xref: /src/lib/libcurses/getch.c

/*	$NetBSD: getch.c,v 1.23 2000/04/22 21:14:19 thorpej Exp $	*/

/*
 * Copyright (c) 1981, 1993, 1994
 *	The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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 <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)getch.c	8.2 (Berkeley) 5/4/94";
#else
__RCSID("$NetBSD: getch.c,v 1.23 2000/04/22 21:14:19 thorpej Exp $");
#endif
#endif					/* not lint */

#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include "curses.h"
#include "curses_private.h"

#define DEFAULT_DELAY 2			/* default delay for timeout() */

/*
 * Keyboard input handler.  Do this by snarfing
 * all the info we can out of the termcap entry for TERM and putting it
 * into a set of keymaps.  A keymap is an array the size of all the possible
 * single characters we can get, the contents of the array is a structure
 * that contains the type of entry this character is (i.e. part/end of a
 * multi-char sequence or a plain char) and either a pointer which will point
 * to another keymap (in the case of a multi-char sequence) OR the data value
 * that this key should return.
 *
 */

/* private data structures for holding the key definitions */
typedef struct keymap keymap_t;
typedef struct key_entry key_entry_t;

struct key_entry {
	short   type;		/* type of key this is */
	union {
		keymap_t *next;	/* next keymap is key is multi-key sequence */
		wchar_t   symbol;	/* key symbol if key is a leaf entry */
	} value;
};
/* Types of key structures we can have */
#define KEYMAP_MULTI  1		/* part of a multi char sequence */
#define KEYMAP_LEAF   2		/* key has a symbol associated with it, either
				 * it is the end of a multi-char sequence or a
				 * single char key that generates a symbol */

/* allocate this many key_entry structs at once to speed start up must
 * be a power of 2.
 */
#define KEYMAP_ALLOC_CHUNK 4

/* The max number of different chars we can receive */
#define MAX_CHAR 256

struct keymap {
	int	count;		/* count of number of key structs allocated */
	short	mapping[MAX_CHAR]; /* mapping of key to allocated structs */
	key_entry_t **key;	/* dynamic array of keys */
};


/* Key buffer */
#define INBUF_SZ 16		/* size of key buffer - must be larger than
				 * longest multi-key sequence */
static wchar_t  inbuf[INBUF_SZ];
static int     start, end, working; /* pointers for manipulating inbuf data */

#define INC_POINTER(ptr)  do {	\
	(ptr)++;		\
	ptr %= INBUF_SZ;	\
} while(/*CONSTCOND*/0)

static short	state;		/* state of the inkey function */

#define INKEY_NORM	 0	/* no key backlog to process */
#define INKEY_ASSEMBLING 1	/* assembling a multi-key sequence */
#define INKEY_BACKOUT	 2	/* recovering from an unrecognised key */
#define INKEY_TIMEOUT	 3	/* multi-key sequence timeout */

/* The termcap data we are interested in and the symbols they map to */
struct tcdata {
	const char	*name;	/* name of termcap entry */
	wchar_t	symbol;		/* the symbol associated with it */
};

static const struct tcdata tc[] = {
	{"K1", KEY_A1},
	{"K2", KEY_B2},
	{"K3", KEY_A3},
	{"K4", KEY_C1},
	{"K5", KEY_C3},
	{"k0", KEY_F0},
	{"k1", KEY_F(1)},
	{"k2", KEY_F(2)},
	{"k3", KEY_F(3)},
	{"k4", KEY_F(4)},
	{"k5", KEY_F(5)},
	{"k6", KEY_F(6)},
	{"k7", KEY_F(7)},
	{"k8", KEY_F(8)},
	{"k9", KEY_F(9)},
	{"kA", KEY_IL},
	{"ka", KEY_CATAB},
	{"kb", KEY_BACKSPACE},
	{"kC", KEY_CLEAR},
	{"kD", KEY_DC},
	{"kd", KEY_DOWN},
	{"kE", KEY_EOL},
	{"kF", KEY_SF},
	{"kH", KEY_LL},
	{"kh", KEY_HOME},
	{"kI", KEY_IC},
	{"kL", KEY_DL},
	{"kl", KEY_LEFT},
	{"kN", KEY_NPAGE},
	{"kP", KEY_PPAGE},
	{"kR", KEY_SR},
	{"kr", KEY_RIGHT},
	{"kS", KEY_EOS},
	{"kT", KEY_STAB},
	{"kt", KEY_CTAB},
	{"ku", KEY_UP}
};
/* Number of TC entries .... */
static const int num_tcs = (sizeof(tc) / sizeof(struct tcdata));

/* The root keymap */

static keymap_t *base_keymap;

/* prototypes for private functions */
static key_entry_t *add_new_key(keymap_t *current, char chr, int key_type,
				int symbol);
static keymap_t		*new_keymap(void);	/* create a new keymap */
static key_entry_t	*new_key(void);		/* create a new key entry */
static wchar_t		inkey(int to, int delay);

/*
 * Add a new key entry to the keymap pointed to by current.  Entry
 * contains the character to add to the keymap, type is the type of
 * entry to add (either multikey or leaf) and symbol is the symbolic
 * value for a leaf type entry.  The function returns a pointer to the
 * new keymap entry.
 */
static key_entry_t *
add_new_key(keymap_t *current, char chr, int key_type, int symbol)
{
	key_entry_t *the_key;
        int i;

#ifdef DEBUG
	__CTRACE("Adding character %s of type %d, symbol 0x%x\n", unctrl(chr),
		 key_type, symbol);
#endif
	if (current->mapping[(unsigned) chr] < 0) {
		  /* first time for this char */
		current->mapping[(unsigned) chr] = current->count;	/* map new entry */
		  /* make sure we have room in the key array first */
		if ((current->count & (KEYMAP_ALLOC_CHUNK - 1)) == 0)
		{
			if ((current->key =
			     realloc(current->key,
				     (current->count) * sizeof(key_entry_t *)
				     + KEYMAP_ALLOC_CHUNK * sizeof(key_entry_t *))) == NULL) {
				fprintf(stderr,
					"Could not malloc for key entry\n");
				exit(1);
			}

			the_key = new_key();
                        for (i = 0; i < KEYMAP_ALLOC_CHUNK; i++) {
                                current->key[current->count + i]
					= &the_key[i];
                        }
                }

                  /* point at the current key array element to use */
                the_key = current->key[current->count];

		the_key->type = key_type;

		switch (key_type) {
		  case KEYMAP_MULTI:
			    /* need for next key */
#ifdef DEBUG
			  __CTRACE("Creating new keymap\n");
#endif
			  the_key->value.next = new_keymap();
			  break;

		  case KEYMAP_LEAF:
				/* the associated symbol for the key */
#ifdef DEBUG
			  __CTRACE("Adding leaf key\n");
#endif
			  the_key->value.symbol = symbol;
			  break;

		  default:
			  fprintf(stderr, "add_new_key: bad type passed\n");
			  exit(1);
		}

		current->count++;
	} else {
		  /* the key is already known - just return the address. */
#ifdef DEBUG
		__CTRACE("Keymap already known\n");
#endif
		the_key = current->key[current->mapping[(unsigned) chr]];
	}

        return the_key;
}

/*
 * Init_getch - initialise all the pointers & structures needed to make
 * getch work in keypad mode.
 *
 */
void
__init_getch(char *sp)
{
	static	struct tinfo *termcap;
	char entry[1024], termname[1024], *p;
	int     i, j, length, key_ent;
	size_t limit;
	key_entry_t *tmp_key;
	keymap_t *current;
#ifdef DEBUG
	int k;
#endif

	/* init the inkey state variable */
	state = INKEY_NORM;

	/* init the base keymap */
	base_keymap = new_keymap();

	/* key input buffer pointers */
	start = end = working = 0;

	/* now do the termcap snarfing ... */
	(void) strncpy(termname, sp, (size_t) 1022);
	termname[1023] = 0;

	if (t_getent(&termcap, termname) > 0) {
		for (i = 0; i < num_tcs; i++) {
			p = entry;
			limit = 1023;
			if (t_getstr(termcap, tc[i].name, &p, &limit) != NULL) {
				current = base_keymap;	/* always start with
							 * base keymap. */
				length = (int) strlen(entry);
#ifdef DEBUG
				__CTRACE("Processing termcap entry %s, sequence ",
					tc[i].name);
				for (k = 0; k <= length -1; k++)
					__CTRACE("%s", unctrl(entry[k]));
				__CTRACE("\n");
#endif
				for (j = 0; j < length - 1; j++) {
					  /* add the entry to the struct */
                                        tmp_key = add_new_key(current,
							      entry[j],
							      KEYMAP_MULTI, 0);

                                          /* index into the key array - it's
                                             clearer if we stash this */
                                        key_ent = current->mapping[
                                                (unsigned) entry[j]];

					current->key[key_ent] = tmp_key;

					  /* next key uses this map... */
					current = current->key[key_ent]->value.next;
				}

				/* this is the last key in the sequence (it
				 * may have been the only one but that does
				 * not matter) this means it is a leaf key and
				 * should have a symbol associated with it.
				 */
				tmp_key = add_new_key(current,
						      entry[length - 1],
						      KEYMAP_LEAF,
						      tc[i].symbol);
				current->key[
					current->mapping[(int)entry[length - 1]]] =
                                        tmp_key;
			}
		}
	}
}


/*
 * new_keymap - allocates & initialises a new keymap structure.  This
 * function returns a pointer to the new keymap.
 *
 */
static keymap_t *
new_keymap(void)
{
	int     i;
	keymap_t *new_map;

	if ((new_map = malloc(sizeof(keymap_t))) == NULL) {
		perror("Inkey: Cannot allocate new keymap");
		exit(2);
	}

	/* Initialise the new map */
	new_map->count = 0;
	for (i = 0; i < MAX_CHAR; i++) {
		new_map->mapping[i] = -1;	/* no mapping for char */
	}

	/* key array will be allocated when first key is added */
	new_map->key = NULL;

	return new_map;
}

/*
 * new_key - allocates & initialises a new key entry.  This function returns
 * a pointer to the newly allocated key entry.
 *
 */
static key_entry_t *
new_key(void)
{
	key_entry_t *new_one;
	int i;

	if ((new_one = malloc(KEYMAP_ALLOC_CHUNK * sizeof(key_entry_t)))
	    == NULL) {
		perror("inkey: Cannot allocate new key entry chunk");
		exit(2);
	}

	for (i = 0; i < KEYMAP_ALLOC_CHUNK; i++) {
		new_one[i].type = 0;
		new_one[i].value.next = NULL;
	}

	return new_one;
}

/*
 * inkey - do the work to process keyboard input, check for multi-key
 * sequences and return the appropriate symbol if we get a match.
 *
 */

wchar_t
inkey(int to, int delay)
{
	wchar_t		 k;
	int              c;
	keymap_t	*current = base_keymap;

	for (;;) {		/* loop until we get a complete key sequence */
reread:
		if (state == INKEY_NORM) {
			if (delay && __timeout(delay) == ERR)
				return ERR;
			if ((c = getchar()) == EOF) {
				clearerr(stdin);
				return ERR;
			}

			if (delay && (__notimeout() == ERR))
				return ERR;

			k = (wchar_t) c;
#ifdef DEBUG
			__CTRACE("inkey (state normal) got '%s'\n", unctrl(k));
#endif

			working = start;
			inbuf[working] = k;
			INC_POINTER(working);
			end = working;
			state = INKEY_ASSEMBLING;	/* go to the assembling
							 * state now */
		} else if (state == INKEY_BACKOUT) {
			k = inbuf[working];
			INC_POINTER(working);
			if (working == end) {	/* see if we have run
						 * out of keys in the
						 * backlog */

				/* if we have then switch to
				   assembling */
				state = INKEY_ASSEMBLING;
			}
		} else if (state == INKEY_ASSEMBLING) {
			/* assembling a key sequence */
			if (delay) {
				if (__timeout(to ? DEFAULT_DELAY : delay) == ERR)
						return ERR;
			} else {
				if (to && (__timeout(DEFAULT_DELAY) == ERR))
					return ERR;
			}

			c = getchar();
			if (ferror(stdin)) {
				clearerr(stdin);
				return ERR;
			}

			if ((to || delay) && (__notimeout() == ERR))
					return ERR;

			k = (wchar_t) c;
#ifdef DEBUG
			__CTRACE("inkey (state assembling) got '%s'\n", unctrl(k));
#endif
			if (feof(stdin)) {	/* inter-char timeout,
						 * start backing out */
				clearerr(stdin);
				if (start == end)
					/* no chars in the buffer, restart */
					goto reread;

				k = inbuf[start];
				state = INKEY_TIMEOUT;
			} else {
				inbuf[working] = k;
				INC_POINTER(working);
				end = working;
			}
		} else {
			fprintf(stderr, "Inkey state screwed - exiting!!!");
			exit(2);
		}

		/* Check key has no special meaning and we have not timed out */
		if ((state == INKEY_TIMEOUT) || (current->mapping[k] < 0)) {
			/* return the first key we know about */
			k = inbuf[start];

			INC_POINTER(start);
			working = start;

			if (start == end) {	/* only one char processed */
				state = INKEY_NORM;
			} else {/* otherwise we must have more than one char
				 * to backout */
				state = INKEY_BACKOUT;
			}
			return k;
		} else {	/* must be part of a multikey sequence */
			/* check for completed key sequence */
			if (current->key[current->mapping[k]]->type == KEYMAP_LEAF) {
				start = working;	/* eat the key sequence
							 * in inbuf */

				/* check if inbuf empty now */
				if (start == end) {
					/* if it is go back to normal */
					state = INKEY_NORM;
				} else {
					/* otherwise go to backout state */
					state = INKEY_BACKOUT;
				}

				/* return the symbol */
				return current->key[current->mapping[k]]->value.symbol;

			} else {
				/*
				 * Step on to next part of the multi-key
				 * sequence.
				 */
				current = current->key[current->mapping[k]]->value.next;
			}
		}
	}
}

#ifndef _CURSES_USE_MACROS
/*
 * getch --
 *	Read in a character from stdscr.
 */
int
getch(void)
{
	return wgetch(stdscr);
}

/*
 * mvgetch --
 *      Read in a character from stdscr at the given location.
 */
int
mvgetch(int y, int x)
{
	return mvwgetch(stdscr, y, x);
}

/*
 * mvwgetch --
 *      Read in a character from stdscr at the given location in the
 *      given window.
 */
int
mvwgetch(WINDOW *win, int y, int x)
{
	if (wmove(win, y, x) == ERR)
		return ERR;

	return wgetch(win);
}

#endif

/*
 * wgetch --
 *	Read in a character from the window.
 */
int
wgetch(WINDOW *win)
{
	int     inp, weset;
	char    c;

	if (!(win->flags & __SCROLLOK) && (win->flags & __FULLWIN)
	    && win->curx == win->maxx - 1 && win->cury == win->maxy - 1
	    && __echoit)
		return (ERR);
#ifdef DEBUG
	__CTRACE("wgetch: __echoit = %d, __rawmode = %d, flags = %0.2o\n",
	    __echoit, __rawmode, win->flags);
#endif
	if (__echoit && !__rawmode) {
		cbreak();
		weset = 1;
	} else
		weset = 0;

	__save_termios();

	if (win->flags & __KEYPAD) {
		switch (win->delay)
		{
		case -1:
			inp = inkey (win->flags & __NOTIMEOUT ? 0 : 1, 0);
			break;
		case 0:
			if (__nodelay() == ERR) {
				__restore_termios();
				return ERR;
			}
			inp = inkey(0, 0);
			break;
		default:
			inp = inkey(win->flags & __NOTIMEOUT ? 0 : 1, win->delay);
			break;
		}
	} else {
		switch (win->delay)
		{
		case -1:
			break;
		case 0:
			if (__nodelay() == ERR) {
				__restore_termios();
				return ERR;
			}
			break;
		default:
			if (__timeout(win->delay) == ERR) {
				__restore_termios();
				return ERR;
			}
			break;
		}

		c = getchar();
		if (feof(stdin)) {
			clearerr(stdin);
			__restore_termios();
			return ERR;	/* we have timed out */
		}

		if (ferror(stdin)) {
			clearerr(stdin);
			inp = ERR;
		} else {
			inp = (unsigned int) c;
		}
	}
#ifdef DEBUG
	if (inp > 255)
		  /* we have a key symbol - treat it differently */
		  /* XXXX perhaps __unctrl should be expanded to include
		   * XXXX the keysyms in the table....
		   */
		__CTRACE("wgetch assembled keysym 0x%x\n", inp);
	else
		__CTRACE("wgetch got '%s'\n", unctrl(inp));
#endif
	if (win->delay > -1) {
		if (__delay() == ERR) {
			__restore_termios();
			return ERR;
		}
	}

	__restore_termios();
	if (__echoit) {
		waddch(win, (chtype) inp);
	}
	if (weset)
		nocbreak();

	wrefresh(win);
	return ((inp < 0) || (inp == ERR) ? ERR : inp);
}

/*
 * ungetch --
 *     Put the character back into the input queue.
 */
int
ungetch(int c)
{
	return ((ungetc(c, stdin) == EOF) ? ERR : OK);
}