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/* $Id$ */

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/**

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 * @file packet.cpp Basic functions to create, fill and read packets.

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 */

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#ifdef ENABLE_NETWORK

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#include "../../stdafx.h"

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#include "packet.h"

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/* Do not want to include functions.h and all required headers */

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extern void NORETURN CDECL error(const char *str, ...);

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/**

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 * Create a packet that is used to read from a network socket

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 * @param cs the socket handler associated with the socket we are reading from

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 */

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Packet::Packet(NetworkSocketHandler *cs)

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{

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	assert(cs != NULL);

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	this->cs   = cs;

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	this->next = NULL;

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	this->pos  = 0; // We start reading from here

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	this->size = 0;

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}

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/**

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 * Creates a packet to send

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 * @param type of the packet to send

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 */

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Packet::Packet(PacketType type)

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{

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	this->cs                   = NULL;

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	this->next                 = NULL;

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	/* Skip the size so we can write that in before sending the packet */

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	this->pos                  = 0;

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	this->size                 = sizeof(PacketSize);

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	this->buffer[this->size++] = type;

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}

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/**

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 * Create a packet for sending

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 * @param type the of packet

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 * @return the newly created packet

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 */

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Packet *NetworkSend_Init(PacketType type)

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{

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	Packet *packet = new Packet(type);

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	/* An error is inplace here, because it simply means we ran out of memory. */

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	if (packet == NULL) error("Failed to allocate Packet");

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	return packet;

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}

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/**

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 * Writes the packet size from the raw packet from packet->size

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 */

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void Packet::PrepareToSend()

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{

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	assert(this->cs == NULL && this->next == NULL);

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	this->buffer[0] = GB(this->size, 0, 8);

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	this->buffer[1] = GB(this->size, 8, 8);

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	this->pos  = 0; // We start reading from here

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}

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/**

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 * The next couple of functions make sure we can send

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 *  uint8, uint16, uint32 and uint64 endian-safe

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 *  over the network. The least significant bytes are

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 *  sent first.

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 *

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 *  So 0x01234567 would be sent as 67 45 23 01.

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 *

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 * A bool is sent as a uint8 where zero means false

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 *  and non-zero means true.

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 */

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void Packet::Send_bool(bool data)

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{

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	this->Send_uint8(data ? 1 : 0);

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}

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void Packet::Send_uint8(uint8 data)

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{

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	assert(this->size < sizeof(this->buffer) - sizeof(data));

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	this->buffer[this->size++] = data;

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}

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void Packet::Send_uint16(uint16 data)

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{

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	assert(this->size < sizeof(this->buffer) - sizeof(data));

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	this->buffer[this->size++] = GB(data, 0, 8);

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	this->buffer[this->size++] = GB(data, 8, 8);

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}

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void Packet::Send_uint32(uint32 data)

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{

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	assert(this->size < sizeof(this->buffer) - sizeof(data));

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	this->buffer[this->size++] = GB(data,  0, 8);

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	this->buffer[this->size++] = GB(data,  8, 8);

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	this->buffer[this->size++] = GB(data, 16, 8);

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	this->buffer[this->size++] = GB(data, 24, 8);

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}

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void Packet::Send_uint64(uint64 data)

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{

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	assert(this->size < sizeof(this->buffer) - sizeof(data));

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	this->buffer[this->size++] = GB(data,  0, 8);

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	this->buffer[this->size++] = GB(data,  8, 8);

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	this->buffer[this->size++] = GB(data, 16, 8);

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	this->buffer[this->size++] = GB(data, 24, 8);

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	this->buffer[this->size++] = GB(data, 32, 8);

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	this->buffer[this->size++] = GB(data, 40, 8);

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	this->buffer[this->size++] = GB(data, 48, 8);

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	this->buffer[this->size++] = GB(data, 56, 8);

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}

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/**

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 *  Sends a string over the network. It sends out

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 *  the string + '\0'. No size-byte or something.

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 * @param data   the string to send

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 */

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void Packet::Send_string(const char* data)

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{

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	assert(data != NULL);

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	/* The <= *is* valid due to the fact that we are comparing sizes and not the index. */

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	assert(this->size + strlen(data) + 1 <= sizeof(this->buffer));

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	while ((this->buffer[this->size++] = *data++) != '\0') {}

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}

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/**

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 * Receiving commands

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 * Again, the next couple of functions are endian-safe

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 *  see the comment before Send_bool for more info.

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 */

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/** Is it safe to read from the packet, i.e. didn't we run over the buffer ? */

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bool Packet::CanReadFromPacket(uint bytes_to_read)

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{

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	/* Don't allow reading from a quit client/client who send bad data */

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	if (this->cs->HasClientQuit()) return false;

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	/* Check if variable is within packet-size */

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	if (this->pos + bytes_to_read > this->size) {

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		this->cs->CloseConnection();

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		return false;

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	}

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	return true;

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}

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/**

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 * Reads the packet size from the raw packet and stores it in the packet->size

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 */

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void Packet::ReadRawPacketSize()

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{

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	assert(this->cs != NULL && this->next == NULL);

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	this->size  = (PacketSize)this->buffer[0];

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	this->size += (PacketSize)this->buffer[1] << 8;

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}

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/**

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 * Prepares the packet so it can be read

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 */

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void Packet::PrepareToRead()

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{

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	this->ReadRawPacketSize();

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	/* Put the position on the right place */

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	this->pos = sizeof(PacketSize);

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}

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bool Packet::Recv_bool()

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{

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	return this->Recv_uint8() != 0;

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}

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uint8 Packet::Recv_uint8()

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{

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	uint8 n;

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	if (!this->CanReadFromPacket(sizeof(n))) return 0;

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	n = this->buffer[this->pos++];

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	return n;

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}

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uint16 Packet::Recv_uint16()

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{

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	uint16 n;

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	if (!this->CanReadFromPacket(sizeof(n))) return 0;

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	n  = (uint16)this->buffer[this->pos++];

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	n += (uint16)this->buffer[this->pos++] << 8;

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	return n;

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}

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uint32 Packet::Recv_uint32()

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{

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	uint32 n;

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	if (!this->CanReadFromPacket(sizeof(n))) return 0;

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	n  = (uint32)this->buffer[this->pos++];

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	n += (uint32)this->buffer[this->pos++] << 8;

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	n += (uint32)this->buffer[this->pos++] << 16;

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	n += (uint32)this->buffer[this->pos++] << 24;

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	return n;

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}

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uint64 Packet::Recv_uint64()

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{

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	uint64 n;

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	if (!this->CanReadFromPacket(sizeof(n))) return 0;

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	n  = (uint64)this->buffer[this->pos++];

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	n += (uint64)this->buffer[this->pos++] << 8;

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	n += (uint64)this->buffer[this->pos++] << 16;

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	n += (uint64)this->buffer[this->pos++] << 24;

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	n += (uint64)this->buffer[this->pos++] << 32;

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	n += (uint64)this->buffer[this->pos++] << 40;

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	n += (uint64)this->buffer[this->pos++] << 48;

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	n += (uint64)this->buffer[this->pos++] << 56;

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	return n;

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}

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/** Reads a string till it finds a '\0' in the stream */

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void Packet::Recv_string(char *buffer, size_t size)

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{

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	PacketSize pos;

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	char *bufp = buffer;

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	/* Don't allow reading from a closed socket */

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	if (cs->HasClientQuit()) return;

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	pos = this->pos;

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	while (--size > 0 && pos < this->size && (*buffer++ = this->buffer[pos++]) != '\0') {}

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	if (size == 0 || pos == this->size) {

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		*buffer = '\0';

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		/* If size was sooner to zero then the string in the stream

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		 *  skip till the \0, so than packet can be read out correctly for the rest */

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		while (pos < this->size && this->buffer[pos] != '\0') pos++;

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		pos++;

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	}

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	this->pos = pos;

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	str_validate(bufp);

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}

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#endif /* ENABLE_NETWORK */