boolcoder.cxx 11.8 KB
Newer Older
John Koleszar's avatar
John Koleszar committed
1
/*
2
 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
John Koleszar's avatar
John Koleszar committed
3
 *
4
 *  Use of this source code is governed by a BSD-style license
5
6
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
7
 *  in the file PATENTS.  All contributing project authors may
8
 *  be found in the AUTHORS file in the root of the source tree.
John Koleszar's avatar
John Koleszar committed
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
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
 */



/* Arithmetic bool coder with largish probability range.
   Timothy S Murphy  6 August 2004 */

#include <assert.h>
#include <math.h>

#include "bool_coder.h"

#if tim_vp8
    extern "C" {
#       include "VP8cx/treewriter.h"
    }
#endif

int_types::~int_types() {}

void bool_coder_spec::check_prec() const {
    assert( w  &&  (r==Up || w > 1)  &&  w < 24  &&  (ebias || w < 17));
}

bool bool_coder_spec::float_init( uint Ebits, uint Mbits) {
    uint b = (ebits = Ebits) + (mbits = Mbits);
    if( b) {
        assert( ebits < 6  &&  w + mbits < 31);
        assert( ebits + mbits  <  sizeof(Index) * 8);
        ebias = (1 << ebits) + 1 + mbits;
        mmask = (1 << mbits) - 1;
        max_index = ( ( half_index = 1 << b ) << 1) - 1;
    } else {
        ebias = 0;
        max_index = 255;
        half_index = 128;
    }
    check_prec();
    return b? 1:0;
}

void bool_coder_spec::cost_init()
{
    static cdouble c = -(1 << 20)/log( 2.);

    FILE *f = fopen( "costs.txt", "w");
    assert( f);

    assert( sizeof(int) >= 4);  /* for C interface */
    assert( max_index <= 255);   /* size of Ctbl */
    uint i = 0;  do {
        cdouble p = ( *this)( (Index) i);
        Ctbl[i] = (uint32) ( log( p) * c);
        fprintf(
            f, "cost( %d -> %10.7f) = %10d = %12.5f bits\n",
            i, p, Ctbl[i], (double) Ctbl[i] / (1<<20)
        );
    } while( ++i <= max_index);
    fclose( f);
}

bool_coder_spec_explicit_table::bool_coder_spec_explicit_table(
    cuint16 tbl[256], Rounding rr, uint prec
)
  : bool_coder_spec( prec, rr)
{
    check_prec();
    uint i = 0;
    if( tbl)
        do { Ptbl[i] = tbl[i];}  while( ++i < 256);
    else
        do { Ptbl[i] = i << 8;}  while( ++i < 256);
    cost_init();
}


bool_coder_spec_exponential_table::bool_coder_spec_exponential_table(
    uint x, Rounding rr, uint prec
)
  : bool_coder_spec( prec, rr)
{
    assert( x > 1  &&  x <= 16);
    check_prec();
    Ptbl[128] = 32768u;
    Ptbl[0] = (uint16) pow( 2., 16. - x);
    --x;
    int i=1;  do {
        cdouble d = pow( .5, 1. + (1. - i/128.)*x) * 65536.;
        uint16 v = (uint16) d;
        if( v < i)
            v = i;
        Ptbl[256-i] = (uint16) ( 65536U - (Ptbl[i] = v));
    } while( ++i < 128);
    cost_init();
}

bool_coder_spec::bool_coder_spec( FILE *fp) {
    fscanf( fp, "%d", &w);
    int v;
    fscanf( fp, "%d", &v);
    assert( 0 <= v  &&  v <= 2);
    r = (Rounding) v;
    fscanf( fp, "%d", &ebits);
    fscanf( fp, "%d", &mbits);
    if( float_init( ebits, mbits))
        return;
    int i=0;  do {
        uint v;
        fscanf( fp, "%d", &v);
        assert( 0 <=v  &&  v <= 65535U);
        Ptbl[i] = v;
    } while( ++i < 256);
    cost_init();
}

void bool_coder_spec::dump( FILE *fp) const {
    fprintf( fp, "%d %d %d %d\n", w, (int) r, ebits, mbits);
    if( ebits  ||  mbits)
        return;
    int i=0;  do { fprintf( fp, "%d\n", Ptbl[i]);}  while( ++i < 256);
}

vp8bc_index_t bool_coder_spec::operator()( double p) const
{
    if( p <= 0.)
        return 0;
    if( p >= 1.)
        return max_index;
    if( ebias) {
        if( p > .5)
            return max_index - ( *this)( 1. - p);
        int e;
        uint m = (uint) ldexp( frexp( p, &e), mbits + 2);
        uint x = 1 << (mbits + 1);
        assert( x <= m  &&  m < x<<1);
        if( (m = (m >> 1) + (m & 1)) >= x) {
            m = x >> 1;
            ++e;
        }
        int y = 1 << ebits;
        if( (e += y) >= y)
            return half_index - 1;
        if( e < 0)
            return 0;
        return (Index) ( (e << mbits) + (m & mmask));
    }

    cuint16 v = (uint16) (p * 65536.);
    int i = 128;
    int j = 128;
    uint16 w;
    while( w = Ptbl[i], j >>= 1) {
        if( w < v)
            i += j;
        else if( w == v)
            return (uchar) i;
        else
            i -= j;
    }
    if( w > v) {
        cuint16 x = Ptbl[i-1];
        if( v <= x  ||  w - v > v - x)
            --i;
    } else if( w < v  &&  i < 255) {
        cuint16 x = Ptbl[i+1];
        if( x <= v  ||  x - v < v - w)
            ++i;
    }
    return (Index) i;
}

double bool_coder_spec::operator()( Index i) const {
    if( !ebias)
        return Ptbl[i]/65536.;
    if( i >= half_index)
        return 1. - ( *this)( (Index) (max_index - i));
    return ldexp( (double)mantissa( i), - (int) exponent( i));
}



void bool_writer::carry() {
    uchar *p = B;
    assert( p > Bstart);
    while( *--p == 255) { assert( p > Bstart);  *p = 0;}
    ++*p;
}


bool_writer::bool_writer( c_spec& s, uchar *Dest, size_t Len)
  : bool_coder( s),
    Bstart( Dest),
    Bend( Len? Dest+Len : 0),
    B( Dest)
{
    assert( Dest);
    reset();
}

bool_writer::~bool_writer() { flush();}

#if 1
    extern "C" { int bc_v = 0;}
#else
#   define bc_v 0
#endif


void bool_writer::raw( bool value, uint32 s) {
    uint32 L = Low;

    assert( Range >= min_range  &&  Range <= spec.max_range());
    assert( !is_toast  &&  s  &&  s < Range);

    if( bc_v) printf(
        "Writing a %d, B %x  Low %x  Range %x  s %x   blag %d ...\n",
        value? 1:0, B-Bstart, Low, Range, s, bit_lag
    );
    if( value) {
        L += s;
        s = Range - s;
    } else
        s -= rinc;
    if( s < min_range) {
        int ct = bit_lag;  do {
            if( !--ct) {
                ct = 8;
                if( L & (1 << 31))
                    carry();
                assert( !Bend  ||  B < Bend);
                *B++ = (uchar) (L >> 23);
                L &= (1<<23) - 1;
            }
        } while( L += L, (s += s + rinc) < min_range);
        bit_lag = ct;
    }
    Low = L;
    Range = s;
    if( bc_v)
        printf(
            "...done, B %x  Low %x  Range %x  blag %d \n",
                B-Bstart, Low, Range, bit_lag
        );
}

bool_writer& bool_writer::flush() {
    if( is_toast)
        return *this;
    int b = bit_lag;
    uint32 L = Low;
    assert( b);
    if( L & (1 << (32 - b)))
        carry();
    L <<= b & 7;
    b >>= 3;
    while( --b >= 0)
        L <<= 8;
    b = 4;
    assert( !Bend  ||  B + 4 <= Bend);
    do {
        *B++ = (uchar) (L >> 24);
        L <<= 8;
    } while( --b);
    is_toast = 1;
    return *this;
}


bool_reader::bool_reader( c_spec& s, cuchar *src, size_t Len)
  : bool_coder( s),
    Bstart( src),
    B( src),
    Bend( Len? src+Len : 0),
    shf( 32 - s.w),
    bct( 8)
{
    int i = 4;  do { Low <<= 8;  Low |= *B++;}  while( --i);
}


bool bool_reader::raw( uint32 s) {

    bool val = 0;
    uint32 L = Low;
    cuint32 S = s << shf;

    assert( Range >= min_range  &&  Range <= spec.max_range());
    assert( s  &&  s < Range  &&  (L >> shf) < Range);

    if( bc_v)
        printf(
            "Reading, B %x  Low %x  Range %x  s %x  bct %d ...\n",
            B-Bstart, Low, Range, s, bct
        );

    if( L >= S) {
        L -= S;
        s = Range - s;
        assert( L < (s << shf));
        val = 1;
    } else
        s -= rinc;
    if( s < min_range) {
        int ct = bct;
        do {
            assert( ~L & (1 << 31));
            L += L;
            if( !--ct) {
                ct = 8;
                if( !Bend  ||  B < Bend)
                    L |= *B++;
            }
        } while( (s += s + rinc) < min_range);
        bct = ct;
    }
    Low = L;
    Range = s;
    if( bc_v)
        printf(
            "...done, val %d  B %x  Low %x  Range %x  bct %d\n",
            val? 1:0, B-Bstart, Low, Range, bct
        );
    return val;
}


/* C interfaces */

// spec interface

struct NS : bool_coder_namespace {
    static Rounding r( vp8bc_c_prec *p, Rounding rr =down_full) {
        return p? (Rounding) p->r : rr;
    }
};

bool_coder_spec *vp8bc_vp6spec() {
    return new bool_coder_spec_explicit_table( 0, bool_coder_namespace::Down, 8);
}
bool_coder_spec *vp8bc_float_spec(
    unsigned int Ebits, unsigned int Mbits, vp8bc_c_prec *p
) {
    return new bool_coder_spec_float( Ebits, Mbits, NS::r( p), p? p->prec : 12);
}
bool_coder_spec *vp8bc_literal_spec(
    const unsigned short m[256], vp8bc_c_prec *p
) {
    return new bool_coder_spec_explicit_table( m, NS::r( p), p? p->prec : 16);
}
bool_coder_spec *vp8bc_exponential_spec( unsigned int x, vp8bc_c_prec *p)
{
    return new bool_coder_spec_exponential_table( x, NS::r( p), p? p->prec : 16);
}
bool_coder_spec *vp8bc_spec_from_file( FILE *fp) {
    return new bool_coder_spec( fp);
}
void vp8bc_destroy_spec( c_bool_coder_spec *p) { delete p;}

void vp8bc_spec_to_file( c_bool_coder_spec *p, FILE *fp) { p->dump( fp);}

vp8bc_index_t vp8bc_index( c_bool_coder_spec *p, double x) {
    return ( *p)( x);
}

vp8bc_index_t vp8bc_index_from_counts(
    c_bool_coder_spec *p, unsigned int L, unsigned int R
) {
    return ( *p)( (R += L)? (double) L/R : .5);
}

double vp8bc_probability( c_bool_coder_spec *p, vp8bc_index_t i) {
    return ( *p)( i);
}

vp8bc_index_t vp8bc_complement( c_bool_coder_spec *p, vp8bc_index_t i) {
    return p->complement( i);
}
unsigned int vp8bc_cost_zero( c_bool_coder_spec *p, vp8bc_index_t i) {
    return p->cost_zero( i);
}
unsigned int vp8bc_cost_one( c_bool_coder_spec *p, vp8bc_index_t i) {
    return p->cost_one( i);
}
unsigned int vp8bc_cost_bit( c_bool_coder_spec *p, vp8bc_index_t i, int v) {
    return p->cost_bit( i, v);
}

#if tim_vp8
    extern "C" int tok_verbose;

#   define dbg_l 1000000

    static vp8bc_index_t dbg_i [dbg_l];
    static char dbg_v [dbg_l];
    static size_t dbg_w = 0, dbg_r = 0;
#endif

// writer interface

bool_writer *vp8bc_create_writer(
    c_bool_coder_spec *p, unsigned char *D, size_t L
) {
    return new bool_writer( *p, D, L);
}

size_t vp8bc_destroy_writer( bool_writer *p) {
    const size_t s = p->flush().bytes_written();
    delete p;
    return s;
}

void vp8bc_write_bool( bool_writer *p, int v, vp8bc_index_t i)
{
#   if tim_vp8
        // bc_v = dbg_w < 10;
        if( bc_v = tok_verbose)
            printf( " writing %d at prob %d\n", v? 1:0, i);
        accum_entropy_bc( &p->Spec(), i, v);

        ( *p)( i, (bool) v);

        if( dbg_w < dbg_l) {
            dbg_i [dbg_w] = i;
            dbg_v [dbg_w++] = v? 1:0;
        }
#   else
        ( *p)( i, (bool) v);
#   endif
}

void vp8bc_write_bits( bool_writer *p, unsigned int v, int n)
{
#   if tim_vp8
        {
            c_bool_coder_spec * const s = & p->Spec();
            const vp8bc_index_t i = s->half_index();
            int m = n;
            while( --m >= 0)
                accum_entropy_bc( s, i, (v>>m) & 1);
        }
#   endif

    p->write_bits( n, v);
}

c_bool_coder_spec *vp8bc_writer_spec( c_bool_writer *w) { return & w->Spec();}

// reader interface

bool_reader *vp8bc_create_reader(
    c_bool_coder_spec *p, const unsigned char *S, size_t L
) {
    return new bool_reader( *p, S, L);
}

void vp8bc_destroy_reader( bool_reader * p) { delete p;}

int vp8bc_read_bool( bool_reader *p, vp8bc_index_t i)
{
#   if tim_vp8
        // bc_v = dbg_r < 10;
        bc_v = tok_verbose;
        const int v = ( *p)( i)? 1:0;
        if( tok_verbose)
            printf( " reading %d at prob %d\n", v, i);
        if( dbg_r < dbg_l) {
            assert( dbg_r <= dbg_w);
            if( i != dbg_i[dbg_r]  ||  v != dbg_v[dbg_r]) {
                printf(
        "Position %d: INCORRECTLY READING %d  prob %d, wrote %d  prob %d\n",
                    dbg_r, v, i, dbg_v[dbg_r], dbg_i[dbg_r]
                );
            }
            ++dbg_r;
        }
        return v;
#   else
        return ( *p)( i)? 1:0;
#   endif
}

unsigned int vp8bc_read_bits( bool_reader *p, int n) { return p->read_bits( n);}

c_bool_coder_spec *vp8bc_reader_spec( c_bool_reader *r) { return & r->Spec();}

#undef bc_v