/*
	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
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STRINGS_H
# include <strings.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 (usercmd_t));

	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 ();
}