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