summaryrefslogtreecommitdiff
path: root/python/cdec/sa/veb.pxi
blob: 40af3a6844e34011f1750a73705f0a872e7d244c (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
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
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
"""This module implements a partial stratified tree (van Emde Boas, 1977).
Only insert findsucc, __iter__, and __contains__ are implemented.
Delete is currently not supported.
There is very little error-checking in this code -- it is designed
to be used in the limited situation described in Lopez (EMNLP-CoNLL 2007),
which doesn't cover all of the possible ways that you could misuse it
(e.g. trying to insert a key larger than the universe size)
Other notes -- this code is really rather ugly C code masquerading as
Pyrex/Python.  Virtual function calls are bypassed by hand in several
places for the sake of efficiency, and other Python niceties are 
removed for the same reason."""

from libc.stdlib cimport malloc, free
from libc.math cimport log, ceil
from libc.string cimport memset

cdef int MIN_BOTTOM_SIZE = 32
cdef int MIN_BOTTOM_BITS = 5
cdef int LOWER_MASK[32]

cdef void _init_lower_mask():
    cdef unsigned i
    cdef int mask = 0
    for i in range(MIN_BOTTOM_SIZE):
        mask = (mask << 1) + 1
        LOWER_MASK[i] = mask

_init_lower_mask()

cdef struct _BitSet:
    long bitset
    int min_val
    int max_val
    int size


cdef _BitSet* new_BitSet():
    cdef _BitSet* b

    b = <_BitSet*> malloc(sizeof(_BitSet))
    b.bitset = 0
    b.min_val = -1
    b.max_val = -1
    b.size = 0
    return b


cdef int bitset_findsucc(_BitSet* b, int i):
    cdef int bitset, mask
    cdef int low, high, mid

    if b.max_val == -1 or i >= b.max_val:
        return -1
    if i < b.min_val:
        return b.min_val

    bitset = b.bitset & ~LOWER_MASK[i]
    low = i+1
    high = b.max_val+1
    while low < high-1:
        mid = (high + low)/2
        mask = ~(LOWER_MASK[high-1] ^ LOWER_MASK[mid-1])
        if bitset & mask == 0:
            low = mid
        else: 
            bitset = bitset & mask
            high = mid
    return low


cdef int bitset_insert(_BitSet* b, int i):
    cdef int val

    val = 1 << i
    if b.bitset & val == 0:
        b.bitset = b.bitset | val
        if b.size == 0:
            b.min_val = i
            b.max_val = i
        else:
            if i < b.min_val:
                b.min_val = i
            if i > b.max_val:
                b.max_val = i
        b.size = b.size + 1
        return 1
    return 0


cdef int bitset_contains(_BitSet* b, int i):
    cdef int val

    val = 1 << i
    if b.bitset & val == 0:
        return 0
    else:
        return 1


cdef class BitSetIterator:
    cdef _BitSet* b
    cdef int next_val

    def __next__(self):
        cdef int ret_val

        if self.next_val == -1:
            raise StopIteration()
        ret_val = self.next_val
        self.next_val = bitset_findsucc(self.b, ret_val)
        return ret_val



# This is a Python wrapper class to give access to the
# (entirely C-implemented) _BitSet struct. 
# Very slow; use only for debugging
cdef class BitSet:

    cdef _BitSet* b

    def __cinit__(self):
        self.b = new_BitSet()

    def __dealloc__(self):
        free(self.b)

    def __iter__(self):
        cdef BitSetIterator it
        it = BitSetIterator()
        it.b = self.b
        it.next_val = self.b.min_val
        return it

    def insert(self, i):
        return bitset_insert(self.b, i)

    def findsucc(self, i):
        return bitset_findsucc(self.b, i)

    def __str__(self):
        return dec2bin(self.b.bitset)+"  ("+str(self.b.size)+","+str(self.b.min_val)+","+str(self.b.max_val)+")"

    def min(self):
        return self.b.min_val

    def max(self):
        return self.b.max_val

    def __len__(self):
        return self.b.size

    def __contains__(self, i):
        return bool(bitset_contains(self.b, i))


cdef str dec2bin(long i):
    cdef str result = ""
    cdef unsigned d
    for d in range(MIN_BOTTOM_SIZE):
        if i & LOWER_MASK[0] == 0:
            result = "0"+result
        else:
            result = "1"+result
        i = i >> 1
    return result

cdef struct _VEB:
    int top_universe_size
    int num_bottom_bits
    int max_val
    int min_val
    int size
    void* top
    void** bottom

cdef _VEB* new_VEB(int n):
    cdef _VEB* veb
    cdef int num_bits, num_top_bits, i

    veb = <_VEB*> malloc(sizeof(_VEB))

    num_bits = int(ceil(log(n) / log(2)))
    veb.num_bottom_bits = num_bits/2
    if veb.num_bottom_bits < MIN_BOTTOM_BITS:
        veb.num_bottom_bits = MIN_BOTTOM_BITS
    veb.top_universe_size = (n >> veb.num_bottom_bits) + 1

    veb.bottom = <void**> malloc(veb.top_universe_size * sizeof(void*))
    memset(veb.bottom, 0, veb.top_universe_size * sizeof(void*))

    if veb.top_universe_size > MIN_BOTTOM_SIZE:
        veb.top = new_VEB(veb.top_universe_size)
    else:
        veb.top = new_BitSet()

    veb.max_val = -1
    veb.min_val = -1
    veb.size = 0
    return veb


cdef int VEB_insert(_VEB* veb, int i):
    cdef _VEB* subv
    cdef _BitSet* subb
    cdef int a, b, tmp

    if veb.size == 0:
        veb.min_val = i
        veb.max_val = i
    elif i == veb.min_val or i == veb.max_val:
        return 0
    else:
        if i < veb.min_val:
            tmp = i
            i = veb.min_val
            veb.min_val = tmp
        a = i >> veb.num_bottom_bits
        b = i & LOWER_MASK[veb.num_bottom_bits-1]
        if veb.bottom[a] == NULL:
            if veb.top_universe_size > MIN_BOTTOM_SIZE:
                subv = <_VEB*> veb.top
                VEB_insert(subv, a)
            else:
                subb = <_BitSet*> veb.top
                bitset_insert(subb, a)
            if veb.num_bottom_bits > MIN_BOTTOM_BITS:
                veb.bottom[a] = new_VEB(1 << veb.num_bottom_bits)
            else:
                veb.bottom[a] = new_BitSet()
        if veb.num_bottom_bits > MIN_BOTTOM_BITS:
            subv = <_VEB*> veb.bottom[a]
            if VEB_insert(subv, b) == 0:
                return 0
        else:
            subb = <_BitSet*> veb.bottom[a]
            if bitset_insert(subb, b) == 0:
                return 0

        if i > veb.max_val:
            veb.max_val = i
    veb.size = veb.size + 1
    return 1


cdef del_VEB(_VEB* veb):
    cdef int i

    if veb.top_universe_size > MIN_BOTTOM_SIZE:
        i = (<_VEB*> veb.top).min_val
    else:
        i = (<_BitSet*> veb.top).min_val

    while i != -1:
        if veb.num_bottom_bits > MIN_BOTTOM_BITS:
            del_VEB(<_VEB*> veb.bottom[i])
        else:
            free(<_BitSet*> veb.bottom[i])

        if veb.top_universe_size > MIN_BOTTOM_SIZE:
            i = VEB_findsucc(<_VEB*> veb.top, i)
        else:
            i = bitset_findsucc(<_BitSet*> veb.top, i)

    if veb.top_universe_size > MIN_BOTTOM_SIZE:
        del_VEB(<_VEB*> veb.top)
    else:
        free(<_BitSet*> veb.top)
    free(veb.bottom)
    free(veb)


cdef int VEB_findsucc(_VEB* veb, int i):
    cdef _VEB* subv
    cdef _BitSet* subb
    cdef int a, b, j, c, found

    if veb.max_val == -1 or i>=veb.max_val:
        return -1
    if i < veb.min_val:
        return veb.min_val

    a = i >> veb.num_bottom_bits
    b = i & LOWER_MASK[veb.num_bottom_bits-1]
    found = 0
    if veb.bottom[a] != NULL:
        if veb.num_bottom_bits > MIN_BOTTOM_BITS:
            subv = <_VEB*> veb.bottom[a]
            if subv.max_val > b:
                j = (a << veb.num_bottom_bits) + VEB_findsucc(subv, b)
                found = 1
        else:
            subb = <_BitSet*> veb.bottom[a]
            if subb.max_val > b:
                j = (a << veb.num_bottom_bits) + bitset_findsucc(subb, b)
                found = 1
    if found==0:
        if veb.top_universe_size > MIN_BOTTOM_SIZE:
            subv = <_VEB*> veb.top
            c = VEB_findsucc(subv, a)
        else:
            subb = <_BitSet*> veb.top
            c = bitset_findsucc(subb, a)
        if veb.num_bottom_bits > MIN_BOTTOM_BITS:
            subv = <_VEB*> veb.bottom[c]
            j = (c << veb.num_bottom_bits) + subv.min_val
        else:
            subb = <_BitSet*> veb.bottom[c]
            j = (c << veb.num_bottom_bits) + subb.min_val
    return j


cdef int VEB_contains(_VEB* veb, int i):
    cdef _VEB* subv
    cdef _BitSet* subb
    cdef int a, b

    if veb.size == 0 or i < veb.min_val or i > veb.max_val:
        return 0

    if veb.min_val == i:
        return 1
    else:
        if veb.size == 1:
            return 0

    a = i >> veb.num_bottom_bits
    b = i & LOWER_MASK[veb.num_bottom_bits-1]
    if veb.bottom[a] == NULL:
        return 0
    else:
        if veb.num_bottom_bits > MIN_BOTTOM_BITS:
            subv = <_VEB*> veb.bottom[a]
            return VEB_contains(subv, b)
        else:
            subb = <_BitSet*> veb.bottom[a]
            return bitset_contains(subb, b)


cdef class VEBIterator:
    cdef _VEB* v
    cdef int next_val

    def __next__(self):
        cdef int ret_val

        if self.next_val == -1:
            raise StopIteration()
        ret_val = self.next_val
        self.next_val = VEB_findsucc(self.v, ret_val)
        return ret_val


cdef class VEB:
    cdef _VEB* veb
    cdef int _findsucc(self, int i)
    cdef int _insert(self, int i)
    cdef int _first(self)

    def __cinit__(self, int size):
        self.veb = new_VEB(size)

    def __dealloc__(self):
        del_VEB(self.veb)

    def __iter__(self):
        cdef VEBIterator it
        it = VEBIterator()
        it.v = self.veb
        it.next_val = self.veb.min_val
        return it

    def insert(self, i):
        return VEB_insert(self.veb, i)

    cdef int _insert(self, int i):
        return VEB_insert(self.veb, i)

    def findsucc(self, i):
        return VEB_findsucc(self.veb, i)

    cdef int _first(self):
        return self.veb.min_val

    cdef int _findsucc(self, int i):
        return VEB_findsucc(self.veb, i)

    def __len__(self):
        return self.veb.size

    def __contains__(self, i):
        return VEB_contains(self.veb, i)