/*
 * File:      grkelot.c
 *
 * Synopsis:    string -> greek ELOT928 or IBM437 string;
 *              4-state FSM implementation.
 *
 * System:      Any (ANSI C)
 *
 * This is code derived from a more generic key remapper written by the same
 * author and used in other environments. It was not written only
 * for greek kbd bindings. An extension to other languages is easy
 * (well don't know how the FSM lends itself to Far East languages).
 *
 * The FSM can have MAX_STATES states (change it for more).
 * Each state contains:
 * 1.  many tranlsation tables (registered via kstate_add_xlat())
 * 2.  many switch codes for transition to other states (registered via
 *      kstate_add_switcher()) : limit is static now: MAX_SWITCHER
 * 3.   life: the number of xlations allowed in a state (0 = unlimited)
 *
 * Format of tranlation strings:
 *      <first>-<last>:n1,n2,n3,...
 * Format of switcher string:
 *      A<char>:<state_no>
 * (other switchers apart from A=ascii can be supported; not in this context)
 * Format of life string:
 *      L<N>            (N=0,1,...)
 *
 * Copyright (c) 1994,1995 Angelo Haritsis. All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted provided
 * that the above copyright notice and this paragraph are duplicated in all
 * such forms and that any documentation, advertising materials, and other
 * materials related to such distribution and use acknowledge that the
 * software was developed by Angelo Haritsis.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * $Id: grkelot.c,v 1.1.1.1 2001-03-14 12:12:36 thep Exp $
 *
 * NB: DO NOT ALTER! THIS CODE IS USED IN MANY PLATFORMS!!!
 *
 * TODO: make it more dynamic (linked lists is an idea but slower)
 */

#define XITERM			/* define for use by xiterm */

#ifdef XITERM
#include "config.h"
#include "feature.h"
#include "grkelot.h"
#endif /* XITERM */

#ifdef GREEK_SUPPORT
#include "grkelot.h"
#include <stdlib.h>
#include <string.h>

/* --- Macros, Types --------- */
#define MAX_STATES	4	/* max # states for the FSM */
#define MAX_SWITCHER	2U	/* per state */
#define MAX_VAL 	256	/* for temp allocation */

typedef unsigned char u_char;
typedef unsigned int u_int;
typedef unsigned long u_long;

typedef struct s_xlat
  {
    u_int first, last;
    u_int *pval;		/* array of translated values */
  }
K_XLAT;

typedef struct s_switch
  {
    u_char type;		/* Ascii, Virtual, Scan */
    u_int code;
    u_char nextstate;
    u_char on;			/* current state of key: 0 = off */
  }
K_SWITCH;

typedef struct s_state
  {
    u_int num_xlat;		/* number of translations */
    K_XLAT *xlat;		/* State translations ((dynamic - realloc'ed) */
    u_int num_switcher;		/* number of switcher keys */
    K_SWITCH switcher[MAX_SWITCHER];	/* switcher keys to other states */
    u_char life;		/* 0 = until switched by key */
    u_char prev_state;		/* filled when jumped to a new state */
  }
K_STATE;

/* type for each one of the different greek standards (xlat types) */
typedef struct s_xlat_type
  {
    char *plain;
    char *accent;
    char *accent_xtra;
    char *umlaut;
    char *acc_uml;
  }
XLAT_TYPE;

/* --- Local Data ------------ */
static K_STATE State[MAX_STATES];
/* Current State */
static u_char nStateNow = 0;
static K_STATE *pStateNow = &State[0];
static int GreekMode = GREEK_ELOT928;

/*
 * The following are hard-coded for now. The idea is that such strings would
 * be read from a config file making it possible to change language/encodings
 * more flexibly.
 */
/* elot 928 xlations */
static char elot_xlat_plain[] = "65-122:193,194,216,196,197,214,195,199,201,206,202,203,204,205,207,208,81,209,211,212,200,217,87,215,213,198,91,92,93,94,95,96,225,226,248,228,229,246,227,231,233,238,234,235,236,237,239,240,113,241,243,244,232,249,242,247,245,230";
/* c and s give copyright and section sign */
static char elot_xlat_acc[] = "65-122:182,194,216,196,184,214,195,185,186,206,202,203,204,205,188,208,81,209,211,212,200,191,87,215,190,198,91,92,93,94,95,96,220,226," /*248 */ "169,228,221,246,227,222,223,238,234,235,236,237,252,240,113,241," /*243 */ "167,244,232,254,242,247,253,230";
static char elot_xlat_acc_xtra[] = "46-62:183,47,48,49,50,51,52,53,54,55,56,57,58,59,171,61,187";	/* anw teleia, quotes */
static char elot_xlat_uml[] = "65-122:193,194,216,196,197,214,195,199,218,206,202,203,204,205,207,208,81,209,211,212,200,217,87,215,219,198,91,92,93,94,95,96,225,226,248,228,229,246,227,231,250,238,234,235,236,237,239,240,113,241,243,244,232,249,242,247,251,230";
static char elot_xlat_umacc[] = "65-122:193,194,216,196,197,214,195,199,201,206,202,203,204,205,207,208,81,209,211,212,200,217,87,215,213,198,91,92,93,94,95,96,225,226,248,228,229,246,227,231,192,238,234,235,236,237,239,240,113,241,243,244,232,249,242,247,224,230";

/* ibm 437 xlations */
static char i437_xlat_plain[] = "65-122:128,129,150,131,132,148,130,134,136,141,137,138,139,140,142,143,81,144,145,146,135,151,87,149,147,133,91,92,93,94,95,96,152,153,175,155,156,173,154,158,160,165,161,162,163,164,166,167,113,168,169,171,159,224,170,174,172,157";
static char i437_xlat_acc[] = "65-122:234,129,150,131,235,148,130,236,237,141,137,138,139,140,238,143,81,144,145,146,135,240,87,149,239,133,91,92,93,94,95,96,225,153,175,155,226,173,154,227,229,165,161,162,163,164,230,167,113,168,169,171,159,233,170,174,231,157";
static char i437_xlat_acc_xtra[] = "46-46:250";		/* anw teleia */
static char i437_xlat_uml[] = "65-122:128,129,150,131,132,148,130,134,136,141,137,138,139,140,142,143,81,144,145,146,135,151,87,149,147,133,91,92,93,94,95,96,152,153,175,155,156,173,154,158,228,165,161,162,163,164,166,167,113,168,169,171,159,224,170,174,232,157";
static char i437_xlat_umacc[] = "65-122:128,129,150,131,132,148,130,134,136,141,137,138,139,140,142,143,81,144,145,146,135,151,87,149,147,133,91,92,93,94,95,96,152,153,175,155,156,173,154,158,42,165,161,162,163,164,166,167,113,168,169,171,159,224,170,174,42,157";

/*
 * currently ELOT928 and IBM437 are supported; easy to include others
 * (not recommended: stick to just these 2 if not only the ELOT one)
 */
static XLAT_TYPE xlat_type[] =
{
  {elot_xlat_plain, elot_xlat_acc, elot_xlat_acc_xtra, elot_xlat_uml, elot_xlat_umacc},
  {i437_xlat_plain, i437_xlat_acc, i437_xlat_acc_xtra, i437_xlat_uml, i437_xlat_umacc},
};

/* the current trasnaltion type */
static XLAT_TYPE *xlat_now = &xlat_type[GREEK_ELOT928];

#define NUM_XLAT_TYPES	(sizeof(xlat_type) / sizeof(xlat_type[0]))

static void kstate_add_xlat (char *str);
static void kstate_add_switcher (char *str);
static void kstate_set_life (char *str);

/* --- Functions ------------- */
static void
kstate_setcurr (int stateno)
{
  u_char prev_state;

  if ((u_int) stateno > (u_int) MAX_STATES)
    return;
  if (pStateNow->life == 1)
    prev_state = pStateNow->prev_state;
  else
    prev_state = nStateNow;
  pStateNow = &State[nStateNow = stateno];
  pStateNow->prev_state = prev_state;
}

static void
kstate_init (void)
{
  pStateNow->num_xlat = pStateNow->num_switcher = pStateNow->life = pStateNow->prev_state = 0;
  pStateNow->xlat = NULL;
}

static void
kstate_end (void)
{
  int i;

  for (i = 0; i < pStateNow->num_xlat; i++)
    free (pStateNow->xlat[i].pval);
  if (pStateNow->num_xlat > 0)
    free (pStateNow->xlat);
}

/*
 * Hard coded ELOT-928 translations. Could read these from an rc-type file
 * to support other remappers.
 */
static void
kstate_init_all (int greek_mode)
{
  /* the translation tables for the 4 FSM states for ELOT-928 mappings */
  int i;

  for (i = 0; i < MAX_STATES; i++)
    {
      kstate_setcurr (i);
      kstate_init ();
    }
  if (greek_mode < 0 || greek_mode >= NUM_XLAT_TYPES)	/* avoid death */
    greek_mode = GREEK_ELOT928;
  xlat_now = &xlat_type[greek_mode];
  kstate_setcurr (0);
  kstate_add_xlat (xlat_now->plain);
  kstate_add_switcher ("A;:1");
  kstate_add_switcher ("A::2");
  kstate_set_life ("L0");

  kstate_setcurr (1);
  kstate_add_xlat (xlat_now->accent);
  kstate_add_xlat (xlat_now->accent_xtra);
  kstate_add_switcher ("A::3");
  kstate_set_life ("L1");

  kstate_setcurr (2);
  kstate_add_xlat (xlat_now->umlaut);
  kstate_add_switcher ("A;:3");
  kstate_set_life ("L1");

  kstate_setcurr (3);
  kstate_add_xlat (xlat_now->acc_uml);
  kstate_set_life ("L1");
}

static void
kstate_end_all (void)
{
  int i;

  for (i = 0; i < MAX_STATES; i++)
    {
      kstate_setcurr (i);
      kstate_end ();
    }
  kstate_setcurr (0);
}

/*
 * reset FSM
 */
static void
kstate_reset (void)
{
  kstate_setcurr (0);
}

static void
kstate_add_xlat (char *str)
{
  K_XLAT *xlat;
  u_int *pval_tmp;
  char *sval;
  int i;

  if (str == NULL)
    return;
  /* add a new xlat table in state */
  if (pStateNow->num_xlat == 0)
    {
      pStateNow->xlat = malloc (sizeof (K_XLAT));
    }
  else				/* prefer contiguous data, realloc */
    pStateNow->xlat = realloc (pStateNow->xlat, (pStateNow->num_xlat + 1) * sizeof (K_XLAT));
  xlat = &pStateNow->xlat[pStateNow->num_xlat];
  /* parse str and derive first, last, values */
  xlat->first = (u_int) atoi (strtok (str, "-"));
  xlat->last = (u_int) atoi (strtok (NULL, ":"));
  i = 0;
  pval_tmp = calloc (MAX_VAL, sizeof (K_XLAT));
  while ((sval = strtok (NULL, ",")) != NULL)
    pval_tmp[i++] = (u_int) (atoi (sval));
  xlat->pval = calloc (i, sizeof (K_XLAT));
  if (xlat->pval != NULL)
    memcpy (xlat->pval, pval_tmp, i * sizeof (u_int));
  free (pval_tmp);
  pStateNow->num_xlat++;
}

/*
 * Ascii only for this implementation
 */
static void
kstate_add_switcher (char *str)
{
  K_SWITCH *switcher;

  if (str == NULL)
    return;
  if (pStateNow->num_switcher >= MAX_SWITCHER)
    return;
  switcher = &pStateNow->switcher[pStateNow->num_switcher];
  switch (switcher->type = str[0])
    {
    case 'A':			/* ascii eg: A;:2 */
      switcher->code = str[1];
      switcher->nextstate = atoi (&str[3]);
      break;
    }
  switcher->on = 0;
  pStateNow->num_switcher++;
}

/* L1 or L0 */
static void
kstate_set_life (char *str)
{
  pStateNow->life = atoi (&str[1]);
}

static unsigned int
kstate_cxlat (unsigned int c)
{
  int i;

  /* check for ascii switcher */
  for (i = 0; i < pStateNow->num_switcher; i++)
    if (pStateNow->switcher[i].type == 'A' &&	/* only ascii here */
	c == pStateNow->switcher[i].code)
      {
	kstate_setcurr (pStateNow->switcher[i].nextstate);
	pStateNow->switcher[i].on = 1;
	return ((unsigned int) -1);
      }
  /* do translation */
  for (i = 0; i < pStateNow->num_xlat; i++)
    if (c >= pStateNow->xlat[i].first && c <= pStateNow->xlat[i].last)
      {
	c = pStateNow->xlat[i].pval[c - pStateNow->xlat[i].first];
	break;
      }
  /* switch back to previous state if life of current is 1 */
  if (pStateNow->life == 1)
    kstate_setcurr (pStateNow->prev_state);
  return (c);
}

#ifdef XITERM
void
greek_init (void)
{
  kstate_init_all (GreekMode);
}

void
greek_end (void)
{
  kstate_end_all ();
}

void
greek_reset (void)
{
  kstate_reset ();
}

void
greek_setmode (int greek_mode)
{
  GreekMode = greek_mode;
}

int
greek_getmode (void)
{
  return (GreekMode);
}

/*
 * xlate a given string in-place - return new string length
 */
int
greek_xlat (char *s, int num_chars)
{
  int i, count;
  unsigned int c;

  for (i = 0, count = 0; i < num_chars; i++)
    {
      c = kstate_cxlat ((unsigned int) s[i]);
      if (c != -1)
	s[count++] = (char) c;
    }
  s[count] = '\0';
  return (count);

}

#ifdef TEST
int
main (void)
{
  /*char text[] = "abcdef;aGDZXC"; */
  char text[] = "abcdef;a:ibgdezhuiklmnjoprstyfxcv";

  kstate_init_all (GREEK_ELOT928);
  printf ("text: %s\n", text);
  greek_xlat (text, strlen (text));
  printf ("xlat'ed text: %s\n", text);
  kstate_end_all ();
  return 0;
}
#endif
#endif /* XITERM */

#endif /* GREEK_SUPPORT */
