1/*
2 * This file is part of the MicroPython project, http://micropython.org/
3 *
4 * The MIT License (MIT)
5 *
6 * Copyright (c) 2013, 2014 Damien P. George
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this software and associated documentation files (the "Software"), to deal
10 * in the Software without restriction, including without limitation the rights
11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12 * copies of the Software, and to permit persons to whom the Software is
13 * furnished to do so, subject to the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24 * THE SOFTWARE.
25 */
26
27#include "py/mpconfig.h"
28#include "py/misc.h"
29#include "py/parsenumbase.h"
30
31// find real radix base, and strip preceding '0x', '0o' and '0b'
32// puts base in *base, and returns number of bytes to skip the prefix
33size_t mp_parse_num_base(const char *str, size_t len, int *base) {
34 const byte *p = (const byte *)str;
35 if (len <= 1) {
36 goto no_prefix;
37 }
38 unichar c = *(p++);
39 if ((*base == 0 || *base == 16) && c == '0') {
40 c = *(p++);
41 if ((c | 32) == 'x') {
42 *base = 16;
43 } else if (*base == 0 && (c | 32) == 'o') {
44 *base = 8;
45 } else if (*base == 0 && (c | 32) == 'b') {
46 *base = 2;
47 } else {
48 if (*base == 0) {
49 *base = 10;
50 }
51 p -= 2;
52 }
53 } else if (*base == 8 && c == '0') {
54 c = *(p++);
55 if ((c | 32) != 'o') {
56 p -= 2;
57 }
58 } else if (*base == 2 && c == '0') {
59 c = *(p++);
60 if ((c | 32) != 'b') {
61 p -= 2;
62 }
63 } else {
64 p--;
65 no_prefix:
66 if (*base == 0) {
67 *base = 10;
68 }
69 }
70 return p - (const byte *)str;
71}
72