unicorn/qemu/qobject/qstring.c
Markus Armbruster b9cf91307e
qstring: Make conversion from QObject * accept null
qobject_to_qstring() crashes on null, which is a trap for the unwary.
Return null instead, and simplify a few callers.

Backports commit 7f0278435df1fa845b3bd9556942f89296d4246b from qemu
2018-02-17 15:24:12 -05:00

150 lines
3.2 KiB
C

/*
* QString Module
*
* Copyright (C) 2009 Red Hat Inc.
*
* Authors:
* Luiz Capitulino <lcapitulino@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 "qapi/qmp/qobject.h"
#include "qapi/qmp/qstring.h"
#include "qemu-common.h"
static void qstring_destroy_obj(QObject *obj);
static const QType qstring_type = {
QTYPE_QSTRING,
qstring_destroy_obj,
};
/**
* qstring_new(): Create a new empty QString
*
* Return strong reference.
*/
QString *qstring_new(void)
{
return qstring_from_str("");
}
/**
* qstring_get_length(): Get the length of a QString
*/
size_t qstring_get_length(const QString *qstring)
{
return qstring->length;
}
/**
* qstring_from_substr(): Create a new QString from a C string substring
*
* Return string reference
*/
QString *qstring_from_substr(const char *str, int start, int end)
{
QString *qstring;
qstring = g_malloc(sizeof(*qstring));
qstring->length = end - start + 1;
qstring->capacity = qstring->length;
qstring->string = g_malloc(qstring->capacity + 1);
memcpy(qstring->string, str + start, qstring->length);
qstring->string[qstring->length] = 0;
QOBJECT_INIT(qstring, &qstring_type);
return qstring;
}
/**
* qstring_from_str(): Create a new QString from a regular C string
*
* Return strong reference.
*/
QString *qstring_from_str(const char *str)
{
return qstring_from_substr(str, 0, strlen(str) - 1);
}
static void capacity_increase(QString *qstring, size_t len)
{
if (qstring->capacity < (qstring->length + len)) {
qstring->capacity += len;
qstring->capacity *= 2; /* use exponential growth */
qstring->string = g_realloc(qstring->string, qstring->capacity + 1);
}
}
/* qstring_append(): Append a C string to a QString
*/
void qstring_append(QString *qstring, const char *str)
{
size_t len = strlen(str);
capacity_increase(qstring, len);
memcpy(qstring->string + qstring->length, str, len);
qstring->length += len;
qstring->string[qstring->length] = 0;
}
void qstring_append_int(QString *qstring, int64_t value)
{
char num[32];
snprintf(num, sizeof(num), "%" PRId64, value);
qstring_append(qstring, num);
}
/**
* qstring_append_chr(): Append a C char to a QString
*/
void qstring_append_chr(QString *qstring, int c)
{
capacity_increase(qstring, 1);
qstring->string[qstring->length++] = c;
qstring->string[qstring->length] = 0;
}
/**
* qobject_to_qstring(): Convert a QObject to a QString
*/
QString *qobject_to_qstring(const QObject *obj)
{
if (!obj || qobject_type(obj) != QTYPE_QSTRING) {
return NULL;
}
return container_of(obj, QString, base);
}
/**
* qstring_get_str(): Return a pointer to the stored string
*
* NOTE: Should be used with caution, if the object is deallocated
* this pointer becomes invalid.
*/
const char *qstring_get_str(const QString *qstring)
{
return qstring->string;
}
/**
* qstring_destroy_obj(): Free all memory allocated by a QString
* object
*/
static void qstring_destroy_obj(QObject *obj)
{
QString *qs;
assert(obj != NULL);
qs = qobject_to_qstring(obj);
g_free(qs->string);
g_free(qs);
}