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
  16 /**
  17  * qstring_new(): Create a new empty QString
  18  *
  19  * Return strong reference.
  20  */
  21 QString *qstring_new(void)
  22 {
  23     return qstring_from_str("");
  24 }
  25
  26 /**
  27  * qstring_get_length(): Get the length of a QString
  28  */
  29 size_t qstring_get_length(const QString *qstring)
  30 {
  31     return qstring->length;
  32 }
  33
  34 /**
  35  * qstring_from_substr(): Create a new QString from a C string substring
  36  *
  37  * Return string reference
  38  */
  39 QString *qstring_from_substr(const char *str, size_t start, size_t end)
  40 {
  41     QString *qstring;
  42
  43     assert(start <= end);
  44
  45     qstring = g_malloc(sizeof(*qstring));
  46     qobject_init(QOBJECT(qstring), QTYPE_QSTRING);
  47
  48     qstring->length = end - start;
  49     qstring->capacity = qstring->length;
  50
  51     assert(qstring->capacity < SIZE_MAX);
  52     qstring->string = g_malloc(qstring->capacity + 1);
  53     memcpy(qstring->string, str + start, qstring->length);
  54     qstring->string[qstring->length] = 0;
  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));
  67 }
  68
  69 /**
  70  * qstring_from_gstring(): Convert a GString to a QString
  71  *
  72  * Return strong reference.
  73  */
  74
  75 QString *qstring_from_gstring(GString *gstr)
  76 {
  77     QString *qstring;
  78
  79     qstring = g_malloc(sizeof(*qstring));
  80     qobject_init(QOBJECT(qstring), QTYPE_QSTRING);
  81     qstring->length = gstr->len;
  82     qstring->capacity = gstr->allocated_len;
  83     qstring->string = g_string_free(gstr, false);
  84     return qstring;
  85 }
  86
  87
  88 static void capacity_increase(QString *qstring, size_t len)
  89 {
  90     if (qstring->capacity < (qstring->length + len)) {
  91         assert(len <= SIZE_MAX - qstring->capacity);
  92         qstring->capacity += len;
  93         assert(qstring->capacity <= SIZE_MAX / 2);
  94         qstring->capacity *= 2; /* use exponential growth */
  95
  96         qstring->string = g_realloc(qstring->string, qstring->capacity + 1);
  97     }
  98 }
  99
 100 /* qstring_append(): Append a C string to a QString
 101  */
 102 void qstring_append(QString *qstring, const char *str)
 103 {
 104     size_t len = strlen(str);
 105
 106     capacity_increase(qstring, len);
 107     memcpy(qstring->string + qstring->length, str, len);
 108     qstring->length += len;
 109     qstring->string[qstring->length] = 0;
 110 }
 111
 112 void qstring_append_int(QString *qstring, int64_t value)
 113 {
 114     char num[32];
 115
 116     snprintf(num, sizeof(num), "%" PRId64, value);
 117     qstring_append(qstring, num);
 118 }
 119
 120 /**
 121  * qstring_append_chr(): Append a C char to a QString
 122  */
 123 void qstring_append_chr(QString *qstring, int c)
 124 {
 125     capacity_increase(qstring, 1);
 126     qstring->string[qstring->length++] = c;
 127     qstring->string[qstring->length] = 0;
 128 }
 129
 130 /**
 131  * qstring_get_str(): Return a pointer to the stored string
 132  *
 133  * NOTE: Should be used with caution, if the object is deallocated
 134  * this pointer becomes invalid.
 135  */
 136 const char *qstring_get_str(const QString *qstring)
 137 {
 138     return qstring->string;
 139 }
 140
 141 /**
 142  * qstring_get_try_str(): Return a pointer to the stored string
 143  *
 144  * NOTE: will return NULL if qstring is not provided.
 145  */
 146 const char *qstring_get_try_str(const QString *qstring)
 147 {
 148     return qstring ? qstring_get_str(qstring) : NULL;
 149 }
 150
 151 /**
 152  * qobject_get_try_str(): Return a pointer to the corresponding string
 153  *
 154  * NOTE: the string will only be returned if the object is valid, and
 155  * its type is QString, otherwise NULL is returned.
 156  */
 157 const char *qobject_get_try_str(const QObject *qstring)
 158 {
 159     return qstring_get_try_str(qobject_to(QString, qstring));
 160 }
 161
 162 /**
 163  * qstring_is_equal(): Test whether the two QStrings are equal
 164  */
 165 bool qstring_is_equal(const QObject *x, const QObject *y)
 166 {
 167     return !strcmp(qobject_to(QString, x)->string,
 168                    qobject_to(QString, y)->string);
 169 }
 170
 171 /**
 172  * qstring_destroy_obj(): Free all memory allocated by a QString
 173  * object
 174  */
 175 void qstring_destroy_obj(QObject *obj)
 176 {
 177     QString *qs;
 178
 179     assert(obj != NULL);
 180     qs = qobject_to(QString, obj);
 181     g_free(qs->string);
 182     g_free(qs);
 183 }