openmw/stream/servers/memory_stream.h

#ifndef MANGLE_STREAM_MEMSERVER_H
#define MANGLE_STREAM_MEMSERVER_H

#include <assert.h>
#include "../stream.h"

namespace Mangle {
namespace Stream {

/** A Stream wrapping a memory buffer

    This will create a fully seekable stream out any pointer/length
    pair you give it.
 */
class MemoryStream : public Stream
{
  const void *data;
  size_t length, pos;

 public:
 MemoryStream(const void *ptr, size_t len)
   : data(ptr), length(len), pos(0)
  {
    isSeekable = true;
    hasPosition = true;
    hasSize = true;
  }

  size_t read(void *buf, size_t count)
  {
    assert(pos <= length);

    // Don't read more than we have
    if(count > (length - pos))
      count = length - pos;

    // Copy data
    if(count)
      memcpy(buf, ((char*)data)+pos, count);

    // aaand remember to increase the count
    pos += count;

    return count;
  }

  void seek(size_t _pos)
  {
    pos = _pos;
    if(pos > length)
      pos = length;
  }

  size_t tell() const { return pos; }
  size_t size() const { return length; }
  bool eof() const { return pos == length; }
};

}} // namespaces
#endif