crnlib/crn_buffer_stream.h

@@ -0,0 +1,196 @@
+// File: crn_buffer_stream.h
+// See Copyright Notice and license at the end of inc/crnlib.h
+#pragma once
+#include "crn_data_stream.h"
+
+namespace crnlib
+{
+   class buffer_stream : public data_stream
+   {
+   public:
+      buffer_stream() :
+         data_stream(),
+         m_pBuf(NULL),
+         m_size(0),
+         m_ofs(0)
+      {
+      }
+
+      buffer_stream(void* p, uint size) :
+         data_stream(),
+         m_pBuf(NULL),
+         m_size(0),
+         m_ofs(0)
+      {
+         open(p, size);
+      }
+
+      buffer_stream(const void* p, uint size) :
+         data_stream(),
+         m_pBuf(NULL),
+         m_size(0),
+         m_ofs(0)
+      {
+         open(p, size);
+      }
+
+      virtual ~buffer_stream()
+      {
+      }
+
+      bool open(const void* p, uint size)
+      {
+         CRNLIB_ASSERT(p);
+
+         close();
+
+         if ((!p) || (!size))
+            return false;
+
+         m_opened = true;
+         m_pBuf = (uint8*)(p);
+         m_size = size;
+         m_ofs = 0;
+         m_attribs = cDataStreamSeekable | cDataStreamReadable;
+         return true;
+      }
+
+      bool open(void* p, uint size)
+      {
+         CRNLIB_ASSERT(p);
+
+         close();
+
+         if ((!p) || (!size))
+            return false;
+
+         m_opened = true;
+         m_pBuf = static_cast<uint8*>(p);
+         m_size = size;
+         m_ofs = 0;
+         m_attribs = cDataStreamSeekable | cDataStreamWritable | cDataStreamReadable;
+         return true;
+      }
+
+      virtual bool close()
+      {
+         if (m_opened)
+         {
+            m_opened = false;
+            m_pBuf = NULL;
+            m_size = 0;
+            m_ofs = 0;
+            return true;
+         }
+
+         return false;
+      }
+
+      const void* get_buf() const   { return m_pBuf; }
+            void* get_buf()         { return m_pBuf; }
+
+      virtual const void* get_ptr() const { return m_pBuf; }
+
+      virtual uint read(void* pBuf, uint len)
+      {
+         CRNLIB_ASSERT(pBuf && (len <= 0x7FFFFFFF));
+
+         if ((!m_opened) || (!is_readable()) || (!len))
+            return 0;
+
+         CRNLIB_ASSERT(m_ofs <= m_size);
+
+         uint bytes_left = m_size - m_ofs;
+
+         len = math::minimum<uint>(len, bytes_left);
+
+         if (len)
+            memcpy(pBuf, &m_pBuf[m_ofs], len);
+
+         m_ofs += len;
+
+         return len;
+      }
+
+      virtual uint write(const void* pBuf, uint len)
+      {
+         CRNLIB_ASSERT(pBuf && (len <= 0x7FFFFFFF));
+
+         if ((!m_opened) || (!is_writable()) || (!len))
+            return 0;
+
+         CRNLIB_ASSERT(m_ofs <= m_size);
+
+         uint bytes_left = m_size - m_ofs;
+
+         len = math::minimum<uint>(len, bytes_left);
+
+         if (len)
+            memcpy(&m_pBuf[m_ofs], pBuf, len);
+
+         m_ofs += len;
+
+         return len;
+      }
+
+      virtual bool flush()
+      {
+         if (!m_opened)
+            return false;
+
+         return true;
+      }
+
+      virtual uint64 get_size()
+      {
+         if (!m_opened)
+            return 0;
+
+         return m_size;
+      }
+
+      virtual uint64 get_remaining()
+      {
+         if (!m_opened)
+            return 0;
+
+         CRNLIB_ASSERT(m_ofs <= m_size);
+
+         return m_size - m_ofs;
+      }
+
+      virtual uint64 get_ofs()
+      {
+         if (!m_opened)
+            return 0;
+
+         return m_ofs;
+      }
+
+      virtual bool seek(int64 ofs, bool relative)
+      {
+         if ((!m_opened) || (!is_seekable()))
+            return false;
+
+         int64 new_ofs = relative ? (m_ofs + ofs) : ofs;
+
+         if (new_ofs < 0)
+            return false;
+         else if (new_ofs > m_size)
+            return false;
+
+         m_ofs = static_cast<uint>(new_ofs);
+
+         post_seek();
+
+         return true;
+      }
+
+   private:
+      uint8*   m_pBuf;
+      uint     m_size;
+      uint     m_ofs;
+   };
+
+} // namespace crnlib
+