Merge remote-tracking branch 'remotes/vivier2/tags/trivial-branch-for-5.2-pull-reques...
[qemu.git] / include / qapi / qmp / qnum.h
1 /*
2 * QNum Module
3 *
4 * Copyright (C) 2009 Red Hat Inc.
5 *
6 * Authors:
7 * Luiz Capitulino <lcapitulino@redhat.com>
8 * Anthony Liguori <aliguori@us.ibm.com>
9 * Marc-André Lureau <marcandre.lureau@redhat.com>
10 *
11 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
12 * See the COPYING.LIB file in the top-level directory.
13 */
14
15 #ifndef QNUM_H
16 #define QNUM_H
17
18 #include "qapi/qmp/qobject.h"
19
20 typedef enum {
21 QNUM_I64,
22 QNUM_U64,
23 QNUM_DOUBLE
24 } QNumKind;
25
26 /*
27 * QNum encapsulates how our dialect of JSON fills in the blanks left
28 * by the JSON specification (RFC 8259) regarding numbers.
29 *
30 * Conceptually, we treat number as an abstract type with three
31 * concrete subtypes: floating-point, signed integer, unsigned
32 * integer. QNum implements this as a discriminated union of double,
33 * int64_t, uint64_t.
34 *
35 * The JSON parser picks the subtype as follows. If the number has a
36 * decimal point or an exponent, it is floating-point. Else if it
37 * fits into int64_t, it's signed integer. Else if it fits into
38 * uint64_t, it's unsigned integer. Else it's floating-point.
39 *
40 * Any number can serve as double: qnum_get_double() converts under
41 * the hood.
42 *
43 * An integer can serve as signed / unsigned integer as long as it is
44 * in range: qnum_get_try_int() / qnum_get_try_uint() check range and
45 * convert under the hood.
46 */
47 struct QNum {
48 struct QObjectBase_ base;
49 QNumKind kind;
50 union {
51 int64_t i64;
52 uint64_t u64;
53 double dbl;
54 } u;
55 };
56
57 QNum *qnum_from_int(int64_t value);
58 QNum *qnum_from_uint(uint64_t value);
59 QNum *qnum_from_double(double value);
60
61 bool qnum_get_try_int(const QNum *qn, int64_t *val);
62 int64_t qnum_get_int(const QNum *qn);
63
64 bool qnum_get_try_uint(const QNum *qn, uint64_t *val);
65 uint64_t qnum_get_uint(const QNum *qn);
66
67 double qnum_get_double(QNum *qn);
68
69 char *qnum_to_string(QNum *qn);
70
71 bool qnum_is_equal(const QObject *x, const QObject *y);
72 void qnum_destroy_obj(QObject *obj);
73
74 #endif /* QNUM_H */