/*
 * Copyright (C) 2019-2020 Robin Gareus <robin@gareus.org>
 * Copyright (C) 2019 Steinberg Media Technologies GmbH
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include <ctype.h>
#include <algorithm>

#if (__cplusplus >= 201103L)
#include <boost/make_unique.hpp>
#endif

#include "ardour/vst3_host.h"

#ifndef VST3_SCANNER_APP
#include "pbd/compose.h"
#include "ardour/debug.h"
#endif

using namespace Steinberg;

DEF_CLASS_IID (FUnknown)
DEF_CLASS_IID (IBStream)
DEF_CLASS_IID (IPluginBase)
DEF_CLASS_IID (IPluginFactory)
DEF_CLASS_IID (IPluginFactory2)
DEF_CLASS_IID (IPlugFrame)
DEF_CLASS_IID (IPlugView)
DEF_CLASS_IID (ISizeableStream)
DEF_CLASS_IID (Vst::IAttributeList)
DEF_CLASS_IID (Vst::IAudioProcessor)
DEF_CLASS_IID (Vst::IAutomationState)
DEF_CLASS_IID (Vst::IComponent)
DEF_CLASS_IID (Vst::IComponentHandler)
DEF_CLASS_IID (Vst::IComponentHandler2)
DEF_CLASS_IID (Vst::IConnectionPoint)
DEF_CLASS_IID (Vst::IEditController)
DEF_CLASS_IID (Vst::IEditController2)
DEF_CLASS_IID (Vst::IEditControllerHostEditing)
DEF_CLASS_IID (Vst::IEventList)
DEF_CLASS_IID (Vst::IHostApplication)
DEF_CLASS_IID (Vst::IMessage)
DEF_CLASS_IID (Vst::IMidiMapping)
DEF_CLASS_IID (Vst::IMidiLearn)
DEF_CLASS_IID (Vst::IParameterChanges)
DEF_CLASS_IID (Vst::IParamValueQueue)
DEF_CLASS_IID (Vst::IPlugInterfaceSupport)
DEF_CLASS_IID (Vst::IProgramListData)
DEF_CLASS_IID (Vst::IStreamAttributes)
DEF_CLASS_IID (Vst::IUnitData)
DEF_CLASS_IID (Vst::IUnitHandler)
DEF_CLASS_IID (Vst::IUnitInfo)
DEF_CLASS_IID (Vst::ChannelContext::IInfoListener)

DEF_CLASS_IID (Presonus::IContextInfoProvider)
DEF_CLASS_IID (Presonus::IContextInfoProvider2)
DEF_CLASS_IID (Presonus::IContextInfoProvider3)
DEF_CLASS_IID (Presonus::IContextInfoHandler)
DEF_CLASS_IID (Presonus::IContextInfoHandler2)
DEF_CLASS_IID (Presonus::IEditControllerExtra)
DEF_CLASS_IID (Presonus::ISlaveControllerHandler)
DEF_CLASS_IID (Presonus::IPlugInViewEmbedding)
DEF_CLASS_IID (Presonus::IPlugInViewScaling)

#if SMTG_OS_LINUX
DEF_CLASS_IID (Linux::IRunLoop);
#endif

std::string
Steinberg::tchar_to_utf8 (Vst::TChar const* s)
{
	glong  len;
	gchar* utf8 = g_utf16_to_utf8 ((const gunichar2*)s, -1, NULL, &len, NULL);
	if (!utf8 || len == 0) {
		return "";
	}
	std::string rv (utf8, len);
	g_free (utf8);
	return rv;
}

bool
Steinberg::utf8_to_tchar (Vst::TChar* rv, const char* s, size_t l)
{
	glong      len;
	gunichar2* s16 = g_utf8_to_utf16 (s, -1, NULL, &len, NULL);
	if (!s16 || len <= 0) {
		memset (rv, 0, sizeof (Vst::TChar));
		return false;
	}
	if (l > 0 && l <= (size_t) len) {
		len = l - 1;
	}
	memcpy (rv, s16, len * sizeof (Vst::TChar));
	rv[len] = '\0';
	g_free (s16);
	return true;
}

bool
Steinberg::utf8_to_tchar (Vst::TChar* rv, std::string const& s, size_t l)
{
	return utf8_to_tchar (rv, s.c_str(), l);
}

/* ****************************************************************************/

RefObject::RefObject ()
{
	g_atomic_int_set (&_cnt, 1);
}

uint32
RefObject::addRef ()
{
	g_atomic_int_inc (&_cnt);
	return g_atomic_int_get (&_cnt);
}

uint32
RefObject::release ()
{
	if (g_atomic_int_dec_and_test (&_cnt)) {
		delete this;
		return 0;
	}
	return g_atomic_int_get (&_cnt);
}

/* ****************************************************************************/
/* copy/edit from public.sdk/source/vst/hosting/hostclasses.cpp               */
/* ****************************************************************************/

#include "vst3/pluginterfaces/base/funknown.cpp"

HostAttributeList::HostAttributeList ()
{
}

HostAttributeList::~HostAttributeList ()
{
	std::map<std::string, HostAttribute*>::reverse_iterator it = list.rbegin ();
	while (it != list.rend ()) {
		delete it->second;
		it++;
	}
}

void
HostAttributeList::removeAttrID (AttrID aid)
{
	std::map<std::string, HostAttribute*>::iterator it = list.find (aid);
	if (it != list.end ()) {
		delete it->second;
		list.erase (it);
	}
}

tresult
HostAttributeList::setInt (AttrID aid, int64 value)
{
	removeAttrID (aid);
	list[aid] = new HostAttribute (value);
	return kResultTrue;
}

tresult
HostAttributeList::getInt (AttrID aid, int64& value)
{
	std::map<std::string, HostAttribute*>::iterator it = list.find (aid);
	if (it != list.end () && it->second) {
		value = it->second->intValue ();
		return kResultTrue;
	}
	return kResultFalse;
}

tresult
HostAttributeList::setFloat (AttrID aid, double value)
{
	removeAttrID (aid);
	list[aid] = new HostAttribute (value);
	return kResultTrue;
}

tresult
HostAttributeList::getFloat (AttrID aid, double& value)
{
	std::map<std::string, HostAttribute*>::iterator it = list.find (aid);
	if (it != list.end () && it->second) {
		value = it->second->floatValue ();
		return kResultTrue;
	}
	return kResultFalse;
}

tresult
HostAttributeList::setString (AttrID aid, const Vst::TChar* string)
{
	removeAttrID (aid);
	list[aid] = new HostAttribute (string, Steinberg::strlen16 (string));
	return kResultTrue;
}

tresult
HostAttributeList::getString (AttrID aid, Vst::TChar* string, uint32 size)
{
	std::map<std::string, HostAttribute*>::iterator it = list.find (aid);
	if (it != list.end () && it->second && size > 0) {
		uint32            stringSize = 0;
		const Vst::TChar* _string    = it->second->stringValue (stringSize);

		size = std::min<uint32> (stringSize, size - 1);
		memcpy (string, _string, size * sizeof (Vst::TChar));
		string[size] = 0;
		return kResultTrue;
	}
	return kResultFalse;
}

tresult
HostAttributeList::setBinary (AttrID aid, const void* data, uint32 size)
{
	removeAttrID (aid);
	list[aid] = new HostAttribute (data, size);
	return kResultTrue;
}

tresult
HostAttributeList::getBinary (AttrID aid, const void*& data, uint32& size)
{
	std::map<std::string, HostAttribute*>::iterator it = list.find (aid);
	if (it != list.end () && it->second) {
		data = it->second->binaryValue (size);
		return kResultTrue;
	}
	size = 0;
	return kResultFalse;
}

/* ****************************************************************************/

HostMessage::HostMessage ()
	: _messageId (0)
{
}

HostMessage::~HostMessage ()
{
	setMessageID (0);
	if (_attribute_list) {
		//_attribute_list->release ();
	}
}

const char*
HostMessage::getMessageID ()
{
	return _messageId;
}

void
HostMessage::setMessageID (const char* mid)
{
	if (_messageId) {
		delete[] _messageId;
	}
	if (mid) {
		size_t len = strlen (mid) + 1;
		_messageId = new char[len];
		strcpy (_messageId, mid);
	} else {
		_messageId = 0;
	}
}

Vst::IAttributeList*
HostMessage::getAttributes ()
{
	if (!_attribute_list) {
		_attribute_list.reset (new HostAttributeList);
	}
	return _attribute_list.get ();
}

/* ****************************************************************************/

PlugInterfaceSupport::PlugInterfaceSupport ()
{
	using namespace Vst;

	//---VST 3.0.0--------------------------------
	addPlugInterfaceSupported (IComponent::iid);
	addPlugInterfaceSupported (IAudioProcessor::iid);
	addPlugInterfaceSupported (IEditController::iid);
	addPlugInterfaceSupported (IConnectionPoint::iid);

	addPlugInterfaceSupported (IUnitInfo::iid);
	addPlugInterfaceSupported (IUnitData::iid);
	addPlugInterfaceSupported (IProgramListData::iid);

	//---VST 3.0.1--------------------------------
	addPlugInterfaceSupported (IMidiMapping::iid);

	//---VST 3.1----------------------------------
	addPlugInterfaceSupported (IEditController2::iid);

#if 0
	//---VST 3.0.2--------------------------------
	addPlugInterfaceSupported (IParameterFinder::iid);

	//---VST 3.1----------------------------------
	addPlugInterfaceSupported (IAudioPresentationLatency::iid);

	//---VST 3.5----------------------------------
	addPlugInterfaceSupported (IKeyswitchController::iid);
	addPlugInterfaceSupported (IContextMenuTarget::iid);
#endif
	addPlugInterfaceSupported (IEditControllerHostEditing::iid);
#if 0
	addPlugInterfaceSupported (IXmlRepresentationController::iid);
	addPlugInterfaceSupported (INoteExpressionController::iid);

	//---VST 3.6.5--------------------------------
#endif
	addPlugInterfaceSupported (ChannelContext::IInfoListener::iid);
#if 0
	addPlugInterfaceSupported (IPrefetchableSupport::iid);
	addPlugInterfaceSupported (IAutomationState::iid);

	//---VST 3.6.11--------------------------------
	addPlugInterfaceSupported (INoteExpressionPhysicalUIMapping::iid);

	//---VST 3.6.12--------------------------------
#endif
	addPlugInterfaceSupported (IMidiLearn::iid);

	//---PSL --------------------------------------
	addPlugInterfaceSupported (Presonus::ISlaveControllerHandler::iid);
	addPlugInterfaceSupported (Presonus::IEditControllerExtra::iid);
	addPlugInterfaceSupported (Presonus::IContextInfoHandler::iid);
	addPlugInterfaceSupported (Presonus::IContextInfoHandler2::iid);
}

tresult
PlugInterfaceSupport::isPlugInterfaceSupported (const TUID _iid)
{
	const FUID uid = FUID::fromTUID (_iid);
	if (std::find (_interfaces.begin (), _interfaces.end (), uid) != _interfaces.end ()) {
		return kResultTrue;
	}
	return kResultFalse;
}

void
PlugInterfaceSupport::addPlugInterfaceSupported (const TUID id)
{
	_interfaces.push_back (FUID::fromTUID (id));
}

/* ****************************************************************************/

HostApplication::HostApplication ()
{
#if (__cplusplus >= 201103L)
	_plug_interface_support = boost::make_unique<PlugInterfaceSupport> ();
#else
	_plug_interface_support.reset (new PlugInterfaceSupport);
#endif
}

tresult
HostApplication::queryInterface (const char* _iid, void** obj)
{
	QUERY_INTERFACE (_iid, obj, FUnknown::iid, IHostApplication)
	QUERY_INTERFACE (_iid, obj, IHostApplication::iid, IHostApplication)

	if (_plug_interface_support && _plug_interface_support->queryInterface (_iid, obj) == kResultTrue) {
		return kResultOk;
	}

#if 1
	/* Presonus specifies IContextInfoProvider as extension to IComponentHandler.
	 * However softube's console queries support for this during initialize()
	 * and tests host-application support.
	 */
	if (FUnknownPrivate::iidEqual (_iid, Presonus::IContextInfoProvider::iid) ||
	    FUnknownPrivate::iidEqual (_iid, Presonus::IContextInfoProvider2::iid) ||
	    FUnknownPrivate::iidEqual (_iid, Presonus::IContextInfoProvider3::iid)) {
		*obj = NULL; // really IComponentHandler* (plugin->_plug)
		return kResultOk;
	}
#endif

#ifndef VST3_SCANNER_APP
	if (DEBUG_ENABLED(PBD::DEBUG::VST3Config)) {
		char fuid[33];
		FUID::fromTUID (_iid).toString (fuid);
		DEBUG_TRACE (PBD::DEBUG::VST3Config, string_compose ("HostApplication::queryInterface not supported: %1\n", fuid));
	}
#endif

	*obj = nullptr;
	return kResultFalse;
}

tresult
HostApplication::getName (Vst::String128 name)
{
	utf8_to_tchar (name, PROGRAM_NAME, 128);
	return kResultTrue;
}

tresult
HostApplication::createInstance (TUID cid, TUID _iid, void** obj)
{
	FUID classID (FUID::fromTUID (cid));
	FUID interfaceID (FUID::fromTUID (_iid));
	if (classID == Vst::IMessage::iid && interfaceID == Vst::IMessage::iid) {
		*obj = (Vst::IMessage*)new HostMessage;
		return kResultTrue;
	} else if (classID == Vst::IAttributeList::iid && interfaceID == Vst::IAttributeList::iid) {
		*obj = (Vst::IAttributeList*)new HostAttributeList;
		return kResultTrue;
	}
	*obj = nullptr;
	return kResultFalse;
}

/* ****************************************************************************/

tresult
Vst3ParamValueQueue::getPoint (int32 index, int32& sampleOffset, Vst::ParamValue& value)
{
	if (index >=0 && index < (int32)_values.size ()) {
		const Value& v = _values[index];
		sampleOffset = v.sampleOffset;
		value        = v.value;
		return kResultTrue;
	}
	return kResultFalse;

}

tresult
Vst3ParamValueQueue::addPoint (int32 sampleOffset, Vst::ParamValue value, int32& index)
{
	int32 dest_index = (int32)_values.size ();
	for (uint32 i = 0; i < _values.size (); ++i) {
		if (_values[i].sampleOffset == sampleOffset) {
			_values[i].value = value;
			index = i;
			return kResultTrue;
		} else if (_values[i].sampleOffset > sampleOffset) {
			dest_index = i;
			break;
		}
	}

	Value v (value, sampleOffset);
	if (dest_index == (int32)_values.size ()) {
		_values.push_back (v);
	} else {
		_values.insert (_values.begin () + dest_index, v);
	}

	index = dest_index;
	return kResultTrue;
}

/* ****************************************************************************/

Vst::IParamValueQueue*
Vst3ParameterChanges::getParameterData (int32 index)
{
  if (index < _used_queue_count) {
    return &_queue[index];
	}
  return 0;
}

Vst::IParamValueQueue*
Vst3ParameterChanges::addParameterData (Vst::ParamID const& pid, int32& index)
{
  for (int32 i = 0; i < _used_queue_count; ++i) {
    if (_queue[i].getParameterId () == pid) {
      index = i;
      return &_queue[i];
    }
  }

  if (_used_queue_count < (int32)_queue.size ()) {
		index = _used_queue_count++;
		_queue[index].setParameterId (pid);
		return &_queue[index];
  }
	index = 0;
	return 0;
}

/* ****************************************************************************/

RAMStream::RAMStream ()
	: _data (0)
	, _size (0)
	, _alloc (0)
	, _pos (0)
	, _readonly (false)
{
}

RAMStream::RAMStream (uint8_t* data, size_t size)
	: _data (0)
	, _size (size)
	, _alloc (0)
	, _pos (0)
	, _readonly (true)
{
	if (_size > 0 && reallocate_buffer (_size, true)) {
		memcpy (_data, data, _size);
	} else {
		_size = 0;
	}
}

RAMStream::RAMStream (std::string const& fn)
	: _data (0)
	, _size (0)
	, _alloc (0)
	, _pos (0)
	, _readonly (true)
{
	gchar* buf = NULL;
	gsize  length = 0;

	if (!g_file_get_contents (fn.c_str (), &buf, &length, NULL)) {
		return;
	}
	if (length > 0 && reallocate_buffer (length, true)) {
		_size = length;
		memcpy (_data, buf, _size);
	}
	g_free (buf);
}

RAMStream::~RAMStream ()
{
	free (_data);
}

tresult
RAMStream::queryInterface (const TUID _iid, void** obj)
{
  QUERY_INTERFACE (_iid, obj, FUnknown::iid, IBStream)
  QUERY_INTERFACE (_iid, obj, IBStream::iid, IBStream)
  QUERY_INTERFACE (_iid, obj, FUnknown::iid, ISizeableStream)
  QUERY_INTERFACE (_iid, obj, ISizeableStream::iid, ISizeableStream)
  QUERY_INTERFACE (_iid, obj, FUnknown::iid, Vst::IStreamAttributes)
  QUERY_INTERFACE (_iid, obj, Vst::IStreamAttributes::iid, Vst::IStreamAttributes)

  *obj = nullptr;
  return kNoInterface;
}

bool
RAMStream::reallocate_buffer (int64 size, bool exact)
{
	if (size <= 0) {
		free (_data);
		_data = 0;
		_alloc = 0;
		return true;
	}

	if (size == _alloc) {
		assert (_data);
		return true;
	}

	if (!exact) {
		if (size <= _alloc) {
			/* don't shrink */
			assert (_data);
			return true;
		}
		if (size > _alloc) {
			size = (((size - 1) / 8192) + 1) * 8192;
		}
	}

	_data = (uint8_t*) realloc (_data, size);

	if (_data) {
		_alloc = size;
		return true;
	} else {
		_alloc = 0;
		return false;
	}
}

tresult
RAMStream::read (void* buffer, int32 n_bytes, int32* n_read)
{
	assert (_pos >= 0 && _pos <= _size);
	int64 available = _size - _pos;

	if (n_bytes < 0 || available < 0) {
		n_bytes = 0;
	} else if (n_bytes > available) {
		n_bytes = available;
	}

	if (n_bytes > 0) {
		memcpy(buffer, &_data[_pos], n_bytes);
		_pos += n_bytes;
	}
	if (n_read) {
		*n_read = n_bytes;
	}
	return kResultTrue;
}

tresult
RAMStream::write (void* buffer, int32 n_bytes, int32* n_written)
{
	if (n_written) {
		*n_written = 0;
	}
	if (_readonly) {
		return kResultFalse;
	}
	if (n_bytes < 0) {
		return kInvalidArgument;
	}

	if (!reallocate_buffer (_pos + n_bytes, false)) {
		return kOutOfMemory;
	}

	if (buffer && _data && _pos >= 0 && n_bytes > 0) {
		memcpy (&_data[_pos], buffer, n_bytes);
		_pos += n_bytes;
		_size = _pos;
	} else {
		n_bytes = 0;
	}

	if (n_written) {
		*n_written = n_bytes;
	}
	return kResultTrue;
}

tresult
RAMStream::seek (int64 pos, int32 mode, int64* result)
{
	switch (mode) {
		case kIBSeekSet:
			_pos = pos;
			break;
		case kIBSeekCur:
			_pos += pos;
			break;
		case kIBSeekEnd:
			_pos = _size + pos;
			break;
		default:
			return kInvalidArgument;
	}
	if (_pos < 0) {
		_pos = 0;
	}
	if (result) {
		*result = _pos;
	}
	return kResultTrue;
}

tresult
RAMStream::tell (int64* pos)
{
	if (!pos) {
		return kInvalidArgument;
	}
	*pos = _pos;
	return kResultTrue;
}

bool
RAMStream::write_int32 (int32 i) {
	/* pluginterfaces/base/ftypes.h */
#if BYTEORDER == kBigEndian
	SWAP_32 (i)
#endif
	return write_pod (i);
}

bool
RAMStream::write_int64 (int64 i)
{
	/* pluginterfaces/base/ftypes.h */
#if BYTEORDER == kBigEndian
	SWAP_64 (i)
#endif
	return write_pod (i);
}

bool
RAMStream::write_ChunkID (const Vst::ChunkID& id)
{
	return write_pod (id);
}

#if COM_COMPATIBLE
/* pluginterfaces/base/funknown.cpp */
struct GUIDStruct {
	uint32_t data1;
	uint16_t data2;
	uint16_t data3;
	uint8_t data4[8];
};
#endif

bool
RAMStream::write_TUID (const TUID& tuid)
{
	int i = 0;
	int32 n_bytes = 0;
	char buf[Vst::kClassIDSize + 1];

#if COM_COMPATIBLE
	GUIDStruct guid;
	memcpy (&guid, tuid, sizeof(GUIDStruct));
	sprintf(buf, "%08X%04X%04X", guid.data1, guid.data2, guid.data3);
	i += 8;
#endif

	for (; i < (int)sizeof(TUID); ++i){
		sprintf(buf + 2 * i, "%02X", (uint8_t)tuid[i]);
	}
	write (buf, Vst::kClassIDSize, &n_bytes);
	return n_bytes == Vst::kClassIDSize;
}

bool
RAMStream::read_int32 (int32& i) {
	if (!read_pod (i)) {
		return false;
	}
#if BYTEORDER == kBigEndian
	SWAP_32 (i)
#endif
	return true;
}

bool
RAMStream::read_int64 (int64& i) {
	if (!read_pod (i)) {
		return false;
	}
#if BYTEORDER == kBigEndian
	SWAP_64 (i)
#endif
	return true;
}

bool
RAMStream::read_ChunkID (Vst::ChunkID& id)
{
	return read_pod (id);
}

bool
RAMStream::read_TUID (TUID& tuid)
{
	int i = 0;
	int32 n_bytes = 0;
	char buf[Vst::kClassIDSize+1];

	read((void *)buf, Vst::kClassIDSize, &n_bytes);
	if (n_bytes != Vst::kClassIDSize) {
		return false;
	}

	buf[Vst::kClassIDSize] = '\0';

#if COM_COMPATIBLE
	GUIDStruct guid;
	sscanf (buf,    "%08x",  &guid.data1);
	sscanf (buf+8,  "%04hx", &guid.data2);
	sscanf (buf+12, "%04hx", &guid.data3);
	memcpy (tuid, &guid, sizeof(TUID) >> 1);
	i += 16;
#endif

	for (; i < Vst::kClassIDSize; i += 2){
		uint32_t temp;
		sscanf (buf + i, "%02X", &temp);
		tuid[i >> 1] = temp;
	}

	return true;
}

tresult
RAMStream::getStreamSize (int64& size)
{
	size = _alloc;
	return kResultTrue;
}

tresult
RAMStream::setStreamSize (int64 size)
{
	if (_readonly) {
		return kResultFalse;
	}
	return reallocate_buffer (size, true) ? kResultOk : kOutOfMemory;
}

tresult
RAMStream::getFileName (Vst::String128 name)
{
	return kNotImplemented;
}

Vst::IAttributeList*
RAMStream::getAttributes ()
{
	return &attribute_list;
}

#ifndef NDEBUG

#include <iostream>
#include <sstream>
#include <iomanip>

void
RAMStream::hexdump (int64 max_len) const
{
	std::ostringstream out;

	size_t row_size = 16;
	size_t length = max_len > 0 ? std::min (max_len, _size) : _size;

	out << std::setfill('0');
	for (size_t i = 0; i < length; i += row_size) {
		out << "0x" << std::setw(6) << std::hex << i << ": ";
		for (size_t j = 0; j < row_size; ++j) {
			if (i + j < length) {
				out << std::hex << std::setw(2) << static_cast<int>(_data[i + j]) << " ";
			} else {
				out << "   ";
			}
		}
		out << " ";
		if (true) {
			for (size_t j = 0; j < row_size; ++j) {
				if (i + j < length) {
					if (isprint(_data[i + j])) {
						out << static_cast<char>(_data[i + j]);
					} else {
						out << ".";
					}
				}
			}
		}
		out << std::endl;
	}
	std::cout << out.str ();
}
#endif

ROMStream::ROMStream (IBStream& src, TSize offset, TSize size)
	: _stream (src)
	, _offset (offset)
	, _size   (size)
	, _pos   (0)
{
	_stream.addRef ();
}

ROMStream::~ROMStream ()
{
	_stream.release ();
}

tresult
ROMStream::queryInterface (const TUID _iid, void** obj)
{
  QUERY_INTERFACE (_iid, obj, FUnknown::iid, IBStream)
  QUERY_INTERFACE (_iid, obj, IBStream::iid, IBStream)

  *obj = nullptr;
  return kNoInterface;
}

tresult
ROMStream::read (void* buffer, int32 n_bytes, int32* n_read)
{
	int64 available = _size - _pos;

	if (n_read) {
		*n_read = 0;
	}

	if (n_bytes < 0 || available < 0) {
		n_bytes = 0;
		return kResultOk;
	}

	if (n_bytes > available) {
		n_bytes = available;
	}

	tresult result = _stream.seek (_offset + _pos, kIBSeekSet);
	if (result != kResultOk) {
		return result;
	}

	int32 _n_read = 0;
	result = _stream.read (buffer, n_bytes, &_n_read);

  if (_n_read > 0) {
    _pos += _n_read;
	}
  if (n_read) {
    *n_read = _n_read;
	}

  return result;
}

tresult
ROMStream::write (void* buffer, int32 n_bytes, int32* n_written)
{
	if (n_written) {
		*n_written = 0;
	}
	return kNotImplemented;
}

tresult
ROMStream::seek (int64 pos, int32 mode, int64* result)
{
	switch (mode) {
		case kIBSeekSet:
			_pos = pos;
			break;
		case kIBSeekCur:
			_pos += pos;
			break;
		case kIBSeekEnd:
			_pos = _size + pos;
			break;
		default:
			return kInvalidArgument;
	}
	if (_pos < 0) {
		_pos = 0;
	}
	if (_pos > _size) {
		_pos = _size;
	}

	if (result) {
		*result = _pos;
	}
	return kResultTrue;
}

tresult
ROMStream::tell (int64* pos)
{
	if (!pos) {
		return kInvalidArgument;
	}
	*pos = _pos;
	return kResultTrue;
}
