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/qobject.h"
  15 #include "qapi/qmp/qstring.h"
  16 #include "qemu-common.h"
  17
  18 /**
  19  * qstring_new(): Create a new empty QString
  20  *
  21  * Return strong reference.
  22  */
  23 QString *qstring_new(void)
  24 {
  25     return qstring_from_str("");
  26 }
  27
  28 /**
  29  * qstring_get_length(): Get the length of a QString
  30  */
  31 size_t qstring_get_length(const QString *qstring)
  32 {
  33     return qstring->length;
  34 }
  35
  36 /**
  37  * qstring_from_substr(): Create a new QString from a C string substring
  38  *
  39  * Return string reference
  40  */
  41 QString *qstring_from_substr(const char *str, int start, int end)
  42 {
  43     QString *qstring;
  44
  45     qstring = g_malloc(sizeof(*qstring));
  46     qobject_init(QOBJECT(qstring), QTYPE_QSTRING);
  47
  48     qstring->length = end - start + 1;
  49     qstring->capacity = qstring->length;
  50
  51     qstring->string = g_malloc(qstring->capacity + 1);
  52     memcpy(qstring->string, str + start, qstring->length);
  53     qstring->string[qstring->length] = 0;
  54
  55
  56     return qstring;
  57 }
  58
  59 /**
  60  * qstring_from_str(): Create a new QString from a regular C string
  61  *
  62  * Return strong reference.
  63  */
  64 QString *qstring_from_str(const char *str)
  65 {
  66     return qstring_from_substr(str, 0, strlen(str) - 1);
  67 }
  68
  69 static void capacity_increase(QString *qstring, size_t len)
  70 {
  71     if (qstring->capacity < (qstring->length + len)) {
  72         qstring->capacity += len;
  73         qstring->capacity *= 2; /* use exponential growth */
  74
  75         qstring->string = g_realloc(qstring->string, qstring->capacity + 1);
  76     }
  77 }
  78
  79 /* qstring_append(): Append a C string to a QString
  80  */
  81 void qstring_append(QString *qstring, const char *str)
  82 {
  83     size_t len = strlen(str);
  84
  85     capacity_increase(qstring, len);
  86     memcpy(qstring->string + qstring->length, str, len);
  87     qstring->length += len;
  88     qstring->string[qstring->length] = 0;
  89 }
  90
  91 void qstring_append_int(QString *qstring, int64_t value)
  92 {
  93     char num[32];
  94
  95     snprintf(num, sizeof(num), "%" PRId64, value);
  96     qstring_append(qstring, num);
  97 }
  98
  99 /**
 100  * qstring_append_chr(): Append a C char to a QString
 101  */
 102 void qstring_append_chr(QString *qstring, int c)
 103 {
 104     capacity_increase(qstring, 1);
 105     qstring->string[qstring->length++] = c;
 106     qstring->string[qstring->length] = 0;
 107 }
 108
 109 /**
 110  * qobject_to_qstring(): Convert a QObject to a QString
 111  */
 112 QString *qobject_to_qstring(const QObject *obj)
 113 {
 114     if (!obj || qobject_type(obj) != QTYPE_QSTRING) {
 115         return NULL;
 116     }
 117     return container_of(obj, QString, base);
 118 }
 119
 120 /**
 121  * qstring_get_str(): Return a pointer to the stored string
 122  *
 123  * NOTE: Should be used with caution, if the object is deallocated
 124  * this pointer becomes invalid.
 125  */
 126 const char *qstring_get_str(const QString *qstring)
 127 {
 128     return qstring->string;
 129 }
 130
 131 /**
 132  * qstring_destroy_obj(): Free all memory allocated by a QString
 133  * object
 134  */
 135 void qstring_destroy_obj(QObject *obj)
 136 {
 137     QString *qs;
 138
 139     assert(obj != NULL);
 140     qs = qobject_to_qstring(obj);
 141     g_free(qs->string);
 142     g_free(qs);
 143 }