include <imhdr.h>
include <imset.h>

define	MEMFUDGE	1.05

# RS_CACHEN -- Cache N same sized images in memory using the image i/o
# buffer sizes.

procedure rs_cachen (cache, nimages, im, old_size)

int	cache			#I cache the image pixels in the imio buffer
int	nimages			#I the number of images
pointer	im			#I the current image descriptor
int	old_size		#O the old working set size

int	i, req_size, buf_size
int	sizeof(), rs_memstat()

begin
	req_size = MEMFUDGE * IM_LEN(im,1) * sizeof (IM_PIXTYPE(im))
	do i = 2, IM_NDIM(im)
	    req_size = req_size * IM_LEN(im,i)
	req_size = nimages * req_size
	if (rs_memstat (cache, req_size, old_size) == YES) 
	    call rs_pcache (im, INDEFI, buf_size)
end


# RS_CACHE1 -- Cache 1 image in memory using the image i/o buffer sizes.

procedure rs_cache1 (cache, im, old_size)

int	cache			#I cache the image pixels in the imio buffer
pointer	im			#I the image descriptor
int	old_size		#O the old working set size

int	i, req_size, buf_size
int	sizeof(), rs_memstat()

begin
	req_size = MEMFUDGE * IM_LEN(im,1) * sizeof (IM_PIXTYPE(im))
	do i = 2, IM_NDIM(im)
	    req_size = req_size * IM_LEN(im,i)
	if (rs_memstat (cache, req_size, old_size) == YES) 
	    call rs_pcache (im, INDEFI, buf_size)
end


# RS_MEMSTAT -- Figure out if there is  enough memory to cache the image
# pixels. If it is necessary to request more memory and the memory is
# avalilable return YES otherwise return NO.

int procedure rs_memstat (cache, req_size, old_size)

int	cache			#I cache memory ?
int	req_size		#I the requested working set size in chars 
int	old_size		#O the original working set size in chars 

int	cur_size, max_size
int	begmem()

begin
        # Find the default working set size.
        cur_size = begmem (0, old_size, max_size)

	# If cacheing is disabled return NO regardless of the working set size.
	if (cache == NO)
	    return (NO)

	# If the requested working set size is less than the current working
	# set size return YES.
	if (req_size <= cur_size)
	    return (YES)

	# Reset the current working set size.
	cur_size = begmem (req_size, old_size, max_size)
	if (req_size <= cur_size) {
	    return (YES)
	} else {
	    return (NO)
	}
end


# RS_PCACHE -- Cache the image pixels im memory by resetting the  default image
# buffer size. If req_size is INDEF the size of the image is used to determine
# the size of the image i/o buffers.

procedure rs_pcache (im, req_size, buf_size)

pointer im                      #I the input image point
int     req_size                #I the requested working set size in chars
int	buf_size		#O the new image buffer size

int     i, def_size, new_imbufsize
int     sizeof(), imstati()

begin
	# Find the default buffer size.
	def_size = imstati (im, IM_BUFSIZE)

        # Compute the new required image i/o buffer size in chars.
        if (IS_INDEFI(req_size)) {
            new_imbufsize = IM_LEN(im,1) * sizeof (IM_PIXTYPE(im))
	    do i = 2, IM_NDIM(im)
		new_imbufsize = new_imbufsize * IM_LEN(im,i)
        } else {
            new_imbufsize = req_size
        }

	# If the default image i/o buffer size is already bigger than
	# the requested size do nothing.
	if (def_size >= new_imbufsize) {
	    buf_size = def_size
	    return
	}

        # Reset the image i/o buffer.
        call imseti (im, IM_BUFSIZE, new_imbufsize)
        call imseti (im, IM_BUFFRAC, 0)
	buf_size = new_imbufsize
end