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