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, size_t start, size_t end)
  41 {
  42     QString *qstring;
  43
  44     assert(start <= end);
  45
  46     qstring = g_malloc(sizeof(*qstring));
  47     qobject_init(QOBJECT(qstring), QTYPE_QSTRING);
  48
  49     qstring->length = end - start;
  50     qstring->capacity = qstring->length;
  51
  52     assert(qstring->capacity < SIZE_MAX);
  53     qstring->string = g_malloc(qstring->capacity + 1);
  54     memcpy(qstring->string, str + start, qstring->length);
  55     qstring->string[qstring->length] = 0;
  56
  57     return qstring;
  58 }
  59
  60 /**
  61  * qstring_from_str(): Create a new QString from a regular C string
  62  *
  63  * Return strong reference.
  64  */
  65 QString *qstring_from_str(const char *str)
  66 {
  67     return qstring_from_substr(str, 0, strlen(str));
  68 }
  69
  70 static void capacity_increase(QString *qstring, size_t len)
  71 {
  72     if (qstring->capacity < (qstring->length + len)) {
  73         assert(len <= SIZE_MAX - qstring->capacity);
  74         qstring->capacity += len;
  75         assert(qstring->capacity <= SIZE_MAX / 2);
  76         qstring->capacity *= 2; /* use exponential growth */
  77
  78         qstring->string = g_realloc(qstring->string, qstring->capacity + 1);
  79     }
  80 }
  81
  82 /* qstring_append(): Append a C string to a QString
  83  */
  84 void qstring_append(QString *qstring, const char *str)
  85 {
  86     size_t len = strlen(str);
  87
  88     capacity_increase(qstring, len);
  89     memcpy(qstring->string + qstring->length, str, len);
  90     qstring->length += len;
  91     qstring->string[qstring->length] = 0;
  92 }
  93
  94 void qstring_append_int(QString *qstring, int64_t value)
  95 {
  96     char num[32];
  97
  98     snprintf(num, sizeof(num), "%" PRId64, value);
  99     qstring_append(qstring, num);
 100 }
 101
 102 /**
 103  * qstring_append_chr(): Append a C char to a QString
 104  */
 105 void qstring_append_chr(QString *qstring, int c)
 106 {
 107     capacity_increase(qstring, 1);
 108     qstring->string[qstring->length++] = c;
 109     qstring->string[qstring->length] = 0;
 110 }
 111
 112 /**
 113  * qstring_get_str(): Return a pointer to the stored string
 114  *
 115  * NOTE: Should be used with caution, if the object is deallocated
 116  * this pointer becomes invalid.
 117  */
 118 const char *qstring_get_str(const QString *qstring)
 119 {
 120     return qstring->string;
 121 }
 122
 123 /**
 124  * qstring_get_try_str(): Return a pointer to the stored string
 125  *
 126  * NOTE: will return NULL if qstring is not provided.
 127  */
 128 const char *qstring_get_try_str(const QString *qstring)
 129 {
 130     return qstring ? qstring_get_str(qstring) : NULL;
 131 }
 132
 133 /**
 134  * qobject_get_try_str(): Return a pointer to the corresponding string
 135  *
 136  * NOTE: the string will only be returned if the object is valid, and
 137  * its type is QString, otherwise NULL is returned.
 138  */
 139 const char *qobject_get_try_str(const QObject *qstring)
 140 {
 141     return qstring_get_try_str(qobject_to(QString, qstring));
 142 }
 143
 144 /**
 145  * qstring_is_equal(): Test whether the two QStrings are equal
 146  */
 147 bool qstring_is_equal(const QObject *x, const QObject *y)
 148 {
 149     return !strcmp(qobject_to(QString, x)->string,
 150                    qobject_to(QString, y)->string);
 151 }
 152
 153 /**
 154  * qstring_destroy_obj(): Free all memory allocated by a QString
 155  * object
 156  */
 157 void qstring_destroy_obj(QObject *obj)
 158 {
 159     QString *qs;
 160
 161     assert(obj != NULL);
 162     qs = qobject_to(QString, obj);
 163     g_free(qs->string);
 164     g_free(qs);
 165 }