qemu/qobject/qnum.c

224 lines
4.6 KiB
C

/*
* QNum Module
*
* Copyright (C) 2009 Red Hat Inc.
*
* Authors:
* Luiz Capitulino <lcapitulino@redhat.com>
* Anthony Liguori <aliguori@us.ibm.com>
* Marc-André Lureau <marcandre.lureau@redhat.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qapi/qmp/qnum.h"
#include "qapi/qmp/qobject.h"
#include "qemu-common.h"
/**
* qnum_from_int(): Create a new QNum from an int64_t
*
* Return strong reference.
*/
QNum *qnum_from_int(int64_t value)
{
QNum *qn = g_new(QNum, 1);
qobject_init(QOBJECT(qn), QTYPE_QNUM);
qn->kind = QNUM_I64;
qn->u.i64 = value;
return qn;
}
/**
* qnum_from_uint(): Create a new QNum from an uint64_t
*
* Return strong reference.
*/
QNum *qnum_from_uint(uint64_t value)
{
QNum *qn = g_new(QNum, 1);
qobject_init(QOBJECT(qn), QTYPE_QNUM);
qn->kind = QNUM_U64;
qn->u.u64 = value;
return qn;
}
/**
* qnum_from_double(): Create a new QNum from a double
*
* Return strong reference.
*/
QNum *qnum_from_double(double value)
{
QNum *qn = g_new(QNum, 1);
qobject_init(QOBJECT(qn), QTYPE_QNUM);
qn->kind = QNUM_DOUBLE;
qn->u.dbl = value;
return qn;
}
/**
* qnum_get_try_int(): Get an integer representation of the number
*
* Return true on success.
*/
bool qnum_get_try_int(const QNum *qn, int64_t *val)
{
switch (qn->kind) {
case QNUM_I64:
*val = qn->u.i64;
return true;
case QNUM_U64:
if (qn->u.u64 > INT64_MAX) {
return false;
}
*val = qn->u.u64;
return true;
case QNUM_DOUBLE:
return false;
}
assert(0);
return false;
}
/**
* qnum_get_int(): Get an integer representation of the number
*
* assert() on failure.
*/
int64_t qnum_get_int(const QNum *qn)
{
int64_t val;
bool success = qnum_get_try_int(qn, &val);
assert(success);
return val;
}
/**
* qnum_get_uint(): Get an unsigned integer from the number
*
* Return true on success.
*/
bool qnum_get_try_uint(const QNum *qn, uint64_t *val)
{
switch (qn->kind) {
case QNUM_I64:
if (qn->u.i64 < 0) {
return false;
}
*val = qn->u.i64;
return true;
case QNUM_U64:
*val = qn->u.u64;
return true;
case QNUM_DOUBLE:
return false;
}
assert(0);
return false;
}
/**
* qnum_get_uint(): Get an unsigned integer from the number
*
* assert() on failure.
*/
uint64_t qnum_get_uint(const QNum *qn)
{
uint64_t val;
bool success = qnum_get_try_uint(qn, &val);
assert(success);
return val;
}
/**
* qnum_get_double(): Get a float representation of the number
*
* qnum_get_double() loses precision for integers beyond 53 bits.
*/
double qnum_get_double(QNum *qn)
{
switch (qn->kind) {
case QNUM_I64:
return qn->u.i64;
case QNUM_U64:
return qn->u.u64;
case QNUM_DOUBLE:
return qn->u.dbl;
}
assert(0);
return 0.0;
}
char *qnum_to_string(QNum *qn)
{
char *buffer;
int len;
switch (qn->kind) {
case QNUM_I64:
return g_strdup_printf("%" PRId64, qn->u.i64);
case QNUM_U64:
return g_strdup_printf("%" PRIu64, qn->u.u64);
case QNUM_DOUBLE:
/* FIXME: snprintf() is locale dependent; but JSON requires
* numbers to be formatted as if in the C locale. Dependence
* on C locale is a pervasive issue in QEMU. */
/* FIXME: This risks printing Inf or NaN, which are not valid
* JSON values. */
/* FIXME: the default precision of 6 for %f often causes
* rounding errors; we should be using DBL_DECIMAL_DIG (17),
* and only rounding to a shorter number if the result would
* still produce the same floating point value. */
buffer = g_strdup_printf("%f" , qn->u.dbl);
len = strlen(buffer);
while (len > 0 && buffer[len - 1] == '0') {
len--;
}
if (len && buffer[len - 1] == '.') {
buffer[len - 1] = 0;
} else {
buffer[len] = 0;
}
return buffer;
}
assert(0);
return NULL;
}
/**
* qobject_to_qnum(): Convert a QObject into a QNum
*/
QNum *qobject_to_qnum(const QObject *obj)
{
if (!obj || qobject_type(obj) != QTYPE_QNUM) {
return NULL;
}
return container_of(obj, QNum, base);
}
/**
* qnum_destroy_obj(): Free all memory allocated by a
* QNum object
*/
void qnum_destroy_obj(QObject *obj)
{
assert(obj != NULL);
g_free(qobject_to_qnum(obj));
}