xenia-canary/third_party/crunch/crnlib/crn_buffer_stream.h

// 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