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hexchat/src/common/tree.c

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/* HexChat
* Copyright (C) 1998-2010 Peter Zelezny.
* Copyright (C) 2009-2013 Berke Viktor.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
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/*
This is used for quick userlist insertion and lookup. It's not really
a tree, but it could be :)
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "tree.h"
#define ARRAY_GROW 32
struct _tree
{
int elements;
int array_size;
void **array;
tree_cmp_func *cmp;
void *data;
};
tree *
tree_new (tree_cmp_func *cmp, void *data)
{
tree *t = g_new0 (tree, 1);
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t->cmp = cmp;
t->data = data;
return t;
}
void
tree_destroy (tree *t)
{
if (t)
{
g_free (t->array);
g_free (t);
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}
}
static int
tree_find_insertion_pos (tree *t, void *key, int *done)
{
int c, u, l, idx;
if (t->elements < 1)
{
*done = 1;
t->array[0] = key;
t->elements++;
return 0;
}
if (t->elements < 2)
{
*done = 1;
c = t->cmp (key, t->array[0], t->data);
if (c == 0)
return -1;
t->elements++;
if (c > 0)
{
t->array[1] = key;
return 1;
}
t->array[1] = t->array[0];
t->array[0] = key;
return 0;
}
*done = 0;
c = t->cmp (key, t->array[0], t->data);
if (c < 0)
return 0; /* prepend */
c = t->cmp (key, t->array[t->elements - 1], t->data);
if (c > 0)
return t->elements; /* append */
l = 0;
u = t->elements - 1;
while (1)
{
idx = (l + u) / 2;
c = t->cmp (key, t->array[idx], t->data);
if (0 > c)
u = idx;
else if (0 < c && 0 > t->cmp (key, t->array[idx+1], t->data))
return idx + 1;
else if (c == 0)
return -1;
else
l = idx + 1;
}
}
static void
tree_insert_at_pos (tree *t, void *key, int pos)
{
int post_bytes;
/* append is easy */
if (pos != t->elements)
{
post_bytes = (t->elements - pos) * sizeof (void *);
memmove (&t->array[pos + 1], &t->array[pos], post_bytes);
}
t->array[pos] = key;
t->elements++;
}
static void *
mybsearch (const void *key, void **array, size_t nmemb,
int (*compar) (const void *, const void *, void *data), void *data, int *pos)
{
int l, u, idx;
int comparison;
l = 0;
u = nmemb;
while (l < u)
{
idx = (l + u) / 2;
comparison = (*compar) (key, array[idx], data);
if (comparison < 0)
u = idx;
else if (comparison > 0)
l = idx + 1;
else
{
*pos = idx;
return array[idx];
}
}
return NULL;
}
void *
tree_find (tree *t, const void *key, tree_cmp_func *cmp, void *data, int *pos)
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{
if (!t || !t->array)
return NULL;
return mybsearch (key, &t->array[0], t->elements, cmp, data, pos);
}
void *
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tree_remove_at_pos (tree *t, int pos)
{
int post_bytes;
void *ret = t->array[pos];
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t->elements--;
if (pos != t->elements)
{
post_bytes = (t->elements - pos) * sizeof (void *);
memmove (&t->array[pos], &t->array[pos + 1], post_bytes);
}
return ret;
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}
int
tree_remove (tree *t, void *key, int *pos)
{
void *data;
data = tree_find (t, key, t->cmp, t->data, pos);
if (!data)
return 0;
tree_remove_at_pos (t, *pos);
return 1;
}
void
tree_foreach (tree *t, tree_traverse_func *func, void *data)
{
int j;
if (!t || !t->array)
return;
for (j = 0; j < t->elements; j++)
{
if (!func (t->array[j], data))
break;
}
}
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static void
tree_grow (tree *t)
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{
if (t->array_size < t->elements + 1)
{
int new_size = t->array_size + ARRAY_GROW;
t->array = realloc (t->array, sizeof (void *) * new_size);
t->array_size = new_size;
}
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}
int
tree_insert (tree *t, void *key)
{
int pos, done;
if (!t)
return -1;
tree_grow (t);
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pos = tree_find_insertion_pos (t, key, &done);
if (!done && pos != -1)
tree_insert_at_pos (t, key, pos);
return pos;
}
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void
tree_append (tree *t, void *key)
{
tree_grow (t);
tree_insert_at_pos (t, key, t->elements);
}
int tree_size (tree *t)
{
return t->elements;
}