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 */ 75