-
Notifications
You must be signed in to change notification settings - Fork 1
/
lib.rs
371 lines (307 loc) · 10.7 KB
/
lib.rs
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
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
#![deny(warnings)]
#![deny(unused_extern_crates)]
use std::collections::{BTreeMap, VecDeque};
use std::collections::btree_map;
use std::fmt;
use std::mem;
use std::ops;
pub struct TopMap<Key, Value> {
top_count: usize,
top: VecDeque<Option<(Key, Value)>>,
rest: BTreeMap<Key, Value>,
}
impl<Key, Value> TopMap<Key, Value>
where
Key: Ord,
{
pub fn new(top_count: usize) -> Self {
Self {
top_count,
top: VecDeque::new(),
rest: BTreeMap::new(),
}
}
}
fn positive(i: isize) -> Option<usize> {
if i >= 0 {
Some(i as usize)
} else {
None
}
}
enum Index {
AboveTop { distance: usize },
InsideTop { index: usize },
Rest,
}
impl Index {
fn from_key<Key, Value>(top_count: usize, top: &VecDeque<Option<(Key, Value)>>, key: Key) -> Self
where
Key: Copy,
isize: From<Key>,
{
let index = if let Some(ref min_entry) = top.front() {
let (min_key, _) = min_entry.as_ref().expect("top entry should be filled");
isize::from(key) - isize::from(*min_key)
} else {
0
};
if let Some(index) = positive(index) {
if index >= top_count {
Index::Rest
} else {
Index::InsideTop { index }
}
} else {
Index::AboveTop {
distance: -index as usize,
}
}
}
}
pub enum Entry<'a, Key: 'a, Value: 'a> {
Vec(Key, &'a mut Option<(Key, Value)>),
BTreeMap(btree_map::Entry<'a, Key, Value>),
}
impl<'a, Key, Value> Entry<'a, Key, Value>
where
Key: Ord,
{
pub fn or_insert(self, default: Value) -> &'a mut Value {
match self {
Entry::Vec(key, entry) => &mut entry.get_or_insert((key, default)).1,
Entry::BTreeMap(entry) => entry.or_insert(default),
}
}
pub fn or_insert_with<F: FnOnce() -> Value>(self, default: F) -> &'a mut Value {
match self {
Entry::Vec(key, entry) => &mut entry.get_or_insert_with(|| (key, default())).1,
Entry::BTreeMap(entry) => entry.or_insert_with(default),
}
}
}
impl<Key, Value> TopMap<Key, Value> {
pub fn len(&self) -> usize {
self.top.len() + self.rest.len()
}
}
impl<Key, Value> TopMap<Key, Value>
where
Key: Copy + Ord,
isize: From<Key>,
{
pub fn reserve(&mut self, additional: usize) {
self.top.reserve(additional)
}
pub fn iter(&self) -> impl Iterator<Item = (Key, &Value)> {
self.top
.iter()
.filter_map(|entry| entry.as_ref().map(|(key, value)| (*key, value)))
.chain(self.rest.iter().map(|(key, value)| (*key, value)))
}
pub fn iter_mut(&mut self) -> impl Iterator<Item = (Key, &mut Value)> {
self.top
.iter_mut()
.filter_map(|entry| entry.as_mut().map(|(key, value)| (*key, value)))
.chain(self.rest.iter_mut().map(|(key, value)| (*key, value)))
}
pub fn entry(&mut self, key: Key) -> Entry<Key, Value> {
match Index::from_key(self.top_count, &self.top, key) {
Index::AboveTop { distance } => {
let new_count = positive(self.top_count as isize - distance as isize).unwrap_or(0);
for entry in self.top.drain(new_count..) {
if let Some((key, value)) = entry {
self.rest.insert(key, value);
}
}
assert_eq!(new_count, self.top.len());
Entry::Vec(key, &mut self.top[0])
}
Index::InsideTop { index } => {
while self.top.len() <= index {
self.top.push_back(None);
}
Entry::Vec(key, &mut self.top[index])
}
Index::Rest => Entry::BTreeMap(self.rest.entry(key)),
}
}
pub fn get(&self, key: Key) -> Option<&Value> {
match Index::from_key(self.top_count, &self.top, key) {
Index::AboveTop { distance: _ } => None,
Index::InsideTop { index } => Some(&self.top.get(index)?.as_ref()?.1),
Index::Rest => self.rest.get(&key),
}
}
pub fn get_mut(&mut self, key: Key) -> Option<&mut Value> {
match Index::from_key(self.top_count, &self.top, key) {
Index::AboveTop { distance: _ } => None,
Index::InsideTop { index } => Some(&mut self.top.get_mut(index)?.as_mut()?.1),
Index::Rest => self.rest.get_mut(&key),
}
}
pub fn insert(&mut self, key: Key, value: Value) -> Option<Value> {
match Index::from_key(self.top_count, &self.top, key) {
Index::AboveTop { distance } => {
let new_count = positive(self.top_count as isize - distance as isize).unwrap_or(0);
for entry in self.top.drain(new_count..) {
if let Some((key, value)) = entry {
self.rest.insert(key, value);
}
}
assert!(self.top.len() <= new_count);
self.top.push_front(Some((key, value)));
None
}
Index::InsideTop { index } => loop {
if let Some(entry) = self.top.get_mut(index) {
return mem::replace(entry, Some((key, value))).map(|(_, value)| value);
}
self.top.push_back(None);
},
Index::Rest => {
self.rest.insert(key, value);
None
}
}
}
pub fn remove(&mut self, key: Key) -> Option<Value> {
match Index::from_key(self.top_count, &self.top, key) {
Index::AboveTop { distance: _ } => None,
Index::InsideTop { index } => {
let (_, value) = mem::replace(self.top.get_mut(index)?, None)?;
if index == 0 || index == self.top.len() - 1 {
self.top.remove(index);
let min_top_key = if let Some(&Some((min_top_key, _))) = self.top.front() {
Some(min_top_key)
} else if let Some((&rest_key, _)) = self.rest.iter().next() {
let rest_value = self.rest.remove(&rest_key).unwrap();
self.top.push_back(Some((rest_key, rest_value)));
Some(rest_key)
} else {
None
};
if let Some(min_top_key) = min_top_key {
while let Some((&rest_key, _)) = self.rest.iter().next() {
let rest_index = positive(isize::from(rest_key) - isize::from(min_top_key)).expect(
"everything in the rest map should have an index higher than everything in the top vec",
);
if rest_index >= self.top_count {
break;
}
while self.top.len() <= rest_index {
self.top.push_back(None);
}
let rest_value = self.rest.remove(&rest_key).unwrap();
mem::replace(&mut self.top[rest_index], Some((rest_key, rest_value)));
}
}
}
Some(value)
}
Index::Rest => self.rest.remove(&key),
}
}
}
impl<Key, Value> ops::Index<Key> for TopMap<Key, Value>
where
Key: Copy + Ord + fmt::Debug,
isize: From<Key>,
{
type Output = Value;
fn index(&self, index: Key) -> &Value {
self.get(index)
.unwrap_or_else(|| panic!("no item with key {:?}", index))
}
}
impl<Key, Value> ops::IndexMut<Key> for TopMap<Key, Value>
where
Key: Copy + Ord + fmt::Debug,
isize: From<Key>,
{
fn index_mut(&mut self, index: Key) -> &mut Value {
self.get_mut(index)
.unwrap_or_else(|| panic!("no item with key {:?}", index))
}
}
impl<Key, Value> Extend<(Key, Value)> for TopMap<Key, Value>
where
Key: Copy + Ord,
isize: From<Key>,
{
fn extend<T: IntoIterator<Item = (Key, Value)>>(&mut self, iter: T) {
for (key, value) in iter {
self.insert(key, value);
}
}
}
#[cfg(test)]
mod tests {
use super::TopMap;
static ITEMS: &[(isize, &'static str)] = &[
(100, "a1"),
(101, "a2"),
(200, "b1"),
(201, "b2"),
(300, "c1"),
(301, "c2"),
];
fn lens<Key, Value>(m: &TopMap<Key, Value>) -> [usize; 3] {
[m.len(), m.top.len(), m.rest.len()]
}
#[test]
fn extend() {
let mut m = TopMap::new(10);
m.extend(ITEMS.iter().cloned());
assert_eq!([6, 2, 4], lens(&m));
let items = m.iter()
.map(|(key, &value)| (key, value))
.collect::<Vec<(isize, &'static str)>>();
assert_eq!(ITEMS, &items[..]);
}
#[test]
fn insert() {
let mut m = TopMap::new(10);
assert_eq!(None, m.get(100isize));
assert_eq!([0, 0, 0], lens(&m));
assert_eq!(None, m.insert(200, "b1"));
assert_eq!([1, 1, 0], lens(&m));
assert_eq!(None, m.insert(201, "b2"));
assert_eq!([2, 2, 0], lens(&m));
assert_eq!(None, m.insert(300, "c1"));
assert_eq!([3, 2, 1], lens(&m));
assert_eq!(None, m.insert(301, "c2"));
assert_eq!([4, 2, 2], lens(&m));
assert_eq!(None, m.insert(100, "a1"));
assert_eq!([5, 1, 4], lens(&m));
assert_eq!(None, m.insert(101, "a2"));
assert_eq!([6, 2, 4], lens(&m));
let items = m.iter()
.map(|(key, &value)| (key, value))
.collect::<Vec<(isize, &'static str)>>();
assert_eq!(ITEMS, &items[..]);
}
#[test]
fn remove() {
let mut m = TopMap::new(10);
m.extend(ITEMS.iter().cloned());
assert_eq!(None, m.remove(-1));
assert_eq!([6, 2, 4], lens(&m));
assert_eq!(Some("a1"), m.remove(100));
assert_eq!([5, 1, 4], lens(&m));
assert_eq!(Some("a2"), m.remove(101));
assert_eq!([4, 2, 2], lens(&m));
assert_eq!(Some("c1"), m.remove(300));
assert_eq!([3, 2, 1], lens(&m));
assert_eq!(Some("c2"), m.remove(301));
assert_eq!([2, 2, 0], lens(&m));
assert_eq!(Some("b1"), m.remove(200));
assert_eq!([1, 1, 0], lens(&m));
assert_eq!(Some("b2"), m.remove(201));
assert_eq!([0, 0, 0], lens(&m));
let items = m.iter()
.map(|(key, &value)| (key, value))
.collect::<Vec<(isize, &'static str)>>();
assert!(items.is_empty());
}
}