misc: add bstring

misc/bstring.h

@@ -0,0 +1,133 @@
+/**
+ * @file bstring.h
+ * @author Ambroz Bizjak <ambrop7@gmail.com>
+ * 
+ * @section LICENSE
+ * 
+ * This file is part of BadVPN.
+ * 
+ * BadVPN is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ * 
+ * BadVPN is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef BADVPN_BSTRING_H
+#define BADVPN_BSTRING_H
+
+#include <misc/debug.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+#define BSTRING_TYPE_STATIC 5
+#define BSTRING_TYPE_DYNAMIC 7
+#define BSTRING_TYPE_EXTERNAL 11
+
+#define BSTRING_STATIC_SIZE 23
+#define BSTRING_STATIC_MAX (BSTRING_STATIC_SIZE - 1)
+
+typedef struct {
+    union {
+        struct {
+            char type;
+            char static_string[BSTRING_STATIC_SIZE];
+        } us;
+        struct {
+            char type;
+            char *dynamic_string;
+        } ud;
+        struct {
+            char type;
+            const char *external_string;
+        } ue;
+    } u;
+} BString;
+
+static void BString__assert (BString *o)
+{
+    switch (o->u.us.type) {
+        case BSTRING_TYPE_STATIC:
+        case BSTRING_TYPE_DYNAMIC:
+        case BSTRING_TYPE_EXTERNAL:
+            return;
+    }
+    
+    ASSERT(0);
+}
+
+static int BString_Init (BString *o, const char *str)
+{
+    if (strlen(str) <= BSTRING_STATIC_MAX) {
+        strcpy(o->u.us.static_string, str);
+        o->u.us.type = BSTRING_TYPE_STATIC;
+    } else {
+        if (!(o->u.ud.dynamic_string = malloc(strlen(str) + 1))) {
+            return 0;
+        }
+        strcpy(o->u.ud.dynamic_string, str);
+        o->u.ud.type = BSTRING_TYPE_DYNAMIC;
+    }
+    
+    BString__assert(o);
+    return 1;
+}
+
+static void BString_InitStatic (BString *o, const char *str)
+{
+    ASSERT(strlen(str) <= BSTRING_STATIC_MAX)
+    
+    strcpy(o->u.us.static_string, str);
+    o->u.us.type = BSTRING_TYPE_STATIC;
+    
+    BString__assert(o);
+}
+
+static void BString_InitExternal (BString *o, const char *str)
+{
+    o->u.ue.external_string = str;
+    o->u.ue.type = BSTRING_TYPE_EXTERNAL;
+    
+    BString__assert(o);
+}
+
+static void BString_InitAllocated (BString *o, char *str)
+{
+    o->u.ud.dynamic_string = str;
+    o->u.ud.type = BSTRING_TYPE_DYNAMIC;
+    
+    BString__assert(o);
+}
+
+static void BString_Free (BString *o)
+{
+    BString__assert(o);
+    
+    if (o->u.ud.type == BSTRING_TYPE_DYNAMIC) {
+        free(o->u.ud.dynamic_string);
+    }
+}
+
+static const char * BString_Get (BString *o)
+{
+    BString__assert(o);
+    
+    switch (o->u.us.type) {
+        case BSTRING_TYPE_STATIC: return o->u.us.static_string;
+        case BSTRING_TYPE_DYNAMIC: return o->u.ud.dynamic_string;
+        case BSTRING_TYPE_EXTERNAL: return o->u.ue.external_string;
+    }
+    
+    ASSERT(0);
+    return NULL;
+}
+
+#endif