co-ordinates. This is done destructively, _✓i._✓e., blanks on _✓w_✓i_✓n_✓1 become blank on _✓w_✓i_✓n_✓2. _✓p_✓r_✓i_✓n_✓t_✓w(_✓f_✓m_✓t, _✓a_✓r_✓g_✓1, _✓a_✓r_✓g_✓2, ...) _✓c_✓h_✓a_✓r *_✓f_✓m_✓t; _✓w_✓p_✓r_✓i_✓n_✓t_✓w(_✓w_✓i_✓n, _✓f_✓m_✓t, _✓a_✓r_✓g_✓1, _✓a_✓r_✓g_✓2, ...) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓c_✓h_✓a_✓r *_✓f_✓m_✓t; Performs a _✓p_✓r_✓i_✓n_✓t_✓f() on the window starting at the current (y, x) co-ordinates. It uses _✓a_✓d_✓d_✓s_✓t_✓r() to add the string on the window. It is often advisable to use the field width options of _✓p_✓r_✓i_✓n_✓t_✓f() to avoid leaving things on the window from earlier calls. This returns ERR if it would cause the screen to scroll illegally. _✓r_✓e_✓f_✓r_✓e_✓s_✓h() [*] _✓w_✓r_✓e_✓f_✓r_✓e_✓s_✓h(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Synchronize the terminal screen with the desired win- dow. If the window is not a screen, only that part covered by it is updated. This returns ERR if it would cause the screen to scroll illegally. In this case, it will update whatever it can without causing the scroll. As a special case, if _✓w_✓r_✓e_✓f_✓r_✓e_✓s_✓h() is called with the window _✓c_✓u_✓r_✓s_✓c_✓r the screen is cleared and repainted as it is currently. This is very useful for allowing the redrawing of the screen when the user has garbage dumped on his terminal. _✓s_✓t_✓a_✓n_✓d_✓o_✓u_✓t() [*] _✓w_✓s_✓t_✓a_✓n_✓d_✓o_✓u_✓t(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓s_✓t_✓a_✓n_✓d_✓e_✓n_✓d() [*] PS1:18-16 Screen Package _✓w_✓s_✓t_✓a_✓n_✓d_✓e_✓n_✓d(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Start and stop putting characters onto _✓w_✓i_✓n in standout mode. _✓s_✓t_✓a_✓n_✓d_✓o_✓u_✓t() causes any characters added to the window to be put in standout mode on the terminal (if it has that capability). _✓s_✓t_✓a_✓n_✓d_✓e_✓n_✓d() stops this. The sequences _✓S_✓O and _✓S_✓E (or _✓U_✓S and _✓U_✓E if they are not de- fined) are used (see Appendix A). _✓5._✓2. _✓I_✓n_✓p_✓u_✓t _✓F_✓u_✓n_✓c_✓t_✓i_✓o_✓n_✓s _✓c_✓b_✓r_✓e_✓a_✓k() [*] _✓n_✓o_✓c_✓b_✓r_✓e_✓a_✓k() [*] _✓c_✓r_✓m_✓o_✓d_✓e() [*] _✓n_✓o_✓c_✓r_✓m_✓o_✓d_✓e() [*] Set or unset the terminal to/from cbreak mode. The misnamed macros _✓c_✓r_✓m_✓o_✓d_✓e() and _✓n_✓o_✓c_✓r_✓m_✓o_✓d_✓e() are retained for backwards compatibility with ealier versions of the library. _✓e_✓c_✓h_✓o() [*] _✓n_✓o_✓e_✓c_✓h_✓o() [*] Sets the terminal to echo or not echo characters. _✓g_✓e_✓t_✓c_✓h() [*] _✓w_✓g_✓e_✓t_✓c_✓h(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Gets a character from the terminal and (if necessary) echos it on the window. This returns ERR if it would cause the screen to scroll illegally. Otherwise, the character gotten is returned. If _✓n_✓o_✓e_✓c_✓h_✓o has been set, then the window is left unaltered. In order to retain control of the terminal, it is necessary to have one of _✓n_✓o_✓e_✓c_✓h_✓o, _✓c_✓b_✓r_✓e_✓a_✓k, or _✓r_✓a_✓w_✓m_✓o_✓d_✓e set. If you do not set one, whatever routine you call to read characters will set _✓c_✓b_✓r_✓e_✓a_✓k for you, and then reset to the original mode when finished. Screen Package PS1:18-17 _✓g_✓e_✓t_✓s_✓t_✓r(_✓s_✓t_✓r) [*] _✓c_✓h_✓a_✓r *_✓s_✓t_✓r; _✓w_✓g_✓e_✓t_✓s_✓t_✓r(_✓w_✓i_✓n, _✓s_✓t_✓r) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓c_✓h_✓a_✓r *_✓s_✓t_✓r; Get a string through the window and put it in the loca- tion pointed to by _✓s_✓t_✓r, which is assumed to be large enough to handle it. It sets tty modes if necessary, and then calls _✓g_✓e_✓t_✓c_✓h() (or _✓w_✓g_✓e_✓t_✓c_✓h(_✓w_✓i_✓n)) to get the characters needed to fill in the string until a newline or EOF is encountered. The newline stripped off the string. This returns ERR if it would cause the screen to scroll illegally. __✓p_✓u_✓t_✓c_✓h_✓a_✓r(_✓c) _✓c_✓h_✓a_✓r _✓c; Put out a character using the _✓p_✓u_✓t_✓c_✓h_✓a_✓r() macro. This function is used to output every character that _✓c_✓u_✓r_✓s_✓e_✓s generates. Thus, it can be redefined by the user who wants to do non-standard things with the output. It is named with an initial "_" because it usually should be invisible to the programmer. _✓r_✓a_✓w() [*] _✓n_✓o_✓r_✓a_✓w() [*] Set or unset the terminal to/from raw mode. On version 7 _✓U_✓N_✓I_✓X[_✓9] this also turns of newline mapping (see _✓n_✓l()). _✓s_✓c_✓a_✓n_✓w(_✓f_✓m_✓t, _✓a_✓r_✓g_✓1, _✓a_✓r_✓g_✓2, ...) _✓c_✓h_✓a_✓r *_✓f_✓m_✓t; _✓w_✓s_✓c_✓a_✓n_✓w(_✓w_✓i_✓n, _✓f_✓m_✓t, _✓a_✓r_✓g_✓1, _✓a_✓r_✓g_✓2, ...) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓c_✓h_✓a_✓r *_✓f_✓m_✓t; ____________________ [9] _✓U_✓N_✓I_✓X is a trademark of Bell Laboratories. PS1:18-18 Screen Package Perform a _✓s_✓c_✓a_✓n_✓f() through the window using _✓f_✓m_✓t. It does this using consecutive _✓g_✓e_✓t_✓c_✓h()'s (or _✓w_✓g_✓e_✓t_✓c_✓h(_✓w_✓i_✓n)'s). This returns ERR if it would cause the screen to scroll illegally. _✓5._✓3. _✓M_✓i_✓s_✓c_✓e_✓l_✓l_✓a_✓n_✓e_✓o_✓u_✓s _✓F_✓u_✓n_✓c_✓t_✓i_✓o_✓n_✓s _✓b_✓a_✓u_✓d_✓r_✓a_✓t_✓e() [*] Returns the output baud rate of the terminal. This is a system dependent constant (defined in <_✓s_✓y_✓s/_✓t_✓t_✓y._✓h> on BSD systems, which is included by <_✓c_✓u_✓r_✓s_✓e_✓s._✓h>). _✓d_✓e_✓l_✓w_✓i_✓n(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Deletes the window from existence. All resources are freed for future use by _✓c_✓a_✓l_✓l_✓o_✓c(3). If a window has a _✓s_✓u_✓b_✓w_✓i_✓n() allocated window inside of it, deleting the outer window the subwindow is not affected, even though this does invalidate it. Therefore, subwindows should be deleted before their outer windows are. _✓e_✓n_✓d_✓w_✓i_✓n() Finish up window routines before exit. This restores the terminal to the state it was before _✓i_✓n_✓i_✓t_✓s_✓c_✓r() (or _✓g_✓e_✓t_✓t_✓m_✓o_✓d_✓e() and _✓s_✓e_✓t_✓t_✓e_✓r_✓m()) was called. It should always be called before exiting. It does not exit. This is especially useful for resetting tty stats when trapping rubouts via _✓s_✓i_✓g_✓n_✓a_✓l(2). _✓e_✓r_✓a_✓s_✓e_✓c_✓h_✓a_✓r() [*] Returns the erase character for the terminal, _✓i._✓e., the character used by the user to erase a single character from the input. _✓c_✓h_✓a_✓r * _✓g_✓e_✓t_✓c_✓a_✓p(_✓s_✓t_✓r) _✓c_✓h_✓a_✓r *_✓s_✓t_✓r; Return a pointer to the _✓t_✓e_✓r_✓m_✓c_✓a_✓p capability described by _✓s_✓t_✓r (see _✓t_✓e_✓r_✓m_✓c_✓a_✓p(5) for details). Screen Package PS1:18-19 _✓g_✓e_✓t_✓y_✓x(_✓w_✓i_✓n, _✓y, _✓x) [*] _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓i_✓n_✓t _✓y, _✓x; Puts the current (y, x) co-ordinates of _✓w_✓i_✓n in the variables _✓y and _✓x. Since it is a macro, not a func- tion, you do not pass the address of _✓y and _✓x. _✓i_✓n_✓c_✓h() [*] _✓w_✓i_✓n_✓c_✓h(_✓w_✓i_✓n) [*] _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Returns the character at the current (y, x) co- ordinates on the given window. This does not make any changes to the window. _✓i_✓n_✓i_✓t_✓s_✓c_✓r() Initialize the screen routines. This must be called before any of the screen routines are used. It ini- tializes the terminal-type data and such, and without it none of the routines can operate. If standard input is not a tty, it sets the specifications to the termi- nal whose name is pointed to by _✓D_✓e_✓f__✓t_✓e_✓r_✓m (initialy "dumb"). If the boolean _✓M_✓y__✓t_✓e_✓r_✓m is true, _✓D_✓e_✓f__✓t_✓e_✓r_✓m is always used. If the system supports the _✓T_✓I_✓O_✓C_✓G_✓W_✓I_✓N_✓S_✓Z _✓i_✓o_✓c_✓t_✓l(_✓2) call, it is used to get the number of lines and columns for the terminal, otherwise it is taken from the _✓t_✓e_✓r_✓m_✓c_✓a_✓p description. _✓k_✓i_✓l_✓l_✓c_✓h_✓a_✓r() [*] Returns the line kill character for the terminal, _✓i._✓e., the character used by the user to erase an entire line from the input. _✓l_✓e_✓a_✓v_✓e_✓o_✓k(_✓w_✓i_✓n, _✓b_✓o_✓o_✓l_✓f) [*] _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓b_✓o_✓o_✓l _✓b_✓o_✓o_✓l_✓f; Sets the boolean flag for leaving the cursor after the last change. If _✓b_✓o_✓o_✓l_✓f is TRUE, the cursor will be left after the last update on the terminal, and the current PS1:18-20 Screen Package (y, x) co-ordinates for _✓w_✓i_✓n will be changed according- ly. If it is FALSE, it will be moved to the current (y, x) co-ordinates. This flag (initialy FALSE) re- tains its value until changed by the user. _✓l_✓o_✓n_✓g_✓n_✓a_✓m_✓e(_✓t_✓e_✓r_✓m_✓b_✓u_✓f, _✓n_✓a_✓m_✓e) _✓c_✓h_✓a_✓r *_✓t_✓e_✓r_✓m_✓b_✓u_✓f, *_✓n_✓a_✓m_✓e; _✓f_✓u_✓l_✓l_✓n_✓a_✓m_✓e(_✓t_✓e_✓r_✓m_✓b_✓u_✓f, _✓n_✓a_✓m_✓e) _✓c_✓h_✓a_✓r *_✓t_✓e_✓r_✓m_✓b_✓u_✓f, *_✓n_✓a_✓m_✓e; _✓l_✓o_✓n_✓g_✓n_✓a_✓m_✓e() fills in _✓n_✓a_✓m_✓e with the long name of the ter- minal described by the _✓t_✓e_✓r_✓m_✓c_✓a_✓p entry in _✓t_✓e_✓r_✓m_✓b_✓u_✓f. It is generally of little use, but is nice for telling the user in a readable format what terminal we think he has. This is available in the global variable _✓t_✓t_✓y_✓t_✓y_✓p_✓e. _✓t_✓e_✓r_✓m_✓b_✓u_✓f is usually set via the termlib routine _✓t_✓g_✓e_✓t_✓e_✓n_✓t(). _✓f_✓u_✓l_✓l_✓n_✓a_✓m_✓e() is the same as _✓l_✓o_✓n_✓g_✓n_✓a_✓m_✓e(), ex- cept that it gives the fullest name given in the entry, which can be quite verbose. _✓m_✓v_✓w_✓i_✓n(_✓w_✓i_✓n, _✓y, _✓x) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓i_✓n_✓t _✓y, _✓x; Move the home position of the window _✓w_✓i_✓n from its current starting coordinates to (_✓y, _✓x). If that would put part or all of the window off the edge of the ter- minal screen, _✓m_✓v_✓w_✓i_✓n() returns ERR and does not change anything. For subwindows, _✓m_✓v_✓w_✓i_✓n() also returns ERR if you attempt to move it off its main window. If you move a main window, all subwindows are moved along with it. _✓W_✓I_✓N_✓D_✓O_✓W * _✓n_✓e_✓w_✓w_✓i_✓n(_✓l_✓i_✓n_✓e_✓s, _✓c_✓o_✓l_✓s, _✓b_✓e_✓g_✓i_✓n__✓y, _✓b_✓e_✓g_✓i_✓n__✓x) _✓i_✓n_✓t _✓l_✓i_✓n_✓e_✓s, _✓c_✓o_✓l_✓s, _✓b_✓e_✓g_✓i_✓n__✓y, _✓b_✓e_✓g_✓i_✓n__✓x; Create a new window with _✓l_✓i_✓n_✓e_✓s lines and _✓c_✓o_✓l_✓s columns starting at position (_✓b_✓e_✓g_✓i_✓n__✓y, _✓b_✓e_✓g_✓i_✓n__✓x). If either _✓l_✓i_✓n_✓e_✓s or _✓c_✓o_✓l_✓s is 0 (zero), that dimension will be set to (_✓L_✓I_✓N_✓E_✓S - _✓b_✓e_✓g_✓i_✓n__✓y) or (_✓C_✓O_✓L_✓S - _✓b_✓e_✓g_✓i_✓n__✓x) respectively. Thus, to get a new window of dimensions _✓L_✓I_✓N_✓E_✓S x _✓C_✓O_✓L_✓S, use _✓n_✓e_✓w_✓w_✓i_✓n(_✓0, _✓0, _✓0, _✓0). _✓n_✓l() [*] Screen Package PS1:18-21 _✓n_✓o_✓n_✓l() [*] Set or unset the terminal to/from nl mode, _✓i._✓e., start/stop the system from mapping <_✓R_✓E_✓T_✓U_✓R_✓N> to <_✓L_✓I_✓N_✓E- _✓F_✓E_✓E_✓D>. If the mapping is not done, _✓r_✓e_✓f_✓r_✓e_✓s_✓h() can do more optimization, so it is recommended, but not re- quired, to turn it off. _✓s_✓c_✓r_✓o_✓l_✓l_✓o_✓k(_✓w_✓i_✓n, _✓b_✓o_✓o_✓l_✓f) [*] _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓b_✓o_✓o_✓l _✓b_✓o_✓o_✓l_✓f; Set the scroll flag for the given window. If _✓b_✓o_✓o_✓l_✓f is FALSE, scrolling is not allowed. This is its default setting. _✓t_✓o_✓u_✓c_✓h_✓l_✓i_✓n_✓e(_✓w_✓i_✓n, _✓y, _✓s_✓t_✓a_✓r_✓t_✓x, _✓e_✓n_✓d_✓x) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓i_✓n_✓t _✓y, _✓s_✓t_✓a_✓r_✓t_✓x, _✓e_✓n_✓d_✓x; This function performs a function similar to _✓t_✓o_✓u_✓c_✓h_✓w_✓i_✓n() on a single line. It marks the first change for the given line to be _✓s_✓t_✓a_✓r_✓t_✓x, if it is before the current first change mark, and the last change mark is set to be _✓e_✓n_✓d_✓x if it is currently less than _✓e_✓n_✓d_✓x. _✓t_✓o_✓u_✓c_✓h_✓o_✓v_✓e_✓r_✓l_✓a_✓p(_✓w_✓i_✓n_✓1, _✓w_✓i_✓n_✓2) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n_✓1, *_✓w_✓i_✓n_✓2; Touch the window _✓w_✓i_✓n_✓2 in the area which overlaps with _✓w_✓i_✓n_✓1. If they do not overlap, no changes are made. _✓t_✓o_✓u_✓c_✓h_✓w_✓i_✓n(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Make it appear that the every location on the window has been changed. This is usually only needed for re- freshes with overlapping windows. _✓W_✓I_✓N_✓D_✓O_✓W * _✓s_✓u_✓b_✓w_✓i_✓n(_✓w_✓i_✓n, _✓l_✓i_✓n_✓e_✓s, _✓c_✓o_✓l_✓s, _✓b_✓e_✓g_✓i_✓n__✓y, _✓b_✓e_✓g_✓i_✓n__✓x) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; _✓i_✓n_✓t _✓l_✓i_✓n_✓e_✓s, _✓c_✓o_✓l_✓s, _✓b_✓e_✓g_✓i_✓n__✓y, _✓b_✓e_✓g_✓i_✓n__✓x; PS1:18-22 Screen Package Create a new window with _✓l_✓i_✓n_✓e_✓s lines and _✓c_✓o_✓l_✓s columns starting at position (_✓b_✓e_✓g_✓i_✓n__✓y, _✓b_✓e_✓g_✓i_✓n__✓x) inside the win- dow _✓w_✓i_✓n. This means that any change made to either window in the area covered by the subwindow will be made on both windows. _✓b_✓e_✓g_✓i_✓n__✓y, _✓b_✓e_✓g_✓i_✓n__✓x are specified relative to the overall screen, not the relative (0, 0) of _✓w_✓i_✓n. If either _✓l_✓i_✓n_✓e_✓s or _✓c_✓o_✓l_✓s is 0 (zero), that di- mension will be set to (_✓L_✓I_✓N_✓E_✓S - _✓b_✓e_✓g_✓i_✓n__✓y) or (_✓C_✓O_✓L_✓S - _✓b_✓e_✓g_✓i_✓n__✓x) respectively. _✓u_✓n_✓c_✓t_✓r_✓l(_✓c_✓h) [*] _✓c_✓h_✓a_✓r _✓c_✓h; This is actually a debug function for the library, but it is of general usefulness. It returns a string which is a representation of _✓c_✓h. Control characters become their upper-case equivalents preceded by a "^". Other letters stay just as they are. To use _✓u_✓n_✓c_✓t_✓r_✓l(), you may have to have #_✓i_✓n_✓c_✓l_✓u_✓d_✓e <_✓u_✓n_✓c_✓t_✓r_✓l._✓h> in your file. _✓5._✓4. _✓D_✓e_✓t_✓a_✓i_✓l_✓s _✓g_✓e_✓t_✓t_✓m_✓o_✓d_✓e() Get the tty stats. This is normally called by _✓i_✓n_✓- _✓i_✓t_✓s_✓c_✓r(). _✓m_✓v_✓c_✓u_✓r(_✓l_✓a_✓s_✓t_✓y, _✓l_✓a_✓s_✓t_✓x, _✓n_✓e_✓w_✓y, _✓n_✓e_✓w_✓x) _✓i_✓n_✓t _✓l_✓a_✓s_✓t_✓y, _✓l_✓a_✓s_✓t_✓x, _✓n_✓e_✓w_✓y, _✓n_✓e_✓w_✓x; Moves the terminal's cursor from (_✓l_✓a_✓s_✓t_✓y, _✓l_✓a_✓s_✓t_✓x) to (_✓n_✓e_✓w_✓y, _✓n_✓e_✓w_✓x) in an approximation of optimal fashion. This routine uses the functions borrowed from _✓e_✓x ver- sion 2.6. It is possible to use this optimization without the benefit of the screen routines. With the screen routines, this should not be called by the user. _✓m_✓o_✓v_✓e() and _✓r_✓e_✓f_✓r_✓e_✓s_✓h() should be used to move the cursor position, so that the routines know what's going on. _✓s_✓c_✓r_✓o_✓l_✓l(_✓w_✓i_✓n) _✓W_✓I_✓N_✓D_✓O_✓W *_✓w_✓i_✓n; Scroll the window upward one line. This is normally not used by the user. Screen Package PS1:18-23 _✓s_✓a_✓v_✓e_✓t_✓t_✓y() [*] _✓r_✓e_✓s_✓e_✓t_✓t_✓y() [*] _✓s_✓a_✓v_✓e_✓t_✓t_✓y() saves the current tty characteristic flags. _✓r_✓e_✓s_✓e_✓t_✓t_✓y() restores them to what _✓s_✓a_✓v_✓e_✓t_✓t_✓y() stored. These functions are performed automatically by _✓i_✓n_✓- _✓i_✓t_✓s_✓c_✓r() and _✓e_✓n_✓d_✓w_✓i_✓n(). _✓s_✓e_✓t_✓t_✓e_✓r_✓m(_✓n_✓a_✓m_✓e) _✓c_✓h_✓a_✓r *_✓n_✓a_✓m_✓e; Set the terminal characteristics to be those of the terminal named _✓n_✓a_✓m_✓e, getting the terminal size from the _✓T_✓I_✓O_✓C_✓G_✓W_✓I_✓N_✓S_✓Z _✓i_✓o_✓c_✓t_✓l(_✓2) if it exists, otherwise from the environment. This is normally called by _✓i_✓n_✓i_✓t_✓s_✓c_✓r(). _✓t_✓s_✓t_✓p() If the new _✓t_✓t_✓y(4) driver is in use, this function will save the current tty state and then put the process to sleep. When the process gets restarted, it restores the tty state and then calls _✓w_✓r_✓e_✓f_✓r_✓e_✓s_✓h(_✓c_✓u_✓r_✓s_✓c_✓r) to redraw the screen. _✓i_✓n_✓i_✓t_✓s_✓c_✓r() sets the signal SIGTSTP to trap to this routine. _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓A _✓1. _✓C_✓a_✓p_✓a_✓b_✓i_✓l_✓i_✓t_✓i_✓e_✓s _✓f_✓r_✓o_✓m _✓t_✓e_✓r_✓m_✓c_✓a_✓p _✓1._✓1. _✓D_✓i_✓s_✓c_✓l_✓a_✓i_✓m_✓e_✓r The description of terminals is a difficult business, and we only attempt to summarize the capabilities here: for a full description see _✓t_✓e_✓r_✓m_✓c_✓a_✓p(5). _✓1._✓2. _✓O_✓v_✓e_✓r_✓v_✓i_✓e_✓w Capabilities from _✓t_✓e_✓r_✓m_✓c_✓a_✓p are of three kinds: string valued options, numeric valued options, and boolean options. The string valued options are the most complicated, since they may include padding information, which we describe now. Intelligent terminals often require padding on intelli- gent operations at high (and sometimes even low) speed. This is specified by a number before the string in the capa- bility, and has meaning for the capabilities which have a _✓P at the front of their comment. This normally is a number of milliseconds to pad the operation. In the current system which has no true programmable delays, we do this by sending a sequence of pad characters (normally nulls, but can be changed (specified by _✓P_✓C)). In some cases, the pad is better computed as some number of milliseconds times the number of affected lines (to the bottom of the screen usual- ly, except when terminals have insert modes which will shift several lines.) This is specified as, i e.g. , _✓1_✓2*. before the capability, to say 12 milliseconds per affected whatever (currently always line). Capabilities where this makes sense say _✓P*. _✓1._✓3. _✓V_✓a_✓r_✓i_✓a_✓b_✓l_✓e_✓s _✓S_✓e_✓t _✓B_✓y _✓s_✓e_✓t_✓t_✓e_✓r_✓m() variables set by _✓s_✓e_✓t_✓t_✓e_✓r_✓m() Type Name Pad Description _____________________________________________________________ char * AL P* Add new blank Line bool AM Automatic Margins char * BC Back Cursor movement bool BS BackSpace works char * BT P Back Tab bool CA Cursor Addressable char * CD P* Clear to end of Display char * CE P Clear to End of line char * CL P* CLear screen char * CM P Cursor Motion char * DC P* Delete Character char * DL P* Delete Line sequence char * DM Delete Mode (enter) _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓A variables set by _✓s_✓e_✓t_✓t_✓e_✓r_✓m() Type Name Pad Description _____________________________________________________________ char * DO DOwn line sequence char * ED End Delete mode bool EO can Erase Overstrikes with ' ' char * EI End Insert mode char * HO HOme cursor bool HZ HaZeltine ~ braindamage char * IC P Insert Character bool IN Insert-Null blessing char * IM enter Insert Mode (IC usually set, too) char * IP P* Pad after char Inserted using IM+IE char * LL quick to Last Line, column 0 char * MA ctrl character MAp for cmd mode bool MI can Move in Insert mode bool NC No Cr: \r sends \r\n then eats \n char * ND Non-Destructive space bool OS OverStrike works char PC Pad Character char * SE Standout End (may leave space) char * SF P Scroll Forwards char * SO Stand Out begin (may leave space) char * SR P Scroll in Reverse char * TA P TAb (not ^I or with padding) char * TE Terminal address enable Ending sequence char * TI Terminal address enable Initialization char * UC Underline a single Character char * UE Underline Ending sequence bool UL UnderLining works even though !OS char * UP UPline char * US Underline Starting sequence char * VB Visible Bell char * VE Visual End sequence char * VS Visual Start sequence bool XN a Newline gets eaten after wrap Names starting with _✓X are reserved for severely nauseous glitches For purposes of _✓s_✓t_✓a_✓n_✓d_✓o_✓u_✓t(), if _✓S_✓G() is not 0, _✓S_✓O() is set to _✓N_✓U_✓L_✓L(), and if _✓U_✓G() is not _✓0(), _✓U_✓S() is set to _✓N_✓U_✓L_✓L(). If, after this, _✓S_✓O() is _✓N_✓U_✓L_✓L(), and _✓U_✓S() is not, _✓S_✓O() is set to be _✓U_✓S(), and _✓S_✓E() is set to be _✓U_✓E(). _✓1._✓4. _✓V_✓a_✓r_✓i_✓a_✓b_✓l_✓e_✓s _✓S_✓e_✓t _✓B_✓y _✓g_✓e_✓t_✓t_✓m_✓o_✓d_✓e() variables set by _✓g_✓e_✓t_✓t_✓m_✓o_✓d_✓e() type name description ____________________________________________________________ _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓A variables set by _✓g_✓e_✓t_✓t_✓m_✓o_✓d_✓e() type name description ____________________________________________________________ bool NONL Term can't hack linefeeds doing a CR bool GT Gtty indicates Tabs bool UPPERCASE Terminal generates only uppercase letters _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓B _✓1. _✓T_✓h_✓e _✓W_✓I_✓N_✓D_✓O_✓W _✓s_✓t_✓r_✓u_✓c_✓t_✓u_✓r_✓e The WINDOW structure is defined as follows: /* * _✓C_✓o_✓p_✓y_✓r_✓i_✓g_✓h_✓t _✓1_✓9_✓8_✓0 _✓K_✓e_✓n_✓n_✓e_✓t_✓h _✓C. _✓R. _✓C. _✓A_✓r_✓n_✓o_✓l_✓d _✓a_✓n_✓d _✓T_✓h_✓e _✓R_✓e_✓g_✓e_✓n_✓t_✓s _✓o_✓f _✓t_✓h_✓e * _✓U_✓n_✓i_✓v_✓e_✓r_✓s_✓i_✓t_✓y _✓o_✓f _✓C_✓a_✓l_✓i_✓f_✓o_✓r_✓n_✓i_✓a. _✓P_✓e_✓r_✓m_✓i_✓s_✓s_✓i_✓o_✓n _✓i_✓s _✓g_✓r_✓a_✓n_✓t_✓e_✓d _✓t_✓o _✓f_✓r_✓e_✓e_✓l_✓y * _✓d_✓i_✓s_✓t_✓r_✓i_✓b_✓u_✓t_✓e _✓c_✓u_✓r_✓s_✓e_✓s _✓a_✓n_✓d _✓i_✓t_✓s _✓d_✓o_✓c_✓u_✓m_✓e_✓n_✓t_✓a_✓t_✓i_✓o_✓n _✓p_✓r_✓o_✓v_✓i_✓d_✓e_✓d _✓t_✓h_✓a_✓t _✓t_✓h_✓i_✓s * _✓n_✓o_✓t_✓i_✓c_✓e _✓i_✓s _✓l_✓e_✓f_✓t _✓i_✓n_✓t_✓a_✓c_✓t. * * @(#)_✓w_✓i_✓n__✓s_✓t._✓c _✓6._✓1 (_✓B_✓e_✓r_✓k_✓e_✓l_✓e_✓y) _✓4/_✓2_✓4/_✓8_✓6"; */ # _✓d_✓e_✓f_✓i_✓n_✓e WINDOW _✓s_✓t_✓r_✓u_✓c_✓t _win_st _✓s_✓t_✓r_✓u_✓c_✓t _win_st { _✓s_✓h_✓o_✓r_✓t _cury, _curx; _✓s_✓h_✓o_✓r_✓t _maxy, _maxx; _✓s_✓h_✓o_✓r_✓t _begy, _begx; _✓s_✓h_✓o_✓r_✓t _flags; _✓s_✓h_✓o_✓r_✓t _ch_off; bool _clear; bool _leave; bool _scroll; _✓c_✓h_✓a_✓r **_y; _✓s_✓h_✓o_✓r_✓t *_firstch; _✓s_✓h_✓o_✓r_✓t *_lastch; _✓s_✓t_✓r_✓u_✓c_✓t _win_st *_nextp, *_orig; }; # _✓d_✓e_✓f_✓i_✓n_✓e _ENDLINE 001 # _✓d_✓e_✓f_✓i_✓n_✓e _FULLWIN 002 # _✓d_✓e_✓f_✓i_✓n_✓e _SCROLLWIN 004 # _✓d_✓e_✓f_✓i_✓n_✓e _FLUSH 010 # _✓d_✓e_✓f_✓i_✓n_✓e _FULLLINE 020 # _✓d_✓e_✓f_✓i_✓n_✓e _IDLINE 040 # _✓d_✓e_✓f_✓i_✓n_✓e _STANDOUT 0200 # _✓d_✓e_✓f_✓i_✓n_✓e _NOCHANGE -1 __✓c_✓u_✓r_✓y and __✓c_✓u_✓r_✓x are the current (y, x) co-ordinates for the window. New characters added to the screen are added at this point. __✓m_✓a_✓x_✓y and __✓m_✓a_✓x_✓x are the maximum values allowed for (__✓c_✓u_✓r_✓y, __✓c_✓u_✓r_✓x). __✓b_✓e_✓g_✓y and __✓b_✓e_✓g_✓x are the starting (y, x) co-ordinates on the terminal for the window, _✓i._✓e., the window's home. __✓c_✓u_✓r_✓y, __✓c_✓u_✓r_✓x, __✓m_✓a_✓x_✓y, and __✓m_✓a_✓x_✓x are measured ____________________ [10] All variables not normally accessed directly by the user are named with an initial "_" to avoid conflicts with the user's variables. _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓B relative to (__✓b_✓e_✓g_✓y, __✓b_✓e_✓g_✓x), not the terminal's home. __✓c_✓l_✓e_✓a_✓r tells if a clear-screen sequence is to be gen- erated on the next _✓r_✓e_✓f_✓r_✓e_✓s_✓h() call. This is only meaningful for screens. The initial clear-screen for the first _✓r_✓e_✓- _✓f_✓r_✓e_✓s_✓h() call is generated by initially setting clear to be TRUE for _✓c_✓u_✓r_✓s_✓c_✓r, which always generates a clear-screen if set, irrelevant of the dimensions of the window involved. __✓l_✓e_✓a_✓v_✓e is TRUE if the current (y, x) co-ordinates and the cursor are to be left after the last character changed on the terminal, or not moved if there is no change. __✓s_✓c_✓r_✓o_✓l_✓l is TRUE if scrolling is allowed. __✓y is a pointer to an array of lines which describe the terminal. Thus: _y[i] is a pointer to the _✓ith line, and _y[i][j] is the _✓jth character on the _✓ith line. __✓f_✓l_✓a_✓g_✓s can have one or more values or'd into it. For windows that are not subwindows, __✓o_✓r_✓i_✓g is NULL . For subwindows, it points to the main window to which the window is subsidiary. __✓n_✓e_✓x_✓t_✓p is a pointer in a circularly linked list of all the windows which are subwindows of the same main window, plus the main window itself. __✓f_✓i_✓r_✓s_✓t_✓c_✓h and __✓l_✓a_✓s_✓t_✓c_✓h are _✓m_✓a_✓l_✓l_✓o_✓c()ed arrays which con- tain the index of the first and last changed characters on the line. __✓c_✓h__✓o_✓f_✓f is the x offset for the window in the __✓f_✓i_✓r_✓s_✓t_✓c_✓h and __✓l_✓a_✓s_✓t_✓c_✓h arrays for this window. For main win- dows, this is always 0; for subwindows it is the difference between the starting point of the main window and that of the subindow, so that change markers can be set relative to the main window. This makes these markers global in scope. All subwindows share the appropriate portions of __✓y, __✓f_✓i_✓r_✓s_✓t_✓c_✓h, __✓l_✓a_✓s_✓t_✓c_✓h, and __✓i_✓n_✓s_✓d_✓e_✓l with their main window. __✓E_✓N_✓D_✓L_✓I_✓N_✓E says that the end of the line for this window is also the end of a screen. __✓F_✓U_✓L_✓L_✓W_✓I_✓N says that this window is a screen. __✓S_✓C_✓R_✓O_✓L_✓L_✓W_✓I_✓N indicates that the last character of this screen is at the lower right-hand corner of the ter- minal; _✓i._✓e., if a character was put there, the terminal would scroll. __✓F_✓U_✓L_✓L_✓L_✓I_✓N_✓E says that the width of a line is the same as the width of the terminal. If __✓F_✓L_✓U_✓S_✓H is set, it says that _✓f_✓f_✓l_✓u_✓s_✓h(_✓s_✓t_✓d_✓o_✓u_✓t) should be called at the end of each _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓B _✓r_✓e_✓f_✓r_✓e_✓s_✓h() __✓S_✓T_✓A_✓N_✓D_✓O_✓U_✓T says that all characters added to the screen are in standout mode. __✓I_✓N_✓S_✓D_✓E_✓L is reserved for future use, and is set by _✓i_✓d_✓l_✓o_✓k(). __✓f_✓i_✓r_✓s_✓t_✓c_✓h is set to __✓N_✓O_✓C_✓H_✓A_✓N_✓G_✓E for lines on which there has been no change since the last _✓r_✓e_✓f_✓r_✓e_✓s_✓h(). _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓C _✓1. _✓E_✓x_✓a_✓m_✓p_✓l_✓e_✓s Here we present a few examples of how to use the pack- age. They attempt to be representative, though not comprehensive. _✓2. _✓S_✓c_✓r_✓e_✓e_✓n _✓U_✓p_✓d_✓a_✓t_✓i_✓n_✓g The following examples are intended to demonstrate the basic structure of a program using the screen updating sec- tions of the package. Several of the programs require cal- culational sections which are irrelevant of to the example, and are therefore usually not included. It is hoped that the data structure definitions give enough of an idea to al- low understanding of what the relevant portions do. The rest is left as an exercise to the reader, and will not be on the final. _✓2._✓1. _✓T_✓w_✓i_✓n_✓k_✓l_✓e This is a moderately simple program which prints pretty patterns on the screen that might even hold your interest for 30 seconds or more. It switches between patterns of as- terisks, putting them on one by one in random order, and then taking them off in the same fashion. It is more effi- cient to write this using only the motion optimization, as is demonstrated below. /* * _✓C_✓o_✓p_✓y_✓r_✓i_✓g_✓h_✓t _✓1_✓9_✓8_✓0 _✓K_✓e_✓n_✓n_✓e_✓t_✓h _✓C. _✓R. _✓C. _✓A_✓r_✓n_✓o_✓l_✓d _✓a_✓n_✓d _✓T_✓h_✓e _✓R_✓e_✓g_✓e_✓n_✓t_✓s _✓o_✓f _✓t_✓h_✓e * _✓U_✓n_✓i_✓v_✓e_✓r_✓s_✓i_✓t_✓y _✓o_✓f _✓C_✓a_✓l_✓i_✓f_✓o_✓r_✓n_✓i_✓a. _✓P_✓e_✓r_✓m_✓i_✓s_✓s_✓i_✓o_✓n _✓i_✓s _✓g_✓r_✓a_✓n_✓t_✓e_✓d _✓t_✓o _✓f_✓r_✓e_✓e_✓l_✓y * _✓d_✓i_✓s_✓t_✓r_✓i_✓b_✓u_✓t_✓e _✓c_✓u_✓r_✓s_✓e_✓s _✓a_✓n_✓d _✓i_✓t_✓s _✓d_✓o_✓c_✓u_✓m_✓e_✓n_✓t_✓a_✓t_✓i_✓o_✓n _✓p_✓r_✓o_✓v_✓i_✓d_✓e_✓d _✓t_✓h_✓a_✓t _✓t_✓h_✓i_✓s * _✓n_✓o_✓t_✓i_✓c_✓e _✓i_✓s _✓l_✓e_✓f_✓t _✓i_✓n_✓t_✓a_✓c_✓t. */ #_✓i_✓f_✓n_✓d_✓e_✓f lint _✓s_✓t_✓a_✓t_✓i_✓c _✓c_✓h_✓a_✓r sccsid[] = "@(#)twinkle1.c 6.1 (Berkeley) 4/24/86"; #_✓e_✓n_✓d_✓i_✓f not lint # _✓i_✓n_✓c_✓l_✓u_✓d_✓e <curses.h> # _✓i_✓n_✓c_✓l_✓u_✓d_✓e <signal.h> /* * _✓t_✓h_✓e _✓i_✓d_✓e_✓a _✓f_✓o_✓r _✓t_✓h_✓i_✓s _✓p_✓r_✓o_✓g_✓r_✓a_✓m _✓w_✓a_✓s _✓a _✓p_✓r_✓o_✓d_✓u_✓c_✓t _✓o_✓f _✓t_✓h_✓e _✓i_✓m_✓a_✓g_✓i_✓n_✓a_✓t_✓i_✓o_✓n _✓o_✓f * _✓K_✓u_✓r_✓t _✓S_✓c_✓h_✓o_✓e_✓n_✓s. _✓N_✓o_✓t _✓r_✓e_✓s_✓p_✓o_✓n_✓s_✓i_✓b_✓l_✓e _✓f_✓o_✓r _✓m_✓i_✓n_✓d_✓s _✓l_✓o_✓s_✓t _✓o_✓r _✓s_✓t_✓o_✓l_✓e_✓n. */ # _✓d_✓e_✓f_✓i_✓n_✓e NCOLS 80 # _✓d_✓e_✓f_✓i_✓n_✓e NLINES 24 # _✓d_✓e_✓f_✓i_✓n_✓e MAXPATTERNS 4 _✓t_✓y_✓p_✓e_✓d_✓e_✓f _✓s_✓t_✓r_✓u_✓c_✓t { _✓i_✓n_✓t y, x; _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓C } LOCS; LOCS Layout[NCOLS * NLINES]; /* _✓c_✓u_✓r_✓r_✓e_✓n_✓t _✓b_✓o_✓a_✓r_✓d _✓l_✓a_✓y_✓o_✓u_✓t */ _✓i_✓n_✓t Pattern, /* _✓c_✓u_✓r_✓r_✓e_✓n_✓t _✓p_✓a_✓t_✓t_✓e_✓r_✓n _✓n_✓u_✓m_✓b_✓e_✓r */ Numstars; /* _✓n_✓u_✓m_✓b_✓e_✓r _✓o_✓f _✓s_✓t_✓a_✓r_✓s _✓i_✓n _✓p_✓a_✓t_✓t_✓e_✓r_✓n */ _✓c_✓h_✓a_✓r *getenv(); _✓i_✓n_✓t die(); main() { srand(getpid()); /* _✓i_✓n_✓i_✓t_✓i_✓a_✓l_✓i_✓z_✓e _✓r_✓a_✓n_✓d_✓o_✓m _✓s_✓e_✓q_✓u_✓e_✓n_✓c_✓e */ initscr(); signal(SIGINT, die); noecho(); nonl(); leaveok(stdscr, TRUE); scrollok(stdscr, FALSE); _✓f_✓o_✓r (;;) { makeboard(); /* _✓m_✓a_✓k_✓e _✓t_✓h_✓e _✓b_✓o_✓a_✓r_✓d _✓s_✓e_✓t_✓u_✓p */ puton('*'); /* _✓p_✓u_✓t _✓o_✓n '*'_✓s */ puton(' '); /* _✓c_✓o_✓v_✓e_✓r _✓u_✓p _✓w_✓i_✓t_✓h ' '_✓s */ } } /* * _✓O_✓n _✓p_✓r_✓o_✓g_✓r_✓a_✓m _✓e_✓x_✓i_✓t, _✓m_✓o_✓v_✓e _✓t_✓h_✓e _✓c_✓u_✓r_✓s_✓o_✓r _✓t_✓o _✓t_✓h_✓e _✓l_✓o_✓w_✓e_✓r _✓l_✓e_✓f_✓t _✓c_✓o_✓r_✓n_✓e_✓r _✓b_✓y * _✓d_✓i_✓r_✓e_✓c_✓t _✓a_✓d_✓d_✓r_✓e_✓s_✓s_✓i_✓n_✓g, _✓s_✓i_✓n_✓c_✓e _✓c_✓u_✓r_✓r_✓e_✓n_✓t _✓l_✓o_✓c_✓a_✓t_✓i_✓o_✓n _✓i_✓s _✓n_✓o_✓t _✓g_✓u_✓a_✓r_✓a_✓n_✓t_✓e_✓e_✓d. * _✓W_✓e _✓l_✓i_✓e _✓a_✓n_✓d _✓s_✓a_✓y _✓w_✓e _✓u_✓s_✓e_✓d _✓t_✓o _✓b_✓e _✓a_✓t _✓t_✓h_✓e _✓u_✓p_✓p_✓e_✓r _✓r_✓i_✓g_✓h_✓t _✓c_✓o_✓r_✓n_✓e_✓r _✓t_✓o _✓g_✓u_✓a_✓r_✓a_✓n_✓t_✓e_✓e * _✓a_✓b_✓s_✓o_✓l_✓u_✓t_✓e _✓a_✓d_✓d_✓r_✓e_✓s_✓s_✓i_✓n_✓g. */ die() { signal(SIGINT, SIG_IGN); mvcur(0, COLS - 1, LINES - 1, 0); endwin(); exit(0); } /* * _✓M_✓a_✓k_✓e _✓t_✓h_✓e _✓c_✓u_✓r_✓r_✓e_✓n_✓t _✓b_✓o_✓a_✓r_✓d _✓s_✓e_✓t_✓u_✓p. _✓I_✓t _✓p_✓i_✓c_✓k_✓s _✓a _✓r_✓a_✓n_✓d_✓o_✓m _✓p_✓a_✓t_✓t_✓e_✓r_✓n _✓a_✓n_✓d * _✓c_✓a_✓l_✓l_✓s _✓i_✓s_✓o_✓n() _✓t_✓o _✓d_✓e_✓t_✓e_✓r_✓m_✓i_✓n_✓e _✓i_✓f _✓t_✓h_✓e _✓c_✓h_✓a_✓r_✓a_✓c_✓t_✓e_✓r _✓i_✓s _✓o_✓n _✓t_✓h_✓a_✓t _✓p_✓a_✓t_✓t_✓e_✓r_✓n * _✓o_✓r _✓n_✓o_✓t. */ makeboard() { reg _✓i_✓n_✓t y, x; reg LOCS *lp; _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓C Pattern = rand() % MAXPATTERNS; lp = Layout; _✓f_✓o_✓r (y = 0; y < NLINES; y++) _✓f_✓o_✓r (x = 0; x < NCOLS; x++) _✓i_✓f (ison(y, x)) { lp->y = y; lp->x = x; lp++; } Numstars = lp - Layout; } /* * _✓R_✓e_✓t_✓u_✓r_✓n _✓T_✓R_✓U_✓E _✓i_✓f (_✓y, _✓x) _✓i_✓s _✓o_✓n _✓t_✓h_✓e _✓c_✓u_✓r_✓r_✓e_✓n_✓t _✓p_✓a_✓t_✓t_✓e_✓r_✓n. */ ison(y, x) reg _✓i_✓n_✓t y, x; { _✓s_✓w_✓i_✓t_✓c_✓h (Pattern) { _✓c_✓a_✓s_✓e 0: /* _✓a_✓l_✓t_✓e_✓r_✓n_✓a_✓t_✓i_✓n_✓g _✓l_✓i_✓n_✓e_✓s */ _✓r_✓e_✓t_✓u_✓r_✓n !(y & 01); _✓c_✓a_✓s_✓e 1: /* _✓b_✓o_✓x */ _✓i_✓f (x >= LINES && y >= NCOLS) _✓r_✓e_✓t_✓u_✓r_✓n FALSE; _✓i_✓f (y < 3 || y >= NLINES - 3) _✓r_✓e_✓t_✓u_✓r_✓n TRUE; _✓r_✓e_✓t_✓u_✓r_✓n (x < 3 || x >= NCOLS - 3); _✓c_✓a_✓s_✓e 2: /* _✓h_✓o_✓l_✓y _✓p_✓a_✓t_✓t_✓e_✓r_✓n! */ _✓r_✓e_✓t_✓u_✓r_✓n ((x + y) & 01); _✓c_✓a_✓s_✓e 3: /* _✓b_✓a_✓r _✓a_✓c_✓r_✓o_✓s_✓s _✓c_✓e_✓n_✓t_✓e_✓r */ _✓r_✓e_✓t_✓u_✓r_✓n (y >= 9 && y <= 15); } /* _✓N_✓O_✓T_✓R_✓E_✓A_✓C_✓H_✓E_✓D */ } puton(ch) reg _✓c_✓h_✓a_✓r ch; { reg LOCS *lp; reg _✓i_✓n_✓t r; reg LOCS *end; LOCS temp; end = &Layout[Numstars]; _✓f_✓o_✓r (lp = Layout; lp < end; lp++) { r = rand() % Numstars; temp = *lp; *lp = Layout[r]; Layout[r] = temp; } _✓f_✓o_✓r (lp = Layout; lp < end; lp++) { mvaddch(lp->y, lp->x, ch); _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓C refresh(); } } _✓2._✓2. _✓L_✓i_✓f_✓e This program fragment models the famous computer pat- tern game of life (Scientific American, May, 1974). The calculational routines create a linked list of structures defining where each piece is. Nothing here claims to be op- timal, merely demonstrative. This code, however, is a very good place to use the screen updating routines, as it allows them to worry about what the last position looked like, so you don't have to. It also demonstrates some of the input routines. /* * _✓C_✓o_✓p_✓y_✓r_✓i_✓g_✓h_✓t _✓1_✓9_✓8_✓0 _✓K_✓e_✓n_✓n_✓e_✓t_✓h _✓C. _✓R. _✓C. _✓A_✓r_✓n_✓o_✓l_✓d _✓a_✓n_✓d _✓T_✓h_✓e _✓R_✓e_✓g_✓e_✓n_✓t_✓s _✓o_✓f _✓t_✓h_✓e * _✓U_✓n_✓i_✓v_✓e_✓r_✓s_✓i_✓t_✓y _✓o_✓f _✓C_✓a_✓l_✓i_✓f_✓o_✓r_✓n_✓i_✓a. _✓P_✓e_✓r_✓m_✓i_✓s_✓s_✓i_✓o_✓n _✓i_✓s _✓g_✓r_✓a_✓n_✓t_✓e_✓d _✓t_✓o _✓f_✓r_✓e_✓e_✓l_✓y * _✓d_✓i_✓s_✓t_✓r_✓i_✓b_✓u_✓t_✓e _✓c_✓u_✓r_✓s_✓e_✓s _✓a_✓n_✓d _✓i_✓t_✓s _✓d_✓o_✓c_✓u_✓m_✓e_✓n_✓t_✓a_✓t_✓i_✓o_✓n _✓p_✓r_✓o_✓v_✓i_✓d_✓e_✓d _✓t_✓h_✓a_✓t _✓t_✓h_✓i_✓s * _✓n_✓o_✓t_✓i_✓c_✓e _✓i_✓s _✓l_✓e_✓f_✓t _✓i_✓n_✓t_✓a_✓c_✓t. */ #_✓i_✓f_✓n_✓d_✓e_✓f lint _✓s_✓t_✓a_✓t_✓i_✓c _✓c_✓h_✓a_✓r sccsid[] = "@(#)life.c 6.1 (Berkeley) 4/23/86"; #_✓e_✓n_✓d_✓i_✓f not lint # _✓i_✓n_✓c_✓l_✓u_✓d_✓e <curses.h> # _✓i_✓n_✓c_✓l_✓u_✓d_✓e <signal.h> /* * _✓R_✓u_✓n _✓a _✓l_✓i_✓f_✓e _✓g_✓a_✓m_✓e. _✓T_✓h_✓i_✓s _✓i_✓s _✓a _✓d_✓e_✓m_✓o_✓n_✓s_✓t_✓r_✓a_✓t_✓i_✓o_✓n _✓p_✓r_✓o_✓g_✓r_✓a_✓m _✓f_✓o_✓r * _✓t_✓h_✓e _✓S_✓c_✓r_✓e_✓e_✓n _✓U_✓p_✓d_✓a_✓t_✓i_✓n_✓g _✓s_✓e_✓c_✓t_✓i_✓o_✓n _✓o_✓f _✓t_✓h_✓e -_✓l_✓c_✓u_✓r_✓s_✓e_✓s _✓c_✓u_✓r_✓s_✓o_✓r _✓p_✓a_✓c_✓k_✓a_✓g_✓e. */ _✓t_✓y_✓p_✓e_✓d_✓e_✓f _✓s_✓t_✓r_✓u_✓c_✓t lst_st { /* _✓l_✓i_✓n_✓k_✓e_✓d _✓l_✓i_✓s_✓t _✓e_✓l_✓e_✓m_✓e_✓n_✓t */ _✓i_✓n_✓t y, x; /* (_✓y, _✓x) _✓p_✓o_✓s_✓i_✓t_✓i_✓o_✓n _✓o_✓f _✓p_✓i_✓e_✓c_✓e */ _✓s_✓t_✓r_✓u_✓c_✓t lst_st *next, *last; /* _✓d_✓o_✓u_✓b_✓l_✓y _✓l_✓i_✓n_✓k_✓e_✓d */ } LIST; LIST *Head; /* _✓h_✓e_✓a_✓d _✓o_✓f _✓l_✓i_✓n_✓k_✓e_✓d _✓l_✓i_✓s_✓t */ _✓i_✓n_✓t die(); main(ac, av) _✓i_✓n_✓t ac; _✓c_✓h_✓a_✓r *av[]; { evalargs(ac, av); /* _✓e_✓v_✓a_✓l_✓u_✓a_✓t_✓e _✓a_✓r_✓g_✓u_✓m_✓e_✓n_✓t_✓s */ _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓C initscr(); /* _✓i_✓n_✓i_✓t_✓i_✓a_✓l_✓i_✓z_✓e _✓s_✓c_✓r_✓e_✓e_✓n _✓p_✓a_✓c_✓k_✓a_✓g_✓e */ signal(SIGINT, die); /* _✓s_✓e_✓t _✓t_✓o _✓r_✓e_✓s_✓t_✓o_✓r_✓e _✓t_✓t_✓y _✓s_✓t_✓a_✓t_✓s */ cbreak(); /* _✓s_✓e_✓t _✓f_✓o_✓r _✓c_✓h_✓a_✓r-_✓b_✓y-_✓c_✓h_✓a_✓r */ noecho(); /* _✓i_✓n_✓p_✓u_✓t */ nonl(); /* _✓f_✓o_✓r _✓o_✓p_✓t_✓i_✓m_✓i_✓z_✓a_✓t_✓i_✓o_✓n */ getstart(); /* _✓g_✓e_✓t _✓s_✓t_✓a_✓r_✓t_✓i_✓n_✓g _✓p_✓o_✓s_✓i_✓t_✓i_✓o_✓n */ _✓f_✓o_✓r (;;) { prboard(); /* _✓p_✓r_✓i_✓n_✓t _✓o_✓u_✓t _✓c_✓u_✓r_✓r_✓e_✓n_✓t _✓b_✓o_✓a_✓r_✓d */ update(); /* _✓u_✓p_✓d_✓a_✓t_✓e _✓b_✓o_✓a_✓r_✓d _✓p_✓o_✓s_✓i_✓t_✓i_✓o_✓n */ } } /* * _✓T_✓h_✓i_✓s _✓i_✓s _✓t_✓h_✓e _✓r_✓o_✓u_✓t_✓i_✓n_✓e _✓w_✓h_✓i_✓c_✓h _✓i_✓s _✓c_✓a_✓l_✓l_✓e_✓d _✓w_✓h_✓e_✓n _✓r_✓u_✓b_✓o_✓u_✓t _✓i_✓s _✓h_✓i_✓t. * _✓I_✓t _✓r_✓e_✓s_✓e_✓t_✓s _✓t_✓h_✓e _✓t_✓t_✓y _✓s_✓t_✓a_✓t_✓s _✓t_✓o _✓t_✓h_✓e_✓i_✓r _✓o_✓r_✓i_✓g_✓i_✓n_✓a_✓l _✓v_✓a_✓l_✓u_✓e_✓s. _✓T_✓h_✓i_✓s * _✓i_✓s _✓t_✓h_✓e _✓n_✓o_✓r_✓m_✓a_✓l _✓w_✓a_✓y _✓o_✓f _✓l_✓e_✓a_✓v_✓i_✓n_✓g _✓t_✓h_✓e _✓p_✓r_✓o_✓g_✓r_✓a_✓m. */ die() { signal(SIGINT, SIG_IGN); /* _✓i_✓g_✓n_✓o_✓r_✓e _✓r_✓u_✓b_✓o_✓u_✓t_✓s */ mvcur(0, COLS - 1, LINES - 1, 0); /* _✓g_✓o _✓t_✓o _✓b_✓o_✓t_✓t_✓o_✓m _✓o_✓f _✓s_✓c_✓r_✓e_✓e_✓n */ endwin(); /* _✓s_✓e_✓t _✓t_✓e_✓r_✓m_✓i_✓n_✓a_✓l _✓t_✓o _✓g_✓o_✓o_✓d _✓s_✓t_✓a_✓t_✓e */ exit(0); } /* * _✓G_✓e_✓t _✓t_✓h_✓e _✓s_✓t_✓a_✓r_✓t_✓i_✓n_✓g _✓p_✓o_✓s_✓i_✓t_✓i_✓o_✓n _✓f_✓r_✓o_✓m _✓t_✓h_✓e _✓u_✓s_✓e_✓r. _✓T_✓h_✓e_✓y _✓k_✓e_✓y_✓s _✓u, _✓i, _✓o, _✓j, _✓l, * _✓m, ,, _✓a_✓n_✓d . _✓a_✓r_✓e _✓u_✓s_✓e_✓d _✓f_✓o_✓r _✓m_✓o_✓v_✓i_✓n_✓g _✓t_✓h_✓e_✓i_✓r _✓r_✓e_✓l_✓a_✓t_✓i_✓v_✓e _✓d_✓i_✓r_✓e_✓c_✓t_✓i_✓o_✓n_✓s _✓f_✓r_✓o_✓m _✓t_✓h_✓e * _✓k _✓k_✓e_✓y. _✓T_✓h_✓u_✓s, _✓u _✓m_✓o_✓v_✓e _✓d_✓i_✓a_✓g_✓o_✓n_✓a_✓l_✓l_✓y _✓u_✓p _✓t_✓o _✓t_✓h_✓e _✓l_✓e_✓f_✓t, , _✓m_✓o_✓v_✓e_✓s _✓d_✓i_✓r_✓e_✓c_✓t_✓l_✓y _✓d_✓o_✓w_✓n, * _✓e_✓t_✓c. _✓x _✓p_✓l_✓a_✓c_✓e_✓s _✓a _✓p_✓i_✓e_✓c_✓e _✓a_✓t _✓t_✓h_✓e _✓c_✓u_✓r_✓r_✓e_✓n_✓t _✓p_✓o_✓s_✓i_✓t_✓i_✓o_✓n, " " _✓t_✓a_✓k_✓e_✓s _✓i_✓t _✓a_✓w_✓a_✓y. * _✓T_✓h_✓e _✓i_✓n_✓p_✓u_✓t _✓c_✓a_✓n _✓a_✓l_✓s_✓o _✓b_✓e _✓f_✓r_✓o_✓m _✓a _✓f_✓i_✓l_✓e. _✓T_✓h_✓e _✓l_✓i_✓s_✓t _✓i_✓s _✓b_✓u_✓i_✓l_✓t _✓a_✓f_✓t_✓e_✓r _✓t_✓h_✓e * _✓b_✓o_✓a_✓r_✓d _✓s_✓e_✓t_✓u_✓p _✓i_✓s _✓r_✓e_✓a_✓d_✓y. */ getstart() { reg _✓c_✓h_✓a_✓r c; reg _✓i_✓n_✓t x, y; _✓a_✓u_✓t_✓o _✓c_✓h_✓a_✓r buf[100]; box(stdscr, '|', '_'); /* _✓b_✓o_✓x _✓i_✓n _✓t_✓h_✓e _✓s_✓c_✓r_✓e_✓e_✓n */ move(1, 1); /* _✓m_✓o_✓v_✓e _✓t_✓o _✓u_✓p_✓p_✓e_✓r _✓l_✓e_✓f_✓t _✓c_✓o_✓r_✓n_✓e_✓r */ _✓f_✓o_✓r (;;) { refresh(); /* _✓p_✓r_✓i_✓n_✓t _✓c_✓u_✓r_✓r_✓e_✓n_✓t _✓p_✓o_✓s_✓i_✓t_✓i_✓o_✓n */ _✓i_✓f ((c = getch()) == 'q') _✓b_✓r_✓e_✓a_✓k; _✓s_✓w_✓i_✓t_✓c_✓h (c) { _✓c_✓a_✓s_✓e 'u': _✓c_✓a_✓s_✓e 'i': _✓c_✓a_✓s_✓e 'o': _✓c_✓a_✓s_✓e 'j': _✓c_✓a_✓s_✓e 'l': _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓C _✓c_✓a_✓s_✓e 'm': _✓c_✓a_✓s_✓e ',': _✓c_✓a_✓s_✓e '.': adjustyx(c); _✓b_✓r_✓e_✓a_✓k; _✓c_✓a_✓s_✓e 'f': mvaddstr(0, 0, "File name: "); getstr(buf); readfile(buf); _✓b_✓r_✓e_✓a_✓k; _✓c_✓a_✓s_✓e 'x': addch('X'); _✓b_✓r_✓e_✓a_✓k; _✓c_✓a_✓s_✓e ' ': addch(' '); _✓b_✓r_✓e_✓a_✓k; } } _✓i_✓f (Head != NULL) /* _✓s_✓t_✓a_✓r_✓t _✓n_✓e_✓w _✓l_✓i_✓s_✓t */ dellist(Head); Head = malloc(_✓s_✓i_✓z_✓e_✓o_✓f (LIST)); /* * _✓l_✓o_✓o_✓p _✓t_✓h_✓r_✓o_✓u_✓g_✓h _✓t_✓h_✓e _✓s_✓c_✓r_✓e_✓e_✓n _✓l_✓o_✓o_✓k_✓i_✓n_✓g _✓f_✓o_✓r '_✓x'_✓s, _✓a_✓n_✓d _✓a_✓d_✓d _✓a _✓l_✓i_✓s_✓t * _✓e_✓l_✓e_✓m_✓e_✓n_✓t _✓f_✓o_✓r _✓e_✓a_✓c_✓h _✓o_✓n_✓e */ _✓f_✓o_✓r (y = 1; y < LINES - 1; y++) _✓f_✓o_✓r (x = 1; x < COLS - 1; x++) { move(y, x); _✓i_✓f (inch() == 'x') addlist(y, x); } } /* * _✓P_✓r_✓i_✓n_✓t _✓o_✓u_✓t _✓t_✓h_✓e _✓c_✓u_✓r_✓r_✓e_✓n_✓t _✓b_✓o_✓a_✓r_✓d _✓p_✓o_✓s_✓i_✓t_✓i_✓o_✓n _✓f_✓r_✓o_✓m _✓t_✓h_✓e _✓l_✓i_✓n_✓k_✓e_✓d _✓l_✓i_✓s_✓t */ prboard() { reg LIST *hp; erase(); /* _✓c_✓l_✓e_✓a_✓r _✓o_✓u_✓t _✓l_✓a_✓s_✓t _✓p_✓o_✓s_✓i_✓t_✓i_✓o_✓n */ box(stdscr, '|', '_'); /* _✓b_✓o_✓x _✓i_✓n _✓t_✓h_✓e _✓s_✓c_✓r_✓e_✓e_✓n */ /* * _✓g_✓o _✓t_✓h_✓r_✓o_✓u_✓g_✓h _✓t_✓h_✓e _✓l_✓i_✓s_✓t _✓a_✓d_✓d_✓i_✓n_✓g _✓e_✓a_✓c_✓h _✓p_✓i_✓e_✓c_✓e _✓t_✓o _✓t_✓h_✓e _✓n_✓e_✓w_✓l_✓y * _✓b_✓l_✓a_✓n_✓k _✓b_✓o_✓a_✓r_✓d */ _✓f_✓o_✓r (hp = Head; hp; hp = hp->next) mvaddch(hp->y, hp->x, 'X'); refresh(); _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓C } _✓3. _✓M_✓o_✓t_✓i_✓o_✓n _✓o_✓p_✓t_✓i_✓m_✓i_✓z_✓a_✓t_✓i_✓o_✓n The following example shows how motion optimization is written on its own. Programs which flit from one place to another without regard for what is already there usually do not need the overhead of both space and time associated with screen updating. They should instead use motion optimiza- tion. _✓3._✓1. _✓T_✓w_✓i_✓n_✓k_✓l_✓e The _✓t_✓w_✓i_✓n_✓k_✓l_✓e program is a good candidate for simple mo- tion optimization. Here is how it could be written (only the routines that have been changed are shown): /* * _✓C_✓o_✓p_✓y_✓r_✓i_✓g_✓h_✓t _✓1_✓9_✓8_✓0 _✓K_✓e_✓n_✓n_✓e_✓t_✓h _✓C. _✓R. _✓C. _✓A_✓r_✓n_✓o_✓l_✓d _✓a_✓n_✓d _✓T_✓h_✓e _✓R_✓e_✓g_✓e_✓n_✓t_✓s _✓o_✓f _✓t_✓h_✓e * _✓U_✓n_✓i_✓v_✓e_✓r_✓s_✓i_✓t_✓y _✓o_✓f _✓C_✓a_✓l_✓i_✓f_✓o_✓r_✓n_✓i_✓a. _✓P_✓e_✓r_✓m_✓i_✓s_✓s_✓i_✓o_✓n _✓i_✓s _✓g_✓r_✓a_✓n_✓t_✓e_✓d _✓t_✓o _✓f_✓r_✓e_✓e_✓l_✓y * _✓d_✓i_✓s_✓t_✓r_✓i_✓b_✓u_✓t_✓e _✓c_✓u_✓r_✓s_✓e_✓s _✓a_✓n_✓d _✓i_✓t_✓s _✓d_✓o_✓c_✓u_✓m_✓e_✓n_✓t_✓a_✓t_✓i_✓o_✓n _✓p_✓r_✓o_✓v_✓i_✓d_✓e_✓d _✓t_✓h_✓a_✓t _✓t_✓h_✓i_✓s * _✓n_✓o_✓t_✓i_✓c_✓e _✓i_✓s _✓l_✓e_✓f_✓t _✓i_✓n_✓t_✓a_✓c_✓t. */ #_✓i_✓f_✓n_✓d_✓e_✓f lint _✓s_✓t_✓a_✓t_✓i_✓c _✓c_✓h_✓a_✓r sccsid[] = "@(#)twinkle2.c 6.1 (Berkeley) 4/24/86"; #_✓e_✓n_✓d_✓i_✓f not lint _✓e_✓x_✓t_✓e_✓r_✓n _✓i_✓n_✓t _putchar(); main() { reg _✓c_✓h_✓a_✓r *sp; srand(getpid()); /* _✓i_✓n_✓i_✓t_✓i_✓a_✓l_✓i_✓z_✓e _✓r_✓a_✓n_✓d_✓o_✓m _✓s_✓e_✓q_✓u_✓e_✓n_✓c_✓e */ _✓i_✓f (isatty(0)) { gettmode(); _✓i_✓f ((sp = getenv("TERM")) != NULL) setterm(sp); signal(SIGINT, die); } _✓e_✓l_✓s_✓e { printf("Need a terminal on %d\n", _tty_ch); exit(1); } _puts(TI); _puts(VS); noecho(); nonl(); tputs(CL, NLINES, _putchar); _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓C _✓f_✓o_✓r (;;) { makeboard(); /* _✓m_✓a_✓k_✓e _✓t_✓h_✓e _✓b_✓o_✓a_✓r_✓d _✓s_✓e_✓t_✓u_✓p */ puton('*'); /* _✓p_✓u_✓t _✓o_✓n '*'_✓s */ puton(' '); /* _✓c_✓o_✓v_✓e_✓r _✓u_✓p _✓w_✓i_✓t_✓h ' '_✓s */ } } puton(ch) _✓c_✓h_✓a_✓r ch; { reg LOCS *lp; reg _✓i_✓n_✓t r; reg LOCS *end; LOCS temp; _✓s_✓t_✓a_✓t_✓i_✓c _✓i_✓n_✓t lasty, lastx; end = &Layout[Numstars]; _✓f_✓o_✓r (lp = Layout; lp < end; lp++) { r = rand() % Numstars; temp = *lp; *lp = Layout[r]; Layout[r] = temp; } _✓f_✓o_✓r (lp = Layout; lp < end; lp++) /* _✓p_✓r_✓e_✓v_✓e_✓n_✓t _✓s_✓c_✓r_✓o_✓l_✓l_✓i_✓n_✓g */ _✓i_✓f (!AM || (lp->y < NLINES - 1 || lp->x < NCOLS - 1)) { mvcur(lasty, lastx, lp->y, lp->x); putchar(ch); lasty = lp->y; _✓i_✓f ((lastx = lp->x + 1) >= NCOLS) _✓i_✓f (AM) { lastx = 0; lasty++; } _✓e_✓l_✓s_✓e lastx = NCOLS - 1; } } PS1:18-2 Screen Package _✓C_✓o_✓n_✓t_✓e_✓n_✓t_✓s 1 Overview ............................................ 3 1.1 Terminology (or, Words You Can Say to Sound Brilliant) ......................................... 3 1.2 Compiling Things ............................... 3 1.3 Screen Updating ................................ 4 1.4 Naming Conventions ............................. 4 2 Variables ........................................... 5 3 Usage ............................................... 6 3.1 Starting up .................................... 6 3.2 The Nitty-Gritty ............................... 7 3.2.1 Output .................................... 7 3.2.2 Input ..................................... 8 3.2.3 Miscellaneous ............................. 8 3.3 Finishing up ................................... 8 4 Cursor Motion Optimization: Standing Alone .......... 8 4.1 Terminal Information ........................... 9 4.2 Movement Optimizations, or, Getting Over Yonder ............................................. 10 5 The Functions ....................................... 10 5.1 Output Functions ............................... 11 5.2 Input Functions ................................ 16 5.3 Miscellaneous Functions ........................ 18 5.4 Details ........................................ 22 _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x_✓e_✓s _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓A ............................................ 24 1 Capabilities from termcap ........................... 24 1.1 Disclaimer ..................................... 24 1.2 Overview ....................................... 24 1.3 Variables Set By setterm() ..................... 24 1.4 Variables Set By gettmode() .................... 25 _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓B ............................................ 27 1 The WINDOW structure ................................ 27 _✓A_✓p_✓p_✓e_✓n_✓d_✓i_✓x _✓C ............................................ 30 1 Examples ............................................ 30 2 Screen Updating ..................................... 30 2.1 Twinkle ........................................ 30 2.2 Life ........................................... 33 3 Motion optimization ................................. 36 3.1 Twinkle ........................................ 36