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 static void capacity_increase(QString *qstring, size_t len)
  70 {
  71     if (qstring->capacity < (qstring->length + len)) {
  72         assert(len <= SIZE_MAX - qstring->capacity);
  73         qstring->capacity += len;
  74         assert(qstring->capacity <= SIZE_MAX / 2);
  75         qstring->capacity *= 2; /* use exponential growth */
  76
  77         qstring->string = g_realloc(qstring->string, qstring->capacity + 1);
  78     }
  79 }
  80
  81 /* qstring_append(): Append a C string to a QString
  82  */
  83 void qstring_append(QString *qstring, const char *str)
  84 {
  85     size_t len = strlen(str);
  86
  87     capacity_increase(qstring, len);
  88     memcpy(qstring->string + qstring->length, str, len);
  89     qstring->length += len;
  90     qstring->string[qstring->length] = 0;
  91 }
  92
  93 void qstring_append_int(QString *qstring, int64_t value)
  94 {
  95     char num[32];
  96
  97     snprintf(num, sizeof(num), "%" PRId64, value);
  98     qstring_append(qstring, num);
  99 }
 100
 101 /**
 102  * qstring_append_chr(): Append a C char to a QString
 103  */
 104 void qstring_append_chr(QString *qstring, int c)
 105 {
 106     capacity_increase(qstring, 1);
 107     qstring->string[qstring->length++] = c;
 108     qstring->string[qstring->length] = 0;
 109 }
 110
 111 /**
 112  * qstring_get_str(): Return a pointer to the stored string
 113  *
 114  * NOTE: Should be used with caution, if the object is deallocated
 115  * this pointer becomes invalid.
 116  */
 117 const char *qstring_get_str(const QString *qstring)
 118 {
 119     return qstring->string;
 120 }
 121
 122 /**
 123  * qstring_get_try_str(): Return a pointer to the stored string
 124  *
 125  * NOTE: will return NULL if qstring is not provided.
 126  */
 127 const char *qstring_get_try_str(const QString *qstring)
 128 {
 129     return qstring ? qstring_get_str(qstring) : NULL;
 130 }
 131
 132 /**
 133  * qobject_get_try_str(): Return a pointer to the corresponding string
 134  *
 135  * NOTE: the string will only be returned if the object is valid, and
 136  * its type is QString, otherwise NULL is returned.
 137  */
 138 const char *qobject_get_try_str(const QObject *qstring)
 139 {
 140     return qstring_get_try_str(qobject_to(QString, qstring));
 141 }
 142
 143 /**
 144  * qstring_is_equal(): Test whether the two QStrings are equal
 145  */
 146 bool qstring_is_equal(const QObject *x, const QObject *y)
 147 {
 148     return !strcmp(qobject_to(QString, x)->string,
 149                    qobject_to(QString, y)->string);
 150 }
 151
 152 /**
 153  * qstring_free(): Free the memory allocated by a QString object
 154  *
 155  * Return: if @return_str, return the underlying string, to be
 156  * g_free(), otherwise NULL is returned.
 157  */
 158 char *qstring_free(QString *qstring, bool return_str)
 159 {
 160     char *rv = NULL;
 161
 162     if (return_str) {
 163         rv = qstring->string;
 164     } else {
 165         g_free(qstring->string);
 166     }
 167
 168     g_free(qstring);
 169
 170     return rv;
 171 }
 172
 173 /**
 174  * qstring_destroy_obj(): Free all memory allocated by a QString
 175  * object
 176  */
 177 void qstring_destroy_obj(QObject *obj)
 178 {
 179     assert(obj != NULL);
 180     qstring_free(qobject_to(QString, obj), FALSE);
 181 }