core.hpp 131 KB
Newer Older
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
// Copyright (c) 2020 INRA Distributed under the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

#ifndef ORG_VLEPROJECT_IRRITATOR_2020
#define ORG_VLEPROJECT_IRRITATOR_2020

#include <algorithm>
#include <limits>
#include <string_view>

#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstring>
K-H-Ismail's avatar
K-H-Ismail committed
16

Gauthier Quesnel's avatar
Gauthier Quesnel committed
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
namespace irt {

using i8 = int8_t;
using i16 = int16_t;
using i32 = int32_t;
using i64 = int64_t;
using u8 = uint8_t;
using u16 = uint16_t;
using u32 = uint32_t;
using u64 = uint64_t;
using sz = size_t;

/*****************************************************************************
 *
 * Return status of many function
 *
 ****************************************************************************/

enum class status
{
    success,

Gauthier Quesnel's avatar
Gauthier Quesnel committed
39
40
    unknown_dynamics,

Gauthier Quesnel's avatar
Gauthier Quesnel committed
41
42
43
44
45
46
47
48
49
50
51
52
53
54
    block_allocator_bad_capacity,
    block_allocator_not_enough_memory,

    head_allocator_bad_capacity,
    head_allocator_not_enough_memory,

    simulation_not_enough_model,
    simulation_not_enough_memory_message_list_allocator,
    simulation_not_enough_memory_input_port_list_allocator,
    simulation_not_enough_memory_output_port_list_allocator,

    data_array_init_capacity_error,
    data_array_not_enough_memory,

55
56
57
    data_array_archive_init_capacity_error,
    data_array_archive_not_enough_memory,

58
59
60
61
    array_init_capacity_zero,
    array_init_capacity_too_big,
    array_init_not_enough_memory,

62
63
64
65
    vector_init_capacity_zero,
    vector_init_capacity_too_big,
    vector_init_not_enough_memory,

Gauthier Quesnel's avatar
Gauthier Quesnel committed
66
67
68
69
    dynamics_unknown_id,
    dynamics_unknown_port_id,
    dynamics_not_enough_memory,

Gauthier Quesnel's avatar
Gauthier Quesnel committed
70
71
72
    model_connect_output_port_unknown,
    model_connect_input_port_unknown,
    model_connect_already_exist,
73
    model_connect_bad_dynamics,
Gauthier Quesnel's avatar
Gauthier Quesnel committed
74

75
76
77
78
79
80
81
82
    model_adder_empty_init_message,
    model_adder_bad_init_message,
    model_adder_bad_external_message,

    model_mult_empty_init_message,
    model_mult_bad_init_message,
    model_mult_bad_external_message,

Gauthier Quesnel's avatar
Gauthier Quesnel committed
83
84
85
86
    model_integrator_internal_error,
    model_integrator_output_error,
    model_integrator_running_without_x_dot,
    model_integrator_ta_with_bad_x_dot,
87
88
    model_integrator_bad_external_message,

Gauthier Quesnel's avatar
Gauthier Quesnel committed
89
90
91
92
    model_quantifier_bad_quantum_parameter,
    model_quantifier_bad_archive_length_parameter,
    model_quantifier_shifting_value_neg,
    model_quantifier_shifting_value_less_1,
93
    model_quantifier_bad_external_message,
Gauthier Quesnel's avatar
Gauthier Quesnel committed
94

95
    model_cross_bad_external_message,
K-H-Ismail's avatar
K-H-Ismail committed
96
97

    model_time_func_bad_init_message,
Gauthier Quesnel's avatar
Gauthier Quesnel committed
98

K-H-Ismail's avatar
K-H-Ismail committed
99
100
    model_accumulator_bad_external_message,

101
    gui_not_enough_memory,
Gauthier Quesnel's avatar
Gauthier Quesnel committed
102
103
104
105
106
107
108
109

    io_file_format_error,
    io_file_format_model_error,
    io_file_format_model_number_error,
    io_file_format_model_unknown,
    io_file_format_dynamics_unknown,
    io_file_format_dynamics_limit_reach,
    io_file_format_dynamics_init_error
Gauthier Quesnel's avatar
Gauthier Quesnel committed
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
};

constexpr bool
is_success(status s) noexcept
{
    return s == status::success;
}

constexpr bool
is_bad(status s) noexcept
{
    return s != status::success;
}

template<typename... Args>
constexpr bool
is_status_equal(status s, Args... args) noexcept
{
    return ((s == args) || ... || false);
}

131
132
template<typename T, typename... Args>
constexpr bool
133
match(const T& s, Args... args) noexcept
134
135
136
137
{
    return ((s == args) || ... || false);
}

Gauthier Quesnel's avatar
Gauthier Quesnel committed
138
#ifndef NDEBUG
Gauthier Quesnel's avatar
Gauthier Quesnel committed
139
#if (defined(__i386__) || defined(__x86_64__)) && defined(__GNUC__) &&         \
140
  __GNUC__ >= 2
Gauthier Quesnel's avatar
Gauthier Quesnel committed
141
142
143
#define irt_breakpoint()                                                       \
    do {                                                                       \
        __asm__ __volatile__("int $03");                                       \
144
145
    } while (0)
#elif (defined(_MSC_VER) || defined(__DMC__)) && defined(_M_IX86)
Gauthier Quesnel's avatar
Gauthier Quesnel committed
146
147
148
#define irt_breakpoint()                                                       \
    do {                                                                       \
        __asm int 3h                                                           \
149
150
    } while (0)
#elif defined(_MSC_VER)
Gauthier Quesnel's avatar
Gauthier Quesnel committed
151
152
153
#define irt_breakpoint()                                                       \
    do {                                                                       \
        __debugbreak();                                                        \
154
    } while (0)
Gauthier Quesnel's avatar
Gauthier Quesnel committed
155
#elif defined(__alpha__) && !defined(__osf__) && defined(__GNUC__) &&          \
156
  __GNUC__ >= 2
Gauthier Quesnel's avatar
Gauthier Quesnel committed
157
158
159
#define irt_breakpoint()                                                       \
    do {                                                                       \
        __asm__ __volatile__("bpt");                                           \
160
161
    } while (0)
#elif defined(__APPLE__)
Gauthier Quesnel's avatar
Gauthier Quesnel committed
162
163
164
#define irt_breakpoint()                                                       \
    do {                                                                       \
        __builtin_trap();                                                      \
165
166
    } while (0)
#else /* !__i386__ && !__alpha__ */
Gauthier Quesnel's avatar
Gauthier Quesnel committed
167
168
169
#define irt_breakpoint()                                                       \
    do {                                                                       \
        raise(SIGTRAP);                                                        \
170
171
    } while (0)
#endif /* __i386__ */
Gauthier Quesnel's avatar
Gauthier Quesnel committed
172
#else
Gauthier Quesnel's avatar
Gauthier Quesnel committed
173
174
#define irt_breakpoint()                                                       \
    do {                                                                       \
175
    } while (0)
Gauthier Quesnel's avatar
Gauthier Quesnel committed
176
177
#endif

Gauthier Quesnel's avatar
Gauthier Quesnel committed
178
179
180
181
#define irt_bad_return(status__)                                               \
    do {                                                                       \
        irt_breakpoint();                                                      \
        return status__;                                                       \
182
183
    } while (0)

Gauthier Quesnel's avatar
Gauthier Quesnel committed
184
#define irt_return_if_bad(expr__)                                              \
Gauthier Quesnel's avatar
Gauthier Quesnel committed
185
    do {                                                                       \
Gauthier Quesnel's avatar
Gauthier Quesnel committed
186
        auto status__ = (expr__);                                              \
Gauthier Quesnel's avatar
Gauthier Quesnel committed
187
188
189
190
        if (status__ != status::success) {                                     \
            irt_breakpoint();                                                  \
            return status__;                                                   \
        }                                                                      \
191
192
    } while (0)

Gauthier Quesnel's avatar
Gauthier Quesnel committed
193
194
195
196
197
198
#define irt_return_if_fail(expr__, status__)                                   \
    do {                                                                       \
        if (!(expr__)) {                                                       \
            irt_breakpoint();                                                  \
            return status__;                                                   \
        }                                                                      \
199
    } while (0)
Gauthier Quesnel's avatar
Gauthier Quesnel committed
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

inline status
check_return(status s) noexcept
{
    if (s != status::success)
        irt_breakpoint();

    return s;
}

/*****************************************************************************
 *
 * Definition of Time
 *
 * TODO:
 * - enable template definition of float or [float|double,bool absolute]
 *   representation of time?
 *
 ****************************************************************************/

using time = double;

template<typename T>
struct time_domain
{};

template<>
struct time_domain<time>
{
    using time_type = time;

    static constexpr const double infinity =
      std::numeric_limits<double>::infinity();
    static constexpr const double negative_infinity =
      -std::numeric_limits<double>::infinity();
    static constexpr const double zero = 0;

237
    static constexpr bool is_infinity(time t) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
238
239
240
241
    {
        return t == infinity || t == negative_infinity;
    }

242
    static constexpr bool is_zero(time t) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
    {
        return t == zero;
    }
};

/*****************************************************************************
 *
 * Small string
 *
 ****************************************************************************/

template<size_t length = 8>
class small_string
{
    char buffer_[length];
    u8 size_;

public:
Gauthier Quesnel's avatar
Gauthier Quesnel committed
261
262
    using iterator = char*;
    using const_iterator = const char*;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
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
    using size_type = u8;

    static_assert(length > size_t{ 1 } && length < size_t{ 254 });

    constexpr small_string() noexcept
    {
        clear();
    }

    constexpr small_string(const small_string& str) noexcept
    {
        std::copy_n(str.buffer_, str.size_, buffer_);
        buffer_[str.size_] = '\0';
        size_ = str.size_;
    }

    constexpr small_string(small_string&& str) noexcept
    {
        std::copy_n(str.buffer_, str.size_, buffer_);
        buffer_[str.size_] = '\0';
        size_ = str.size_;
        str.clear();
    }

    constexpr small_string& operator=(const small_string& str) noexcept
    {
        if (&str != this) {
            std::copy_n(str.buffer_, str.size_, buffer_);
            buffer_[str.size_] = '\0';
            size_ = str.size_;
        }

        return *this;
    }

    constexpr small_string& operator=(small_string&& str) noexcept
    {
        if (&str != this) {
            std::copy_n(str.buffer_, str.size_, buffer_);
            buffer_[str.size_] = '\0';
            size_ = str.size_;
        }

        return *this;
    }

    constexpr small_string(const char* str) noexcept
    {
        std::strncpy(buffer_, str, length - 1);
        buffer_[length - 1] = '\0';
        size_ = static_cast<u8>(std::strlen(buffer_));
    }

    constexpr small_string(const std::string_view str) noexcept
    {
        assign(str);
    }

    constexpr bool empty() const noexcept
    {
        constexpr unsigned char zero{ 0 };

        return zero == size_;
    }

Gauthier Quesnel's avatar
Gauthier Quesnel committed
328
329
    constexpr void size(std::size_t sz) noexcept
    {
330
331
        size_ = static_cast<u8>(std::min(sz, length - 1));
        buffer_[size_] = '\0';
Gauthier Quesnel's avatar
Gauthier Quesnel committed
332
333
    }

Gauthier Quesnel's avatar
Gauthier Quesnel committed
334
335
336
337
338
339
340
    constexpr std::size_t size() const noexcept
    {
        return size_;
    }

    constexpr std::size_t capacity() const noexcept
    {
341
        return length;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
342
343
344
345
    }

    constexpr void assign(const std::string_view str) noexcept
    {
346
        const size_t copy_length = std::min(str.size(), length - 1);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
347
348

        std::memcpy(buffer_, str.data(), copy_length);
349
350
351
        buffer_[copy_length] = '\0';

        size_ = static_cast<unsigned char>(copy_length);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
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
    }

    constexpr std::string_view sv() const noexcept
    {
        return { buffer_, size_ };
    }

    constexpr void append(const std::string_view str) noexcept
    {
        const size_t remaining = length - size_;

        if (remaining) {
            size_t copy = std::min(remaining - 1, str.size());
            std::strncpy(buffer_ + size_, str.data(), copy);
            copy += size_;
            size_ = static_cast<unsigned char>(copy);
            assert(size_ < length);

            buffer_[size_] = '\0';
        }
    }

    constexpr void clear() noexcept
    {
        std::fill_n(buffer_, length, '\0');
        size_ = 0;
    }

    constexpr const char* c_str() const noexcept
    {
        return buffer_;
    }

Gauthier Quesnel's avatar
Gauthier Quesnel committed
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
    constexpr iterator begin() noexcept
    {
        return buffer_;
    }

    constexpr iterator end() noexcept
    {
        return buffer_ + size_;
    }

    constexpr const_iterator begin() const noexcept
    {
        return buffer_;
    }

    constexpr const_iterator end() const noexcept
    {
        return buffer_ + size_;
    }

Gauthier Quesnel's avatar
Gauthier Quesnel committed
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
    constexpr bool operator==(const small_string& rhs) const noexcept
    {
        return std::strncmp(buffer_, rhs.buffer_, length) == 0;
    }

    constexpr bool operator!=(const small_string& rhs) const noexcept
    {
        return std::strncmp(buffer_, rhs.buffer_, length) != 0;
    }

    constexpr bool operator>(const small_string& rhs) const noexcept
    {
        return std::strncmp(buffer_, rhs.buffer_, length) > 0;
    }

    constexpr bool operator<(const small_string& rhs) const noexcept
    {
        return std::strncmp(buffer_, rhs.buffer_, length) < 0;
    }

    constexpr bool operator==(const char* rhs) const noexcept
    {
        return std::strncmp(buffer_, rhs, length) == 0;
    }

    constexpr bool operator!=(const char* rhs) const noexcept
    {
        return std::strncmp(buffer_, rhs, length) != 0;
    }

    constexpr bool operator>(const char* rhs) const noexcept
    {
        return std::strncmp(buffer_, rhs, length) > 0;
    }

    constexpr bool operator<(const char* rhs) const noexcept
    {
        return std::strncmp(buffer_, rhs, length) < 0;
    }
};

/*****************************************************************************
 *
448
 * value
Gauthier Quesnel's avatar
Gauthier Quesnel committed
449
450
451
 *
 ****************************************************************************/

452
enum class value_type : i8
Gauthier Quesnel's avatar
Gauthier Quesnel committed
453
{
454
455
456
457
458
459
460
    none,
    integer_8,
    integer_32,
    integer_64,
    real_32,
    real_64
};
Gauthier Quesnel's avatar
Gauthier Quesnel committed
461

462
463
template<typename T, size_t length>
struct span
Gauthier Quesnel's avatar
Gauthier Quesnel committed
464
{
465
466
467
468
469
470
471
472
public:
    using value_type = T;
    using difference_type = std::ptrdiff_t;
    using pointer = T*;
    using reference = T&;
    using const_reference = T&;
    using iterator = T*;
    using const_iterator = const T*;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
473

474
475
private:
    const T* data_;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
476

477
478
479
480
public:
    constexpr span(const T* ptr)
      : data_(ptr)
    {}
Gauthier Quesnel's avatar
Gauthier Quesnel committed
481

482
483
484
485
    constexpr T* data() noexcept
    {
        return data_;
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
486

487
488
489
490
    constexpr const T* data() const noexcept
    {
        return data_;
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
491

492
493
494
495
    constexpr size_t size() const noexcept
    {
        return length;
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
496

497
498
499
500
501
    constexpr T operator[](size_t i) const noexcept
    {
        assert(i < length);
        return data_[i];
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
502

503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
    constexpr iterator begin() noexcept
    {
        return iterator{ data_ };
    }

    constexpr iterator end() noexcept
    {
        return iterator{ data_ + length };
    }

    constexpr const_iterator begin() const noexcept
    {
        return iterator{ data_ };
    }

    constexpr const_iterator end() const noexcept
    {
        return iterator{ data_ + length };
    }
};

template<class T, class... Rest>
constexpr bool
are_all_same() noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
527
{
528
    return (std::is_same_v<T, Rest> && ...);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
529
530
}

531
struct message
Gauthier Quesnel's avatar
Gauthier Quesnel committed
532
{
533
534
    using size_type = std::size_t;
    using difference_type = std::ptrdiff_t;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
535

536
    union
Gauthier Quesnel's avatar
Gauthier Quesnel committed
537
    {
538
539
540
541
542
        i8 integer_8[32];  // 32 bytes
        i32 integer_32[8]; // 8 * 4 bytes
        i64 integer_64[4]; // 4 * 8 bytes
        float real_32[8];  // 8 * 4 bytes
        double real_64[4]; // 4 * 8 bytes
Gauthier Quesnel's avatar
Gauthier Quesnel committed
543
544
    };

545
546
    u8 length;
    value_type type;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
547

548
549
550
551
    constexpr std::size_t size() const noexcept
    {
        return length;
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
552

553
554
555
556
557
    constexpr message() noexcept
      : integer_8{ 0 }
      , length{ 0 }
      , type{ value_type::none }
    {}
Gauthier Quesnel's avatar
Gauthier Quesnel committed
558

559
560
    template<typename... T>
    constexpr message(T... args) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
561
    {
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
        if constexpr (are_all_same<i8, T...>()) {
            static_assert(sizeof...(args) <= 32, "i8 message limited to 32");
            using unused = i8[];
            length = 0;
            (void)unused{ i8(0), (integer_8[length++] = args, i8(0))... };
            type = value_type::integer_8;
        } else if constexpr (are_all_same<i32, T...>()) {
            static_assert(sizeof...(args) <= 8, "i32 message limited to 32");
            using unused = i32[];
            length = 0;
            (void)unused{ i32(0), (integer_32[length++] = args, i32(0))... };
            type = value_type::integer_32;
        } else if constexpr (are_all_same<i64, T...>()) {
            static_assert(sizeof...(args) <= 4, "i64 message limited to 32");
            using unused = i64[];
            length = 0;
            (void)unused{ i64(0), (integer_64[length++] = args, i64(0))... };
            type = value_type::integer_64;
        } else if constexpr (are_all_same<float, T...>()) {
            static_assert(sizeof...(args) <= 8, "float message limited to 8");
            using unused = float[];
            length = 0;
            (void)unused{ 0.0f, (real_32[length++] = args, 0.0f)... };
            type = value_type::real_32;
            return;
        } else if constexpr (are_all_same<double, T...>()) {
            static_assert(sizeof...(args) <= 4, "double message limited to 4");
            using unused = double[];
            length = 0;
            (void)unused{ 0.0, (real_64[length++] = args, 0.0)... };
            type = value_type::real_64;
        }
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
595

596
597
598
599
    constexpr span<i8, 32> to_integer_8() const
    {
        assert(type == value_type::integer_8);
        return span<i8, 32>(integer_8);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
600
601
    }

602
    constexpr span<i32, 8> to_integer_32() const
Gauthier Quesnel's avatar
Gauthier Quesnel committed
603
    {
604
605
606
        assert(type == value_type::integer_32);
        return span<i32, 8>(integer_32);
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
607

608
609
610
611
612
    constexpr span<i64, 4> to_integer_64() const
    {
        assert(type == value_type::integer_64);
        return span<i64, 4>(integer_64);
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
613

614
615
616
617
618
    constexpr span<float, 8> to_real_32() const
    {
        assert(type == value_type::real_32);
        return span<float, 8>(real_32);
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
619

620
621
622
623
    constexpr span<double, 4> to_real_64() const
    {
        assert(type == value_type::real_64);
        return span<double, 4>(real_64);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
624
625
    }

626
627
    template<typename T>
    constexpr i8 to_integer_8(T i) const
Gauthier Quesnel's avatar
Gauthier Quesnel committed
628
    {
629
        static_assert(std::is_integral_v<T>, "need [unsigned] integer");
Gauthier Quesnel's avatar
Gauthier Quesnel committed
630

631
632
633
634
635
636
637
        if constexpr (std::is_signed_v<T>)
            assert(i >= 0);

        assert(type == value_type::integer_8);
        assert(i < static_cast<T>(length));

        return integer_8[i];
Gauthier Quesnel's avatar
Gauthier Quesnel committed
638
639
    }

640
641
    template<typename T>
    constexpr i32 to_integer_32(T i) const
Gauthier Quesnel's avatar
Gauthier Quesnel committed
642
    {
643
        static_assert(std::is_integral_v<T>, "need [unsigned] integer");
Gauthier Quesnel's avatar
Gauthier Quesnel committed
644

645
646
        if constexpr (std::is_signed_v<T>)
            assert(i >= 0);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
647

648
649
        assert(type == value_type::integer_32);
        assert(i < static_cast<T>(length));
Gauthier Quesnel's avatar
Gauthier Quesnel committed
650

651
652
        return integer_32[i];
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
653

654
655
656
657
    template<typename T>
    constexpr i64 to_integer_64(T i) const
    {
        static_assert(std::is_integral_v<T>, "need [unsigned] integer");
Gauthier Quesnel's avatar
Gauthier Quesnel committed
658

659
660
        if constexpr (std::is_signed_v<T>)
            assert(i >= 0);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
661

662
663
664
665
        assert(type == value_type::integer_64);
        assert(i < static_cast<T>(length));

        return integer_64[i];
Gauthier Quesnel's avatar
Gauthier Quesnel committed
666
667
    }

668
669
    template<typename T>
    constexpr float to_real_32(T i) const
Gauthier Quesnel's avatar
Gauthier Quesnel committed
670
    {
671
        static_assert(std::is_integral_v<T>, "need [unsigned] integer");
Gauthier Quesnel's avatar
Gauthier Quesnel committed
672

673
674
        if constexpr (std::is_signed_v<T>)
            assert(i >= 0);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
675

676
677
        assert(type == value_type::real_32);
        assert(i < static_cast<T>(length));
Gauthier Quesnel's avatar
Gauthier Quesnel committed
678

679
680
        return real_32[i];
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
681

682
683
684
685
    template<typename T>
    constexpr double to_real_64(T i) const
    {
        static_assert(std::is_integral_v<T>, "need [unsigned] integer");
Gauthier Quesnel's avatar
Gauthier Quesnel committed
686

687
688
        if constexpr (std::is_signed_v<T>)
            assert(i >= 0);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
689

690
691
692
693
        assert(type == value_type::real_64);
        assert(i < static_cast<T>(length));

        return real_64[i];
Gauthier Quesnel's avatar
Gauthier Quesnel committed
694
    }
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712

    template<typename T>
    constexpr double cast_to_real_64(T i) const
    {
        if constexpr (std::is_signed_v<T>)
            assert(i >= 0);

        switch (type) {
        case value_type::integer_8:
            return static_cast<double>(to_integer_8(i));
        case value_type::integer_32:
            return static_cast<double>(to_integer_32(i));
        case value_type::integer_64:
            return static_cast<double>(to_integer_64(i));
        case value_type::real_32:
            return static_cast<double>(to_real_32(i));
        case value_type::real_64:
            return static_cast<double>(to_real_64(i));
Gauthier Quesnel's avatar
Gauthier Quesnel committed
713
714
        default:
            return 0.0;
715
716
717
718
        }

        return 0.0;
    }
719
};
Gauthier Quesnel's avatar
Gauthier Quesnel committed
720

721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
/*****************************************************************************
 *
 * Flat list
 *
 ****************************************************************************/

template<typename T>
class block_allocator
{
public:
    static_assert(std::is_trivially_destructible_v<T>,
                  "block_allocator is only for POD object");

    using value_type = T;

    union block
Gauthier Quesnel's avatar
Gauthier Quesnel committed
737
    {
738
739
740
        block* next;
        typename std::aligned_storage<sizeof(T), alignof(T)>::type storage;
    };
Gauthier Quesnel's avatar
Gauthier Quesnel committed
741

742
private:
Gauthier Quesnel's avatar
Gauthier Quesnel committed
743
    block* blocks{ nullptr };    // contains all preallocated blocks
744
745
746
747
    block* free_head{ nullptr }; // a free list
    sz size{ 0 };                // number of active elements allocated
    sz max_size{ 0 }; // number of elements allocated (with free_head)
    sz capacity{ 0 }; // capacity of the allocator
Gauthier Quesnel's avatar
Gauthier Quesnel committed
748

749
750
public:
    block_allocator() = default;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
751

752
753
    block_allocator(const block_allocator&) = delete;
    block_allocator& operator=(const block_allocator&) = delete;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
754

755
756
757
758
    ~block_allocator() noexcept
    {
        if (blocks)
            std::free(blocks);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
759
760
    }

761
    status init(std::size_t new_capacity) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
762
    {
763
764
        if (new_capacity == 0)
            return status::block_allocator_bad_capacity;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
765

766
767
768
769
770
771
772
773
        if (new_capacity != capacity) {
            if (blocks)
                std::free(blocks);
            blocks =
              static_cast<block*>(std::malloc(new_capacity * sizeof(block)));
            if (blocks == nullptr)
                return status::block_allocator_not_enough_memory;
        }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
774

775
776
777
778
        size = 0;
        max_size = 0;
        capacity = new_capacity;
        free_head = nullptr;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
779

780
        return status::success;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
781
782
    }

783
    void reset() noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
784
    {
785
786
787
788
789
        if (capacity > 0) {
            size = 0;
            max_size = 0;
            free_head = nullptr;
        }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
790
791
    }

792
    std::pair<bool, T*> try_alloc() noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
793
    {
794
795
        if (free_head == nullptr && max_size >= capacity)
            return { false, nullptr };
Gauthier Quesnel's avatar
Gauthier Quesnel committed
796

797
        return { true, alloc() };
Gauthier Quesnel's avatar
Gauthier Quesnel committed
798
799
    }

800
    T* alloc() noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
801
    {
802
803
804
805
806
807
808
809
810
        ++size;
        block* new_block = nullptr;

        if (free_head != nullptr) {
            new_block = free_head;
            free_head = free_head->next;
        } else {
            assert(max_size < capacity);
            new_block = reinterpret_cast<block*>(&blocks[max_size++]);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
811
812
        }

813
        return reinterpret_cast<T*>(new_block);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
814
815
    }

816
    void free(T* n) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
817
    {
818
        assert(n);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
819

820
        block* ptr = reinterpret_cast<block*>(n);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
821

822
823
        ptr->next = free_head;
        free_head = ptr;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
824

825
        --size;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
826

827
828
829
830
        if (size == 0) {         // A special part: if it no longer exists
            max_size = 0;        // we reset the free list and the number
            free_head = nullptr; // of elements allocated.
        }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
831
    }
832
};
Gauthier Quesnel's avatar
Gauthier Quesnel committed
833

834
835
836
837
838
template<typename T>
class flat_list
{
public:
    struct node_type
Gauthier Quesnel's avatar
Gauthier Quesnel committed
839
    {
840
841
842
        T value;
        node_type* next = nullptr;
    };
Gauthier Quesnel's avatar
Gauthier Quesnel committed
843

844
845
846
847
public:
    using allocator_type = block_allocator<node_type>;
    using value_type = T;
    using reference = T&;
848
    using const_reference = const T&;
849
    using pointer = T*;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
850

851
    class iterator
Gauthier Quesnel's avatar
Gauthier Quesnel committed
852
    {
853
854
    private:
        node_type* node{ nullptr };
Gauthier Quesnel's avatar
Gauthier Quesnel committed
855

856
857
858
859
860
861
    public:
        using iterator_category = std::forward_iterator_tag;
        using value_type = T;
        using pointer = T*;
        using reference = T&;
        using difference_type = std::ptrdiff_t;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
862

863
        iterator() noexcept = default;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
864

865
866
867
        iterator(node_type* n) noexcept
          : node(n)
        {}
Gauthier Quesnel's avatar
Gauthier Quesnel committed
868

869
870
871
        iterator(const iterator& other) noexcept
          : node(other.node)
        {}
Gauthier Quesnel's avatar
Gauthier Quesnel committed
872

873
874
875
876
877
        iterator& operator=(const iterator& other) noexcept
        {
            node = other.node;
            return *this;
        }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
878

879
880
881
882
        T& operator*() noexcept
        {
            return node->value;
        }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
883

884
885
886
887
        T* operator->() noexcept
        {
            return &node->value;
        }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
888

889
890
891
892
        iterator operator++() noexcept
        {
            if (node != nullptr)
                node = node->next;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
893

894
895
            return *this;
        }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
896

897
898
899
        iterator operator++(int) noexcept
        {
            iterator tmp(*this);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
900

901
902
            if (node != nullptr)
                node = node->next;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
903

904
905
            return tmp;
        }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
906

907
908
909
910
        bool operator==(const iterator& other) const noexcept
        {
            return node == other.node;
        }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
911

912
913
914
915
        bool operator!=(const iterator& other) const noexcept
        {
            return node != other.node;
        }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
916

917
918
919
920
        void swap(iterator& other) noexcept
        {
            std::swap(node, other.node);
        }
921

Gauthier Quesnel's avatar
Gauthier Quesnel committed
922
        friend class flat_list<T>;
923
    };
Gauthier Quesnel's avatar
Gauthier Quesnel committed
924

925
    class const_iterator
Gauthier Quesnel's avatar
Gauthier Quesnel committed
926
    {
927
928
    private:
        const node_type* node{ nullptr };
Gauthier Quesnel's avatar
Gauthier Quesnel committed
929

930
931
932
933
934
935
    public:
        using iterator_category = std::forward_iterator_tag;
        using value_type = T;
        using pointer = T*;
        using reference = T&;
        using difference_type = std::ptrdiff_t;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
936

937
        const_iterator() noexcept = default;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
938

939
940
941
        const_iterator(node_type* n) noexcept
          : node(n)
        {}
Gauthier Quesnel's avatar
Gauthier Quesnel committed
942

943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
        const_iterator(const const_iterator& other) noexcept
          : node(other.node)
        {}

        const_iterator& operator=(const const_iterator& other) noexcept
        {
            node = other.node;
            return *this;
        }

        const T& operator*() noexcept
        {
            return node->value;
        }

        const T* operator->() noexcept
        {
            return &node->value;
        }

        const_iterator operator++() noexcept
        {
            if (node != nullptr)
                node = node->next;

            return *this;
        }

        const_iterator operator++(int) noexcept
        {
            const_iterator tmp(*this);

            if (node != nullptr)
                node = node->next;

            return tmp;
        }

        bool operator==(const const_iterator& other) const noexcept
        {
            return node == other.node;
        }

        bool operator!=(const const_iterator& other) const noexcept
        {
            return node != other.node;
        }

        void swap(const_iterator& other) noexcept
        {
            std::swap(node, other.node);
        }
995

Gauthier Quesnel's avatar
Gauthier Quesnel committed
996
        friend class flat_list<T>;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
997
998
    };

999
1000
1001
private:
    allocator_type* allocator{ nullptr };
    node_type* node{ nullptr };
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1002

1003
1004
public:
    flat_list() = default;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1005

1006
1007
    flat_list(allocator_type* allocator_new) noexcept
      : allocator(allocator_new)
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1008
1009
    {}

1010
1011
1012
1013
1014
1015
    flat_list(const flat_list& other) = delete;
    flat_list& operator=(const flat_list& other) = delete;

    flat_list(flat_list&& other) noexcept
      : allocator(other.allocator)
      , node(other.node)
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1016
    {
1017
1018
        other.allocator = nullptr;
        other.node = nullptr;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1019
1020
    }

1021
    void set_allocator(allocator_type* allocator_new) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1022
    {
1023
1024
1025
        clear();
        allocator = allocator_new;
        node = nullptr;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1026
1027
    }

1028
    flat_list& operator=(flat_list&& other) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1029
    {
1030
1031
1032
1033
1034
1035
1036
1037
1038
        if (this != &other) {
            clear();
            allocator = other.allocator;
            other.allocator = nullptr;
            node = other.node;
            other.node = nullptr;
        }

        return *this;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1039
1040
    }

1041
    ~flat_list() noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1042
    {
1043
        clear();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1044
1045
    }

1046
    void clear() noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1047
    {
1048
1049
1050
1051
1052
1053
1054
        node_type* prev = node;

        while (node != nullptr) {
            node = node->next;
            allocator->free(prev);
            prev = node;
        }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1055
1056
    }

1057
    bool empty() const noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1058
    {
1059
        return node == nullptr;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1060
1061
    }

1062
    iterator begin() noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1063
    {
1064
1065
        return iterator(node);
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1066

1067
1068
1069
1070
    iterator end() noexcept
    {
        return iterator(nullptr);
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1071

1072
1073
1074
1075
    const_iterator begin() const noexcept
    {
        return const_iterator(node);
    }
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1076

1077
1078
1079
    const_iterator end() const noexcept
    {
        return const_iterator(nullptr);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1080
1081
    }

1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
    reference front() noexcept
    {
        assert(!empty());

        return node->value;
    }

    const_reference front() const noexcept
    {
        assert(!empty());

        return node->value;
    }

1096
1097
    template<typename... Args>
    iterator emplace_front(Args&&... args) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1098
    {
1099
        node_type* new_node = allocator->alloc();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1100

1101
        new (&new_node->value) T(std::forward<Args>(args)...);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1102

1103
1104
        new_node->next = node;
        node = new_node;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1105

1106
        return begin();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1107
1108
    }

1109
1110
    template<typename... Args>
    iterator emplace_after(iterator it, Args&&... args) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1111
    {
1112
1113
        node_type* new_node = allocator->alloc();
        new (&new_node->value) T(std::forward<Args>(args)...);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1114

1115
1116
        if (it->node == nullptr)
            return emplace_front(std::forward<Args>(args)...);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1117

1118
1119
        new_node->next = it->node->next;
        it->node->next = new_node;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1120

1121
        return iterator(new_node);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1122
1123
    }

1124
1125
    template<typename... Args>
    iterator try_emplace_front(Args&&... args) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1126
    {
1127
        auto [success, new_node] = allocator->try_alloc();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1128

1129
1130
        if (!success)
            return end();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1131

1132
        new (&new_node->value) T(std::forward<Args>(args)...);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1133

1134
1135
1136
1137
        new_node->next = node;
        node = new_node;

        return begin();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1138
1139
    }

1140
1141
    template<typename... Args>
    iterator try_emplace_after(iterator it, Args&&... args) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1142
    {
1143
        auto [success, new_node] = allocator->try_alloc();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1144

1145
1146
        if (!success)
            return end();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1147

1148
        new (&new_node->value) T(std::forward<Args>(args)...);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1149

1150
1151
        if (it->node == nullptr)
            return emplace_front(std::forward<Args>(args)...);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1152

1153
1154
        new_node->next = it->node->next;
        it->node->next = new_node;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1155

1156
        return iterator(new_node);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1157
1158
    }

1159
    void pop_front() noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1160
    {
1161
1162
        if (node == nullptr)
            return;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1163

1164
1165
        node_type* to_delete = node;
        node = node->next;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1166

1167
        if constexpr (!std::is_trivial_v<T>)
1168
            to_delete->value.~T();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1169

1170
        allocator->free(to_delete);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1171
1172
    }

1173
    iterator erase_after(iterator it) noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1174
    {
1175
        assert(allocator);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1176

1177
1178
        if (it.node == nullptr)
            return end();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1179

1180
1181
1182
        node_type* to_delete = it.node->next;
        if (to_delete == nullptr)
            return end();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1183

1184
1185
        node_type* next = to_delete->next;
        it.node->next = next;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1186

1187
        if constexpr (!std::is_trivial_v<T>)
1188
            to_delete->value.~T();
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1189

1190
        allocator->free(to_delete);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1191

1192
        return iterator(next);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1193
1194
1195
1196
    }
};

template<typename T>
1197
class flat_double_list
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1198
{
1199
private:
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1200
1201
1202
1203
    struct node_type
    {
        T value;
        node_type* next = nullptr;
1204
        node_type* prev = nullptr;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
    };

public:
    using allocator_type = block_allocator<node_type>;
    using value_type = T;
    using reference = T&;
    using pointer = T*;

    class iterator
    {
    private:
1216
        flat_double_list* list{ nullptr };
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1217
1218
1219
        node_type* node{ nullptr };

    public:
1220
        using iterator_category = std::bidirectional_iterator_tag;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1221
1222
1223
1224
1225
1226
        using value_type = T;
        using pointer = T*;
        using reference = T&;

        iterator() noexcept = default;

1227
1228
1229
        iterator(flat_double_list* lst, node_type* n) noexcept
          : list(lst)
          , node(n)
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1230
1231
1232
        {}

        iterator(const iterator& other) noexcept
1233
1234
          : list(other.list)
          , node(other.node)
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1235
1236
1237
1238
        {}

        iterator& operator=(const iterator& other) noexcept
        {
1239
            list = other.list;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1240
1241
1242
1243
1244
1245
1246
1247
1248
            node = other.node;
            return *this;
        }

        T& operator*() noexcept
        {
            return node->value;
        }

1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
        T* operator*() const noexcept
        {
            return node->value;
        }

        pointer operator->() noexcept
        {
            return &(node->value);
        }

        pointer operator->() const noexcept
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1260
1261
1262
1263
1264
1265
        {
            return &node->value;
        }

        iterator operator++() noexcept
        {
1266
            node = (node == nullptr) ? list->m_front : node->next;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1267
1268
1269
1270
1271
1272
1273
1274

            return *this;
        }

        iterator operator++(int) noexcept
        {
            iterator tmp(*this);

1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
            node = (node == nullptr) ? list->m_front : node->next;

            return tmp;
        }

        iterator operator--() noexcept
        {
            node = (node == nullptr) ? list->m_back : node->prev;

            return *this;
        }

        iterator operator--(int) noexcept
        {
            iterator tmp(*this);

            node = (node == nullptr) ? list->m_back : node->prev;
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307

            return tmp;
        }

        bool operator==(const iterator& other) const noexcept
        {
            return node == other.node;
        }

        bool operator!=(const iterator& other) const noexcept
        {
            return node != other.node;
        }

        void swap(iterator& other) noexcept
        {
1308
            std::swap(list, other.list);
Gauthier Quesnel's avatar
Gauthier Quesnel committed
1309
1310
1311
1312
1313
1314
1315
            std::swap(node, other.node);
        }
    };

    class const_iterator
    {
    private:
1316
1317
        const flat_double_list* list{ nullptr };
        node_type* node{ nullptr };