1 files changed, 122 insertions, 0 deletions
diff --git a/src/refcountstring.h b/src/refcountstring.h
new file mode 100644
index 0000000..f91a4a0
--- /dev/null
+++ b/src/refcountstring.h
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2017-2024 OARC, Inc.
+ * Copyright (c) 2011-2017, IIS - The Internet Foundation in Sweden
+ * All rights reserved.
+ *
+ * This file is part of PacketQ.
+ *
+ * PacketQ is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * PacketQ 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 PacketQ.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __packetq_refcountstring_h
+#define __packetq_refcountstring_h
+
+#include <cstdlib>
+#include <cstring>
+
+// A simple reference-counted C string, intended to be used through a pointer
+// as RefCountString * with manual management of the reference count in order
+// to stay a POD (for use in unions). For the same reason, constructors are
+// static. The wrapper RefCountStringHandle can be used where automatic
+// reference handling is possible.
+struct RefCountString {
+    // data
+    int  count;
+    char data[];
+
+    // implementation
+    void inc_refcount()
+    {
+        count += 1;
+    }
+
+    void dec_refcount()
+    {
+        count -= 1;
+        if (count == 0)
+            std::free(this);
+    }
+
+    static RefCountString* allocate(int data_length)
+    {
+        void* chunk = std::calloc(1, sizeof(RefCountString) + data_length);
+        if (!chunk)
+            throw std::bad_alloc();
+
+        RefCountString* new_str = static_cast<RefCountString*>(chunk);
+        new_str->count          = 1;
+        return new_str;
+    }
+
+    static RefCountString* construct(const char* c_string)
+    {
+        std::size_t     length = std::strlen(c_string);
+        RefCountString* str    = RefCountString::allocate(length + 1);
+        std::memcpy(str->data, c_string, length + 1);
+        return str;
+    }
+
+    static RefCountString* construct(const char* data, int from, int to)
+    {
+        int length = to - from;
+        if (length < 0)
+            length = 0;
+        RefCountString* str = RefCountString::allocate(length + 1);
+        std::memcpy(str->data, data + from, length);
+        str->data[length - 1 + 1] = '\0';
+        return str;
+    }
+};
+
+class RefCountStringHandle {
+private:
+    RefCountStringHandle& operator=(const RefCountStringHandle& other);
+    RefCountStringHandle(RefCountStringHandle&& other) noexcept;
+    RefCountStringHandle const& operator=(RefCountStringHandle&& other);
+
+public:
+    RefCountStringHandle()
+    {
+        value = 0;
+    }
+
+    RefCountStringHandle(RefCountString* str)
+    {
+        value = str;
+    }
+
+    ~RefCountStringHandle()
+    {
+        if (value)
+            value->dec_refcount();
+    }
+
+    RefCountString* operator*()
+    {
+        return value;
+    }
+
+    void set(RefCountString* str)
+    {
+        if (value != str) {
+            if (value)
+                value->dec_refcount();
+            value = str;
+        }
+    }
+
+    RefCountString* value;
+};
+
+#endif // __packetq_refcountstring_h