aboutsummaryrefslogtreecommitdiff
path: root/circuitpython/extmod/modutimeq.c
blob: 495675ad1d53e3cab7628b29cbab8fd247106748 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
// Copyright (c) 2016-2017 Paul Sokolovsky
// SPDX-FileCopyrightText: 2014 MicroPython & CircuitPython contributors (https://github.com/adafruit/circuitpython/graphs/contributors)
// SPDX-FileCopyrightText: Copyright (c) 2014 Damien P. George
//
// SPDX-License-Identifier: MIT

#include <string.h>

#include "py/objlist.h"
#include "py/runtime.h"
#include "py/smallint.h"

#include "supervisor/shared/translate.h"

#if MICROPY_PY_UTIMEQ

#define MODULO MICROPY_PY_UTIME_TICKS_PERIOD

#define DEBUG 0

// the algorithm here is modelled on CPython's heapq.py

struct qentry {
    mp_uint_t time;
    mp_uint_t id;
    mp_obj_t callback;
    mp_obj_t args;
};

typedef struct _mp_obj_utimeq_t {
    mp_obj_base_t base;
    mp_uint_t alloc;
    mp_uint_t len;
    struct qentry items[];
} mp_obj_utimeq_t;

STATIC mp_uint_t utimeq_id;

STATIC mp_obj_utimeq_t *utimeq_get_heap(mp_obj_t heap_in) {
    return MP_OBJ_TO_PTR(heap_in);
}

STATIC bool time_less_than(struct qentry *item, struct qentry *parent) {
    mp_uint_t item_tm = item->time;
    mp_uint_t parent_tm = parent->time;
    mp_uint_t res = parent_tm - item_tm;
    if (res == 0) {
        // TODO: This actually should use the same "ring" logic
        // as for time, to avoid artifacts when id's overflow.
        return item->id < parent->id;
    }
    if ((mp_int_t)res < 0) {
        res += MODULO;
    }
    return res && res < (MODULO / 2);
}

STATIC mp_obj_t utimeq_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
    mp_arg_check_num(n_args, n_kw, 1, 1, false);
    mp_uint_t alloc = mp_obj_get_int(args[0]);
    mp_obj_utimeq_t *o = m_new_obj_var(mp_obj_utimeq_t, struct qentry, alloc);
    o->base.type = type;
    memset(o->items, 0, sizeof(*o->items) * alloc);
    o->alloc = alloc;
    o->len = 0;
    return MP_OBJ_FROM_PTR(o);
}

STATIC void utimeq_heap_siftdown(mp_obj_utimeq_t *heap, mp_uint_t start_pos, mp_uint_t pos) {
    struct qentry item = heap->items[pos];
    while (pos > start_pos) {
        mp_uint_t parent_pos = (pos - 1) >> 1;
        struct qentry *parent = &heap->items[parent_pos];
        bool lessthan = time_less_than(&item, parent);
        if (lessthan) {
            heap->items[pos] = *parent;
            pos = parent_pos;
        } else {
            break;
        }
    }
    heap->items[pos] = item;
}

STATIC void utimeq_heap_siftup(mp_obj_utimeq_t *heap, mp_uint_t pos) {
    mp_uint_t start_pos = pos;
    mp_uint_t end_pos = heap->len;
    struct qentry item = heap->items[pos];
    for (mp_uint_t child_pos = 2 * pos + 1; child_pos < end_pos; child_pos = 2 * pos + 1) {
        // choose right child if it's <= left child
        if (child_pos + 1 < end_pos) {
            bool lessthan = time_less_than(&heap->items[child_pos], &heap->items[child_pos + 1]);
            if (!lessthan) {
                child_pos += 1;
            }
        }
        // bubble up the smaller child
        heap->items[pos] = heap->items[child_pos];
        pos = child_pos;
    }
    heap->items[pos] = item;
    utimeq_heap_siftdown(heap, start_pos, pos);
}

STATIC mp_obj_t mod_utimeq_heappush(size_t n_args, const mp_obj_t *args) {
    (void)n_args;
    mp_obj_t heap_in = args[0];
    mp_obj_utimeq_t *heap = utimeq_get_heap(heap_in);
    if (heap->len == heap->alloc) {
        mp_raise_IndexError(MP_ERROR_TEXT("queue overflow"));
    }
    mp_uint_t l = heap->len;
    heap->items[l].time = MP_OBJ_SMALL_INT_VALUE(args[1]);
    heap->items[l].id = utimeq_id++;
    heap->items[l].callback = args[2];
    heap->items[l].args = args[3];
    utimeq_heap_siftdown(heap, 0, heap->len);
    heap->len++;
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_utimeq_heappush_obj, 4, 4, mod_utimeq_heappush);

STATIC mp_obj_t mod_utimeq_heappop(mp_obj_t heap_in, mp_obj_t list_ref) {
    mp_obj_utimeq_t *heap = utimeq_get_heap(heap_in);
    if (heap->len == 0) {
        mp_raise_IndexError(MP_ERROR_TEXT("empty heap"));
    }
    mp_obj_list_t *ret = MP_OBJ_TO_PTR(list_ref);
    if (!mp_obj_is_type(list_ref, &mp_type_list) || ret->len < 3) {
        mp_raise_TypeError(NULL);
    }

    struct qentry *item = &heap->items[0];
    ret->items[0] = MP_OBJ_NEW_SMALL_INT(item->time);
    ret->items[1] = item->callback;
    ret->items[2] = item->args;
    heap->len -= 1;
    heap->items[0] = heap->items[heap->len];
    heap->items[heap->len].callback = MP_OBJ_NULL; // so we don't retain a pointer
    heap->items[heap->len].args = MP_OBJ_NULL;
    if (heap->len) {
        utimeq_heap_siftup(heap, 0);
    }
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_utimeq_heappop_obj, mod_utimeq_heappop);

STATIC mp_obj_t mod_utimeq_peektime(mp_obj_t heap_in) {
    mp_obj_utimeq_t *heap = utimeq_get_heap(heap_in);
    if (heap->len == 0) {
        mp_raise_IndexError(MP_ERROR_TEXT("empty heap"));
    }

    struct qentry *item = &heap->items[0];
    return MP_OBJ_NEW_SMALL_INT(item->time);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_utimeq_peektime_obj, mod_utimeq_peektime);

#if DEBUG
STATIC mp_obj_t mod_utimeq_dump(mp_obj_t heap_in) {
    mp_obj_utimeq_t *heap = utimeq_get_heap(heap_in);
    for (int i = 0; i < heap->len; i++) {
        printf(UINT_FMT "\t%p\t%p\n", heap->items[i].time,
            MP_OBJ_TO_PTR(heap->items[i].callback), MP_OBJ_TO_PTR(heap->items[i].args));
    }
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_utimeq_dump_obj, mod_utimeq_dump);
#endif

STATIC mp_obj_t utimeq_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
    mp_obj_utimeq_t *self = MP_OBJ_TO_PTR(self_in);
    switch (op) {
        case MP_UNARY_OP_BOOL:
            return mp_obj_new_bool(self->len != 0);
        case MP_UNARY_OP_LEN:
            return MP_OBJ_NEW_SMALL_INT(self->len);
        default:
            return MP_OBJ_NULL;      // op not supported
    }
}

STATIC const mp_rom_map_elem_t utimeq_locals_dict_table[] = {
    { MP_ROM_QSTR(MP_QSTR_push), MP_ROM_PTR(&mod_utimeq_heappush_obj) },
    { MP_ROM_QSTR(MP_QSTR_pop), MP_ROM_PTR(&mod_utimeq_heappop_obj) },
    { MP_ROM_QSTR(MP_QSTR_peektime), MP_ROM_PTR(&mod_utimeq_peektime_obj) },
    #if DEBUG
    { MP_ROM_QSTR(MP_QSTR_dump), MP_ROM_PTR(&mod_utimeq_dump_obj) },
    #endif
};

STATIC MP_DEFINE_CONST_DICT(utimeq_locals_dict, utimeq_locals_dict_table);

STATIC const mp_obj_type_t utimeq_type = {
    { &mp_type_type },
    .flags = MP_TYPE_FLAG_EXTENDED,
    .name = MP_QSTR_utimeq,
    .make_new = utimeq_make_new,
    .locals_dict = (void *)&utimeq_locals_dict,
    MP_TYPE_EXTENDED_FIELDS(
        .unary_op = utimeq_unary_op,
        ),
};

STATIC const mp_rom_map_elem_t mp_module_utimeq_globals_table[] = {
    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_utimeq) },
    { MP_ROM_QSTR(MP_QSTR_utimeq), MP_ROM_PTR(&utimeq_type) },
};

STATIC MP_DEFINE_CONST_DICT(mp_module_utimeq_globals, mp_module_utimeq_globals_table);

const mp_obj_module_t mp_module_utimeq = {
    .base = { &mp_type_module },
    .globals = (mp_obj_dict_t *)&mp_module_utimeq_globals,
};

#endif // MICROPY_PY_UTIMEQ