keytab.c

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/*
 * Copyright (c) 2000, 2001 by Martin C. Shepherd.
 * 
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, and/or sell copies of the Software, and to permit persons
 * to whom the Software is furnished to do so, provided that the above
 * copyright notice(s) and this permission notice appear in all copies of
 * the Software and that both the above copyright notice(s) and this
 * permission notice appear in supporting documentation.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
 * OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * HOLDERS INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
 * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 * 
 * Except as contained in this notice, the name of a copyright holder
 * shall not be used in advertising or otherwise to promote the sale, use
 * or other dealings in this Software without prior written authorization
 * of the copyright holder.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "keytab.h"
#include "getline.h"
#include "strngmem.h"

static int _kt_extend_table(KeyTab *kt);
#if 0
static int _kt_parse_keybinding_string(const char *keyseq,
				       char *binary, int *nc);
#endif
static int _kt_compare_strings(const char *s1, int n1, const char *s2, int n2);
static void _kt_assign_action(KeySym *sym, KtBinder binder, KtKeyFn *keyfn);
static char _kt_backslash_escape(const char *string, const char **endp);
static int _kt_is_emacs_meta(const char *string);
static int _kt_is_emacs_ctrl(const char *string);

/*.......................................................................
 * Create a new key-binding symbol table.
 *
 * Output:
 *  return  KeyTab *  The new object, or NULL on error.
 */
KeyTab *_new_KeyTab(void)
{
  KeyTab *kt;  /* The object to be returned */
/*
 * Allocate the container.
 */
  kt = (KeyTab *) malloc(sizeof(KeyTab));
  if(!kt) {
    fprintf(stderr, "new_KeyTab: Insufficient memory.\n");
    return NULL;
  };
/*
 * Before attempting any operation that might fail, initialize the
 * container at least up to the point at which it can safely be passed
 * to del_KeyTab().
 */
  kt->size = KT_TABLE_INC;
  kt->nkey = 0;
  kt->table = NULL;
  kt->actions = NULL;
  kt->smem = NULL;
/*
 * Allocate the table.
 */
  kt->table = (KeySym *) malloc(sizeof(kt->table[0]) * kt->size);
  if(!kt->table) {
    fprintf(stderr, "new_KeyTab: Insufficient memory for table of size %d.\n",
	    kt->size);
    return _del_KeyTab(kt);
  };
/*
 * Allocate a hash table of actions.
 */
  kt->actions = _new_HashTable(NULL, KT_HASH_SIZE, IGNORE_CASE, NULL, 0);
  if(!kt->actions)
    return _del_KeyTab(kt);
/*
 * Allocate a string allocation object. This allows allocation of
 * small strings without fragmenting the heap.
 */
  kt->smem = _new_StringMem("new_KeyTab", KT_TABLE_INC);
  if(!kt->smem)
    return _del_KeyTab(kt);
  return kt;
}

/*.......................................................................
 * Delete a KeyTab object.
 *
 * Input:
 *  kt   KeyTab *  The object to be deleted.
 * Output:
 *  return KeyTab *  The deleted object (always NULL).
 */
KeyTab *_del_KeyTab(KeyTab *kt)
{
  if(kt) {
    if(kt->table)
      free(kt->table);
    kt->actions = _del_HashTable(kt->actions);
    kt->smem = _del_StringMem("del_KeyTab", kt->smem, 1);
    free(kt);
  };
  return NULL;
}

/*.......................................................................
 * Increase the size of the table to accomodate more keys.
 *
 * Input:
 *  kt       KeyTab *  The table to be extended.
 * Output:
 *  return      int    0 - OK.
 *                     1 - Error.
 */
static int _kt_extend_table(KeyTab *kt)
{
/*
 * Attempt to increase the size of the table.
 */
  KeySym *newtab = (KeySym *) realloc(kt->table, sizeof(kt->table[0]) *
				      (kt->size + KT_TABLE_INC));
/*
 * Failed?
 */
  if(!newtab) {
    fprintf(stderr,
	    "getline(): Insufficient memory to extend keybinding table.\n");
    return 1;
  };
/*
 * Install the resized table.
 */
  kt->table = newtab;
  kt->size += KT_TABLE_INC;
  return 0;
}

/*.......................................................................
 * Add, update or remove a keybinding to the table.
 *
 * Input:
 *  kt           KeyTab *  The table to add the binding to.
 *  binder     KtBinder    The source of the binding.
 *  keyseq   const char *  The key-sequence to bind.
 *  action         char *  The action to associate with the key sequence, or
 *                         NULL to remove the action associated with the
 *                         key sequence.
 * Output:
 *  return          int    0 - OK.
 *                         1 - Error.
 */
int _kt_set_keybinding(KeyTab *kt, KtBinder binder, const char *keyseq,
		       const char *action)
{
  KtKeyFn *keyfn; /* The action function */
/*
 * Check arguments.
 */
  if(kt==NULL || !keyseq) {
    fprintf(stderr, "kt_set_keybinding: NULL argument(s).\n");
    return 1;
  };
/*
 * Lookup the function that implements the specified action.
 */
  if(!action) {
    keyfn = 0;
  } else {
    Symbol *sym = _find_HashSymbol(kt->actions, action);
    if(!sym) {
      fprintf(stderr, "getline: Unknown key-binding action: %s\n", action);
      return 1;
    };
    keyfn = (KtKeyFn *) sym->fn;
  };
/*
 * Record the action in the table.
 */
  return _kt_set_keyfn(kt, binder, keyseq, keyfn);
}

/*.......................................................................
 * Add, update or remove a keybinding to the table, specifying an action
 * function directly.
 *
 * Input:
 *  kt       KeyTab *  The table to add the binding to.
 *  binder KtBinder    The source of the binding.
 *  keyseq     char *  The key-sequence to bind.
 *  keyfn   KtKeyFn *  The action function, or NULL to remove any existing
 *                     action function.
 * Output:
 *  return     int    0 - OK.
 *                    1 - Error.
 */
int _kt_set_keyfn(KeyTab *kt, KtBinder binder, const char *keyseq,
		  KtKeyFn *keyfn)
{
  const char *kptr;  /* A pointer into keyseq[] */
  char *binary;      /* The binary version of keyseq[] */
  int nc;            /* The number of characters in binary[] */
  int first,last;    /* The first and last entries in the table which */
                     /*  minimally match. */
  int size;          /* The size to allocate for the binary string */
/*
 * Check arguments.
 */
  if(kt==NULL || !keyseq) {
    fprintf(stderr, "kt_set_keybinding: NULL argument(s).\n");
    return 1;
  };
/*
 * Work out a pessimistic estimate of how much space will be needed
 * for the binary copy of the string, noting that binary meta characters
 * embedded in the input string get split into two characters.
 */
  for(size=0,kptr = keyseq; *kptr; kptr++)
    size += IS_META_CHAR(*kptr) ? 2 : 1;
/*
 * Allocate a string that has the length of keyseq[].
 */
  binary = _new_StringMemString(kt->smem, size + 1);
  if(!binary) {
    fprintf(stderr,
	    "gl_get_line: Insufficient memory to record key sequence.\n");
    return 1;
  };
/*
 * Convert control and octal character specifications to binary characters.
 */
  if(_kt_parse_keybinding_string(keyseq, binary, &nc)) {
    binary = _del_StringMemString(kt->smem, binary);
    return 1;
  };
/*
 * Lookup the position in the table at which to insert the binding.
 */
  switch(_kt_lookup_keybinding(kt, binary, nc, &first, &last)) {
/*
 * If an exact match for the key-sequence is already in the table,
 * simply replace its binding function (or delete the entry if
 * the new binding is 0).
 */
  case KT_EXACT_MATCH:
    if(keyfn) {
      _kt_assign_action(kt->table + first, binder, keyfn);
    } else {
      _del_StringMemString(kt->smem, kt->table[first].keyseq);
      memmove(kt->table + first, kt->table + first + 1,
	      (kt->nkey - first - 1) * sizeof(kt->table[0]));
      kt->nkey--;
    };
    binary = _del_StringMemString(kt->smem, binary);
    break;
/*
 * If an ambiguous match has been found and we are installing a
 * callback, then our new key-sequence would hide all of the ambiguous
 * matches, so we shouldn't allow it.
 */
  case KT_AMBIG_MATCH:
    if(keyfn) {
      fprintf(stderr,
	      "getline: Can't bind \"%s\", because it's a prefix of another binding.\n",
	      keyseq);
      binary = _del_StringMemString(kt->smem, binary);
      return 1;
    };
    break;
/*
 * If the entry doesn't exist, create it.
 */
  case KT_NO_MATCH:
/*
 * Add a new binding?
 */
    if(keyfn) {
      KeySym *sym;
/*
 * We will need a new entry, extend the table if needed.
 */
      if(kt->nkey + 1 > kt->size) {
	if(_kt_extend_table(kt)) {
	  binary = _del_StringMemString(kt->smem, binary);
	  return 1;
	};
      };
/*
 * Make space to insert the new key-sequence before 'last'.
 */
      if(last < kt->nkey) {
	memmove(kt->table + last + 1, kt->table + last,
		(kt->nkey - last) * sizeof(kt->table[0]));
      };
/*
 * Insert the new binding in the vacated position.
 */
      sym = kt->table + last;
      sym->keyseq = binary;
      sym->nc = nc;
      sym->user_fn = sym->term_fn = sym->norm_fn = sym->keyfn = 0;
      _kt_assign_action(sym, binder, keyfn);
      kt->nkey++;
    };
    break;
  case KT_BAD_MATCH:
    binary = _del_StringMemString(kt->smem, binary);
    return 1;
    break;
  };
  return 0;
}

/*.......................................................................
 * Perform a min-match lookup of a key-binding.
 *
 * Input:
 *  kt          KeyTab *  The keybinding table to lookup in.
 *  binary_keyseq char *  The binary key-sequence to lookup.
 *  nc             int    the number of characters in keyseq[].
 * Input/Output:
 *  first,last     int *  If there is an ambiguous or exact match, the indexes
 *                        of the first and last symbols that minimally match
 *                        will be assigned to *first and *last respectively.
 *                        If there is no match, then first and last will
 *                        bracket the location where the symbol should be
 *                        inserted.
 *                      
 * Output:
 *  return  KtKeyMatch    One of the following enumerators:
 *                         KT_EXACT_MATCH - An exact match was found.
 *                         KT_AMBIG_MATCH - An ambiguous match was found.
 *                         KT_NO_MATCH    - No match was found.
 *                         KT_BAD_MATCH   - An error occurred while searching.
 */
KtKeyMatch _kt_lookup_keybinding(KeyTab *kt, const char *binary_keyseq, int nc,
				 int *first, int *last)
{
  int mid;     /* The index at which to bisect the table */
  int bot;     /* The lowest index of the table not searched yet */
  int top;     /* The highest index of the table not searched yet */
  int test;    /* The return value of strcmp() */
/*
 * Check the arguments.
 */
  if(!kt || !binary_keyseq || !first || !last || nc < 0) {
    fprintf(stderr, "kt_lookup_keybinding: NULL argument(s).\n");
    return KT_BAD_MATCH;
  };
/*
 * Perform a binary search for the key-sequence.
 */
  bot = 0;
  top = kt->nkey - 1;
  while(top >= bot) {
    mid = (top + bot)/2;
    test = _kt_compare_strings(kt->table[mid].keyseq, kt->table[mid].nc,
			   binary_keyseq, nc);
    if(test > 0)
      top = mid - 1;
    else if(test < 0)
      bot = mid + 1;
    else {
      *first = *last = mid;
      return KT_EXACT_MATCH;
    };
  };
/*
 * An exact match wasn't found, but top is the index just below the
 * index where a match would be found, and bot is the index just above
 * where the match ought to be found.
 */
  *first = top;
  *last = bot;
/*
 * See if any ambiguous matches exist, and if so make *first and *last
 * refer to the first and last matches.
 */
  if(*last < kt->nkey && kt->table[*last].nc > nc &&
     _kt_compare_strings(kt->table[*last].keyseq, nc, binary_keyseq, nc)==0) {
    *first = *last;
    while(*last+1 < kt->nkey && kt->table[*last+1].nc > nc &&
	  _kt_compare_strings(kt->table[*last+1].keyseq, nc, binary_keyseq, nc)==0)
      (*last)++;
    return KT_AMBIG_MATCH;
  };
/*
 * No match.
 */
  return KT_NO_MATCH;
}

/*.......................................................................
 * Convert a keybinding string into a uniq binary representation.
 *
 * Control characters can be given directly in their binary form,
 * expressed as either ^ or C-, followed by the character, expressed in
 * octal, like \129 or via C-style backslash escapes, with the addition