Array_item *add_to_array (Array *array, Array_item *item)
{
int count;
int location = 0;
Array_item *ret = (void *) 0 ;
u_32int_t mask;
if (array->hash == HASH_INSENSITIVE)
item->hash = ci_alist_hash(item->name, &mask);
else
item->hash = cs_alist_hash(item->name, &mask);
check_array_size(array);
if (array->max)
{
find_array_item(array, item->name, &count, &location);
if (count < 0)
{
ret = ((Array_item *) (( array ) -> list [ ( location ) ])) ;
array->max--;
}
else
move_array_items(array, location, array->max, 1);
}
array->list[location] = item;
array->max++;
return ret;
}
/*
* Returns an entry that has been displaced, if any.
*/
Array_item *BX_add_to_array (Array *array, Array_item *item)
{
int count;
int location = 0;
Array_item *ret = NULL;
u_32int_t mask; /* Dummy var */
if (array->hash == HASH_INSENSITIVE)
item->hash = ci_alist_hash(item->name, &mask);
else
item->hash = cs_alist_hash(item->name, &mask);
check_array_size(array);
if (array->max)
{
find_array_item(array, item->name, &count, &location);
if (count < 0)
{
ret = ARRAY_ITEM(array, location);
array->max--;
}
else
move_array_items(array, location, array->max, 1);
}
array->list[location] = item;
array->max++;
return ret;
}
/*
* This is just a generalization of the old function ``find_command''
*
* You give it an alist_item and a name, and it gives you the number of
* items that are completed by that name, and where you could find/put that
* item in the list. It returns the alist_item most appropriate.
*
* If ``cnt'' is less than -1, then there was one exact match and one or
* more ambiguous matches in addition. The exact match's location
* is put into ``loc'' and its entry is returned. The ambigous matches
* are (of course) immediately subsequent to it.
*
* If ``cnt'' is -1, then there was one exact match. Its location is
* put into ``loc'' and its entry is returned.
*
* If ``cnt'' is zero, then there were no matches for ``name'', but ``loc''
* is set to the location in the array in which you could place the
* specified name in the sorted list.
*
* If ``cnt'' is one, then there was one command that non-ambiguously
* completes ``name''
*
* If ``cnt'' is greater than one, then there was exactly ``cnt'' number
* of entries that completed ``name'', but they are all ambiguous.
* The entry that is lowest alphabetically is returned, and its
* location is put into ``loc''.
*/
array_item *
find_array_item (array *set, const char *name, int *cnt, int *loc)
{
size_t len = strlen(name);
int c = 0,
pos = 0,
tospot, /* :-) */
min,
max;
u_32int_t mask;
u_32int_t hash;
if (set->hash == HASH_INSENSITIVE)
hash = ci_alist_hash(name, &mask);
else
hash = cs_alist_hash(name, &mask);
*cnt = 0;
if (!set->list || !set->max)
{
*loc = 0;
return NULL;
}
alist_searches++;
/*
* The first search is a cheap refinement. Using the hash
* value, find a range of symbols that have the same first
* four letters as 'name'. Since we're doing all integer
* comparisons, its cheaper than the full blown string compares.
*/
/*
* OK, well all of that has been rolled into these two loops,
* designed to find the start and end of the range directly.
*/
tospot = max = set->max - 1;
min = 0;
while (max >= min)
{
bin_ints++;
pos = (max - min) / 2 + min;
c = (hash & mask) - (ARRAY_ITEM(set, pos)->hash & mask);
if (c == 0) {
bin_chars++;
c = set->func(name, ARRAY_ITEM(set, pos)->name, len);
}
if (c == 0) {
if (max == pos)
break;
max = pos;
}
else if (c < 0)
tospot = max = pos - 1;
else
min = pos + 1;
}
/*
* If we can't find a symbol that qualifies, then we can just drop
* out here. This is good because a "pass" (lookup for a symbol that
* does not exist) requires only cheap integer comparisons.
*/
if (c != 0)
{
if (c > 0)
*loc = pos + 1;
else
*loc = pos;
return NULL;
}
/*
* At this point, min is set to the first matching name in
* the range and tospot is set to a higher position than
* the last. These are used to refine the next search.
*/
max = tospot;
tospot = pos;
while (max >= min)
{
bin_ints++;
pos = (min - max) / 2 + max; /* Don't ask */
c = (hash & mask) - (ARRAY_ITEM(set, pos)->hash & mask);
if (c == 0) {
bin_chars++;
c = set->func(name, ARRAY_ITEM(set, pos)->name, len);
}
if (c == 0) {
if (min == pos)
break;
min = pos;
}
else if (c < 0)
max = pos - 1;
else
min = pos + 1;
}
min = tospot;
char_searches++;
/*
* If we've gotten this far, then we've found at least
* one appropriate entry. So we set *cnt to one
*/
*cnt = 1 + pos - min;
#if 0
/*
* So we know that 'pos' is a match. So we start 'min'
* at one less than 'pos' and walk downard until we find
* an entry that is NOT matched.
*/
min = pos - 1;
while (min >= 0 && !set->func(name, ARRAY_ITEM(set, min)->name, len))
(*cnt)++, min--, lin_chars++;
min++;
/*
* Repeat the same ordeal, except this time we walk upwards
* from 'pos' until we dont find a match.
*/
max = pos + 1;
while (max < set->max && !set->func(name, ARRAY_ITEM(set, max)->name, len))
(*cnt)++, max++, lin_chars++;
#endif
/*
* Alphabetically, the string that would be identical to
* 'name' would be the first item in a string of items that
* all began with 'name'. That is to say, if there is an
* exact match, its sitting under item 'min'. So we check
* for that and whack the count appropriately.
*/
if (0 == (ARRAY_ITEM(set, min)->name)[len])
*cnt *= -1;
/*
* Then we tell the caller where the lowest match is,
* in case they want to insert here.
*/
if (loc)
*loc = min;
/*
* Then we return the first item that matches.
*/
return ARRAY_ITEM(set, min);
}