kits/media/ParameterWeb.cpp

/*
 * Copyright 2002-2012, Haiku. All Rights Reserved.
 * This file may be used under the terms of the MIT License.
 *
 * Author: Zousar Shaker
 *         Axel D��rfler, axeld@pinc-software.de
 *         Marcus Overhagen
 */


/*! Implements the following classes:
	BParameterWeb, BParameterGroup, BParameter, BNullParameter,
	BContinuousParameter, BDiscreteParameter
*/


#include <ParameterWeb.h>

#include <new>
#include <string.h>

#include <MediaNode.h>
#include <MediaRoster.h>

#include "DataExchange.h"
#include "debug.h"
#include "MediaMisc.h"


/*
	The following is documentation on the flattened format
	of structures/classes in this module:

	//--------BEGIN-CORE-BPARAMETER-STRUCT---------------------
	?? (0x02040607): 4 bytes
	BParameter Struct Size (in bytes): 4 bytes
	ID: 4 bytes
	Name String Length: 1 byte (??)
		Name String: 'Name String Length' bytes
	Kind String Length: 1 byte (??)
		Kind String: 'Kind String Length' bytes
	Unit String Length: 1 byte (??)
		Unit String: 'Unit String Length' bytes
	Inputs Count: 4 bytes
		Inputs (pointers): ('Inputs Count')*4 bytes
	Outputs Count: 4 bytes
		Outputs (pointers): ('Outputs Count')*4 bytes
	Media Type: 4 bytes
	ChannelCount: 4 bytes
	Flags: 4 bytes
	//---------END-CORE-BPARAMETER-STRUCT-----------------------
	//--------BEGIN-BCONTINUOUSPARAMETER-STRUCT---------
	Min: 4 bytes (as float)
	Max: 4 bytes (as float)
	Stepping: 4 bytes (as float)
	Response: 4 bytes (as int or enum)
	Factor: 4 bytes (as float)
	Offset: 4 bytes (as float)
	//--------END-BCONTINUOUSPARAMETER-STRUCT-------------
	//--------BEGIN-BDISCRETEPARAMETER-STRUCT----------------
	NumItems: 4 bytes (as int)
		//for each item BEGIN
		Item Name String Length: 1 byte
			Item Name String: 'Item Name String Length' bytes
		Item Value: 4 bytes (as int)
		//for each item END
	//--------END-BDISCRETEPARAMETER-STRUCT-------------------

	//--------BEGIN-CORE-BPARAMETERGROUP-STRUCT-----------
	?? (0x03040507 OR 0x03040509 depending if the flags field is included or not???): 4 bytes
	(possible) Flags: 4 bytes
	Name String Length: 1 byte (??)
		Name String: 'Name String Length' bytes
	Param Count: 4 bytes
		//for each Param BEGIN
		Pointer: 4 bytes
		Parameter Type: 4 bytes
		Flattened Parameter Size: 4 bytes
		Flattened Parameter: 'Flattened Parameter Size' bytes
		//for each Param END
	Subgroup Count: 4 bytes
		//for each SubGroup BEGIN
		Pointer: 4 bytes
		MEDIA PARAMETER GROUP TYPE('BMCG' (opposite byte order in file)): 4 bytes
		Flattened Group Size: 4 bytes
		Flattened Group: 'Flattened Group Size' bytes
		//for each SubGroup END

	//---------END-CORE-BPARAMETERGROUP-STRUCT--------------

	//--------BEGIN-CORE-BPARAMETERWEB-STRUCT-----------
	?? 0x01030506: 4 bytes
	??: 4 bytes (is always 1)
	Group Count: 4 bytes
	Node (as media_node): 0x18 bytes (decimal 24 bytes)
		//for each Group BEGIN
		Flattened Group Size: 4 bytes
		Flattened Group: 'Flattened Group Size' bytes
		//for each Group END
		//for each Group BEGIN
		??: 4 bytes (never get written to (holds uninitialized value))
		//for each Group END
	//---------END-CORE-BPARAMETERWEB-STRUCT--------------

*/


const char * const B_GENERIC			 = "";
const char * const B_MASTER_GAIN		 = "Master";
const char * const B_GAIN				 = "Gain";
const char * const B_BALANCE			 = "Balance";
const char * const B_FREQUENCY			 = "Frequency";
const char * const B_LEVEL				 = "Level";
const char * const B_SHUTTLE_SPEED		 = "Speed";
const char * const B_CROSSFADE			 = "XFade";
const char * const B_EQUALIZATION		 = "EQ";
const char * const B_COMPRESSION		 = "Compression";
const char * const B_QUALITY			 = "Quality";
const char * const B_BITRATE			 = "Bitrate";
const char * const B_GOP_SIZE			 = "GOPSize";
const char * const B_MUTE				 = "Mute";
const char * const B_ENABLE				 = "Enable";
const char * const B_INPUT_MUX			 = "Input";
const char * const B_OUTPUT_MUX			 = "Output";
const char * const B_TUNER_CHANNEL		 = "Channel";
const char * const B_TRACK				 = "Track";
const char * const B_RECSTATE			 = "RecState";
const char * const B_SHUTTLE_MODE		 = "Shuttle";
const char * const B_RESOLUTION			 = "Resolution";
const char * const B_COLOR_SPACE		 = "Colorspace";
const char * const B_FRAME_RATE			 = "FrameRate";
const char * const B_VIDEO_FORMAT		 = "VideoFormat";
const char * const B_WEB_PHYSICAL_INPUT	 = "PhysInput";
const char * const B_WEB_PHYSICAL_OUTPUT = "PhysOutput";
const char * const B_WEB_ADC_CONVERTER	 = "ADC";
const char * const B_WEB_DAC_CONVERTER	 = "DAC";
const char * const B_WEB_LOGICAL_INPUT	 = "LogInput";
const char * const B_WEB_LOGICAL_OUTPUT	 = "LogOutput";
const char * const B_WEB_LOGICAL_BUS	 = "LogBus";
const char * const B_WEB_BUFFER_INPUT	 = "DataInput";
const char * const B_WEB_BUFFER_OUTPUT	 = "DataOutput";
const char * const B_SIMPLE_TRANSPORT	 = "SimpleTransport";

// Flattened data

static const int32 kCurrentParameterWebVersion = 1;
static const uint32 kParameterWebMagic = 0x01030506;
static const uint32 kBufferGroupMagic = 0x03040509;
static const uint32 kBufferGroupMagicNoFlags = 0x03040507;
static const uint32 kParameterMagic = 0x02040607;

static const ssize_t kAdditionalParameterGroupSize = 12;
static const ssize_t kAdditionalParameterSize = 35;

/* BContinuousParameter - FlattenedSize() fixed part
 *	Min: 4 bytes (as float)
 *	Max: 4 bytes (as float)
 *	Stepping: 4 bytes (as float)
 *	Response: 4 bytes (as int or enum)
 *	Factor: 4 bytes (as float)
 *	Offset: 4 bytes (as float)
 */
static const ssize_t kAdditionalContinuousParameterSize = 24;
static const ssize_t kAdditionalDiscreteParameterSize = sizeof(ssize_t);


// helper functions


template<class Type> Type
read_from_buffer(const void **_buffer)
{
	const Type *typedBuffer = static_cast<const Type *>(*_buffer);
	Type value = *typedBuffer;

	typedBuffer++;
	*_buffer = static_cast<const void *>(typedBuffer);

	return value;
}


static status_t
read_string_from_buffer(const void **_buffer, char **_string, ssize_t size)
{
	if (size < 1)
		return B_BAD_VALUE;

	const uint8 *buffer = static_cast<const uint8 *>(*_buffer);
	uint8 length = *buffer++;
	if (length > size - 1)
		return B_BAD_VALUE;

	char *string = (char *)malloc(length + 1);
	if (string == NULL)
		return B_NO_MEMORY;

	memcpy(string, buffer, length);
	string[length] = '\0';

	*_buffer = static_cast<const void *>(buffer + length);
	*_string = string;
	return B_OK;
}


// currently unused
#if 0
template<class Type> Type *
reserve_in_buffer(void **_buffer)
{
	Type *typedBuffer = static_cast<Type *>(*_buffer);

	*typedBuffer = 0;
	typedBuffer++;

	*_buffer = static_cast<void *>(typedBuffer);
}
#endif

template<class Type> void
write_to_buffer(void **_buffer, Type value)
{
	Type *typedBuffer = static_cast<Type *>(*_buffer);

	*typedBuffer = value;
	typedBuffer++;

	*_buffer = static_cast<void *>(typedBuffer);
}


void
write_string_to_buffer(void **_buffer, const char *string)
{
	uint8 *buffer = static_cast<uint8 *>(*_buffer);
	uint32 length = string ? strlen(string) : 0;
	if (length > 255)
		length = 255;

	*buffer++ = static_cast<uint8>(length);
	if (length) {
		memcpy(buffer, string, length);
		buffer += length;
	}

	*_buffer = static_cast<void *>(buffer);
}


static void
skip_in_buffer(const void **_buffer, uint32 bytes)
{
	const uint8 *buffer = static_cast<const uint8 *>(*_buffer);

	buffer += bytes;

	*_buffer = static_cast<const void *>(buffer);
}


static void inline
skip_in_buffer(void **_buffer, uint32 bytes)
{
	// This actually shouldn't be necessary, but I believe it's a
	// bug in Be's gcc - it complains about "adds cv-quals without intervening `const'"
	// when passing a "const void **" pointer as the first argument.
	// Maybe I am just stupid, though -- axeld.

	skip_in_buffer((const void **)_buffer, bytes);
}


template<class Type> Type
swap32(Type value, bool doSwap)
{
	STATIC_ASSERT(sizeof(Type) == 4);

	if (doSwap)
		return (Type)B_SWAP_INT32((int32)value);

	return value;
}


template<class Type> Type
swap64(Type value, bool doSwap)
{
	STATIC_ASSERT(sizeof(Type) == 8);

	if (doSwap)
		return (Type)B_SWAP_INT64((int64)value);

	return value;
}


template<class Type> Type
read_from_buffer_swap32(const void **_buffer, bool doSwap)
{
	return swap32<Type>(read_from_buffer<Type>(_buffer), doSwap);
}


template<class Type> Type
read_pointer_from_buffer_swap(const void **_buffer, bool doSwap)
{
#if B_HAIKU_32_BIT
	return swap32<Type>(read_from_buffer<Type>(_buffer), doSwap);
#elif B_HAIKU_64_BIT
	return swap64<Type>(read_from_buffer<Type>(_buffer), doSwap);
#else
#	error Interesting
#endif
}


static inline ssize_t
size_left(ssize_t size, const void *bufferStart, const void *buffer)
{
	return size - static_cast<ssize_t>((const uint8 *)buffer - (const uint8 *)bufferStart);
}


//	#pragma mark - BParameterWeb


BParameterWeb::BParameterWeb()
	:
	fNode(media_node::null)
		// fNode is set in BControllable::SetParameterWeb()
{
	CALLED();

	fGroups = new BList();
	fOldRefs = new BList();
	fNewRefs = new BList();
}


BParameterWeb::~BParameterWeb()
{
	CALLED();

	for (int32 i = fGroups->CountItems(); i-- > 0;) {
		delete static_cast<BParameterGroup*>(fGroups->ItemAt(i));
	}

	delete fGroups;
	delete fOldRefs;
	delete fNewRefs;
}


media_node
BParameterWeb::Node()
{
	return fNode;
}


BParameterGroup*
BParameterWeb::MakeGroup(const char* name)
{
	CALLED();

	BParameterGroup* group = new(std::nothrow) BParameterGroup(this, name);
	if (group == NULL)
		return NULL;

	if (!fGroups->AddItem(group)) {
		delete group;
		return NULL;
	}

	return group;
}


int32
BParameterWeb::CountGroups()
{
	return fGroups->CountItems();
}


BParameterGroup*
BParameterWeb::GroupAt(int32 index)
{
	return static_cast<BParameterGroup*>(fGroups->ItemAt(index));
}


int32
BParameterWeb::CountParameters()
{
	CALLED();

	// Counts over all groups (and sub-groups) in the web.
	// The "groups" list is used as count stack

	BList groups(*fGroups);
	int32 count = 0;

	for (int32 i = 0; i < groups.CountItems(); i++) {
		BParameterGroup* group
			= static_cast<BParameterGroup*>(groups.ItemAt(i));

		count += group->CountParameters();

		if (group->fGroups != NULL)
			groups.AddList(group->fGroups);
	}

	return count;
}


BParameter*
BParameterWeb::ParameterAt(int32 index)
{
	CALLED();

	// Iterates over all groups (and sub-groups) in the web.
	// The "groups" list is used as iteration stack (breadth search style)
	// Maintains the same order as the Be implementation

	BList groups(*fGroups);

	for (int32 i = 0; i < groups.CountItems(); i++) {
		BParameterGroup* group
			= static_cast<BParameterGroup*>(groups.ItemAt(i));
		int32 count = group->CountParameters();
		if (index < count)
			return group->ParameterAt(index);

		index -= count;
			// the index is always relative to the start of the current group

		if (group->fGroups != NULL)
			groups.AddList(group->fGroups);
	}

	TRACE("*** could not find parameter at %ld (count = %ld)\n", index,
		CountParameters());
	return NULL;
}


bool
BParameterWeb::IsFixedSize() const
{
	return false;
}


type_code
BParameterWeb::TypeCode() const
{
	return B_MEDIA_PARAMETER_WEB_TYPE;
}


ssize_t
BParameterWeb::FlattenedSize() const
{
	CALLED();

/*
	//--------BEGIN-CORE-BPARAMETERWEB-STRUCT-----------
	?? 0x01030506: 4 bytes
	??: 4 bytes (is always 1)
	Group Count: 4 bytes
	Node (as media_node): 0x18 bytes (decimal 24 bytes)
		//for each Group BEGIN
		Flattened Group Size: 4 bytes
		Flattened Group: 'Flattened Group Size' bytes
		//for each Group END
		//for each Group BEGIN
		??: 4 bytes (never get written to (holds uninitialized value))
		//for each Group END
	//---------END-CORE-BPARAMETERWEB-STRUCT--------------
*/
	//36 guaranteed bytes, variable after that.
	ssize_t size = sizeof(int32) + 2 * sizeof(int32) + sizeof(media_node);

	for (int32 i = fGroups->CountItems(); i-- > 0;) {
		BParameterGroup* group
			= static_cast<BParameterGroup*>(fGroups->ItemAt(i));
		if (group != NULL) {
			size += 4 + group->FlattenedSize();
				// 4 bytes for the flattened size
		}
	}

	return size;
}


status_t
BParameterWeb::Flatten(void* buffer, ssize_t size) const
{
	CALLED();

	if (buffer == NULL)
		return B_NO_INIT;

	ssize_t actualSize = BParameterWeb::FlattenedSize();
	if (size < actualSize)
		return B_NO_MEMORY;

	void* bufferStart = buffer;

	write_to_buffer<int32>(&buffer, kParameterWebMagic);
	write_to_buffer<int32>(&buffer, kCurrentParameterWebVersion);

	// flatten all groups into this buffer

	int32 count = fGroups->CountItems();
	write_to_buffer<int32>(&buffer, count);

	write_to_buffer<media_node>(&buffer, fNode);

	for (int32 i = 0; i < count; i++) {
		BParameterGroup* group
			= static_cast<BParameterGroup*>(fGroups->ItemAt(i));
		if (group == NULL) {
			ERROR("BParameterWeb::Flatten(): group is NULL\n");
			continue;
		}

		ssize_t groupSize = group->FlattenedSize();
		if (groupSize > size_left(size, bufferStart, buffer)) {
			ERROR("BParameterWeb::Flatten(): buffer too small\n");
			return B_BAD_VALUE;
		}

		write_to_buffer<ssize_t>(&buffer, groupSize);

		// write the flattened sub group
		status_t status = group->Flatten(buffer, groupSize);
		if (status < B_OK)
			return status;

		skip_in_buffer(&buffer, groupSize);
	}

	return B_OK;
}


bool
BParameterWeb::AllowsTypeCode(type_code code) const
{
	return code == TypeCode();
}


status_t
BParameterWeb::Unflatten(type_code code, const void* buffer, ssize_t size)
{
	CALLED();

	if (!AllowsTypeCode(code)) {
		ERROR("BParameterWeb::Unflatten(): wrong type code\n");
		return B_BAD_TYPE;
	}

	if (buffer == NULL) {
		ERROR("BParameterWeb::Unflatten(): NULL buffer pointer\n");
		return B_NO_INIT;
	}

	// if the buffer is smaller than the size needed to read the
	// signature field, the mystery field, the group count, and the Node, then there is a problem
	if (size < static_cast<ssize_t>(sizeof(int32) + sizeof(int32)
			+ sizeof(ssize_t) + sizeof(media_node))) {
		ERROR("BParameterWeb::Unflatten(): size to small\n");
		return B_ERROR;
	}

	const void* bufferStart = buffer;

	uint32 magic = read_from_buffer<uint32>(&buffer);
	bool isSwapped = false;

	if (magic == B_SWAP_INT32(kParameterWebMagic)) {
		isSwapped = true;
		magic = B_SWAP_INT32(magic);
	}
	if (magic != kParameterWebMagic)
		return B_BAD_DATA;

	// Note, it's not completely sure that this field is the version
	// information - but it doesn't seem to have another purpose
	int32 version = read_from_buffer_swap32<int32>(&buffer, isSwapped);
	if (version != kCurrentParameterWebVersion) {
		ERROR("BParameterWeb::Unflatten(): wrong version %" B_PRId32 " (%"
			B_PRIx32 ")?!\n", version, version);
		return B_ERROR;
	}

	for (int32 i = 0; i < fGroups->CountItems(); i++) {
		delete static_cast<BParameterGroup*>(fGroups->ItemAt(i));
	}
	fGroups->MakeEmpty();

	int32 count = read_from_buffer_swap32<int32>(&buffer, isSwapped);

	fNode = read_from_buffer<media_node>(&buffer);
	if (isSwapped)
		swap_data(B_INT32_TYPE, &fNode, sizeof(media_node), B_SWAP_ALWAYS);

	for (int32 i = 0; i < count; i++) {
		ssize_t groupSize
			= read_from_buffer_swap32<ssize_t>(&buffer, isSwapped);
		if (groupSize > size_left(size, bufferStart, buffer)) {
			ERROR("BParameterWeb::Unflatten(): buffer too small\n");
			return B_BAD_DATA;
		}

		BParameterGroup* group = new BParameterGroup(this, "unnamed");
		status_t status = group->Unflatten(group->TypeCode(), buffer,
			groupSize);
		if (status < B_OK) {
			ERROR("BParameterWeb::Unflatten(): unflatten group failed\n");
			delete group;
			return status;
		}

		skip_in_buffer(&buffer, groupSize);

		fGroups->AddItem(group);
	}

	// fix all references (ParameterAt() style)

	BList groups(*fGroups);

	for (int32 i = 0; i < groups.CountItems(); i++) {
		BParameterGroup* group
			= static_cast<BParameterGroup*>(groups.ItemAt(i));

		for (int32 index = group->CountParameters(); index-- > 0;) {
			BParameter* parameter
				= static_cast<BParameter*>(group->ParameterAt(index));

			parameter->FixRefs(*fOldRefs, *fNewRefs);
		}

		if (group->fGroups != NULL)
			groups.AddList(group->fGroups);
	}

	fOldRefs->MakeEmpty();
	fNewRefs->MakeEmpty();

	return B_OK;
}


void
BParameterWeb::AddRefFix(void* oldItem, void* newItem)
{
	fOldRefs->AddItem(oldItem);
	fNewRefs->AddItem(newItem);
}


//	#pragma mark - BParameterGroup


BParameterGroup::BParameterGroup(BParameterWeb* web, const char* name)
	:
	fWeb(web),
	fFlags(0)
{
	CALLED();
	TRACE("BParameterGroup: web = %p, name = \"%s\"\n", web, name);

	fName = strndup(name, 255);

	fControls = new BList();
	fGroups = new BList();
}


BParameterGroup::~BParameterGroup()
{
	CALLED();

	for (int i = fControls->CountItems(); i-- > 0;) {
		delete static_cast<BParameter*>(fControls->ItemAt(i));
	}
	delete fControls;

	for (int i = fGroups->CountItems(); i-- > 0;) {
		delete static_cast<BParameterGroup*>(fGroups->ItemAt(i));
	}
	delete fGroups;

	free(fName);
}


BParameterWeb*
BParameterGroup::Web() const
{
	return fWeb;
}


const char*
BParameterGroup::Name() const
{
	return fName;
}


void
BParameterGroup::SetFlags(uint32 flags)
{
	fFlags = flags;
}


uint32
BParameterGroup::Flags() const
{
	return fFlags;
}


BNullParameter*
BParameterGroup::MakeNullParameter(int32 id, media_type mediaType,
	const char* name, const char* kind)
{
	CALLED();

	BNullParameter* parameter = new(std::nothrow) BNullParameter(id, mediaType,
		fWeb, name, kind);
	if (parameter == NULL)
		return NULL;

	parameter->fGroup = this;
	fControls->AddItem(parameter);

	return parameter;
}


BContinuousParameter*
BParameterGroup::MakeContinuousParameter(int32 id, media_type mediaType,
	const char* name, const char* kind, const char* unit,
	float minimum, float maximum, float stepping)
{
	CALLED();

	BContinuousParameter* parameter
		= new(std::nothrow) BContinuousParameter(id, mediaType, fWeb, name,
			kind, unit, minimum, maximum, stepping);
	if (parameter == NULL)
		return NULL;

	parameter->fGroup = this;
	fControls->AddItem(parameter);

	return parameter;
}


BDiscreteParameter*
BParameterGroup::MakeDiscreteParameter(int32 id, media_type mediaType,
	const char* name, const char* kind)
{
	CALLED();

	BDiscreteParameter* parameter = new(std::nothrow) BDiscreteParameter(id,
		mediaType, fWeb, name, kind);
	if (parameter == NULL)
		return NULL;

	parameter->fGroup = this;
	fControls->AddItem(parameter);

	return parameter;
}


BTextParameter*
BParameterGroup::MakeTextParameter(int32 id, media_type mediaType,
	const char* name, const char* kind, size_t maxBytes)
{
	CALLED();

	BTextParameter* parameter = new(std::nothrow) BTextParameter(id, mediaType,
		fWeb, name, kind, maxBytes);
	if (parameter == NULL)
		return NULL;

	parameter->fGroup = this;
	fControls->AddItem(parameter);

	return parameter;
}


BParameterGroup*
BParameterGroup::MakeGroup(const char* name)
{
	CALLED();

	BParameterGroup* group = new(std::nothrow) BParameterGroup(fWeb, name);
	if (group != NULL)
		fGroups->AddItem(group);

	return group;
}


int32
BParameterGroup::CountParameters()
{
	return fControls->CountItems();
}


BParameter*
BParameterGroup::ParameterAt(int32 index)
{
	return static_cast<BParameter*>(fControls->ItemAt(index));
}


int32
BParameterGroup::CountGroups()
{
	return fGroups->CountItems();
}


BParameterGroup*
BParameterGroup::GroupAt(int32 index)
{
	return static_cast<BParameterGroup*>(fGroups->ItemAt(index));
}


bool
BParameterGroup::IsFixedSize() const
{
	return false;
}


type_code
BParameterGroup::TypeCode() const
{
	return B_MEDIA_PARAMETER_GROUP_TYPE;
}


ssize_t
BParameterGroup::FlattenedSize() const
{
	CALLED();

	/*
		//--------BEGIN-CORE-BPARAMETERGROUP-STRUCT-----------
		?? (0x03040507 OR 0x03040509 depending if the flags field is included or not???): 4 bytes
		(possible) Flags: 4 bytes
		Name String Length: 1 byte (??)
			Name String: 'Name String Length' bytes
		Param Count: 4 bytes
			//for each Param BEGIN
			Pointer: 4 bytes
			Parameter Type: 4 bytes
			Flattened Parameter Size: 4 bytes
			Flattened Parameter: 'Flattened Parameter Size' bytes
			//for each Param END
		Subgroup Count: 4 bytes
			//for each SubGroup BEGIN
			Pointer: 4 bytes
			MEDIA PARAMETER GROUP TYPE('BMCG' (opposite byte order in file)): 4 bytes
			Flattened Group Size: 4 bytes
			Flattened Group: 'Flattened Group Size' bytes
			//for each SubGroup END

		//---------END-CORE-BPARAMETERGROUP-STRUCT--------------
	*/
	//13 guaranteed bytes, variable after that.
	ssize_t size = 13;

	if (fFlags != 0)
		size += 4;

	if (fName != NULL)
		size += min_c(strlen(fName), 255);

	int limit = fControls->CountItems();
	for (int i = 0; i < limit; i++) {
		BParameter* parameter = static_cast<BParameter*>(fControls->ItemAt(i));
		if (parameter != NULL) {
			// overhead for each parameter flattened
			size += 16 + parameter->FlattenedSize();
		}
	}

	limit = fGroups->CountItems();
	for (int i = 0; i < limit; i++) {
		BParameterGroup* group
			= static_cast<BParameterGroup*>(fGroups->ItemAt(i));
		if (group != NULL) {
			// overhead for each group flattened
			size += 16 + group->FlattenedSize();
		}
	}

	return size;
}


status_t
BParameterGroup::Flatten(void* buffer, ssize_t size) const
{
	CALLED();

	if (buffer == NULL) {
		ERROR("BParameterGroup::Flatten buffer is NULL\n");
		return B_NO_INIT;
	}

	// NOTICE: It is important that this value is the size returned by
	// BParameterGroup::FlattenedSize, not by a descendent's override of this method.
	ssize_t actualSize = BParameterGroup::FlattenedSize();
	if (size < actualSize) {
		ERROR("BParameterGroup::Flatten size to small\n");
		return B_NO_MEMORY;
	}

	if (fFlags != 0) {
		write_to_buffer<int32>(&buffer, kBufferGroupMagic);
		write_to_buffer<uint32>(&buffer, fFlags);
	} else
		write_to_buffer<int32>(&buffer, kBufferGroupMagicNoFlags);

	write_string_to_buffer(&buffer, fName);

	int32 count = fControls->CountItems();
	write_to_buffer<int32>(&buffer, count);

	for (int32 i = 0; i < count; i++) {
		BParameter* parameter = static_cast<BParameter*>(fControls->ItemAt(i));
		if (parameter == NULL) {
			ERROR("BParameterGroup::Flatten(): NULL parameter\n");
			continue;
		}

		write_to_buffer<BParameter*>(&buffer, parameter);
		write_to_buffer<BParameter::media_parameter_type>(&buffer,
			parameter->Type());

		// flatten parameter into this buffer

		ssize_t parameterSize = parameter->FlattenedSize();
		write_to_buffer<ssize_t>(&buffer, parameterSize);

		status_t status = parameter->Flatten(buffer, parameterSize);
			// we have only that much bytes left to write in this buffer
		if (status < B_OK)
			return status;

		skip_in_buffer(&buffer, parameterSize);
	}

	count = fGroups->CountItems();
	write_to_buffer<int32>(&buffer, count);

	for (int32 i = 0; i < count; i++) {
		BParameterGroup* group
			= static_cast<BParameterGroup*>(fGroups->ItemAt(i));
		if (group == NULL) {
			ERROR("BParameterGroup::Flatten(): NULL group\n");
			continue;
		}

		write_to_buffer<BParameterGroup*>(&buffer, group);
		write_to_buffer<type_code>(&buffer, group->TypeCode());

		// flatten sub group into this buffer

		ssize_t groupSize = group->FlattenedSize();
		write_to_buffer<ssize_t>(&buffer, groupSize);

		status_t status = group->Flatten(buffer, groupSize);
			// we have only that much bytes left to write in this buffer
		if (status < B_OK)
			return status;

		skip_in_buffer(&buffer, groupSize);
	}

	return B_OK;
}


bool
BParameterGroup::AllowsTypeCode(type_code code) const
{
	return code == TypeCode();
}


status_t
BParameterGroup::Unflatten(type_code code, const void* buffer, ssize_t size)
{
	CALLED();

	if (!AllowsTypeCode(code)) {
		ERROR("BParameterGroup::Unflatten() wrong type code\n");
		return B_BAD_TYPE;
	}

	if (buffer == NULL) {
		ERROR("BParameterGroup::Unflatten() buffer is NULL\n");
		return B_NO_INIT;
	}

	// if the buffer is smaller than the size needed to read the
	// signature field, then there is a problem
	if (size < static_cast<ssize_t>(sizeof(int32))) {
		ERROR("BParameterGroup::Unflatten() size to small\n");
		return B_ERROR;
	}

	const void* bufferStart = buffer;
		// used to compute the rest length of the buffer when needed

	uint32 magic = read_from_buffer<uint32>(&buffer);
	bool isSwapped = false;

	if (magic == B_SWAP_INT32(kBufferGroupMagic)
		|| magic == B_SWAP_INT32(kBufferGroupMagicNoFlags)) {
		isSwapped = true;
		magic = B_SWAP_INT32(magic);
	}

	if (magic == kBufferGroupMagic)
		fFlags = read_from_buffer_swap32<int32>(&buffer, isSwapped);
	else if (magic == kBufferGroupMagicNoFlags)
		fFlags = 0;
	else
		return B_BAD_TYPE;

	if (read_string_from_buffer(&buffer, &fName,
			size - (ssize_t)((uint8*)buffer - (uint8*)bufferStart)) < B_OK)
		return B_BAD_VALUE;

	// Clear all existing parameters/subgroups
	for (int32 i = 0; i < fControls->CountItems(); i++) {
		delete static_cast<BParameter*>(fControls->ItemAt(i));
	}
	fControls->MakeEmpty();

	for (int32 i = 0; i < fGroups->CountItems(); i++) {
		delete static_cast<BParameterGroup*>(fGroups->ItemAt(i));
	}
	fGroups->MakeEmpty();

	// unflatten parameter list

	int32 count = read_from_buffer_swap32<int32>(&buffer, isSwapped);
	if (count < 0 || count * kAdditionalParameterSize
			> size_left(size, bufferStart, buffer))
		return B_BAD_VALUE;

	for (int32 i = 0; i < count; i++) {
		// make sure we can read as many bytes
		if (size_left(size, bufferStart, buffer) < 12)
			return B_BAD_VALUE;

		BParameter* oldPointer = read_pointer_from_buffer_swap<BParameter*>(
			&buffer, isSwapped);
		BParameter::media_parameter_type mediaType
			= read_from_buffer_swap32<BParameter::media_parameter_type>(&buffer,
				isSwapped);

		ssize_t parameterSize = read_from_buffer_swap32<ssize_t>(&buffer,
			isSwapped);
		if (parameterSize > size_left(size, bufferStart, buffer))
			return B_BAD_VALUE;

		BParameter* parameter = MakeControl(mediaType);
		if (parameter == NULL) {
			ERROR("BParameterGroup::Unflatten(): MakeControl() failed\n");
			return B_ERROR;
		}

		status_t status = parameter->Unflatten(parameter->TypeCode(), buffer,
			parameterSize);
		if (status < B_OK) {
			ERROR("BParameterGroup::Unflatten(): parameter->Unflatten() failed\n");
			delete parameter;
			return status;
		}

		skip_in_buffer(&buffer, parameterSize);

		// add the item to the list
		parameter->fGroup = this;
		parameter->fWeb = fWeb;
		fControls->AddItem(parameter);

		// add it's old pointer value to the RefFix list kept by the owner web
		if (fWeb != NULL)
			fWeb->AddRefFix(oldPointer, parameter);
	}

	// unflatten sub groups

	count = read_from_buffer_swap32<int32>(&buffer, isSwapped);
	if (count < 0 || count * kAdditionalParameterGroupSize
			> size_left(size, bufferStart, buffer))
		return B_BAD_VALUE;

	for (int32 i = 0; i < count; i++) {
		// make sure we can read as many bytes
		if (size_left(size, bufferStart, buffer) < 12)
			return B_BAD_VALUE;

		BParameterGroup* oldPointer = read_pointer_from_buffer_swap<
			BParameterGroup*>(&buffer, isSwapped);
		type_code type = read_from_buffer_swap32<type_code>(&buffer, isSwapped);

		ssize_t groupSize
			= read_from_buffer_swap32<ssize_t>(&buffer, isSwapped);
		if (groupSize > size_left(size, bufferStart, buffer))
			return B_BAD_VALUE;

		BParameterGroup* group = new BParameterGroup(fWeb, "sub-unnamed");
		if (group == NULL) {
			ERROR("BParameterGroup::Unflatten(): MakeGroup() failed\n");
			return B_ERROR;
		}

		status_t status = group->Unflatten(type, buffer, groupSize);
		if (status != B_OK) {
			ERROR("BParameterGroup::Unflatten(): group->Unflatten() failed\n");
			delete group;
			return status;
		}

		skip_in_buffer(&buffer, groupSize);

		fGroups->AddItem(group);

		// add it's old pointer value to the RefFix list kept by the owner web
		if (fWeb != NULL)
			fWeb->AddRefFix(oldPointer, group);
	}

	return B_OK;
}


/*!	Creates an uninitialized parameter of the specified type.
	Unlike the BParameterGroup::MakeXXXParameter() type of methods, this
	method does not add the parameter to this group automatically.
*/
BParameter*
BParameterGroup::MakeControl(int32 type)
{
	CALLED();

	switch (type) {
		case BParameter::B_NULL_PARAMETER:
			return new BNullParameter(-1, B_MEDIA_NO_TYPE, NULL, NULL, NULL);

		case BParameter::B_DISCRETE_PARAMETER:
			return new BDiscreteParameter(-1, B_MEDIA_NO_TYPE, NULL, NULL,
				NULL);

		case BParameter::B_CONTINUOUS_PARAMETER:
			return new BContinuousParameter(-1, B_MEDIA_NO_TYPE, NULL, NULL,
				NULL, NULL, 0, 0, 0);

		case BParameter::B_TEXT_PARAMETER:
			return new BTextParameter(-1, B_MEDIA_NO_TYPE, NULL, NULL, NULL, 0);

		default:
			ERROR("BParameterGroup::MakeControl unknown type %" B_PRId32 "\n",
				type);
			return NULL;
	}
}


//	#pragma mark - BParameter


BParameter::media_parameter_type
BParameter::Type() const
{
	return fType;
}


BParameterWeb*
BParameter::Web() const
{
	return fWeb;
}


BParameterGroup*
BParameter::Group() const
{
	return fGroup;
}


const char*
BParameter::Name() const
{
	return fName;
}


const char*
BParameter::Kind() const
{
	return fKind;
}


const char*
BParameter::Unit() const
{
	return fUnit;
}


int32
BParameter::ID() const
{
	return fID;
}


void
BParameter::SetFlags(uint32 flags)
{
	fFlags = flags;
}


uint32
BParameter::Flags() const
{
	return fFlags;
}


status_t
BParameter::GetValue(void* buffer, size_t* _size, bigtime_t* _when)
{
	CALLED();

	if (buffer == NULL || _size == NULL)
		return B_BAD_VALUE;

	size_t size = *_size;
	if (size <= 0)
		return B_NO_MEMORY;

	if (fWeb == NULL) {
		ERROR("BParameter::GetValue: no parent BParameterWeb\n");
		return B_NO_INIT;
	}

	media_node node = fWeb->Node();
	if (IS_INVALID_NODE(node)) {
		ERROR("BParameter::GetValue: the parent BParameterWeb is not assigned to a BMediaNode\n");
		return B_NO_INIT;
	}

	controllable_get_parameter_data_request request;
	controllable_get_parameter_data_reply reply;

	area_id area;
	void* data;
	if (size > MAX_PARAMETER_DATA) {
		// create an area if large data needs to be transfered
		area = create_area("get parameter data", &data, B_ANY_ADDRESS,
			ROUND_UP_TO_PAGE(size), B_NO_LOCK, B_READ_AREA | B_WRITE_AREA);
		if (area < B_OK) {
			ERROR("BParameter::GetValue can't create area of %ld bytes\n",
				size);
			return B_NO_MEMORY;
		}
	} else {
		area = -1;
		data = reply.raw_data;
	}

	request.parameter_id = fID;
	request.request_size = size;
	request.area = area;

	status_t status = QueryPort(node.port, CONTROLLABLE_GET_PARAMETER_DATA,
		&request, sizeof(request), &reply, sizeof(reply));
	if (status == B_OK) {
		// we don't want to copy more than the buffer provides
		if (reply.size < size)
			size = reply.size;

		memcpy(buffer, data, size);

		// store reported values

		*_size = reply.size;
		if (_when != NULL)
			*_when = reply.last_change;
	} else {
		ERROR("BParameter::GetValue parameter '%s' querying node %d, "
			"port %d failed: %s\n",  fName, (int)node.node, (int)node.port,
			strerror(status));
	}

	if (area >= B_OK)
		delete_area(area);

	return status;
}


status_t
BParameter::SetValue(const void* buffer, size_t size, bigtime_t when)
{
	CALLED();

	if (buffer == 0)
		return B_BAD_VALUE;
	if (size <= 0)
		return B_NO_MEMORY;

	if (fWeb == 0) {
		ERROR("BParameter::SetValue: no parent BParameterWeb\n");
		return B_NO_INIT;
	}

	media_node node = fWeb->Node();
	if (IS_INVALID_NODE(node)) {
		ERROR("BParameter::SetValue: the parent BParameterWeb is not assigned "
			"to a BMediaNode\n");
		return B_NO_INIT;
	}

	controllable_set_parameter_data_request request;
	controllable_set_parameter_data_reply reply;
	area_id area;
	void* data;

	if (size > MAX_PARAMETER_DATA) {
		// create an area if large data needs to be transfered
		area = create_area("set parameter data", &data, B_ANY_ADDRESS,
			ROUND_UP_TO_PAGE(size), B_NO_LOCK, B_READ_AREA | B_WRITE_AREA);
		if (area < B_OK) {
			ERROR("BParameter::SetValue can't create area of %ld bytes\n", size);
			return B_NO_MEMORY;
		}
	} else {
		area = -1;
		data = request.raw_data;
	}

	memcpy(data, buffer, size);
	request.parameter_id = fID;
	request.when = when;
	request.area = area;
	request.size = size;

	status_t status = QueryPort(node.port, CONTROLLABLE_SET_PARAMETER_DATA,
		&request, sizeof(request), &reply, sizeof(reply));
	if (status != B_OK) {
		ERROR("BParameter::SetValue querying node failed: %s\n",
			strerror(status));
	}

	if (area != -1)
		delete_area(area);

	return status;
}


int32
BParameter::CountChannels()
{
	return fChannels;
}


void
BParameter::SetChannelCount(int32 count)
{
	fChannels = count;
}


media_type
BParameter::MediaType()
{
	return fMediaType;
}


void
BParameter::SetMediaType(media_type type)
{
	fMediaType = type;
}


int32
BParameter::CountInputs()
{
	return fInputs->CountItems();
}


BParameter*
BParameter::InputAt(int32 index)
{
	return static_cast<BParameter*>(fInputs->ItemAt(index));
}


void
BParameter::AddInput(BParameter* input)
{
	CALLED();

	// BeBook has this method returning a status value,
	// but it should be updated
	if (input == NULL)
		return;

	if (fInputs->HasItem(input)) {
		// if already in input list, don't duplicate.
		return;
	}

	fInputs->AddItem(input);
	input->AddOutput(this);
}


int32
BParameter::CountOutputs()
{
	return fOutputs->CountItems();
}


BParameter*
BParameter::OutputAt(int32 index)
{
	return static_cast<BParameter*>(fOutputs->ItemAt(index));
}


void
BParameter::AddOutput(BParameter* output)
{
	CALLED();

	// BeBook has this method returning a status value,
	// but it should be updated
	if (output == NULL)
		return;

	if (fOutputs->HasItem(output)) {
		// if already in output list, don't duplicate.
		return;
	}

	fOutputs->AddItem(output);
	output->AddInput(this);
}


bool
BParameter::IsFixedSize() const
{
	return false;
}


type_code
BParameter::TypeCode() const
{
	return B_MEDIA_PARAMETER_TYPE;
}


ssize_t
BParameter::FlattenedSize() const
{
	CALLED();
	/*
		?? (0x02040607): 4 bytes
		BParameter Struct Size (in bytes): 4 bytes
		ID: 4 bytes
		Name String Length: 1 byte (??)
			Name String: 'Name String Length' bytes
		Kind String Length: 1 byte (??)
			Kind String: 'Kind String Length' bytes
		Unit String Length: 1 byte (??)
			Unit String: 'Unit String Length' bytes
		Inputs Count: 4 bytes
			Inputs (pointers): ('Inputs Count')*4 bytes
		Outputs Count: 4 bytes
			Outputs (pointers): ('Outputs Count')*4 bytes
		Media Type: 4 bytes
		ChannelCount: 4 bytes
		Flags: 4 bytes
	*/
	//35 bytes are guaranteed, after that, add the variable length parts.
	ssize_t size = 35;

	if (fName != NULL)
		size += strlen(fName);
	if (fKind != NULL)
		size += strlen(fKind);
	if (fUnit != NULL)
		size += strlen(fUnit);

	size += fInputs->CountItems() * sizeof(BParameter*);
	size += fOutputs->CountItems() * sizeof(BParameter*);

	return size;
}


status_t
BParameter::Flatten(void* buffer, ssize_t size) const
{
	CALLED();

	if (buffer == NULL) {
		ERROR("BParameter::Flatten buffer is NULL\n");
		return B_NO_INIT;
	}

	// NOTICE: It is important that this value is the size returned by
	// BParameter::FlattenedSize(), not by a descendent's override of this method.
	ssize_t actualSize = BParameter::FlattenedSize();
	if (size < actualSize) {
		ERROR("BParameter::Flatten(): size too small\n");
		return B_NO_MEMORY;
	}

	write_to_buffer<uint32>(&buffer, kParameterMagic);
	write_to_buffer<ssize_t>(&buffer, actualSize);
	write_to_buffer<int32>(&buffer, fID);

	write_string_to_buffer(&buffer, fName);
	write_string_to_buffer(&buffer, fKind);
	write_string_to_buffer(&buffer, fUnit);

	// flatten and write the list of inputs
	ssize_t count = fInputs->CountItems();
	write_to_buffer<ssize_t>(&buffer, count);

	if (count > 0) {
		memcpy(buffer, fInputs->Items(), sizeof(BParameter*) * count);
		skip_in_buffer(&buffer, sizeof(BParameter*) * count);
	}

	// flatten and write the list of outputs
	count = fOutputs->CountItems();
	write_to_buffer<ssize_t>(&buffer, count);

	if (count > 0) {
		memcpy(buffer, fOutputs->Items(), sizeof(BParameter*) * count);
		skip_in_buffer(&buffer, sizeof(BParameter*) * count);
	}

	write_to_buffer<media_type>(&buffer, fMediaType);
	write_to_buffer<int32>(&buffer, fChannels);
	write_to_buffer<uint32>(&buffer, fFlags);

	return B_OK;
}


bool
BParameter::AllowsTypeCode(type_code code) const
{
	return code == TypeCode();
}


status_t
BParameter::Unflatten(type_code code, const void* buffer, ssize_t size)
{
	CALLED();

	if (!AllowsTypeCode(code)) {
		ERROR("BParameter::Unflatten(): wrong type code\n");
		return B_BAD_TYPE;
	}

	if (buffer == NULL) {
		ERROR("BParameter::Unflatten(): buffer is NULL\n");
		return B_NO_INIT;
	}

	// if the buffer is smaller than the size needed to read the
	// signature and struct size fields, then there is a problem
	if (size < static_cast<ssize_t>(sizeof(int32) + sizeof(ssize_t))) {
		ERROR("BParameter::Unflatten() size too small\n");
		return B_BAD_VALUE;
	}

	const void* bufferStart = buffer;

	// check magic

	uint32 magic = read_from_buffer<uint32>(&buffer);
	if (magic == B_SWAP_INT32(kParameterMagic))
		fSwapDetected = true;
	else if (magic == kParameterMagic)
		fSwapDetected = false;
	else {
		ERROR("BParameter::Unflatten(): bad magic\n");
		return B_BAD_TYPE;
	}

	ssize_t parameterSize = read_from_buffer_swap32<ssize_t>(&buffer,
		fSwapDetected);
	if (parameterSize > size) {
		ERROR("BParameter::Unflatten(): buffer too small (%ld > %ld)\n",
			parameterSize, size);
		return B_BAD_VALUE;
	}

	// if the struct doesn't meet the minimum size for
	// a flattened BParameter, then return an error.
	// MinFlattenedParamSize =
	// ID (4 bytes)
	// Name String Length (1 byte)
	// Kind String Length (1 byte)
	// Unit String Length (1 byte)
	// Inputs Count (4 bytes)
	// Outputs Count (4 bytes)
	// Media Type (4 bytes)
	// Channel Count (4 bytes)
	// Flags (4 bytes)
	// TOTAL: 27 bytes
	const ssize_t MinFlattenedParamSize(27);
	if (parameterSize < MinFlattenedParamSize) {
		ERROR("BParameter::Unflatten out of memory (2)\n");
		return B_ERROR;
	}

	fID = read_from_buffer_swap32<int32>(&buffer, fSwapDetected);

	if (read_string_from_buffer(&buffer, &fName,
				size_left(size, bufferStart, buffer)) < B_OK
		|| read_string_from_buffer(&buffer, &fKind,
				size_left(size, bufferStart, buffer)) < B_OK
		|| read_string_from_buffer(&buffer, &fUnit,
				size_left(size, bufferStart, buffer)) < B_OK)
		return B_NO_MEMORY;

	// read the list of inputs

	// it will directly add the pointers in the flattened message to the list;
	// these will be fixed to point to the real inputs/outputs later in FixRefs()

	int32 count = read_from_buffer_swap32<int32>(&buffer, fSwapDetected);

	fInputs->MakeEmpty();
	for (int32 i = 0; i < count; i++) {
		fInputs->AddItem(read_pointer_from_buffer_swap<BParameter * const>(
			&buffer, fSwapDetected));
	}

	// read the list of outputs

	count = read_from_buffer_swap32<int32>(&buffer, fSwapDetected);

	fOutputs->MakeEmpty();
	for (int32 i = 0; i < count; i++) {
		fOutputs->AddItem(read_pointer_from_buffer_swap<BParameter * const>(
			&buffer, fSwapDetected));
	}

	fMediaType = read_from_buffer_swap32<media_type>(&buffer, fSwapDetected);
	fChannels = read_from_buffer_swap32<int32>(&buffer, fSwapDetected);
	fFlags = read_from_buffer_swap32<uint32>(&buffer, fSwapDetected);

	return B_OK;
}


BParameter::BParameter(int32 id, media_type mediaType,
		media_parameter_type type, BParameterWeb* web, const char* name,
		const char* kind, const char* unit)
	:
	fID(id),
	fType(type),
	fWeb(web),
	fGroup(NULL),
	fSwapDetected(true),
	fMediaType(mediaType),
	fChannels(1),
	fFlags(0)
{
	CALLED();

	fName = strndup(name, 255);
	fKind = strndup(kind, 255);
	fUnit = strndup(unit, 255);

	// create empty input/output lists
	fInputs = new BList();
	fOutputs = new BList();
}


BParameter::~BParameter()
{
	CALLED();

	// don't worry about the fWeb/fGroup properties, you don't need
	// to remove yourself from a web/group since the only way in which
	// a parameter is destroyed is when the owner web/group destroys it

	free(fName);
	free(fKind);
	free(fUnit);

	delete fInputs;
	delete fOutputs;
}


/*!	Replaces references to items in the old list with the corresponding
	items in the updated list. The references are replaced in the input
	and output lists.
	This is called by BParameterWeb::Unflatten().
*/
void
BParameter::FixRefs(BList& old, BList& updated)
{
	CALLED();

	// update inputs

	void** items = static_cast<void**>(fInputs->Items());
	int32 count = fInputs->CountItems();

	for (int32 i = 0; i < count; i++) {
		int32 index = old.IndexOf(items[i]);
		if (index >= 0)
			items[i] = updated.ItemAt(index);
		else {
			ERROR("BParameter::FixRefs(): No mapping found for input");
			items[i] = NULL;
		}
	}

	// remove all NULL inputs (those which couldn't be mapped)

	for (int32 i = count; i-- > 0;) {
		if (items[i] == NULL)
			fInputs->RemoveItem(i);
	}

	// update outputs

	items = static_cast<void **>(fOutputs->Items());
	count = fOutputs->CountItems();

	for (int32 i = 0; i < count; i++) {
		int32 index = old.IndexOf(items[i]);
		if (index >= 0)
			items[i] = updated.ItemAt(index);
		else {
			ERROR("BParameter::FixRefs(): No mapping found for output");
			items[i] = NULL;
		}
	}

	// remove all NULL outputs (those which couldn't be mapped)

	for (int32 i = count; i-- > 0;) {
		if (items[i] == NULL)
			fOutputs->RemoveItem(i);
	}
}


//	#pragma mark - public BContinuousParameter


type_code
BContinuousParameter::ValueType()
{
	return B_FLOAT_TYPE;
}


float
BContinuousParameter::MinValue()
{
	return fMinimum;
}


float
BContinuousParameter::MaxValue()
{
	return fMaximum;
}


float
BContinuousParameter::ValueStep()
{
	return fStepping;
}


void
BContinuousParameter::SetResponse(int resp, float factor, float offset)
{
	fResponse = static_cast<response>(resp);
	fFactor = factor;
	fOffset = offset;
}


void
BContinuousParameter::GetResponse(int* _resp, float* _factor, float* _offset)
{
	if (_resp != NULL)
		*_resp = fResponse;
	if (_factor != NULL)
		*_factor = fFactor;
	if (_offset != NULL)
		*_offset = fOffset;
}


ssize_t
BContinuousParameter::FlattenedSize() const
{
	CALLED();

	// only adds a fixed amount of bytes
	return BParameter::FlattenedSize() + kAdditionalContinuousParameterSize;
}


status_t
BContinuousParameter::Flatten(void* buffer, ssize_t size) const
{
	CALLED();

	if (buffer == NULL) {
		ERROR("BContinuousParameter::Flatten(): buffer is NULL\n");
		return B_NO_INIT;
	}

	ssize_t parameterSize = BParameter::FlattenedSize();
	if (size < (parameterSize + kAdditionalContinuousParameterSize)) {
		ERROR("BContinuousParameter::Flatten(): size to small\n");
		return B_NO_MEMORY;
	}

	status_t status = BParameter::Flatten(buffer, size);
	if (status != B_OK) {
		ERROR("BContinuousParameter::Flatten(): BParameter::Flatten() failed\n");
		return status;
	}

	// add our data to the general flattened BParameter

	skip_in_buffer(&buffer, parameterSize);

	write_to_buffer<float>(&buffer, fMinimum);
	write_to_buffer<float>(&buffer, fMaximum);
	write_to_buffer<float>(&buffer, fStepping);
	write_to_buffer<response>(&buffer, fResponse);
	write_to_buffer<float>(&buffer, fFactor);
	write_to_buffer<float>(&buffer, fOffset);

	return B_OK;
}


status_t
BContinuousParameter::Unflatten(type_code code, const void* buffer,
	ssize_t size)
{
	CALLED();

	// we try to check if the buffer size is long enough to hold an object
	// as early as possible.

	if (!AllowsTypeCode(code)) {
		ERROR("BContinuousParameter::Unflatten wrong type code\n");
		return B_BAD_TYPE;
	}

	if (buffer == NULL) {
		ERROR("BContinuousParameter::Unflatten buffer is NULL\n");
		return B_NO_INIT;
	}

	// if the buffer is smaller than the size needed to read the
	// signature and struct size fields, then there is a problem
	if (size < static_cast<ssize_t>(sizeof(int32) + sizeof(ssize_t))) {
		ERROR("BContinuousParameter::Unflatten size too small\n");
		return B_ERROR;
	}

	status_t status = BParameter::Unflatten(code, buffer, size);
	if (status != B_OK) {
		ERROR("BContinuousParameter::Unflatten(): BParameter::Unflatten "
			"failed: %s\n", strerror(status));
		return status;
	}

	ssize_t parameterSize = BParameter::FlattenedSize();
	skip_in_buffer(&buffer, parameterSize);

	if (size < (parameterSize + kAdditionalContinuousParameterSize)) {
		ERROR("BContinuousParameter::Unflatten(): buffer too small\n");
		return B_BAD_VALUE;
	}

	fMinimum = read_from_buffer_swap32<float>(&buffer, SwapOnUnflatten());
	fMaximum = read_from_buffer_swap32<float>(&buffer, SwapOnUnflatten());
	fStepping = read_from_buffer_swap32<float>(&buffer, SwapOnUnflatten());
	fResponse = read_from_buffer_swap32<response>(&buffer, SwapOnUnflatten());
	fFactor = read_from_buffer_swap32<float>(&buffer, SwapOnUnflatten());
	fOffset = read_from_buffer_swap32<float>(&buffer, SwapOnUnflatten());

	return B_OK;
}


BContinuousParameter::BContinuousParameter(int32 id, media_type mediaType,
		BParameterWeb* web, const char* name, const char* kind,
		const char* unit, float minimum, float maximum, float stepping)
	: BParameter(id, mediaType, B_CONTINUOUS_PARAMETER, web, name, kind, unit),
	fMinimum(minimum),
	fMaximum(maximum),
	fStepping(stepping),
	fResponse(B_LINEAR),
	fFactor(1.0),
	fOffset(0.0)
{
	CALLED();
}


BContinuousParameter::~BContinuousParameter()
{
	CALLED();
}


//	#pragma mark - public BDiscreteParameter


type_code
BDiscreteParameter::ValueType()
{
	return B_INT32_TYPE;
}


int32
BDiscreteParameter::CountItems()
{
	return fValues->CountItems();
}


const char*
BDiscreteParameter::ItemNameAt(int32 index)
{
	return reinterpret_cast<const char*>(fSelections->ItemAt(index));
}


int32
BDiscreteParameter::ItemValueAt(int32 index)
{
	int32* item = static_cast<int32*>(fValues->ItemAt(index));
	if (item == NULL)
		return 0;

	return *item;
}


status_t
BDiscreteParameter::AddItem(int32 value, const char* name)
{
	CALLED();

	int32* valueCopy = new int32(value);
	char* nameCopy = strndup(name, 255);
	if (name != NULL && nameCopy == NULL) {
		delete valueCopy;
		return B_NO_MEMORY;
	}

	if (!fValues->AddItem(valueCopy) || !fSelections->AddItem(nameCopy))
		return B_NO_MEMORY;

	return B_OK;
}


status_t
BDiscreteParameter::MakeItemsFromInputs()
{
	CALLED();

	int32 count = fInputs->CountItems();
	for (int32 i = 0; i < count; i++) {
		BParameter* parameter = static_cast<BParameter*>(fInputs->ItemAt(i));
		AddItem(i, parameter->Name());
	}

	return B_OK;
}


status_t
BDiscreteParameter::MakeItemsFromOutputs()
{
	CALLED();

	int32 count = fOutputs->CountItems();
	for (int32 i = 0; i < count; i++) {
		BParameter* parameter = static_cast<BParameter*>(fOutputs->ItemAt(i));
		AddItem(i, parameter->Name());
	}

	return B_OK;
}


void
BDiscreteParameter::MakeEmpty()
{
	CALLED();

	for (int32 i = fValues->CountItems(); i-- > 0;) {
		delete static_cast<int32*>(fValues->ItemAt(i));
	}
	fValues->MakeEmpty();

	for (int32 i = fSelections->CountItems(); i-- > 0;) {
		free(static_cast<char*>(fSelections->ItemAt(i)));
	}
	fSelections->MakeEmpty();
}


ssize_t
BDiscreteParameter::FlattenedSize() const
{
	CALLED();

	ssize_t size = BParameter::FlattenedSize()
		+ kAdditionalDiscreteParameterSize;

	int32 count = fValues->CountItems();
	for (int32 i = 0; i < count; i++) {
		char* selection = static_cast<char*>(fSelections->ItemAt(i));

		if (selection != NULL)
			size += min_c(strlen(selection), 255);

		size += 5;
			// string length + value
	}

	return size;
}


status_t
BDiscreteParameter::Flatten(void* buffer, ssize_t size) const
{
	CALLED();

	if (buffer == NULL) {
		ERROR("BDiscreteParameter::Flatten(): buffer is NULL\n");
		return B_NO_INIT;
	}

	ssize_t parameterSize = BParameter::FlattenedSize();

	if (size < FlattenedSize()) {
		ERROR("BDiscreteParameter::Flatten(): size too small\n");
		return B_NO_MEMORY;
	}

	status_t status = BParameter::Flatten(buffer, size);
	if (status != B_OK) {
		ERROR("BDiscreteParameter::Flatten(): BParameter::Flatten failed\n");
		return status;
	}

	skip_in_buffer(&buffer, parameterSize);

	int32 count = fValues->CountItems();
	write_to_buffer<int32>(&buffer, count);

	// write out all value/name pairs
	for (int32 i = 0; i < count; i++) {
		const char* selection = static_cast<char*>(fSelections->ItemAt(i));
		const int32* value = static_cast<int32*>(fValues->ItemAt(i));

		write_string_to_buffer(&buffer, selection);
		write_to_buffer<int32>(&buffer, value ? *value : 0);
	}

	return B_OK;
}


status_t
BDiscreteParameter::Unflatten(type_code code, const void* buffer, ssize_t size)
{
	CALLED();

	if (!AllowsTypeCode(code)) {
		ERROR("BDiscreteParameter::Unflatten(): bad type code\n");
		return B_BAD_TYPE;
	}

	if (buffer == NULL) {
		ERROR("BDiscreteParameter::Unflatten(): buffer is NULL\n");
		return B_NO_INIT;
	}

	// if the buffer is smaller than the size needed to read the
	// signature and struct size fields, then there is a problem
	if (size < static_cast<ssize_t>(sizeof(int32) + sizeof(ssize_t))) {
		ERROR("BDiscreteParameter::Unflatten(): size too small\n");
		return B_ERROR;
	}

	const void* bufferStart = buffer;

	status_t status = BParameter::Unflatten(code, buffer, size);
	if (status != B_OK) {
		ERROR("BDiscreteParameter::Unflatten(): BParameter::Unflatten failed\n");
		return status;
	}

	ssize_t parameterSize = BParameter::FlattenedSize();
	skip_in_buffer(&buffer, parameterSize);

	if (size < (parameterSize + kAdditionalDiscreteParameterSize)) {
		ERROR("BDiscreteParameter::Unflatten(): buffer too small\n");
		return B_BAD_VALUE;
	}

	int32 count = read_from_buffer_swap32<int32>(&buffer, SwapOnUnflatten());

	// clear any existing name/value pairs
	MakeEmpty();

	for (int32 i = 0; i < count; i++) {
		char* name;
		if (read_string_from_buffer(&buffer, &name, size_left(size, bufferStart,
				buffer)) < B_OK)
			return B_BAD_DATA;

		if (size_left(size, bufferStart, buffer) < (int)sizeof(int32)) {
			free(name);
			return B_BAD_DATA;
		}

		int32 value = read_from_buffer_swap32<int32>(&buffer,
			SwapOnUnflatten());

		AddItem(value, name);
		free(name);
	}

	return B_OK;
}


BDiscreteParameter::BDiscreteParameter(int32 id, media_type mediaType,
	BParameterWeb* web, const char* name, const char* kind)
	:	BParameter(id, mediaType, B_DISCRETE_PARAMETER, web, name, kind, NULL)
{
	CALLED();

	fSelections = new BList();
	fValues = new BList();
}


BDiscreteParameter::~BDiscreteParameter()
{
	CALLED();

	MakeEmpty();

	delete fSelections;
	delete fValues;
}


//	#pragma mark - public BTextParameter


size_t
BTextParameter::MaxBytes() const
{
	return fMaxBytes;
}


type_code
BTextParameter::ValueType()
{
	return B_FLOAT_TYPE;
}


ssize_t
BTextParameter::FlattenedSize() const
{
	return BParameter::FlattenedSize() + sizeof(fMaxBytes);
}


status_t
BTextParameter::Flatten(void* buffer, ssize_t size) const
{
	if (buffer == NULL) {
		ERROR("BTextParameter::Flatten(): buffer is NULL\n");
		return B_NO_INIT;
	}

	ssize_t parameterSize = BParameter::FlattenedSize();
	if (size < static_cast<ssize_t>(parameterSize + sizeof(fMaxBytes))) {
		ERROR("BContinuousParameter::Flatten(): size to small\n");
		return B_NO_MEMORY;
	}

	status_t status = BParameter::Flatten(buffer, size);
	if (status != B_OK) {
		ERROR("BTextParameter::Flatten(): BParameter::Flatten() failed\n");
		return status;
	}

	// add our data to the general flattened BParameter

	skip_in_buffer(&buffer, parameterSize);

	write_to_buffer<uint32>(&buffer, fMaxBytes);

	return B_OK;
}


status_t
BTextParameter::Unflatten(type_code code, const void* buffer, ssize_t size)
{
	// we try to check if the buffer size is long enough to hold an object
	// as early as possible.

	if (!AllowsTypeCode(code)) {
		ERROR("BTextParameter::Unflatten wrong type code\n");
		return B_BAD_TYPE;
	}

	if (buffer == NULL) {
		ERROR("BTextParameter::Unflatten buffer is NULL\n");
		return B_NO_INIT;
	}

	if (size < static_cast<ssize_t>(sizeof(fMaxBytes))) {
		ERROR("BTextParameter::Unflatten size too small\n");
		return B_ERROR;
	}

	status_t status = BParameter::Unflatten(code, buffer, size);
	if (status != B_OK) {
		ERROR("BTextParameter::Unflatten(): BParameter::Unflatten failed\n");
		return status;
	}

	ssize_t parameterSize = BParameter::FlattenedSize();
	skip_in_buffer(&buffer, parameterSize);

	if (size < static_cast<ssize_t>(parameterSize + sizeof(fMaxBytes))) {
		ERROR("BTextParameter::Unflatten(): buffer too small\n");
		return B_BAD_VALUE;
	}

	fMaxBytes = read_from_buffer_swap32<uint32>(&buffer, SwapOnUnflatten());

	return B_OK;
}


BTextParameter::BTextParameter(int32 id, media_type mediaType,
		BParameterWeb* web, const char* name, const char* kind,
		size_t maxBytes)
	: BParameter(id, mediaType, B_TEXT_PARAMETER, web, name, kind, NULL)
{
	fMaxBytes = maxBytes;
}


BTextParameter::~BTextParameter()
{
}


//	#pragma mark - public BNullParameter


type_code
BNullParameter::ValueType()
{
	// NULL parameters have no value type
	return 0;
}


ssize_t
BNullParameter::FlattenedSize() const
{
	return BParameter::FlattenedSize();
}


status_t
BNullParameter::Flatten(void* buffer, ssize_t size) const
{
	return BParameter::Flatten(buffer, size);
}


status_t
BNullParameter::Unflatten(type_code code, const void* buffer, ssize_t size)
{
	return BParameter::Unflatten(code, buffer, size);
}


BNullParameter::BNullParameter(int32 id, media_type mediaType,
		BParameterWeb* web, const char* name, const char* kind)
	: BParameter(id, mediaType, B_NULL_PARAMETER, web, name, kind, NULL)
{
}


BNullParameter::~BNullParameter()
{
}


//	#pragma mark - reserved functions


status_t BParameterWeb::_Reserved_ControlWeb_0(void *) { return B_ERROR; }
status_t BParameterWeb::_Reserved_ControlWeb_1(void *) { return B_ERROR; }
status_t BParameterWeb::_Reserved_ControlWeb_2(void *) { return B_ERROR; }
status_t BParameterWeb::_Reserved_ControlWeb_3(void *) { return B_ERROR; }
status_t BParameterWeb::_Reserved_ControlWeb_4(void *) { return B_ERROR; }
status_t BParameterWeb::_Reserved_ControlWeb_5(void *) { return B_ERROR; }
status_t BParameterWeb::_Reserved_ControlWeb_6(void *) { return B_ERROR; }
status_t BParameterWeb::_Reserved_ControlWeb_7(void *) { return B_ERROR; }

status_t BParameterGroup::_Reserved_ControlGroup_0(void *) { return B_ERROR; }
status_t BParameterGroup::_Reserved_ControlGroup_1(void *) { return B_ERROR; }
status_t BParameterGroup::_Reserved_ControlGroup_2(void *) { return B_ERROR; }
status_t BParameterGroup::_Reserved_ControlGroup_3(void *) { return B_ERROR; }
status_t BParameterGroup::_Reserved_ControlGroup_4(void *) { return B_ERROR; }
status_t BParameterGroup::_Reserved_ControlGroup_5(void *) { return B_ERROR; }
status_t BParameterGroup::_Reserved_ControlGroup_6(void *) { return B_ERROR; }
status_t BParameterGroup::_Reserved_ControlGroup_7(void *) { return B_ERROR; }

status_t BParameter::_Reserved_Control_0(void *) { return B_ERROR; }
status_t BParameter::_Reserved_Control_1(void *) { return B_ERROR; }
status_t BParameter::_Reserved_Control_2(void *) { return B_ERROR; }
status_t BParameter::_Reserved_Control_3(void *) { return B_ERROR; }
status_t BParameter::_Reserved_Control_4(void *) { return B_ERROR; }
status_t BParameter::_Reserved_Control_5(void *) { return B_ERROR; }
status_t BParameter::_Reserved_Control_6(void *) { return B_ERROR; }
status_t BParameter::_Reserved_Control_7(void *) { return B_ERROR; }

status_t BContinuousParameter::_Reserved_ContinuousParameter_0(void *) { return B_ERROR; }
status_t BContinuousParameter::_Reserved_ContinuousParameter_1(void *) { return B_ERROR; }
status_t BContinuousParameter::_Reserved_ContinuousParameter_2(void *) { return B_ERROR; }
status_t BContinuousParameter::_Reserved_ContinuousParameter_3(void *) { return B_ERROR; }
status_t BContinuousParameter::_Reserved_ContinuousParameter_4(void *) { return B_ERROR; }
status_t BContinuousParameter::_Reserved_ContinuousParameter_5(void *) { return B_ERROR; }
status_t BContinuousParameter::_Reserved_ContinuousParameter_6(void *) { return B_ERROR; }
status_t BContinuousParameter::_Reserved_ContinuousParameter_7(void *) { return B_ERROR; }

status_t BDiscreteParameter::_Reserved_DiscreteParameter_0(void *) { return B_ERROR; }
status_t BDiscreteParameter::_Reserved_DiscreteParameter_1(void *) { return B_ERROR; }
status_t BDiscreteParameter::_Reserved_DiscreteParameter_2(void *) { return B_ERROR; }
status_t BDiscreteParameter::_Reserved_DiscreteParameter_3(void *) { return B_ERROR; }
status_t BDiscreteParameter::_Reserved_DiscreteParameter_4(void *) { return B_ERROR; }
status_t BDiscreteParameter::_Reserved_DiscreteParameter_5(void *) { return B_ERROR; }
status_t BDiscreteParameter::_Reserved_DiscreteParameter_6(void *) { return B_ERROR; }
status_t BDiscreteParameter::_Reserved_DiscreteParameter_7(void *) { return B_ERROR; }

status_t BNullParameter::_Reserved_NullParameter_0(void *) { return B_ERROR; }
status_t BNullParameter::_Reserved_NullParameter_1(void *) { return B_ERROR; }
status_t BNullParameter::_Reserved_NullParameter_2(void *) { return B_ERROR; }
status_t BNullParameter::_Reserved_NullParameter_3(void *) { return B_ERROR; }
status_t BNullParameter::_Reserved_NullParameter_4(void *) { return B_ERROR; }
status_t BNullParameter::_Reserved_NullParameter_5(void *) { return B_ERROR; }
status_t BNullParameter::_Reserved_NullParameter_6(void *) { return B_ERROR; }
status_t BNullParameter::_Reserved_NullParameter_7(void *) { return B_ERROR; }

status_t BTextParameter::_Reserved_TextParameter_0(void *) { return B_ERROR; }
status_t BTextParameter::_Reserved_TextParameter_1(void *) { return B_ERROR; }
status_t BTextParameter::_Reserved_TextParameter_2(void *) { return B_ERROR; }
status_t BTextParameter::_Reserved_TextParameter_3(void *) { return B_ERROR; }
status_t BTextParameter::_Reserved_TextParameter_4(void *) { return B_ERROR; }
status_t BTextParameter::_Reserved_TextParameter_5(void *) { return B_ERROR; }
status_t BTextParameter::_Reserved_TextParameter_6(void *) { return B_ERROR; }
status_t BTextParameter::_Reserved_TextParameter_7(void *) { return B_ERROR; }