encode.c 26.2 KB
Newer Older
1
/**
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
2
 * @file encode.c
3
 *
4
 * @author Mathis Rosenhauer, Deutsches Klimarechenzentrum
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
 * @author Moritz Hanke, Deutsches Klimarechenzentrum
 * @author Joerg Behrens, Deutsches Klimarechenzentrum
 * @author Luis Kornblueh, Max-Planck-Institut fuer Meteorologie
 *
 * @section LICENSE
 * Copyright 2012
 *
 * Mathis Rosenhauer,                 Luis Kornblueh
 * Moritz Hanke,
 * Joerg Behrens
 *
 * Deutsches Klimarechenzentrum GmbH  Max-Planck-Institut fuer Meteorologie
 * Bundesstr. 45a                     Bundesstr. 53
 * 20146 Hamburg                      20146 Hamburg
 * Germany                            Germany
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials provided
 *    with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
47 48 49
 * @section DESCRIPTION
 *
 * Adaptive Entropy Encoder
50
 * Based on CCSDS documents 121.0-B-2 and 120.0-G-2
51 52
 *
 */
53

54 55 56 57 58 59
#include <config.h>

#if HAVE_STDINT_H
# include <stdint.h>
#endif

60 61
#include <stdio.h>
#include <stdlib.h>
62
#include <unistd.h>
63 64
#include <string.h>

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
65 66 67
#include "libaec.h"
#include "encode.h"
#include "encode_accessors.h"
68

69
/* Marker for Remainder Of Segment condition in zero block encoding */
70
#define ROS -1
71

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
72 73 74 75
static int m_get_block(struct aec_stream *strm);

static inline void emit(struct internal_state *state,
                        uint32_t data, int bits)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
76
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
77 78 79 80
    /**
       Emit sequence of bits.
     */

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
81 82 83
    if (bits <= state->bits) {
        state->bits -= bits;
        *state->cds += data << state->bits;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
84
    } else {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
85 86
        bits -= state->bits;
        *state->cds++ += (uint64_t)data >> bits;
87

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
88
        while (bits & ~7) {
89
            bits -= 8;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
90
            *state->cds++ = data >> bits;
91
        }
92

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
93 94
        state->bits = 8 - bits;
        *state->cds = data << state->bits;
95
    }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
96 97
}

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
98
static inline void emitfs(struct internal_state *state, int fs)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
99
{
100 101
    /**
       Emits a fundamental sequence.
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
102

103 104
       fs zero bits followed by one 1 bit.
     */
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
105

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
106
    for(;;) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
107 108 109
        if (fs < state->bits) {
            state->bits -= fs + 1;
            *state->cds += 1U << state->bits;
110
            break;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
111
        } else {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
112 113 114
            fs -= state->bits;
            *++state->cds = 0;
            state->bits = 8;
115 116
        }
    }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
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
static inline void copy64(uint8_t *dst, uint64_t src)
{
    dst[0] = src >> 56;
    dst[1] = src >> 48;
    dst[2] = src >> 40;
    dst[3] = src >> 32;
    dst[4] = src >> 24;
    dst[5] = src >> 16;
    dst[6] = src >> 8;
    dst[7] = src;
}

#define EMITBLOCK_FS(ref)                                           \
    static inline void emitblock_fs_##ref(struct aec_stream *strm,  \
                                          int k)                    \
    {                                                               \
        int i;                                                      \
        int used; /* used bits in 64 bit accumulator */             \
        uint64_t acc; /* accumulator */                             \
        struct internal_state *state = strm->state;                 \
                                                                    \
        acc = (uint64_t)*state->cds << 56;                          \
        used = 7 - state->bits;                                     \
                                                                    \
        for (i = ref; i < strm->block_size; i++) {                  \
            used += (state->block[i] >> k) + 1;                     \
            if (used > 63) {                                        \
                copy64(state->cds, acc);                            \
                state->cds += 8;                                    \
                acc = 0;                                            \
                used &= 0x3f;                                       \
            }                                                       \
            acc |= 1ULL << (63 - used);                             \
        }                                                           \
                                                                    \
        copy64(state->cds, acc);                                    \
        state->cds += used >> 3;                                    \
        state->bits = 7 - (used & 7);                               \
    }

EMITBLOCK_FS(0);
EMITBLOCK_FS(1);

#define EMITBLOCK(ref)                                              \
    static inline void emitblock_##ref(struct aec_stream *strm,     \
                                       int k)                       \
    {                                                               \
        /**                                                         \
           Emit the k LSB of a whole block of input data.           \
        */                                                          \
                                                                    \
        int b;                                                      \
        uint64_t a;                                                 \
        struct internal_state *state = strm->state;                 \
        uint32_t *in = state->block + ref;                          \
        uint32_t *in_end = state->block + strm->block_size;         \
        uint64_t mask = (1ULL << k) - 1;                            \
        uint8_t *o = state->cds;                                    \
        int p = state->bits;                                        \
                                                                    \
        a = *o;                                                     \
                                                                    \
        while(in < in_end) {                                        \
            a <<= 56;                                               \
            p = (p % 8) + 56;                                       \
                                                                    \
            while (p > k && in < in_end) {                          \
                p -= k;                                             \
                a += ((uint64_t)(*in++) & mask) << p;               \
            }                                                       \
                                                                    \
            for (b = 56; b > (p & ~7); b -= 8)                      \
                *o++ = a >> b;                                      \
            a >>= b;                                                \
        }                                                           \
                                                                    \
        *o = a;                                                     \
        state->cds = o;                                             \
        state->bits = p % 8;                                        \
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
198 199 200 201 202
    }

EMITBLOCK(0);
EMITBLOCK(1);

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
203
static void preprocess_unsigned(struct aec_stream *strm)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
204
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
205 206
    /**
       Preprocess RSI of unsigned samples.
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
207 208 209

       Combining preprocessing and converting to uint32_t in one loop
       is slower due to the data dependance on x_i-1.
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
210 211
    */

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
212
    uint32_t D;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
213
    struct internal_state *state = strm->state;
214 215
    const uint32_t *x = state->data_raw;
    uint32_t *d = state->data_pp;
216 217
    uint32_t xmax = state->xmax;
    uint32_t rsi = strm->rsi * strm->block_size - 1;
218

219
    *d++ = x[0];
220
    while (rsi--) {
221 222
        if (x[1] >= x[0]) {
            D = x[1] - x[0];
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
223
            if (D <= x[0])
224
                *d = 2 * D;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
225
            else
226
                *d = x[1];
227
        } else {
228
            D = x[0] - x[1];
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
229
            if (D <= xmax - x[0])
230
                *d = 2 * D - 1;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
231
            else
232
                *d = xmax - x[1];
233
        }
234
        d++;
235
        x++;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
236
    }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
237
    state->ref = 1;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
238 239
}

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
240
static void preprocess_signed(struct aec_stream *strm)
241
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
242 243 244 245
    /**
       Preprocess RSI of signed samples.
    */

246
    int64_t D;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
247
    struct internal_state *state = strm->state;
248 249
    uint32_t *d = state->data_pp;
    int32_t *x = (int32_t *)state->data_raw;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
250
    uint64_t m = 1ULL << (strm->bits_per_sample - 1);
251 252 253
    int64_t xmax = state->xmax;
    int64_t xmin = state->xmin;
    uint32_t rsi = strm->rsi * strm->block_size - 1;
254

255 256 257
    *d++ = (uint32_t)x[0];
    x[0] = (x[0] ^ m) - m;

258
    while (rsi--) {
259 260 261 262 263
        x[1] = (x[1] ^ m) - m;
        if (x[1] < x[0]) {
            D = (int64_t)x[0] - x[1];
            if (D <= xmax - x[0])
                *d = 2 * D - 1;
264
            else
265
                *d = xmax - x[1];
266
        } else {
267 268 269
            D = (int64_t)x[1] - x[0];
            if (D <= x[0] - xmin)
                *d = 2 * D;
270
            else
271
                *d = x[1] - xmin;
272
        }
273 274
        x++;
        d++;
275
    }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
276
    state->ref = 1;
277
}
278

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
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
static uint64_t block_fs(struct aec_stream *strm, int k)
{
    /**
       Sum FS of all samples in block for given splitting position.
    */

    int j;
    uint64_t fs;
    struct internal_state *state = strm->state;

    fs = (uint64_t)(state->block[1] >> k)
        + (uint64_t)(state->block[2] >> k)
        + (uint64_t)(state->block[3] >> k)
        + (uint64_t)(state->block[4] >> k)
        + (uint64_t)(state->block[5] >> k)
        + (uint64_t)(state->block[6] >> k)
        + (uint64_t)(state->block[7] >> k);

    if (strm->block_size > 8)
        for (j = 8; j < strm->block_size; j += 8)
            fs +=
                (uint64_t)(state->block[j + 0] >> k)
                + (uint64_t)(state->block[j + 1] >> k)
                + (uint64_t)(state->block[j + 2] >> k)
                + (uint64_t)(state->block[j + 3] >> k)
                + (uint64_t)(state->block[j + 4] >> k)
                + (uint64_t)(state->block[j + 5] >> k)
                + (uint64_t)(state->block[j + 6] >> k)
                + (uint64_t)(state->block[j + 7] >> k);

    if (!state->ref)
        fs += (uint64_t)(state->block[0] >> k);

    return fs;
}

static int assess_splitting_option(struct aec_stream *strm)
{
    /**
       Length of CDS encoded with splitting option and optimal k.

       In Rice coding each sample in a block of samples is split at
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
321
       the same position into k LSB and bits_per_sample - k MSB. The
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
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
       LSB part is left binary and the MSB part is coded as a
       fundamental sequence a.k.a. unary (see CCSDS 121.0-B-2). The
       function of the length of the Coded Data Set (CDS) depending on
       k has exactly one minimum (see A. Kiely, IPN Progress Report
       42-159).

       To find that minimum with only a few costly evaluations of the
       CDS length, we start with the k of the previous CDS. K is
       increased and the CDS length evaluated. If the CDS length gets
       smaller, then we are moving towards the minimum. If the length
       increases, then the minimum will be found with smaller k.

       For increasing k we know that we will gain block_size bits in
       length through the larger binary part. If the FS lenth is less
       than the block size then a reduced FS part can't compensate the
       larger binary part. So we know that the CDS for k+1 will be
       larger than for k without actually computing the length. An
       analogue check can be done for decreasing k.
     */

    int k;
    int k_min;
    int this_bs; /* Block size of current block */
    int no_turn; /* 1 if we shouldn't reverse */
    int dir; /* Direction, 1 means increasing k, 0 decreasing k */
    uint64_t len; /* CDS length for current k */
    uint64_t len_min; /* CDS length minimum so far */
    uint64_t fs_len; /* Length of FS part (not including 1s) */

    struct internal_state *state = strm->state;

    this_bs = strm->block_size - state->ref;
    len_min = UINT64_MAX;
    k = k_min = state->k;
    no_turn = (k == 0) ? 1 : 0;
    dir = 1;

    for (;;) {
        fs_len = block_fs(strm, k);
        len = fs_len + this_bs * (k + 1);

        if (len < len_min) {
            if (len_min < UINT64_MAX)
                no_turn = 1;

            len_min = len;
            k_min = k;

            if (dir) {
                if (fs_len < this_bs || k >= state->kmax) {
                    if (no_turn)
                        break;
                    k = state->k - 1;
                    dir = 0;
                    no_turn = 1;
                } else {
                    k++;
                }
            } else {
                if (fs_len >= this_bs || k == 0)
                    break;
                k--;
            }
        } else {
            if (no_turn)
                break;
            k = state->k - 1;
            dir = 0;
            no_turn = 1;
        }
    }
    state->k = k_min;

    return len_min;
}

static int assess_se_option(uint64_t limit, struct aec_stream *strm)
{
    /**
       Length of CDS encoded with Second Extension option.

       If length is above limit just return UINT64_MAX.
    */

    int i;
    uint64_t d;
    uint64_t len;
    struct internal_state *state = strm->state;

    len = 1;

    for (i = 0; i < strm->block_size; i+= 2) {
        d = (uint64_t)state->block[i]
            + (uint64_t)state->block[i + 1];
        /* we have to worry about overflow here */
        if (d > limit) {
            len = UINT64_MAX;
            break;
        } else {
            len += d * (d + 1) / 2
                + (uint64_t)state->block[i + 1];
        }
    }
    return len;
}

428 429 430 431 432 433
/*
 *
 * FSM functions
 *
 */

434
static int m_flush_block_resumable(struct aec_stream *strm)
435
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
436
    /**
437
       Slow and restartable flushing
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
438
    */
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
439
    struct internal_state *state = strm->state;
440

441 442 443
    while(state->cds_buf + state->i < state->cds) {
        if (strm->avail_out == 0)
            return M_EXIT;
444

445 446 447 448
        *strm->next_out++ = state->cds_buf[state->i];
        strm->avail_out--;
        strm->total_out++;
        state->i++;
449
    }
450
    state->mode = m_get_block;
451
    return M_CONTINUE;
452 453
}

454
static int m_flush_block(struct aec_stream *strm)
455
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
456
    /**
457
       Flush block in direct_out mode by updating counters.
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
458

459
       Fall back to slow flushing if in buffered mode.
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
460
    */
461
    int n;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
462
    struct internal_state *state = strm->state;
463

464 465 466 467 468
    if (state->direct_out) {
        n = state->cds - strm->next_out;
        strm->next_out += n;
        strm->avail_out -= n;
        strm->total_out += n;
469 470
        state->mode = m_get_block;
        return M_CONTINUE;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
471
    }
472

473 474 475
    state->i = 0;
    state->mode = m_flush_block_resumable;
    return M_CONTINUE;
476
}
477

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
478
static int m_encode_splitting(struct aec_stream *strm)
479
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
480
    struct internal_state *state = strm->state;
481
    int k = state->k;
482

483
    emit(state, k + 1, state->id_len);
484

485
    if (state->ref)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
486
    {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
487
        emit(state, state->block[0], strm->bits_per_sample);
488
        emitblock_fs_1(strm, k);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
489 490
        if (k)
            emitblock_1(strm, k);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
491 492 493
    }
    else
    {
494
        emitblock_fs_0(strm, k);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
495 496
        if (k)
            emitblock_0(strm, k);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
497
    }
498

499 500
    return m_flush_block(strm);
}
501

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
502
static int m_encode_uncomp(struct aec_stream *strm)
503
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
504
    struct internal_state *state = strm->state;
505

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
506
    emit(state, (1U << state->id_len) - 1, state->id_len);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
507
    emitblock_0(strm, strm->bits_per_sample);
508

509 510
    return m_flush_block(strm);
}
511

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
512
static int m_encode_se(struct aec_stream *strm)
513 514
{
    int i;
515
    uint32_t d;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
516
    struct internal_state *state = strm->state;
517

518 519
    emit(state, 1, state->id_len + 1);
    if (state->ref)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
520
        emit(state, state->block[0], strm->bits_per_sample);
521

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
522
    for (i = 0; i < strm->block_size; i+= 2) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
523 524
        d = state->block[i] + state->block[i + 1];
        emitfs(state, d * (d + 1) / 2 + state->block[i + 1]);
525
    }
526

527 528
    return m_flush_block(strm);
}
529

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
530
static int m_encode_zero(struct aec_stream *strm)
531
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
532
    struct internal_state *state = strm->state;
533

534
    emit(state, 0, state->id_len + 1);
535

536
    if (state->zero_ref)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
537
        emit(state, state->zero_ref_sample, strm->bits_per_sample);
538

539 540 541 542 543 544
    if (state->zero_blocks == ROS)
        emitfs(state, 4);
    else if (state->zero_blocks >= 5)
        emitfs(state, state->zero_blocks);
    else
        emitfs(state, state->zero_blocks - 1);
545

546 547 548
    state->zero_blocks = 0;
    return m_flush_block(strm);
}
549

550
static int m_select_code_option(struct aec_stream *strm)
551
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
552
    /**
553 554
       Decide which code option to use.
    */
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
555

556 557 558 559 560 561
    uint64_t uncomp_len;
    uint64_t split_len;
    uint64_t se_len;
    struct internal_state *state = strm->state;

    uncomp_len = (strm->block_size - state->ref)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
562
        * strm->bits_per_sample;
563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585
    split_len = assess_splitting_option(strm);
    se_len = assess_se_option(split_len, strm);

    if (split_len < uncomp_len) {
        if (split_len < se_len)
            return m_encode_splitting(strm);
        else
            return m_encode_se(strm);
    } else {
        if (uncomp_len <= se_len)
            return m_encode_uncomp(strm);
        else
            return m_encode_se(strm);
    }
}

static int m_check_zero_block(struct aec_stream *strm)
{
    /**
       Check if input block is all zero.

       Aggregate consecutive zero blocks until we find !0 or reach the
       end of a segment or RSI.
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
586
    */
587

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
588
    struct internal_state *state = strm->state;
589 590
    uint32_t *p = state->block + state->ref;
    uint32_t *end = state->block + strm->block_size;
591

592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620
    while(p < end && *p == 0)
        p++;

    if (p < end) {
        if (state->zero_blocks) {
            /* The current block isn't zero but we have to emit a
             * previous zero block first. The current block will be
             * handled later.
             */
            state->block -= strm->block_size;
            state->blocks_avail++;
            state->mode = m_encode_zero;
            return M_CONTINUE;
        }
        state->mode = m_select_code_option;
        return M_CONTINUE;
    } else {
        state->zero_blocks++;
        if (state->zero_blocks == 1) {
            state->zero_ref = state->ref;
            state->zero_ref_sample = state->block[0];
        }
        if (state->blocks_avail == 0
            || (strm->rsi - state->blocks_avail) % 64 == 0) {
            if (state->zero_blocks > 4)
                state->zero_blocks = ROS;
            state->mode = m_encode_zero;
            return M_CONTINUE;
        }
621 622 623
        state->mode = m_get_block;
        return M_CONTINUE;
    }
624
}
625

626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653
static int m_get_rsi_resumable(struct aec_stream *strm)
{
    /**
       Get RSI while input buffer is short.

       Let user provide more input. Once we got all input pad buffer
       to full RSI.
    */

    int j;
    struct internal_state *state = strm->state;

    do {
        if (strm->avail_in > 0) {
            state->data_raw[state->i] = state->get_sample(strm);
        } else {
            if (state->flush == AEC_FLUSH) {
                if (state->i > 0) {
                    for (j = state->i; j < strm->rsi * strm->block_size; j++)
                        state->data_raw[j] = state->data_raw[state->i - 1];
                    state->i = strm->rsi * strm->block_size;
                } else {
                    if (state->zero_blocks) {
                        state->mode = m_encode_zero;
                        return M_CONTINUE;
                    }

                    emit(state, 0, state->bits);
654
                    if (strm->avail_out > 0) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
655
                        if (!state->direct_out)
656 657 658 659
                            *strm->next_out++ = *state->cds;
                        strm->avail_out--;
                        strm->total_out++;
                    }
660 661 662 663 664 665 666 667
                    return M_EXIT;
                }
            } else {
                return M_EXIT;
            }
        }
    } while (++state->i < strm->rsi * strm->block_size);

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
668
    if (strm->flags & AEC_DATA_PREPROCESS)
669 670 671
        state->preprocess(strm);

    return m_check_zero_block(strm);
672 673
}

674
static int m_get_block(struct aec_stream *strm)
675
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
676
    /**
677 678 679 680
       Provide the next block of preprocessed input data.

       Pull in a whole Reference Sample Interval (RSI) of data if
       block buffer is empty.
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
681
    */
682

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
683
    struct internal_state *state = strm->state;
684

685 686 687 688 689 690 691 692 693 694 695 696 697 698
    if (strm->avail_out > state->cds_len) {
        if (!state->direct_out) {
            state->direct_out = 1;
            *strm->next_out = *state->cds;
            state->cds = strm->next_out;
        }
    } else {
        if (state->zero_blocks == 0 || state->direct_out) {
            /* copy leftover from last block */
            *state->cds_buf = *state->cds;
            state->cds = state->cds_buf;
        }
        state->direct_out = 0;
    }
699

700
    if (state->blocks_avail == 0) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
701
        state->blocks_avail = strm->rsi - 1;
702 703
        state->block = state->data_pp;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
704
        if (strm->avail_in >= state->rsi_len) {
705
            state->get_rsi(strm);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
706
            if (strm->flags & AEC_DATA_PREPROCESS)
707
                state->preprocess(strm);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
708

709 710 711 712 713 714 715 716 717 718
            return m_check_zero_block(strm);
        } else {
            state->i = 0;
            state->mode = m_get_rsi_resumable;
        }
    } else {
        state->ref = 0;
        state->block += strm->block_size;
        state->blocks_avail--;
        return m_check_zero_block(strm);
719 720 721 722 723 724 725 726 727
    }
    return M_CONTINUE;
}

/*
 *
 * API functions
 *
 */
728

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
729
int aec_encode_init(struct aec_stream *strm)
730
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
731
    struct internal_state *state;
732

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
733
    if (strm->bits_per_sample > 32 || strm->bits_per_sample == 0)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
734
        return AEC_CONF_ERROR;
735 736 737 738 739

    if (strm->block_size != 8
        && strm->block_size != 16
        && strm->block_size != 32
        && strm->block_size != 64)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
740
        return AEC_CONF_ERROR;
741 742

    if (strm->rsi > 4096)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
743
        return AEC_CONF_ERROR;
744

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
745
    state = malloc(sizeof(struct internal_state));
746
    if (state == NULL)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
747
        return AEC_MEM_ERROR;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
748 749

    memset(state, 0, sizeof(struct internal_state));
750 751
    strm->state = state;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
752
    if (strm->bits_per_sample > 16) {
753
        /* 24/32 input bit settings */
754 755
        state->id_len = 5;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
756
        if (strm->bits_per_sample <= 24
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
757
            && strm->flags & AEC_DATA_3BYTE) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
758
            state->rsi_len = 3;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
759
            if (strm->flags & AEC_DATA_MSB) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
760 761
                state->get_sample = aec_get_msb_24;
                state->get_rsi = aec_get_rsi_msb_24;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
762
            } else {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
763 764
                state->get_sample = aec_get_lsb_24;
                state->get_rsi = aec_get_rsi_lsb_24;
765
            }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
766
        } else {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
767
            state->rsi_len = 4;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
768
            if (strm->flags & AEC_DATA_MSB) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
769 770
                state->get_sample = aec_get_msb_32;
                state->get_rsi = aec_get_rsi_msb_32;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
771
            } else {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
772 773
                state->get_sample = aec_get_lsb_32;
                state->get_rsi = aec_get_rsi_lsb_32;
774 775
            }
        }
776
    }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
777
    else if (strm->bits_per_sample > 8) {
778 779
        /* 16 bit settings */
        state->id_len = 4;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
780
        state->rsi_len = 2;
781

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
782
        if (strm->flags & AEC_DATA_MSB) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
783 784
            state->get_sample = aec_get_msb_16;
            state->get_rsi = aec_get_rsi_msb_16;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
785
        } else {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
786 787
            state->get_sample = aec_get_lsb_16;
            state->get_rsi = aec_get_rsi_lsb_16;
788
        }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
789
    } else {
790 791
        /* 8 bit settings */
        state->id_len = 3;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
792
        state->rsi_len = 1;
793

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
794 795
        state->get_sample = aec_get_8;
        state->get_rsi = aec_get_rsi_8;
796
    }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
797
    state->rsi_len *= strm->rsi * strm->block_size;
798

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
799
    if (strm->flags & AEC_DATA_SIGNED) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
800 801
        state->xmin = -(1ULL << (strm->bits_per_sample - 1));
        state->xmax = (1ULL << (strm->bits_per_sample - 1)) - 1;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
802
        state->preprocess = preprocess_signed;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
803
    } else {
804
        state->xmin = 0;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
805
        state->xmax = (1ULL << strm->bits_per_sample) - 1;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
806
        state->preprocess = preprocess_unsigned;
807 808
    }

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
809 810
    state->kmax = (1U << state->id_len) - 3;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
811 812 813
    state->data_pp = malloc(strm->rsi
                            * strm->block_size
                            * sizeof(uint32_t));
814
    if (state->data_pp == NULL)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
815
        return AEC_MEM_ERROR;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
816

817
    if (strm->flags & AEC_DATA_PREPROCESS) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
818 819 820
        state->data_raw = malloc(strm->rsi
                                 * strm->block_size
                                 * sizeof(uint32_t));
821 822 823 824 825 826
        if (state->data_raw == NULL)
            return AEC_MEM_ERROR;
    } else {
        state->data_raw = state->data_pp;
    }

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
827
    state->block = state->data_pp;
828

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
829
    /* Largest possible CDS according to specs */
830
    state->cds_len = (5 + 64 * 32) / 8 + 3;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
831
    state->cds_buf = malloc(state->cds_len);
832
    if (state->cds_buf == NULL)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
833
        return AEC_MEM_ERROR;
834

835 836 837
    strm->total_in = 0;
    strm->total_out = 0;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
838 839 840
    state->cds = state->cds_buf;
    *state->cds = 0;
    state->bits = 8;
841 842
    state->mode = m_get_block;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
843
    return AEC_OK;
844 845
}

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
846
int aec_encode(struct aec_stream *strm, int flush)
847 848 849 850 851
{
    /**
       Finite-state machine implementation of the adaptive entropy
       encoder.
    */
852
    int n;
853 854
    struct internal_state *state = strm->state;

855 856 857 858
    state->flush = flush;

    while (state->mode(strm) == M_CONTINUE);

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
859
    if (state->direct_out) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
860
        n = state->cds - strm->next_out;
861 862 863 864
        strm->next_out += n;
        strm->avail_out -= n;
        strm->total_out += n;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
865 866
        *state->cds_buf = *state->cds;
        state->cds = state->cds_buf;
867
        state->direct_out = 0;
868
    }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
869
    return AEC_OK;
870 871
}

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
872
int aec_encode_end(struct aec_stream *strm)
873
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
874
    struct internal_state *state = strm->state;
875

876 877 878
    if (strm->flags & AEC_DATA_PREPROCESS)
        free(state->data_raw);
    free(state->data_pp);
879
    free(state->cds_buf);
880
    free(state);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
881
    return AEC_OK;
882
}
883

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
884
int aec_buffer_encode(struct aec_stream *strm)
885 886 887 888 889 890 891 892 893 894 895 896 897
{
    int status;

    status = aec_encode_init(strm);
    if (status != AEC_OK)
        return status;
    status = aec_encode(strm, AEC_FLUSH);
    if (strm->avail_in > 0 || strm->avail_out == 0)
        status = AEC_DATA_ERROR;

    aec_encode_end(strm);
    return status;
}