qstring.c

   1 /*
   2  * QString data type.
   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 GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  */
  12 #include "qobject.h"
  13 #include "qstring.h"
  14 #include "qemu-common.h"
  15
  16 static void qstring_destroy_obj(QObject *obj);
  17
  18 static const QType qstring_type = {
  19     .code = QTYPE_QSTRING,
  20     .destroy = qstring_destroy_obj,
  21 };
  22
  23 /**
  24  * qstring_new(): Create a new empty QString
  25  *
  26  * Return strong reference.
  27  */
  28 QString *qstring_new(void)
  29 {
  30     return qstring_from_str("");
  31 }
  32
  33 /**
  34  * qstring_from_str(): Create a new QString from a regular C string
  35  *
  36  * Return strong reference.
  37  */
  38 QString *qstring_from_str(const char *str)
  39 {
  40     QString *qstring;
  41
  42     qstring = qemu_malloc(sizeof(*qstring));
  43
  44     qstring->length = strlen(str);
  45     qstring->capacity = qstring->length;
  46
  47     qstring->string = qemu_malloc(qstring->capacity + 1);
  48     memcpy(qstring->string, str, qstring->length);
  49     qstring->string[qstring->length] = 0;
  50
  51     QOBJECT_INIT(qstring, &qstring_type);
  52
  53     return qstring;
  54 }
  55
  56 /* qstring_append(): Append a C string to a QString
  57  */
  58 void qstring_append(QString *qstring, const char *str)
  59 {
  60     size_t len = strlen(str);
  61
  62     if (qstring->capacity < (qstring->length + len)) {
  63         qstring->capacity += len;
  64         qstring->capacity *= 2; /* use exponential growth */
  65
  66         qstring->string = qemu_realloc(qstring->string, qstring->capacity + 1);
  67     }
  68
  69     memcpy(qstring->string + qstring->length, str, len);
  70     qstring->length += len;
  71     qstring->string[qstring->length] = 0;
  72 }
  73
  74 /**
  75  * qobject_to_qstring(): Convert a QObject to a QString
  76  */
  77 QString *qobject_to_qstring(const QObject *obj)
  78 {
  79     if (qobject_type(obj) != QTYPE_QSTRING)
  80         return NULL;
  81
  82     return container_of(obj, QString, base);
  83 }
  84
  85 /**
  86  * qstring_get_str(): Return a pointer to the stored string
  87  *
  88  * NOTE: Should be used with caution, if the object is deallocated
  89  * this pointer becomes invalid.
  90  */
  91 const char *qstring_get_str(const QString *qstring)
  92 {
  93     return qstring->string;
  94 }
  95
  96 /**
  97  * qstring_destroy_obj(): Free all memory allocated by a QString
  98  * object
  99  */
 100 static void qstring_destroy_obj(QObject *obj)
 101 {
 102     QString *qs;
 103
 104     assert(obj != NULL);
 105     qs = qobject_to_qstring(obj);
 106     qemu_free(qs->string);
 107     qemu_free(qs);
 108 }