qobject/qstring.c

   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
  17 static void qstring_destroy_obj(QObject *obj);
  18
  19 static 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  */
  29 QString *qstring_new(void)
  30 {
  31     return qstring_from_str("");
  32 }
  33
  34 /**
  35  * qstring_get_length(): Get the length of a QString
  36  */
  37 size_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  */
  47 QString *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  */
  70 QString *qstring_from_str(const char *str)
  71 {
  72     return qstring_from_substr(str, 0, strlen(str) - 1);
  73 }
  74
  75 static 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  */
  87 void 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
  97 void 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  */
 108 void 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  */
 118 QString *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  */
 132 const 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  */
 141 static 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 }