encode.c 25.7 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
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);

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
static inline void emitblock(struct aec_stream *strm, int k, int ref)
{
    /**
       Emit the k LSB of a whole block of input data.
    */

    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;
        }

        switch (p & ~ 7) {
        case 0:
            o[0] = a >> 56;
            o[1] = a >> 48;
            o[2] = a >> 40;
            o[3] = a >> 32;
            o[4] = a >> 24;
            o[5] = a >> 16;
            o[6] = a >> 8;
            o += 7;
            break;
        case 8:
            o[0] = a >> 56;
            o[1] = a >> 48;
            o[2] = a >> 40;
            o[3] = a >> 32;
            o[4] = a >> 24;
            o[5] = a >> 16;
            a >>= 8;
            o += 6;
            break;
        case 16:
            o[0] = a >> 56;
            o[1] = a >> 48;
            o[2] = a >> 40;
            o[3] = a >> 32;
            o[4] = a >> 24;
            a >>= 16;
            o += 5;
            break;
        case 24:
            o[0] = a >> 56;
            o[1] = a >> 48;
            o[2] = a >> 40;
            o[3] = a >> 32;
            a >>= 24;
            o += 4;
            break;
        case 32:
            o[0] = a >> 56;
            o[1] = a >> 48;
            o[2] = a >> 40;
            a >>= 32;
            o += 3;
            break;
        case 40:
            o[0] = a >> 56;
            o[1] = a >> 48;
            a >>= 40;
            o += 2;
            break;
        case 48:
            *o++ = a >> 56;
            a >>= 48;
            break;
        default:
            a >>= 56;
            break;
        }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
246 247
    }

248 249 250 251
    *o = a;
    state->cds = o;
    state->bits = p % 8;
}
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
252

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
253
static void preprocess_unsigned(struct aec_stream *strm)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
254
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
255 256
    /**
       Preprocess RSI of unsigned samples.
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
257 258 259

       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
260 261
    */

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
262
    uint32_t D;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
263
    struct internal_state *state = strm->state;
264 265
    const uint32_t *x = state->data_raw;
    uint32_t *d = state->data_pp;
266 267
    uint32_t xmax = state->xmax;
    uint32_t rsi = strm->rsi * strm->block_size - 1;
268

269
    *d++ = x[0];
270
    while (rsi--) {
271 272
        if (x[1] >= x[0]) {
            D = x[1] - x[0];
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
273
            if (D <= x[0])
274
                *d = 2 * D;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
275
            else
276
                *d = x[1];
277
        } else {
278
            D = x[0] - x[1];
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
279
            if (D <= xmax - x[0])
280
                *d = 2 * D - 1;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
281
            else
282
                *d = xmax - x[1];
283
        }
284
        d++;
285
        x++;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
286
    }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
287
    state->ref = 1;
288
    state->uncomp_len = (strm->block_size - 1) * strm->bits_per_sample;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
289 290
}

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
291
static void preprocess_signed(struct aec_stream *strm)
292
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
293 294 295 296
    /**
       Preprocess RSI of signed samples.
    */

297
    int64_t D;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
298
    struct internal_state *state = strm->state;
299 300
    uint32_t *d = state->data_pp;
    int32_t *x = (int32_t *)state->data_raw;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
301
    uint64_t m = 1ULL << (strm->bits_per_sample - 1);
302 303 304
    int64_t xmax = state->xmax;
    int64_t xmin = state->xmin;
    uint32_t rsi = strm->rsi * strm->block_size - 1;
305

306 307 308
    *d++ = (uint32_t)x[0];
    x[0] = (x[0] ^ m) - m;

309
    while (rsi--) {
310 311 312 313 314
        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;
315
            else
316
                *d = xmax - x[1];
317
        } else {
318 319 320
            D = (int64_t)x[1] - x[0];
            if (D <= x[0] - xmin)
                *d = 2 * D;
321
            else
322
                *d = x[1] - xmin;
323
        }
324 325
        x++;
        d++;
326
    }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
327
    state->ref = 1;
328
    state->uncomp_len = (strm->block_size - 1) * strm->bits_per_sample;
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
static uint64_t block_fs(struct aec_stream *strm, int k)
{
    /**
       Sum FS of all samples in block for given splitting position.
    */

    int i;
    uint64_t fs = 0;
    struct internal_state *state = strm->state;

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

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

    return fs;
}

358
static uint32_t assess_splitting_option(struct aec_stream *strm)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
359 360 361 362 363
{
    /**
       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
364
       the same position into k LSB and bits_per_sample - k MSB. The
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384
       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.
     */

385
    int k;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
386 387 388 389 390 391 392 393 394 395 396 397 398
    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;
399
    no_turn = k == 0;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
400 401 402
    dir = 1;

    for (;;) {
403
        fs_len = block_fs(strm, k);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
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
        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;
}

441
static uint32_t assess_se_option(struct aec_stream *strm)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
442 443 444 445
{
    /**
       Length of CDS encoded with Second Extension option.

446
       If length is above limit just return UINT32_MAX.
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
447 448 449 450
    */

    int i;
    uint64_t d;
451
    uint32_t len;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
452 453 454 455 456 457 458 459
    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 */
460 461
        if (d > state->uncomp_len) {
            len = UINT32_MAX;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
462 463
            break;
        } else {
464
            len += d * (d + 1) / 2 + state->block[i + 1];
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
465 466 467 468 469
        }
    }
    return len;
}

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
static void init_output(struct aec_stream *strm)
{
    /**
       Direct output to next_out if next_out can hold a Coded Data
       Set, use internal buffer otherwise.
    */

    struct internal_state *state = strm->state;

    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;
    }
}

495 496 497 498 499 500
/*
 *
 * FSM functions
 *
 */

501
static int m_flush_block_resumable(struct aec_stream *strm)
502
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
503
    /**
504
       Slow and restartable flushing
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
505
    */
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
506
    struct internal_state *state = strm->state;
507

508 509 510 511 512 513 514 515 516 517 518
    int n = MIN(state->cds - state->cds_buf - state->i, strm->avail_out);
    memcpy(strm->next_out, state->cds_buf + state->i, n);
    strm->next_out += n;
    strm->avail_out -= n;
    state->i += n;

    if (strm->avail_out == 0) {
        return M_EXIT;
    } else {
        state->mode = m_get_block;
        return M_CONTINUE;
519 520 521
    }
}

522
static int m_flush_block(struct aec_stream *strm)
523
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
524
    /**
525
       Flush block in direct_out mode by updating counters.
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
526

527
       Fall back to slow flushing if in buffered mode.
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
528
    */
529
    int n;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
530
    struct internal_state *state = strm->state;
531

532 533 534 535
    if (state->direct_out) {
        n = state->cds - strm->next_out;
        strm->next_out += n;
        strm->avail_out -= n;
536 537
        state->mode = m_get_block;
        return M_CONTINUE;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
538
    }
539

540 541 542
    state->i = 0;
    state->mode = m_flush_block_resumable;
    return M_CONTINUE;
543
}
544

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
545
static int m_encode_splitting(struct aec_stream *strm)
546
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
547
    struct internal_state *state = strm->state;
548
    int k = state->k;
549

550
    emit(state, k + 1, state->id_len);
551

552
    if (state->ref)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
553
    {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
554
        emit(state, state->block[0], strm->bits_per_sample);
555
        emitblock_fs_1(strm, k);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
556
        if (k)
557
            emitblock(strm, k, 1);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
558 559 560
    }
    else
    {
561
        emitblock_fs_0(strm, k);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
562
        if (k)
563
            emitblock(strm, k, 0);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
564
    }
565

566 567
    return m_flush_block(strm);
}
568

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
569
static int m_encode_uncomp(struct aec_stream *strm)
570
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
571
    struct internal_state *state = strm->state;
572

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
573
    emit(state, (1U << state->id_len) - 1, state->id_len);
574
    emitblock(strm, strm->bits_per_sample, 0);
575

576 577
    return m_flush_block(strm);
}
578

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
579
static int m_encode_se(struct aec_stream *strm)
580 581
{
    int i;
582
    uint32_t d;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
583
    struct internal_state *state = strm->state;
584

585 586
    emit(state, 1, state->id_len + 1);
    if (state->ref)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
587
        emit(state, state->block[0], strm->bits_per_sample);
588

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
589
    for (i = 0; i < strm->block_size; i+= 2) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
590 591
        d = state->block[i] + state->block[i + 1];
        emitfs(state, d * (d + 1) / 2 + state->block[i + 1]);
592
    }
593

594 595
    return m_flush_block(strm);
}
596

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
597
static int m_encode_zero(struct aec_stream *strm)
598
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
599
    struct internal_state *state = strm->state;
600

601
    emit(state, 0, state->id_len + 1);
602

603
    if (state->zero_ref)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
604
        emit(state, state->zero_ref_sample, strm->bits_per_sample);
605

606 607 608 609 610 611
    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);
612

613 614 615
    state->zero_blocks = 0;
    return m_flush_block(strm);
}
616

617
static int m_select_code_option(struct aec_stream *strm)
618
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
619
    /**
620 621
       Decide which code option to use.
    */
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
622

623 624
    uint32_t split_len;
    uint32_t se_len;
625 626 627
    struct internal_state *state = strm->state;

    split_len = assess_splitting_option(strm);
628
    se_len = assess_se_option(strm);
629

630
    if (split_len < state->uncomp_len) {
631 632 633 634 635
        if (split_len < se_len)
            return m_encode_splitting(strm);
        else
            return m_encode_se(strm);
    } else {
636
        if (state->uncomp_len <= se_len)
637 638 639 640 641 642 643 644 645 646 647 648 649
            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
650
    */
651

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
652
    struct internal_state *state = strm->state;
653 654
    uint32_t *p = state->block + state->ref;
    uint32_t *end = state->block + strm->block_size;
655

656 657 658 659 660 661 662
    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
663
             * flagged and handled later.
664
             */
665
            state->block_nonzero = 1;
666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683
            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;
        }
684 685 686
        state->mode = m_get_block;
        return M_CONTINUE;
    }
687
}
688

689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705
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.
    */

    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) {
706 707 708 709
                    do
                        state->data_raw[state->i] =
                            state->data_raw[state->i - 1];
                    while(++state->i < strm->rsi * strm->block_size);
710 711
                } else {
                    emit(state, 0, state->bits);
712
                    if (strm->avail_out > 0) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
713
                        if (!state->direct_out)
714 715 716
                            *strm->next_out++ = *state->cds;
                        strm->avail_out--;
                    }
717 718 719 720 721 722 723 724
                    return M_EXIT;
                }
            } else {
                return M_EXIT;
            }
        }
    } while (++state->i < strm->rsi * strm->block_size);

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
725
    if (strm->flags & AEC_DATA_PREPROCESS)
726 727 728
        state->preprocess(strm);

    return m_check_zero_block(strm);
729 730
}

731
static int m_get_block(struct aec_stream *strm)
732
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
733
    /**
734 735 736 737
       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
738
    */
739

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
740
    struct internal_state *state = strm->state;
741

742 743 744 745 746 747
    init_output(strm);

    if (state->block_nonzero) {
        state->block_nonzero = 0;
        state->mode = m_select_code_option;
        return M_CONTINUE;
748
    }
749

750
    if (state->blocks_avail == 0) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
751
        state->blocks_avail = strm->rsi - 1;
752 753
        state->block = state->data_pp;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
754
        if (strm->avail_in >= state->rsi_len) {
755
            state->get_rsi(strm);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
756
            if (strm->flags & AEC_DATA_PREPROCESS)
757
                state->preprocess(strm);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
758

759 760 761 762 763 764
            return m_check_zero_block(strm);
        } else {
            state->i = 0;
            state->mode = m_get_rsi_resumable;
        }
    } else {
765 766 767 768
        if (state->ref) {
            state->ref = 0;
            state->uncomp_len = strm->block_size * strm->bits_per_sample;
        }
769 770 771
        state->block += strm->block_size;
        state->blocks_avail--;
        return m_check_zero_block(strm);
772 773 774 775 776 777 778 779 780
    }
    return M_CONTINUE;
}

/*
 *
 * API functions
 *
 */
781

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
782
int aec_encode_init(struct aec_stream *strm)
783
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
784
    struct internal_state *state;
785

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
786
    if (strm->bits_per_sample > 32 || strm->bits_per_sample == 0)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
787
        return AEC_CONF_ERROR;
788 789 790 791 792

    if (strm->block_size != 8
        && strm->block_size != 16
        && strm->block_size != 32
        && strm->block_size != 64)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
793
        return AEC_CONF_ERROR;
794 795

    if (strm->rsi > 4096)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
796
        return AEC_CONF_ERROR;
797

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
798
    state = malloc(sizeof(struct internal_state));
799
    if (state == NULL)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
800
        return AEC_MEM_ERROR;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
801 802

    memset(state, 0, sizeof(struct internal_state));
803 804
    strm->state = state;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
805
    if (strm->bits_per_sample > 16) {
806
        /* 24/32 input bit settings */
807 808
        state->id_len = 5;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
809
        if (strm->bits_per_sample <= 24
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
810
            && strm->flags & AEC_DATA_3BYTE) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
811
            state->rsi_len = 3;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
812
            if (strm->flags & AEC_DATA_MSB) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
813 814
                state->get_sample = aec_get_msb_24;
                state->get_rsi = aec_get_rsi_msb_24;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
815
            } else {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
816 817
                state->get_sample = aec_get_lsb_24;
                state->get_rsi = aec_get_rsi_lsb_24;
818
            }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
819
        } else {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
820
            state->rsi_len = 4;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
821
            if (strm->flags & AEC_DATA_MSB) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
822 823
                state->get_sample = aec_get_msb_32;
                state->get_rsi = aec_get_rsi_msb_32;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
824
            } else {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
825 826
                state->get_sample = aec_get_lsb_32;
                state->get_rsi = aec_get_rsi_lsb_32;
827 828
            }
        }
829
    }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
830
    else if (strm->bits_per_sample > 8) {
831 832
        /* 16 bit settings */
        state->id_len = 4;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
833
        state->rsi_len = 2;
834

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
835
        if (strm->flags & AEC_DATA_MSB) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
836 837
            state->get_sample = aec_get_msb_16;
            state->get_rsi = aec_get_rsi_msb_16;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
838
        } else {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
839 840
            state->get_sample = aec_get_lsb_16;
            state->get_rsi = aec_get_rsi_lsb_16;
841
        }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
842
    } else {
843 844
        /* 8 bit settings */
        state->id_len = 3;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
845
        state->rsi_len = 1;
846

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
847 848
        state->get_sample = aec_get_8;
        state->get_rsi = aec_get_rsi_8;
849
    }
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
850
    state->rsi_len *= strm->rsi * strm->block_size;
851

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
852
    if (strm->flags & AEC_DATA_SIGNED) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
853 854
        state->xmin = -(1ULL << (strm->bits_per_sample - 1));
        state->xmax = (1ULL << (strm->bits_per_sample - 1)) - 1;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
855
        state->preprocess = preprocess_signed;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
856
    } else {
857
        state->xmin = 0;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
858
        state->xmax = (1ULL << strm->bits_per_sample) - 1;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
859
        state->preprocess = preprocess_unsigned;
860 861
    }

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
862 863
    state->kmax = (1U << state->id_len) - 3;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
864 865 866
    state->data_pp = malloc(strm->rsi
                            * strm->block_size
                            * sizeof(uint32_t));
867
    if (state->data_pp == NULL)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
868
        return AEC_MEM_ERROR;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
869

870
    if (strm->flags & AEC_DATA_PREPROCESS) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
871 872 873
        state->data_raw = malloc(strm->rsi
                                 * strm->block_size
                                 * sizeof(uint32_t));
874 875 876 877 878 879
        if (state->data_raw == NULL)
            return AEC_MEM_ERROR;
    } else {
        state->data_raw = state->data_pp;
    }

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
880
    state->block = state->data_pp;
881

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
882
    /* Largest possible CDS according to specs */
883
    state->cds_len = (5 + 64 * 32) / 8 + 3;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
884
    state->cds_buf = malloc(state->cds_len);
885
    if (state->cds_buf == NULL)
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
886
        return AEC_MEM_ERROR;
887

888 889 890
    strm->total_in = 0;
    strm->total_out = 0;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
891 892 893
    state->cds = state->cds_buf;
    *state->cds = 0;
    state->bits = 8;
894 895
    state->mode = m_get_block;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
896
    return AEC_OK;
897 898
}

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
899
int aec_encode(struct aec_stream *strm, int flush)
900 901 902 903 904
{
    /**
       Finite-state machine implementation of the adaptive entropy
       encoder.
    */
905
    int n;
906 907
    struct internal_state *state = strm->state;

908
    state->flush = flush;
909 910
    strm->total_in += strm->avail_in;
    strm->total_out += strm->avail_out;
911 912 913

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

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
914
    if (state->direct_out) {
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
915
        n = state->cds - strm->next_out;
916 917 918
        strm->next_out += n;
        strm->avail_out -= n;

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
919 920
        *state->cds_buf = *state->cds;
        state->cds = state->cds_buf;
921
        state->direct_out = 0;
922
    }
923 924
    strm->total_in -= strm->avail_in;
    strm->total_out -= strm->avail_out;
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
925
    return AEC_OK;
926 927
}

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
928
int aec_encode_end(struct aec_stream *strm)
929
{
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
930
    struct internal_state *state = strm->state;
931

932 933 934
    if (strm->flags & AEC_DATA_PREPROCESS)
        free(state->data_raw);
    free(state->data_pp);
935
    free(state->cds_buf);
936
    free(state);
Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
937
    return AEC_OK;
938
}
939

Mathis Rosenhauer's avatar
Mathis Rosenhauer committed
940
int aec_buffer_encode(struct aec_stream *strm)
941 942 943 944 945 946 947
{
    int status;

    status = aec_encode_init(strm);
    if (status != AEC_OK)
        return status;
    status = aec_encode(strm, AEC_FLUSH);
948
    if (strm->avail_in > 0)
949 950 951 952 953
        status = AEC_DATA_ERROR;

    aec_encode_end(strm);
    return status;
}