qstring.c revision 910aea96b67d7f0357f586c47f20848ec435aa1b 
1/*
2 * QString Module
3 *
4 * Copyright (C) 2009 Red Hat Inc.
5 *
6 * Authors:
7 *  Luiz Capitulino <lcapitulino@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
10 * See the COPYING.LIB file in the top-level directory.
11 */
12
13#include "qapi/qmp/qobject.h"
14#include "qapi/qmp/qstring.h"
15#include "qemu-common.h"
16
17static void qstring_destroy_obj(QObject *obj);
18
19static const QType qstring_type = {
20    .code = QTYPE_QSTRING,
21    .destroy = qstring_destroy_obj,
22};
23
24/**
25 * qstring_new(): Create a new empty QString
26 *
27 * Return strong reference.
28 */
29QString *qstring_new(void)
30{
31    return qstring_from_str("");
32}
33
34/**
35 * qstring_get_length(): Get the length of a QString
36 */
37size_t qstring_get_length(const QString *qstring)
38{
39    return qstring->length;
40}
41
42/**
43 * qstring_from_substr(): Create a new QString from a C string substring
44 *
45 * Return string reference
46 */
47QString *qstring_from_substr(const char *str, int start, int end)
48{
49    QString *qstring;
50
51    qstring = g_malloc(sizeof(*qstring));
52
53    qstring->length = end - start + 1;
54    qstring->capacity = qstring->length;
55
56    qstring->string = g_malloc(qstring->capacity + 1);
57    memcpy(qstring->string, str + start, qstring->length);
58    qstring->string[qstring->length] = 0;
59
60    QOBJECT_INIT(qstring, &qstring_type);
61
62    return qstring;
63}
64
65/**
66 * qstring_from_str(): Create a new QString from a regular C string
67 *
68 * Return strong reference.
69 */
70QString *qstring_from_str(const char *str)
71{
72    return qstring_from_substr(str, 0, strlen(str) - 1);
73}
74
75static void capacity_increase(QString *qstring, size_t len)
76{
77    if (qstring->capacity < (qstring->length + len)) {
78        qstring->capacity += len;
79        qstring->capacity *= 2; /* use exponential growth */
80
81        qstring->string = g_realloc(qstring->string, qstring->capacity + 1);
82    }
83}
84
85/* qstring_append(): Append a C string to a QString
86 */
87void qstring_append(QString *qstring, const char *str)
88{
89    size_t len = strlen(str);
90
91    capacity_increase(qstring, len);
92    memcpy(qstring->string + qstring->length, str, len);
93    qstring->length += len;
94    qstring->string[qstring->length] = 0;
95}
96
97void qstring_append_int(QString *qstring, int64_t value)
98{
99    char num[32];
100
101    snprintf(num, sizeof(num), "%" PRId64, value);
102    qstring_append(qstring, num);
103}
104
105/**
106 * qstring_append_chr(): Append a C char to a QString
107 */
108void qstring_append_chr(QString *qstring, int c)
109{
110    capacity_increase(qstring, 1);
111    qstring->string[qstring->length++] = c;
112    qstring->string[qstring->length] = 0;
113}
114
115/**
116 * qobject_to_qstring(): Convert a QObject to a QString
117 */
118QString *qobject_to_qstring(const QObject *obj)
119{
120    if (qobject_type(obj) != QTYPE_QSTRING)
121        return NULL;
122
123    return container_of(obj, QString, base);
124}
125
126/**
127 * qstring_get_str(): Return a pointer to the stored string
128 *
129 * NOTE: Should be used with caution, if the object is deallocated
130 * this pointer becomes invalid.
131 */
132const char *qstring_get_str(const QString *qstring)
133{
134    return qstring->string;
135}
136
137/**
138 * qstring_destroy_obj(): Free all memory allocated by a QString
139 * object
140 */
141static void qstring_destroy_obj(QObject *obj)
142{
143    QString *qs;
144
145    assert(obj != NULL);
146    qs = qobject_to_qstring(obj);
147    g_free(qs->string);
148    g_free(qs);
149}
150