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 "qobject.h"
  14 #include "qstring.h"
  15 #include "qemu-common.h"
  16
  17 static void qstring_destroy_obj(QObject *obj);
  18
  19 static const QType qstring_type = {
  20     .code = QTYPE_QSTRING,
  21     .destroy = qstring_destroy_obj,
  22 };
  23
  24 /**
  25  * qstring_new(): Create a new empty QString
  26  *
  27  * Return strong reference.
  28  */
  29 QString *qstring_new(void)
  30 {
  31     return qstring_from_str("");
  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, int start, int end)
  40 {
  41     QString *qstring;
  42
  43     qstring = qemu_malloc(sizeof(*qstring));
  44
  45     qstring->length = end - start + 1;
  46     qstring->capacity = qstring->length;
  47
  48     qstring->string = qemu_malloc(qstring->capacity + 1);
  49     memcpy(qstring->string, str + start, qstring->length);
  50     qstring->string[qstring->length] = 0;
  51
  52     QOBJECT_INIT(qstring, &qstring_type);
  53
  54     return qstring;
  55 }
  56
  57 /**
  58  * qstring_from_str(): Create a new QString from a regular C string
  59  *
  60  * Return strong reference.
  61  */
  62 QString *qstring_from_str(const char *str)
  63 {
  64     return qstring_from_substr(str, 0, strlen(str) - 1);
  65 }
  66
  67 static void capacity_increase(QString *qstring, size_t len)
  68 {
  69     if (qstring->capacity < (qstring->length + len)) {
  70         qstring->capacity += len;
  71         qstring->capacity *= 2; /* use exponential growth */
  72
  73         qstring->string = qemu_realloc(qstring->string, qstring->capacity + 1);
  74     }
  75 }
  76
  77 /* qstring_append(): Append a C string to a QString
  78  */
  79 void qstring_append(QString *qstring, const char *str)
  80 {
  81     size_t len = strlen(str);
  82
  83     capacity_increase(qstring, len);
  84     memcpy(qstring->string + qstring->length, str, len);
  85     qstring->length += len;
  86     qstring->string[qstring->length] = 0;
  87 }
  88
  89 void qstring_append_int(QString *qstring, int64_t value)
  90 {
  91     char num[32];
  92
  93     snprintf(num, sizeof(num), "%" PRId64, value);
  94     qstring_append(qstring, num);
  95 }
  96
  97 /**
  98  * qstring_append_chr(): Append a C char to a QString
  99  */
 100 void qstring_append_chr(QString *qstring, int c)
 101 {
 102     capacity_increase(qstring, 1);
 103     qstring->string[qstring->length++] = c;
 104     qstring->string[qstring->length] = 0;
 105 }
 106
 107 /**
 108  * qobject_to_qstring(): Convert a QObject to a QString
 109  */
 110 QString *qobject_to_qstring(const QObject *obj)
 111 {
 112     if (qobject_type(obj) != QTYPE_QSTRING)
 113         return NULL;
 114
 115     return container_of(obj, QString, base);
 116 }
 117
 118 /**
 119  * qstring_get_str(): Return a pointer to the stored string
 120  *
 121  * NOTE: Should be used with caution, if the object is deallocated
 122  * this pointer becomes invalid.
 123  */
 124 const char *qstring_get_str(const QString *qstring)
 125 {
 126     return qstring->string;
 127 }
 128
 129 /**
 130  * qstring_destroy_obj(): Free all memory allocated by a QString
 131  * object
 132  */
 133 static void qstring_destroy_obj(QObject *obj)
 134 {
 135     QString *qs;
 136
 137     assert(obj != NULL);
 138     qs = qobject_to_qstring(obj);
 139     qemu_free(qs->string);
 140     qemu_free(qs);
 141 }