qstring.c

   1 /*
   2  * QString data type.
   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 GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  */
  12 #include "qobject.h"
  13 #include "qstring.h"
  14 #include "qemu-common.h"
  15
  16 static void qstring_destroy_obj(QObject *obj);
  17
  18 static const QType qstring_type = {
  19     .code = QTYPE_QSTRING,
  20     .destroy = qstring_destroy_obj,
  21 };
  22
  23 /**
  24  * qstring_new(): Create a new empty QString
  25  *
  26  * Return strong reference.
  27  */
  28 QString *qstring_new(void)
  29 {
  30     return qstring_from_str("");
  31 }
  32
  33 /**
  34  * qstring_from_substr(): Create a new QString from a C string substring
  35  *
  36  * Return string reference
  37  */
  38 QString *qstring_from_substr(const char *str, int start, int end)
  39 {
  40     QString *qstring;
  41
  42     qstring = qemu_malloc(sizeof(*qstring));
  43
  44     qstring->length = end - start + 1;
  45     qstring->capacity = qstring->length;
  46
  47     qstring->string = qemu_malloc(qstring->capacity + 1);
  48     memcpy(qstring->string, str + start, qstring->length);
  49     qstring->string[qstring->length] = 0;
  50
  51     QOBJECT_INIT(qstring, &qstring_type);
  52
  53     return qstring;
  54 }
  55
  56 /**
  57  * qstring_from_str(): Create a new QString from a regular C string
  58  *
  59  * Return strong reference.
  60  */
  61 QString *qstring_from_str(const char *str)
  62 {
  63     return qstring_from_substr(str, 0, strlen(str) - 1);
  64 }
  65
  66 static void capacity_increase(QString *qstring, size_t len)
  67 {
  68     if (qstring->capacity < (qstring->length + len)) {
  69         qstring->capacity += len;
  70         qstring->capacity *= 2; /* use exponential growth */
  71
  72         qstring->string = qemu_realloc(qstring->string, qstring->capacity + 1);
  73     }
  74 }
  75
  76 /* qstring_append(): Append a C string to a QString
  77  */
  78 void qstring_append(QString *qstring, const char *str)
  79 {
  80     size_t len = strlen(str);
  81
  82     capacity_increase(qstring, len);
  83     memcpy(qstring->string + qstring->length, str, len);
  84     qstring->length += len;
  85     qstring->string[qstring->length] = 0;
  86 }
  87
  88 void qstring_append_int(QString *qstring, int64_t value)
  89 {
  90     char num[32];
  91
  92     snprintf(num, sizeof(num), "%" PRId64, value);
  93     qstring_append(qstring, num);
  94 }
  95
  96 /**
  97  * qstring_append_chr(): Append a C char to a QString
  98  */
  99 void qstring_append_chr(QString *qstring, int c)
 100 {
 101     capacity_increase(qstring, 1);
 102     qstring->string[qstring->length++] = c;
 103     qstring->string[qstring->length] = 0;
 104 }
 105
 106 /**
 107  * qobject_to_qstring(): Convert a QObject to a QString
 108  */
 109 QString *qobject_to_qstring(const QObject *obj)
 110 {
 111     if (qobject_type(obj) != QTYPE_QSTRING)
 112         return NULL;
 113
 114     return container_of(obj, QString, base);
 115 }
 116
 117 /**
 118  * qstring_get_str(): Return a pointer to the stored string
 119  *
 120  * NOTE: Should be used with caution, if the object is deallocated
 121  * this pointer becomes invalid.
 122  */
 123 const char *qstring_get_str(const QString *qstring)
 124 {
 125     return qstring->string;
 126 }
 127
 128 /**
 129  * qstring_destroy_obj(): Free all memory allocated by a QString
 130  * object
 131  */
 132 static void qstring_destroy_obj(QObject *obj)
 133 {
 134     QString *qs;
 135
 136     assert(obj != NULL);
 137     qs = qobject_to_qstring(obj);
 138     qemu_free(qs->string);
 139     qemu_free(qs);
 140 }