modstruct.c 7.01 KB
Newer Older
1
2
3
4
5
6
/*
 * This file is part of the Micro Python project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013, 2014 Damien P. George
7
 * Copyright (c) 2014 Paul Sokolovsky
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

28
29
#include <assert.h>
#include <string.h>
30

31
#include "py/runtime.h"
32
33
34
35
#include "py/builtin.h"
#include "py/objtuple.h"
#include "py/binary.h"
#include "py/parsenum.h"
36

37
#if MICROPY_PY_STRUCT
38

39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
/*
    This module implements most of character typecodes from CPython, with
    some extensions:

    O - (Pointer to) an arbitrary Python object. This is useful for callback
        data, etc. Note that you must keep reference to passed object in
        your Python application, otherwise it may be garbage-collected,
        and then when you get back this value from callback it may be
        invalid (and lead to crash).
    S - Pointer to a string (returned as a Python string). Note the
        difference from "Ns", - the latter says "in this place of structure
        is character data of up to N bytes length", while "S" means
        "in this place of a structure is a pointer to zero-terminated
        character data".
 */

55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
STATIC char get_fmt_type(const char **fmt) {
    char t = **fmt;
    switch (t) {
        case '!':
            t = '>';
            break;
        case '@':
        case '=':
        case '<':
        case '>':
            break;
        default:
            return '@';
    }
    // Skip type char
    (*fmt)++;
    return t;
}

74
STATIC mp_uint_t get_fmt_num(const char **p) {
75
76
77
78
79
    const char *num = *p;
    uint len = 1;
    while (unichar_isdigit(*++num)) {
        len++;
    }
80
    mp_uint_t val = (mp_uint_t)MP_OBJ_SMALL_INT_VALUE(mp_parse_num_integer(*p, len, 10, NULL));
81
82
83
84
    *p = num;
    return val;
}

85
STATIC uint calcsize_items(const char *fmt) {
86
87
88
89
90
91
92
93
    uint cnt = 0;
    while (*fmt) {
        // TODO supports size spec only for "s"
        if (!unichar_isdigit(*fmt++)) {
            cnt++;
        }
    }
    return cnt;
94
95
96
97
98
}

STATIC mp_obj_t struct_calcsize(mp_obj_t fmt_in) {
    const char *fmt = mp_obj_str_get_str(fmt_in);
    char fmt_type = get_fmt_type(&fmt);
99
    mp_uint_t size;
100
    for (size = 0; *fmt; fmt++) {
101
        mp_uint_t align = 1;
102
        mp_uint_t cnt = 1;
103
104
105
106
107
        if (unichar_isdigit(*fmt)) {
            cnt = get_fmt_num(&fmt);
        }
        if (cnt > 1) {
            // TODO: count spec support only for string len
108
109
110
            if (*fmt != 's') {
                mp_not_implemented("count>1");
            }
111
112
        }

113
        mp_uint_t sz;
114
115
116
        if (*fmt == 's') {
            sz = cnt;
        } else {
117
            sz = (mp_uint_t)mp_binary_get_size(fmt_type, *fmt, &align);
118
        }
119
        // TODO
120
        assert(sz != (mp_uint_t)-1);
121
122
        // Apply alignment
        size = (size + align - 1) & ~(align - 1);
123
124
125
126
127
128
129
130
131
132
133
134
        size += sz;
    }
    return MP_OBJ_NEW_SMALL_INT(size);
}
MP_DEFINE_CONST_FUN_OBJ_1(struct_calcsize_obj, struct_calcsize);

STATIC mp_obj_t struct_unpack(mp_obj_t fmt_in, mp_obj_t data_in) {
    // TODO: "The buffer must contain exactly the amount of data required by the format (len(bytes) must equal calcsize(fmt))."
    const char *fmt = mp_obj_str_get_str(fmt_in);
    char fmt_type = get_fmt_type(&fmt);
    uint size = calcsize_items(fmt);
    mp_obj_tuple_t *res = mp_obj_new_tuple(size, NULL);
135
    mp_buffer_info_t bufinfo;
136
    mp_get_buffer_raise(data_in, &bufinfo, MP_BUFFER_READ);
137
138
139
    byte *p = bufinfo.buf;

    for (uint i = 0; i < size; i++) {
140
        mp_uint_t sz = 1;
141
142
143
144
145
        if (unichar_isdigit(*fmt)) {
            sz = get_fmt_num(&fmt);
        }
        if (sz > 1) {
            // TODO: size spec support only for string len
146
147
148
            if (*fmt != 's') {
                mp_not_implemented("count>1");
            }
149
150
151
152
153
154
155
156
157
        }
        mp_obj_t item;
        if (*fmt == 's') {
            item = mp_obj_new_bytes(p, sz);
            p += sz;
            fmt++;
        } else {
            item = mp_binary_get_val(fmt_type, *fmt++, &p);
        }
158
159
160
161
162
163
        res->items[i] = item;
    }
    return res;
}
MP_DEFINE_CONST_FUN_OBJ_2(struct_unpack_obj, struct_unpack);

164
STATIC mp_obj_t struct_pack(mp_uint_t n_args, const mp_obj_t *args) {
165
166
167
    // TODO: "The arguments must match the values required by the format exactly."
    const char *fmt = mp_obj_str_get_str(args[0]);
    char fmt_type = get_fmt_type(&fmt);
168
    mp_int_t size = MP_OBJ_SMALL_INT_VALUE(struct_calcsize(args[0]));
169
170
171
    vstr_t vstr;
    vstr_init_len(&vstr, size);
    byte *p = (byte*)vstr.buf;
172
173
    memset(p, 0, size);

174
    for (mp_uint_t i = 1; i < n_args; i++) {
175
        mp_uint_t sz = 1;
176
177
178
179
180
        if (unichar_isdigit(*fmt)) {
            sz = get_fmt_num(&fmt);
        }
        if (sz > 1) {
            // TODO: size spec support only for string len
181
182
183
            if (*fmt != 's') {
                mp_not_implemented("count>1");
            }
184
185
186
187
188
        }

        if (*fmt == 's') {
            mp_buffer_info_t bufinfo;
            mp_get_buffer_raise(args[i], &bufinfo, MP_BUFFER_READ);
189
            mp_uint_t to_copy = sz;
190
191
192
193
194
195
196
197
198
199
            if (bufinfo.len < to_copy) {
                to_copy = bufinfo.len;
            }
            memcpy(p, bufinfo.buf, to_copy);
            memset(p + to_copy, 0, sz - to_copy);
            p += sz;
            fmt++;
        } else {
            mp_binary_set_val(fmt_type, *fmt++, args[i], &p);
        }
200
    }
201
202

    return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
203
}
204
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(struct_pack_obj, 1, MP_OBJ_FUN_ARGS_MAX, struct_pack);
205

206
STATIC const mp_map_elem_t mp_module_struct_globals_table[] = {
207
    { MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR_ustruct) },
208
    { MP_OBJ_NEW_QSTR(MP_QSTR_calcsize), (mp_obj_t)&struct_calcsize_obj },
209
    { MP_OBJ_NEW_QSTR(MP_QSTR_pack), (mp_obj_t)&struct_pack_obj },
210
211
212
    { MP_OBJ_NEW_QSTR(MP_QSTR_unpack), (mp_obj_t)&struct_unpack_obj },
};

213
STATIC MP_DEFINE_CONST_DICT(mp_module_struct_globals, mp_module_struct_globals_table);
214

215
const mp_obj_module_t mp_module_ustruct = {
216
    .base = { &mp_type_module },
217
    .name = MP_QSTR_ustruct,
218
219
220
221
    .globals = (mp_obj_dict_t*)&mp_module_struct_globals,
};

#endif