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openmw-tes3mp/components/nif/nifstream.hpp
Nathan Jeffords 03ee7663a3 reworked NIFStream to use a type-handler
Reworked NIFStream to use a type-handler system to decide how to extract
data from the NIF. It also has the capability to perform bulk reads on
compatible platforms, thus improving cell-load performance.
2013-04-24 20:20:00 -07:00

293 lines
10 KiB
C++

#ifndef OPENMW_COMPONENTS_NIF_NIFSTREAM_HPP
#define OPENMW_COMPONENTS_NIF_NIFSTREAM_HPP
#include <boost/static_assert.hpp>
namespace Nif
{
class NIFFile;
class NIFStream {
/// Input stream
Ogre::DataStreamPtr inp;
template <typename value_t>
value_t read_le ()
{
uint8_t buffer [sizeof (value_t)];
if (inp->read (buffer, sizeof (buffer)) != sizeof (buffer))
throw std::runtime_error ("unexpected");
value_t Value = 0;
value_t Shift = 0;
for (size_t i = 0; i < sizeof (value_t); ++i)
{
Value |= value_t (buffer[i]) << Shift;
Shift += 8;
}
return Value;
}
public:
/*
* This should be true for any processor/platform whose endianess, alignment
* and packing rules would be compatible with x86 and not fault or degrade
* with misaligned reads. This enables some pretty big savings when reading in
* animations and meshes.
*/
#if defined (__i386__) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_X64)
static const bool FileCompatiblePlatform = true;
#else
static const bool FileCompatiblePlatform = false;
#endif
template <typename type>
struct handler;
template <typename presentation_type, typename backing_type>
struct le_handler;
template <typename presentation_type, typename backing_type>
friend struct le_handler;
template <typename store_type, typename final_type, bool SameLayout>
struct conversion_handler;
NIFFile * const file;
NIFStream (NIFFile * file, Ogre::DataStreamPtr inp) : file (file), inp (inp) {}
/*************************************************
Parser functions
****************************************************/
void skip(size_t size) { return inp->skip (size); }
size_t read (void * data, size_t size) { return inp->read (data, size); }
template <typename T>
void uncheckedRead (T & Value)
{
typedef handler <T> handler_t;
handler_t::extract (*this, Value);
}
template <typename T>
T getValue ()
{
T Value;
getValue (Value);
return Value;
}
template <typename T>
void getValue (T & Value)
{
typedef handler <T> handler_t;
if (FileCompatiblePlatform && handler_t::FileCompatibleLayout)
{
BOOST_STATIC_ASSERT_MSG (handler_t::FixedLength, "non-fixed length encoding not supported...");
BOOST_STATIC_ASSERT_MSG (handler_t::EncodedLength == sizeof (T), "unexpected structure size");
inp->read (&Value, handler_t::EncodedLength);
}
else
{
handler_t::extract (*this, Value);
}
}
template <typename element_type>
void getArray (element_type * Array, size_t Size)
{
typedef handler <element_type> handler_t;
if (FileCompatiblePlatform && handler_t::FileCompatibleLayout)
{
BOOST_STATIC_ASSERT_MSG (handler_t::FixedLength, "non-fixed length encoding not supported...");
BOOST_STATIC_ASSERT_MSG (handler_t::EncodedLength == sizeof (element_type), "unexpected structure size");
inp->read (Array, handler_t::EncodedLength * Size);
}
else
{
for(size_t i = 0; i < Size; i++)
handler_t::extract (*this, Array[i]);
}
}
template <typename element_type, typename allocator_type>
void getStdVector (std::vector <element_type, allocator_type> & Vector, size_t Size)
{
Vector.resize(Size);
getArray (&Vector.front (), Vector.size ());
}
template <typename length_type, typename element_type, typename allocator_type>
void getStdVector (std::vector <element_type, allocator_type> & Vector)
{
length_type Length;
getValue (Length);
getStdVector (Vector, Length);
}
char getChar() { return getValue <char> (); }
signed int getInt() { return getValue <int32_t> (); }
unsigned int getUInt() { return getValue <uint32_t> (); }
signed short getShort() { return getValue <int16_t> (); }
unsigned short getUShort() { return getValue <uint16_t> (); }
//signed long getLong() { return getValue <signed long> (); }
//unsigned long getULong() { return getValue <unsigned long> (); }
float getFloat() { return getValue <float> (); }
Ogre::Vector2 getVector2() { return getValue <Ogre::Vector2> (); }
Ogre::Vector3 getVector3() { return getValue <Ogre::Vector3> (); }
Ogre::Vector4 getVector4() { return getValue <Ogre::Vector4> (); }
Ogre::Matrix3 getMatrix3() { return getValue <Ogre::Matrix3> (); }
Ogre::Quaternion getQuaternion() { return getValue <Ogre::Quaternion> (); }
Transformation getTrafo() { return getValue <Transformation> (); }
void getShorts(std::vector<short> &vec, size_t size) { return getStdVector (vec, size); }
void getFloats(std::vector<float> &vec, size_t size) { return getStdVector (vec, size); }
void getVector2s(std::vector<Ogre::Vector2> &vec, size_t size) { return getStdVector (vec, size); }
void getVector3s(std::vector<Ogre::Vector3> &vec, size_t size) { return getStdVector (vec, size); }
void getVector4s(std::vector<Ogre::Vector4> &vec, size_t size) { return getStdVector (vec, size); }
void getQuaternions(std::vector<Ogre::Quaternion> &vec, size_t size) { return getStdVector (vec, size); }
std::string getString(size_t length)
{
std::vector<char> str (length+1, 0);
if(read(&str[0], length) != length)
throw std::runtime_error ("string length in NIF file does not match");
return &str[0];
}
std::string getString()
{
size_t size = getValue <uint32_t> ();
return getString(size);
}
};
/*
* generic type handlers
*/
template <typename type, size_t Size>
struct NIFStream::handler < type [Size] >
{
typedef handler <type> inner_handler;
static const bool FixedLength = inner_handler::FixedLength;
static const size_t EncodedLength = inner_handler::EncodedLength * Size;
static const bool FileCompatibleLayout = inner_handler::FileCompatibleLayout;
static void extract (NIFStream & Stream, type (&Value) [Size])
{
for (size_t i = 0; i < Size; ++i)
inner_handler::extract (Stream, Value [i]);
}
};
template <typename presentation_type, typename backing_type>
struct NIFStream::le_handler
{
static const bool FixedLength = true;
static const size_t EncodedLength = sizeof (backing_type);
static const bool FileCompatibleLayout = true;
static void extract (NIFStream & Stream, presentation_type & Value)
{
BOOST_STATIC_ASSERT_MSG(sizeof (presentation_type) == sizeof (backing_type), "Invalid use of NIFile::le_handler template");
union {
backing_type Backing;
presentation_type Presentation;
} u;
u.Backing = Stream.read_le <backing_type> ();
Value = u.Presentation;
}
};
template <typename store_type, typename final_type>
struct NIFStream::conversion_handler <store_type, final_type, false>
{
typedef handler <store_type> store_handler;
static const bool FixedLength = store_handler::FixedLength;
static const size_t EncodedLength = store_handler::EncodedLength;
static const bool FileCompatibleLayout = false;
static void extract (NIFStream & Stream, final_type & Value)
{
store_type StoreValue;
store_handler::extract (Stream, StoreValue);
Value = final_type (StoreValue);
}
};
template <typename store_type, typename final_type>
struct NIFStream::conversion_handler <store_type, final_type, true>
{
typedef handler <store_type> store_handler;
static const bool FixedLength = store_handler::FixedLength;
static const size_t EncodedLength = store_handler::EncodedLength;
static const bool FileCompatibleLayout = store_handler::FileCompatibleLayout;
static void extract (NIFStream & Stream, final_type & FinalValue)
{
store_handler::extract (Stream, reinterpret_cast <store_type &> (FinalValue));
}
};
template <> struct NIFStream::handler <int8_t> : NIFStream::le_handler <int8_t, uint8_t> {};
template <> struct NIFStream::handler <uint8_t> : NIFStream::le_handler <uint8_t, uint8_t> {};
template <> struct NIFStream::handler <int16_t> : NIFStream::le_handler <int16_t, uint16_t> {};
template <> struct NIFStream::handler <uint16_t> : NIFStream::le_handler <uint16_t, uint16_t> {};
template <> struct NIFStream::handler <int32_t> : NIFStream::le_handler <int32_t, uint32_t> {};
template <> struct NIFStream::handler <uint32_t> : NIFStream::le_handler <uint32_t, uint32_t> {};
template <> struct NIFStream::handler <char> : NIFStream::le_handler <char, uint8_t> {};
template <> struct NIFStream::handler <float> : NIFStream::le_handler <float, uint32_t> {};
template <> struct NIFStream::handler <Ogre::Vector2> : NIFStream::conversion_handler <float[2], Ogre::Vector2, true> {};
template <> struct NIFStream::handler <Ogre::Vector3> : NIFStream::conversion_handler <float[3], Ogre::Vector3, true> {};
template <> struct NIFStream::handler <Ogre::Vector4> : NIFStream::conversion_handler <float[4], Ogre::Vector4, true> {};
template <> struct NIFStream::handler <Ogre::Matrix3> : NIFStream::conversion_handler <float[3][3], Ogre::Matrix3, true> {};
template <> struct NIFStream::handler <Ogre::Quaternion> : NIFStream::conversion_handler <float[4], Ogre::Quaternion, true> {};
template <> struct NIFStream::handler <Transformation>
{
static const bool FixedLength = true;
static const size_t EncodedLength =
handler <Ogre::Vector3>::EncodedLength +
handler <Ogre::Matrix3>::EncodedLength +
handler <Ogre::Real>::EncodedLength;
static const bool FileCompatibleLayout = true;
static void extract (NIFStream & stream, Transformation & value)
{
stream.uncheckedRead (value.pos);
stream.uncheckedRead (value.rotation);
stream.uncheckedRead (value.scale);
}
};
}
#endif