summaryrefslogtreecommitdiffstats
path: root/src/tree.c
blob: 59979ee48620a495b90d3ccc2b53c601cf125278 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
/*
 * Tree data structure
 *
 * Copyright (C) 2017  Patrick McDermott
 *
 * This file is part of Marquee.
 *
 * Marquee 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 3 of the License, or
 * (at your option) any later version.
 *
 * Marquee 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 Marquee.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "tree.h"

#include <inttypes.h>

#include <glib.h>

#if MQ_TREE_DEBUG

#include <math.h>

#define PRIWxPTR ((int) (logl(UINTPTR_MAX) / logl(16)))

static void
debug_print_tree_recurse(MqTree *node, gsize indent)
{
	gsize i;

	for (; node; node = node->next) {
		for (i = 0; i < indent; ++i) {
			g_print("\t");
		}
		g_print("\t0x%0*" PRIxPTR " (size %d, position %d)\n",
			PRIWxPTR, (uintptr_t) node, node->size, node->position);
		for (i = 0; i < indent; ++i) {
			g_print("\t");
		}
		g_print("\t\t\t(parent   0x%0*" PRIxPTR ")\n",
			PRIWxPTR, (uintptr_t) node->parent);
		for (i = 0; i < indent; ++i) {
			g_print("\t");
		}
		g_print("\t\t\t(siblings 0x%0*" PRIxPTR " and "
			"0x%0*" PRIxPTR ")\n",
			PRIWxPTR, (uintptr_t) node->prev,
			PRIWxPTR, (uintptr_t) node->next);
		for (i = 0; i < indent; ++i) {
			g_print("\t");
		}
		g_print("\t\t\t(children 0x%0*" PRIxPTR " to  "
			"0x%0*" PRIxPTR ")\n",
			PRIWxPTR, (uintptr_t) node->first_child,
			PRIWxPTR, (uintptr_t) node->last_child);

		if (node->first_child) {
			debug_print_tree_recurse(node->first_child, indent + 1);
		}
	}
}

static void
debug_print_tree(const gchar *msg, MqTree *node)
{
	g_print("%s 0x%0*" PRIxPTR ", ", msg, PRIWxPTR, (uintptr_t) node);
	node = node->root;
	g_print("new tree (size %d):\n", node->size);
	debug_print_tree_recurse(node, 0);
}

static void
debug_print_node(MqTree *node)
{
	g_print("\t0x%0*" PRIxPTR "\n", PRIWxPTR, (uintptr_t) node);
}

static void
debug_print_head(const gchar *head, MqTree *node)
{
	g_print("%s, starting at 0x%0*" PRIxPTR "\n",
		head, PRIWxPTR, (uintptr_t) node);
}

#else  /* MQ_TREE_DEBUG */

#define debug_print_tree(msg, node)
#define debug_print_node(node)
#define debug_print_head(head, node)

#endif  /* MQ_TREE_DEBUG */

MqTree *
mq_tree_insert_root_allocated(MqTree *node, gpointer data)
{
	node->root = node;
	node->size = 1;
	node->data = data;

	return node;
}

static void
update_sizes(MqTree *node, gint step)
{
	if (node) {
		node->size += step;
		update_sizes(node->parent, step);
	}
}

static gboolean
update_position(MqTree *node, gpointer user_data)
{
	gint *step;

	step = (gint *) user_data;

	node->position += *step;

	return MQ_TREE_CONTINUE;
}

static void
update_positions(MqTree *node, gint step)
{
	debug_print_head("Updating positions", node);

	mq_tree_foreach_from(node, update_position, &step);
}

MqTree *
mq_tree_append_child_allocated(MqTree *node, MqTree *parent, gpointer data)
{
	/* Copy ancestor pointers. */
	node->root   = parent->root;
	node->parent = parent;

	if (parent->last_child) {
		/* Parent has children, so get position from sibling and append
		 * to list of children. */
		node->position = parent->last_child->position;
		node->prev = parent->last_child;
		parent->last_child->next = node;
	} else {
		/* Parent has no children, so get position from parent and add
		 * first child to parent. */
		node->position = parent->position;
		parent->first_child = node;
	}
	parent->last_child = node;
	update_positions(node, 1);

	node->size = 0;
	update_sizes(node, 1);

	node->data = data;

	debug_print_tree("Appended child", node);

	return node;
}

MqTree *
mq_tree_append_sibling_allocated(MqTree *node, MqTree *sibling, gpointer data)
{
	/* Copy ancestor pointers. */
	node->root   = sibling->root;
	node->parent = sibling->parent;

	/* Link new node and parent's last child. */
	node->prev = node->parent->last_child;
	if (node->prev) {
		node->prev->next = node;
	}

	/* Set parent's new last child. */
	node->parent->last_child = node;

	node->position = node->parent->position + node->parent->size - 1;
	update_positions(node, 1);

	node->size = 0;
	update_sizes(node, 1);

	node->data = data;

	debug_print_tree("Appended sibling", node);

	return node;
}

void
mq_tree_remove_allocated(MqTree *node)
{
	MqTree *child;

	/* Link siblings to children or each other. */
	if (node->prev) {
		node->prev->next = node->first_child ?
			node->first_child : node->next;
	}
	if (node->next) {
		node->next->prev = node->last_child ?
			node->last_child : node->prev;
	}

	/* Update parent's links. */
	if (node->parent->first_child == node) {
		node->parent->first_child = node->first_child ?
			node->first_child : node->next;
	}
	if (node->parent->last_child == node) {
		node->parent->last_child = node->last_child ?
			node->last_child : node->prev;
	}

	/* Link children to siblings (may be NULL). */
	if (node->first_child) {
		node->first_child->prev = node->prev;
	}
	if (node->last_child) {
		node->last_child->next = node->next;
	}

	/* Link children to parent. */
	for (child = node->first_child; child; child = child->next) {
		child->parent = node->parent;
	}
	
	update_positions(node, -1);

	update_sizes(node, -1);

	debug_print_tree("Removed node", node);
}

static MqTree * G_GNUC_PURE
seek(MqTree *node, gint offset)
{
	/* Skip forward to the containing subtree. */
	while (node && node->position + node->size <= offset) {
		node = node->next;
	}

	/* Check whether we've gone past the end of the tree. */
	if (!node) {
		return NULL;
	}

	/* Check whether the sibling we've reached is the node we want. */
	if (node->position == offset) {
		return node;
	}

	/* Recurse down the subtree. */
	return seek(node->first_child, offset);
}

MqTree *
mq_tree_seek(MqTree *node, gint offset)
{
	/* XXX: Only forward seeking from a tree's root is supported. */
	g_assert(node);
	g_assert(node->position == 0);
	g_assert(offset > 0);

	return seek(node, offset);
}

static gboolean
foreach_down(MqTree *node, gboolean (*cb)(MqTree *node, gpointer user_data),
	gpointer user_data)
{
	for (; node; node = node->next) {
		/* XXX: Warning: Does not skip root node */
		debug_print_node(node);
		if (cb(node, user_data) == MQ_TREE_STOP) {
			return MQ_TREE_STOP;
		}

		if (node->first_child) {
			if (foreach_down(node->first_child, cb, user_data) ==
					MQ_TREE_STOP) {
				return MQ_TREE_STOP;
			}
		}
	}

	return MQ_TREE_CONTINUE;
}

void
mq_tree_foreach(MqTree *node, gboolean (*cb)(MqTree *node, gpointer user_data),
	gpointer user_data)
{
	debug_print_head("Traversing full tree", node);

	foreach_down(node->root->first_child, cb, user_data);
}

static gboolean
foreach_up(MqTree *node, gboolean (*cb)(MqTree *node, gpointer user_data),
	gpointer user_data)
{
	node = node->parent;
	if (!node) {
		return MQ_TREE_CONTINUE;
	}

	if (foreach_down(node->next, cb, user_data) == MQ_TREE_STOP) {
		return MQ_TREE_STOP;
	}

	if (foreach_up(node, cb, user_data) == MQ_TREE_STOP) {
		return MQ_TREE_STOP;
	}

	return MQ_TREE_CONTINUE;
}

void
mq_tree_foreach_from(MqTree *node,
	gboolean (*cb)(MqTree *node, gpointer user_data), gpointer user_data)
{
	debug_print_head("Traversing tree from position", node);

	if (foreach_down(node, cb, user_data) == MQ_TREE_CONTINUE) {
		foreach_up(node, cb, user_data);
	}
}