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/error.h" 17 #include "qapi/qmp/qnum.h" 18 #include "qapi/qmp/qobject.h" 19 #include "qemu-common.h" 20 21 /** 22 * qnum_from_int(): Create a new QNum from an int64_t 23 * 24 * Return strong reference. 25 */ 26 QNum *qnum_from_int(int64_t value) 27 { 28 QNum *qn = g_new(QNum, 1); 29 30 qobject_init(QOBJECT(qn), QTYPE_QNUM); 31 qn->kind = QNUM_I64; 32 qn->u.i64 = value; 33 34 return qn; 35 } 36 37 /** 38 * qnum_from_double(): Create a new QNum from a double 39 * 40 * Return strong reference. 41 */ 42 QNum *qnum_from_double(double value) 43 { 44 QNum *qn = g_new(QNum, 1); 45 46 qobject_init(QOBJECT(qn), QTYPE_QNUM); 47 qn->kind = QNUM_DOUBLE; 48 qn->u.dbl = value; 49 50 return qn; 51 } 52 53 /** 54 * qnum_get_try_int(): Get an integer representation of the number 55 * 56 * Return true on success. 57 */ 58 bool qnum_get_try_int(const QNum *qn, int64_t *val) 59 { 60 switch (qn->kind) { 61 case QNUM_I64: 62 *val = qn->u.i64; 63 return true; 64 case QNUM_DOUBLE: 65 return false; 66 } 67 68 assert(0); 69 return false; 70 } 71 72 /** 73 * qnum_get_int(): Get an integer representation of the number 74 * 75 * assert() on failure. 76 */ 77 int64_t qnum_get_int(const QNum *qn) 78 { 79 int64_t val; 80 bool success = qnum_get_try_int(qn, &val); 81 assert(success); 82 return val; 83 } 84 85 /** 86 * qnum_get_double(): Get a float representation of the number 87 * 88 * qnum_get_double() loses precision for integers beyond 53 bits. 89 */ 90 double qnum_get_double(QNum *qn) 91 { 92 switch (qn->kind) { 93 case QNUM_I64: 94 return qn->u.i64; 95 case QNUM_DOUBLE: 96 return qn->u.dbl; 97 } 98 99 assert(0); 100 return 0.0; 101 } 102 103 char *qnum_to_string(QNum *qn) 104 { 105 char *buffer; 106 int len; 107 108 switch (qn->kind) { 109 case QNUM_I64: 110 return g_strdup_printf("%" PRId64, qn->u.i64); 111 case QNUM_DOUBLE: 112 /* FIXME: snprintf() is locale dependent; but JSON requires 113 * numbers to be formatted as if in the C locale. Dependence 114 * on C locale is a pervasive issue in QEMU. */ 115 /* FIXME: This risks printing Inf or NaN, which are not valid 116 * JSON values. */ 117 /* FIXME: the default precision of 6 for %f often causes 118 * rounding errors; we should be using DBL_DECIMAL_DIG (17), 119 * and only rounding to a shorter number if the result would 120 * still produce the same floating point value. */ 121 buffer = g_strdup_printf("%f" , qn->u.dbl); 122 len = strlen(buffer); 123 while (len > 0 && buffer[len - 1] == '0') { 124 len--; 125 } 126 127 if (len && buffer[len - 1] == '.') { 128 buffer[len - 1] = 0; 129 } else { 130 buffer[len] = 0; 131 } 132 133 return buffer; 134 } 135 136 assert(0); 137 return NULL; 138 } 139 140 /** 141 * qobject_to_qnum(): Convert a QObject into a QNum 142 */ 143 QNum *qobject_to_qnum(const QObject *obj) 144 { 145 if (!obj || qobject_type(obj) != QTYPE_QNUM) { 146 return NULL; 147 } 148 return container_of(obj, QNum, base); 149 } 150 151 /** 152 * qnum_destroy_obj(): Free all memory allocated by a 153 * QNum object 154 */ 155 void qnum_destroy_obj(QObject *obj) 156 { 157 assert(obj != NULL); 158 g_free(qobject_to_qnum(obj)); 159 } 160