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 "qemu/osdep.h"
  14 #include "qapi/qmp/qstring.h"
  15 #include "qemu-common.h"
  16
  17 /**
  18  * qstring_new(): Create a new empty QString
  19  *
  20  * Return strong reference.
  21  */
  22 QString *qstring_new(void)
  23 {
  24     return qstring_from_str("");
  25 }
  26
  27 /**
  28  * qstring_get_length(): Get the length of a QString
  29  */
  30 size_t qstring_get_length(const QString *qstring)
  31 {
  32     return qstring->length;
  33 }
  34
  35 /**
  36  * qstring_from_substr(): Create a new QString from a C string substring
  37  *
  38  * Return string reference
  39  */
  40 QString *qstring_from_substr(const char *str, int start, int end)
  41 {
  42     QString *qstring;
  43
  44     qstring = g_malloc(sizeof(*qstring));
  45     qobject_init(QOBJECT(qstring), QTYPE_QSTRING);
  46
  47     qstring->length = end - start + 1;
  48     qstring->capacity = qstring->length;
  49
  50     qstring->string = g_malloc(qstring->capacity + 1);
  51     memcpy(qstring->string, str + start, qstring->length);
  52     qstring->string[qstring->length] = 0;
  53
  54
  55     return qstring;
  56 }
  57
  58 /**
  59  * qstring_from_str(): Create a new QString from a regular C string
  60  *
  61  * Return strong reference.
  62  */
  63 QString *qstring_from_str(const char *str)
  64 {
  65     return qstring_from_substr(str, 0, strlen(str) - 1);
  66 }
  67
  68 static void capacity_increase(QString *qstring, size_t len)
  69 {
  70     if (qstring->capacity < (qstring->length + len)) {
  71         qstring->capacity += len;
  72         qstring->capacity *= 2; /* use exponential growth */
  73
  74         qstring->string = g_realloc(qstring->string, qstring->capacity + 1);
  75     }
  76 }
  77
  78 /* qstring_append(): Append a C string to a QString
  79  */
  80 void qstring_append(QString *qstring, const char *str)
  81 {
  82     size_t len = strlen(str);
  83
  84     capacity_increase(qstring, len);
  85     memcpy(qstring->string + qstring->length, str, len);
  86     qstring->length += len;
  87     qstring->string[qstring->length] = 0;
  88 }
  89
  90 void qstring_append_int(QString *qstring, int64_t value)
  91 {
  92     char num[32];
  93
  94     snprintf(num, sizeof(num), "%" PRId64, value);
  95     qstring_append(qstring, num);
  96 }
  97
  98 /**
  99  * qstring_append_chr(): Append a C char to a QString
 100  */
 101 void qstring_append_chr(QString *qstring, int c)
 102 {
 103     capacity_increase(qstring, 1);
 104     qstring->string[qstring->length++] = c;
 105     qstring->string[qstring->length] = 0;
 106 }
 107
 108 /**
 109  * qstring_get_str(): Return a pointer to the stored string
 110  *
 111  * NOTE: Should be used with caution, if the object is deallocated
 112  * this pointer becomes invalid.
 113  */
 114 const char *qstring_get_str(const QString *qstring)
 115 {
 116     return qstring->string;
 117 }
 118
 119 /**
 120  * qstring_get_try_str(): Return a pointer to the stored string
 121  *
 122  * NOTE: will return NULL if qstring is not provided.
 123  */
 124 const char *qstring_get_try_str(const QString *qstring)
 125 {
 126     return qstring ? qstring_get_str(qstring) : NULL;
 127 }
 128
 129 /**
 130  * qobject_get_try_str(): Return a pointer to the corresponding string
 131  *
 132  * NOTE: the string will only be returned if the object is valid, and
 133  * its type is QString, otherwise NULL is returned.
 134  */
 135 const char *qobject_get_try_str(const QObject *qstring)
 136 {
 137     return qstring_get_try_str(qobject_to(QString, qstring));
 138 }
 139
 140 /**
 141  * qstring_is_equal(): Test whether the two QStrings are equal
 142  */
 143 bool qstring_is_equal(const QObject *x, const QObject *y)
 144 {
 145     return !strcmp(qobject_to(QString, x)->string,
 146                    qobject_to(QString, y)->string);
 147 }
 148
 149 /**
 150  * qstring_destroy_obj(): Free all memory allocated by a QString
 151  * object
 152  */
 153 void qstring_destroy_obj(QObject *obj)
 154 {
 155     QString *qs;
 156
 157     assert(obj != NULL);
 158     qs = qobject_to(QString, obj);
 159     g_free(qs->string);
 160     g_free(qs);
 161 }