/*
	sizebuf.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 "sizebuf.h"
#include "sys.h"
#include "zone.h"

void SZ_Alloc (sizebuf_t *buf, int startsize)
{
	if (startsize < 256)
		startsize = 256;
	buf->data = Hunk_AllocName (startsize, "sizebuf");
	buf->maxsize = startsize;
	buf->cursize = 0;
}

void SZ_Clear (sizebuf_t *buf)
{
	buf->cursize = 0;
	buf->overflowed = false;
}

void *SZ_GetSpace (sizebuf_t *buf, int length)
{
	void	*data;
	
	if (buf->cursize + length > buf->maxsize)
	{
		if (!buf->allowoverflow)
			Sys_Error ("SZ_GetSpace: overflow without allowoverflow set (%d)", buf->maxsize);
		
		if (length > buf->maxsize)
			Sys_Error ("SZ_GetSpace: %i is > full buffer size", length);
			
		Sys_Printf ("SZ_GetSpace: overflow\n");	// because Con_Printf may be redirected
		SZ_Clear (buf); 
		buf->overflowed = true;
	}

	data = buf->data + buf->cursize;
	buf->cursize += length;
	
	return data;
}

void SZ_Write (sizebuf_t *buf, void *data, int length)
{
	memcpy (SZ_GetSpace(buf,length),data,length);		
}

void SZ_Print (sizebuf_t *buf, char *data)
{
	int		len;
	
	len = strlen(data)+1;

	if (!buf->cursize || buf->data[buf->cursize-1])
		memcpy ((byte *)SZ_GetSpace(buf, len),data,len); // no trailing 0
	else
		memcpy ((byte *)SZ_GetSpace(buf, len-1)-1,data,len); // write over trailing 0
}