/*
	msg.c

	(description)

	Copyright (C) 1996-1997  Id Software, Inc.

	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 2
	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, write to:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

	$Id$
*/

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "msg.h"
#include "net.h"
#include "protocol.h"
#include "qendian.h"
#include "sys.h"

/*
==============================================================================

			MESSAGE IO FUNCTIONS

Handles byte ordering and avoids alignment errors
==============================================================================
*/

//
// writing functions
//

void MSG_WriteChar (sizebuf_t *sb, int c)
{
	byte	*buf;
	
#ifdef PARANOID
	if (c < -128 || c > 127)
		Sys_Error ("MSG_WriteChar: range error");
#endif

	buf = SZ_GetSpace (sb, 1);
	buf[0] = c;
}

void MSG_WriteByte (sizebuf_t *sb, int c)
{
	byte	*buf;
	
#ifdef PARANOID
	if (c < 0 || c > 255)
		Sys_Error ("MSG_WriteByte: range error");
#endif

	buf = SZ_GetSpace (sb, 1);
	buf[0] = c;
}

void MSG_WriteShort (sizebuf_t *sb, int c)
{
	byte	*buf;
	
#ifdef PARANOID
	if (c < ((short)0x8000) || c > (short)0x7fff)
		Sys_Error ("MSG_WriteShort: range error");
#endif

	buf = SZ_GetSpace (sb, 2);
	buf[0] = c&0xff;
	buf[1] = c>>8;
}

void MSG_WriteLong (sizebuf_t *sb, int c)
{
	byte	*buf;
	
	buf = SZ_GetSpace (sb, 4);
	buf[0] = c&0xff;
	buf[1] = (c>>8)&0xff;
	buf[2] = (c>>16)&0xff;
	buf[3] = c>>24;
}

void MSG_WriteFloat (sizebuf_t *sb, float f)
{
	union
	{
		float	f;
		int	l;
	} dat;
	
	
	dat.f = f;
	dat.l = LittleLong (dat.l);
	
	SZ_Write (sb, &dat.l, 4);
}

void MSG_WriteString (sizebuf_t *sb, char *s)
{
	if (!s)
		SZ_Write (sb, "", 1);
	else
		SZ_Write (sb, s, strlen(s)+1);
}

void MSG_WriteCoord (sizebuf_t *sb, float f)
{
	MSG_WriteShort (sb, (int)(f*8));
}

void MSG_WriteAngle (sizebuf_t *sb, float f)
{
	MSG_WriteByte (sb, (int)(f*256/360) & 255);
}

void MSG_WriteAngle16 (sizebuf_t *sb, float f)
{
	MSG_WriteShort (sb, (int)(f*65536/360) & 65535);
}

void MSG_WriteDeltaUsercmd (sizebuf_t *buf, usercmd_t *from, usercmd_t *cmd)
{
	int		bits;

//
// send the movement message
//
	bits = 0;
	if (cmd->angles[0] != from->angles[0])
		bits |= CM_ANGLE1;
	if (cmd->angles[1] != from->angles[1])
		bits |= CM_ANGLE2;
	if (cmd->angles[2] != from->angles[2])
		bits |= CM_ANGLE3;
	if (cmd->forwardmove != from->forwardmove)
		bits |= CM_FORWARD;
	if (cmd->sidemove != from->sidemove)
		bits |= CM_SIDE;
	if (cmd->upmove != from->upmove)
		bits |= CM_UP;
	if (cmd->buttons != from->buttons)
		bits |= CM_BUTTONS;
	if (cmd->impulse != from->impulse)
		bits |= CM_IMPULSE;

    MSG_WriteByte (buf, bits);

	if (bits & CM_ANGLE1)
		MSG_WriteAngle16 (buf, cmd->angles[0]);
	if (bits & CM_ANGLE2)
		MSG_WriteAngle16 (buf, cmd->angles[1]);
	if (bits & CM_ANGLE3)
		MSG_WriteAngle16 (buf, cmd->angles[2]);
	
	if (bits & CM_FORWARD)
		MSG_WriteShort (buf, cmd->forwardmove);
	if (bits & CM_SIDE)
	  	MSG_WriteShort (buf, cmd->sidemove);
	if (bits & CM_UP)
		MSG_WriteShort (buf, cmd->upmove);

 	if (bits & CM_BUTTONS)
	  	MSG_WriteByte (buf, cmd->buttons);
 	if (bits & CM_IMPULSE)
	    MSG_WriteByte (buf, cmd->impulse);
	MSG_WriteByte (buf, cmd->msec);
}


//
// reading functions
//
int			msg_readcount;
qboolean	msg_badread;

void MSG_BeginReading (void)
{
	msg_readcount = 0;
	msg_badread = false;
}

int MSG_GetReadCount(void)
{
	return msg_readcount;
}

// returns -1 and sets msg_badread if no more characters are available
int MSG_ReadChar (void)
{
	int	c;
	
	if (msg_readcount+1 > net_message.cursize)
	{
		msg_badread = true;
		return -1;
	}
		
	c = (signed char)net_message.data[msg_readcount];
	msg_readcount++;
	
	return c;
}

int MSG_ReadByte (void)
{
	int	c;
	
	if (msg_readcount+1 > net_message.cursize)
	{
		msg_badread = true;
		return -1;
	}
		
	c = (unsigned char)net_message.data[msg_readcount];
	msg_readcount++;
	
	return c;
}

int MSG_ReadShort (void)
{
	int	c;
	
	if (msg_readcount+2 > net_message.cursize)
	{
		msg_badread = true;
		return -1;
	}
		
	c = (short)(net_message.data[msg_readcount]
	+ (net_message.data[msg_readcount+1]<<8));
	
	msg_readcount += 2;
	
	return c;
}

int MSG_ReadLong (void)
{
	int	c;
	
	if (msg_readcount+4 > net_message.cursize)
	{
		msg_badread = true;
		return -1;
	}
		
	c = net_message.data[msg_readcount]
	+ (net_message.data[msg_readcount+1]<<8)
	+ (net_message.data[msg_readcount+2]<<16)
	+ (net_message.data[msg_readcount+3]<<24);
	
	msg_readcount += 4;
	
	return c;
}

float MSG_ReadFloat (void)
{
	union
	{
		byte	b[4];
		float	f;
		int	l;
	} dat;
	
	dat.b[0] =	net_message.data[msg_readcount];
	dat.b[1] =	net_message.data[msg_readcount+1];
	dat.b[2] =	net_message.data[msg_readcount+2];
	dat.b[3] =	net_message.data[msg_readcount+3];
	msg_readcount += 4;
	
	dat.l = LittleLong (dat.l);

	return dat.f;	
}

char *MSG_ReadString (void)
{
	static char	string[2048];
	int		l,c;
	
	l = 0;
	do
	{
		c = MSG_ReadChar ();
		if (c == -1 || c == 0)
			break;
		string[l] = c;
		l++;
	} while (l < sizeof(string)-1);
	
	string[l] = 0;
	
	return string;
}

char *MSG_ReadStringLine (void)
{
	static char	string[2048];
	int		l,c;
	
	l = 0;
	do
	{
		c = MSG_ReadChar ();
		if (c == -1 || c == 0 || c == '\n')
			break;
		string[l] = c;
		l++;
	} while (l < sizeof(string)-1);
	
	string[l] = 0;
	
	return string;
}

float MSG_ReadCoord (void)
{
	return MSG_ReadShort() * (1.0/8);
}

float MSG_ReadAngle (void)
{
	return MSG_ReadChar() * (360.0/256);
}

float MSG_ReadAngle16 (void)
{
	return MSG_ReadShort() * (360.0/65536);
}

void MSG_ReadDeltaUsercmd (usercmd_t *from, usercmd_t *move)
{
	int bits;

	memcpy (move, from, sizeof(*move));

	bits = MSG_ReadByte ();
		
// read current angles
	if (bits & CM_ANGLE1)
		move->angles[0] = MSG_ReadAngle16 ();
	if (bits & CM_ANGLE2)
		move->angles[1] = MSG_ReadAngle16 ();
	if (bits & CM_ANGLE3)
		move->angles[2] = MSG_ReadAngle16 ();
		
// read movement
	if (bits & CM_FORWARD)
		move->forwardmove = MSG_ReadShort ();
	if (bits & CM_SIDE)
		move->sidemove = MSG_ReadShort ();
	if (bits & CM_UP)
		move->upmove = MSG_ReadShort ();
	
// read buttons
	if (bits & CM_BUTTONS)
		move->buttons = MSG_ReadByte ();

	if (bits & CM_IMPULSE)
		move->impulse = MSG_ReadByte ();

// read time to run command
	move->msec = MSG_ReadByte ();
}