/***************************************************************************
 * dos.c:	AmigaDOS and Requestor related functions.
 *
 * Part of...
 *
 *	FREE:	Display free space on your disk volumes.
 *		Author:  Daniel Jay Barrett, barrett@cs.jhu.edu.
 *
 * This program is Freely Distributable.  Make all the copies you want
 * and give them away.  Use this code in any way you like.
***************************************************************************/


#include "free.h"

/* Given a disk volume name, return how much space is on it.  The units
 * of space are either bytes or blocks, depending on whether the user
 * specified the option OPT_BLOCKS or not. */

long GetMem(char *volume)
{
	long freeSpace;
	struct FileLock *lock;

	lock = NULL;
	if (lock = (struct FileLock *)Lock(volume, ACCESS_READ))
	{
		freeSpace = AvailSpace(lock);
		UnLock((BPTR)lock);
	}
	else
		freeSpace = NO_DRIVE;
	return(freeSpace);
}


/* This function comes from Tom Smythe's "avail()" function.
 * Given a lock on a disk, calculate how much space is left on the disk
 * and return that value.  The value is in bytes, by default; but if the
 * user specified the option OPT_BLOCKS on the command-line, it's in 
 * blocks. */

long AvailSpace(struct FileLock *disk)
{
	struct InfoData *info;
	long answer = 0L;

	info = AllocMem((long)sizeof(struct InfoData), MEMF_PUBLIC);
	Info((BPTR)disk, info);
	answer = (info->id_NumBlocks - info->id_NumBlocksUsed);
	if (!(flags & FLAG_BLOCKS))
		answer *= info->id_BytesPerBlock;
	FreeMem(info, (long)sizeof(struct InfoData));
	return(answer);
}


/* Return the amount of free RAM on the system, broken into CHIP and
 * FAST RAM. */

void GetFreeRam(long *chip, long *fast)
{
	(*chip) = (*fast) = 0L;
	Forbid();
	*chip = AvailMem(MEMF_CHIP);
	*fast = AvailMem(MEMF_FAST);
	Permit();
}


/* Turn off system requestors for this process. */

void DisableRequestors(struct Process **proc, APTR *oldWindowPtr)
{
	*proc = (struct Process *)FindTask(NULL);
	*oldWindowPtr = (*proc)->pr_WindowPtr;
	(*proc)->pr_WindowPtr = (APTR)(-1L);
}


/* Turn on system requestors for this process, after they have been
 * turned off by DisableRequestors(), above. */

void EnableRequestors(struct Process *proc, APTR oldWindowPtr)
{
	proc->pr_WindowPtr = oldWindowPtr;
}