xref: /openbmc/qemu/qobject/qnum.c (revision 7d87775f) 
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 #include "qemu/osdep.h"
16 #include "qapi/qmp/qnum.h"
17 #include "qobject-internal.h"
18 
19 /**
20  * qnum_from_int(): Create a new QNum from an int64_t
21  *
22  * Return strong reference.
23  */
24 QNum *qnum_from_int(int64_t value)
25 {
26     QNum *qn = g_new(QNum, 1);
27 
28     qobject_init(QOBJECT(qn), QTYPE_QNUM);
29     qn->kind = QNUM_I64;
30     qn->u.i64 = value;
31 
32     return qn;
33 }
34 
35 /**
36  * qnum_from_uint(): Create a new QNum from an uint64_t
37  *
38  * Return strong reference.
39  */
40 QNum *qnum_from_uint(uint64_t value)
41 {
42     QNum *qn = g_new(QNum, 1);
43 
44     qobject_init(QOBJECT(qn), QTYPE_QNUM);
45     qn->kind = QNUM_U64;
46     qn->u.u64 = value;
47 
48     return qn;
49 }
50 
51 /**
52  * qnum_from_double(): Create a new QNum from a double
53  *
54  * Return strong reference.
55  */
56 QNum *qnum_from_double(double value)
57 {
58     QNum *qn = g_new(QNum, 1);
59 
60     qobject_init(QOBJECT(qn), QTYPE_QNUM);
61     qn->kind = QNUM_DOUBLE;
62     qn->u.dbl = value;
63 
64     return qn;
65 }
66 
67 /**
68  * qnum_get_try_int(): Get an integer representation of the number
69  *
70  * Return true on success.
71  */
72 bool qnum_get_try_int(const QNum *qn, int64_t *val)
73 {
74     switch (qn->kind) {
75     case QNUM_I64:
76         *val = qn->u.i64;
77         return true;
78     case QNUM_U64:
79         if (qn->u.u64 > INT64_MAX) {
80             return false;
81         }
82         *val = qn->u.u64;
83         return true;
84     case QNUM_DOUBLE:
85         return false;
86     }
87 
88     g_assert_not_reached();
89 }
90 
91 /**
92  * qnum_get_int(): Get an integer representation of the number
93  *
94  * assert() on failure.
95  */
96 int64_t qnum_get_int(const QNum *qn)
97 {
98     int64_t val;
99     bool success = qnum_get_try_int(qn, &val);
100     assert(success);
101     return val;
102 }
103 
104 /**
105  * qnum_get_uint(): Get an unsigned integer from the number
106  *
107  * Return true on success.
108  */
109 bool qnum_get_try_uint(const QNum *qn, uint64_t *val)
110 {
111     switch (qn->kind) {
112     case QNUM_I64:
113         if (qn->u.i64 < 0) {
114             return false;
115         }
116         *val = qn->u.i64;
117         return true;
118     case QNUM_U64:
119         *val = qn->u.u64;
120         return true;
121     case QNUM_DOUBLE:
122         return false;
123     }
124 
125     g_assert_not_reached();
126 }
127 
128 /**
129  * qnum_get_uint(): Get an unsigned integer from the number
130  *
131  * assert() on failure.
132  */
133 uint64_t qnum_get_uint(const QNum *qn)
134 {
135     uint64_t val;
136     bool success = qnum_get_try_uint(qn, &val);
137     assert(success);
138     return val;
139 }
140 
141 /**
142  * qnum_get_double(): Get a float representation of the number
143  *
144  * qnum_get_double() loses precision for integers beyond 53 bits.
145  */
146 double qnum_get_double(QNum *qn)
147 {
148     switch (qn->kind) {
149     case QNUM_I64:
150         return qn->u.i64;
151     case QNUM_U64:
152         return qn->u.u64;
153     case QNUM_DOUBLE:
154         return qn->u.dbl;
155     }
156 
157     g_assert_not_reached();
158 }
159 
160 char *qnum_to_string(QNum *qn)
161 {
162     switch (qn->kind) {
163     case QNUM_I64:
164         return g_strdup_printf("%" PRId64, qn->u.i64);
165     case QNUM_U64:
166         return g_strdup_printf("%" PRIu64, qn->u.u64);
167     case QNUM_DOUBLE:
168         /* 17 digits suffice for IEEE double */
169         return g_strdup_printf("%.17g", qn->u.dbl);
170     }
171 
172     g_assert_not_reached();
173 }
174 
175 /**
176  * qnum_is_equal(): Test whether the two QNums are equal
177  *
178  * Negative integers are never considered equal to unsigned integers,
179  * but positive integers in the range [0, INT64_MAX] are considered
180  * equal independently of whether the QNum's kind is i64 or u64.
181  *
182  * Doubles are never considered equal to integers.
183  */
184 bool qnum_is_equal(const QObject *x, const QObject *y)
185 {
186     QNum *num_x = qobject_to(QNum, x);
187     QNum *num_y = qobject_to(QNum, y);
188 
189     switch (num_x->kind) {
190     case QNUM_I64:
191         switch (num_y->kind) {
192         case QNUM_I64:
193             /* Comparison in native int64_t type */
194             return num_x->u.i64 == num_y->u.i64;
195         case QNUM_U64:
196             /* Implicit conversion of x to uin64_t, so we have to
197              * check its sign before */
198             return num_x->u.i64 >= 0 && num_x->u.i64 == num_y->u.u64;
199         case QNUM_DOUBLE:
200             return false;
201         }
202         abort();
203     case QNUM_U64:
204         switch (num_y->kind) {
205         case QNUM_I64:
206             return qnum_is_equal(y, x);
207         case QNUM_U64:
208             /* Comparison in native uint64_t type */
209             return num_x->u.u64 == num_y->u.u64;
210         case QNUM_DOUBLE:
211             return false;
212         }
213         abort();
214     case QNUM_DOUBLE:
215         switch (num_y->kind) {
216         case QNUM_I64:
217         case QNUM_U64:
218             return false;
219         case QNUM_DOUBLE:
220             /* Comparison in native double type */
221             return num_x->u.dbl == num_y->u.dbl;
222         }
223         abort();
224     }
225 
226     abort();
227 }
228 
229 /**
230  * qnum_destroy_obj(): Free all memory allocated by a
231  * QNum object
232  */
233 void qnum_destroy_obj(QObject *obj)
234 {
235     assert(obj != NULL);
236     g_free(qobject_to(QNum, obj));
237 }
238 
239 void qnum_unref(QNum *q)
240 {
241     qobject_unref(q);
242 }
243