libvips/libsrc/iofuncs/im_demand_hint.c

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2007-08-29 18:23:50 +02:00
/* @(#) Hint to the evaluation mechanism that it should ask for output from
* @(#) this image with a certain shape of patch.
* @(#)
* @(#) int
* @(#) im_demand_hint( im, hint, in1, in2, ..., NULL )
* @(#) IMAGE *im, *in1, *in2, ...;
* @(#) im_demand_type hint;
* @(#)
* @(#) hint may be one of
* @(#)
* @(#) IM_THINSTRIP
* @(#) This operation would like to output strips the width of the
* @(#) image and a few pels high. This is option suitable for
* @(#) point-to-point operations, such as those in the arithmetic
* @(#) package.
* @(#)
* @(#) This is the fastest style for most simple operations.
* @(#)
* @(#) IM_FATSTRIP
* @(#) This operation would like to output strips the width of the
* @(#) image and as high as possible. This option is suitable for
* @(#) area operations which do not violently transform coordinates,
* @(#) such as im_conv().
* @(#)
* @(#) IM_SMALLTILE
* @(#) This is the most general demand format, and is the default.
* @(#) Output is demanded in small (around 100x100 pel) sections.
* @(#) This style works reasonably efficiently, even for bizzare
* @(#) operations like 45 degree rotate.
* @(#)
* @(#) IM_ANY
* @(#) Not from a disc file, so any geometry is OK.
* @(#)
* @(#) NOTE: demand style falls back to the most restrictive in the pipeline.
* @(#) All pipeline elements in the pipeline must agree on IM_THINSTRIP
* @(#) before output will be asked for in this manner. If you do not set a
* @(#) hint, you will get IM_SMALLTILE.
* @(#)
* @(#) in1, in2, ... are the images on which out will make demands. You
* @(#) should terminate the list with NULL.
* @(#)
* @(#) int
* @(#) im_demand_hint_array( im, hint, in )
* @(#) IMAGE *im, **in;
* @(#) im_demand_type hint;
* @(#)
* @(#) As above, but in is a NULL-terminated array of input images. Use
* @(#) im_allocate_input_array() to build the input array.
* @(#)
* @(#) Returns non-zero on failure.
* @(#)
*
* Copyright: The National Gallery, 1993
* Written on: 6/9/93
* Modified on :
* 2/3/98 JC
* - IM_ANY added
* 19/5/06
* - minor change to rules: don't force ANY on no-input operations ...
* fails for image import
* 1/12/06
* - build parent/child links as well
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
/*
#define DEBUG
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <vips/vips.h>
#include <vips/internal.h>
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/
/* Max number of images we can handle.
*/
#define MAX_IMAGES (1000)
/* Given two im_demand_type, return the most restrictive.
*/
static im_demand_type
find_least( im_demand_type a, im_demand_type b )
{
return( (im_demand_type) IM_MIN( (int) a, (int) b ) );
}
/* Set hint for this image.
*/
int
im_demand_hint_array( IMAGE *im, im_demand_type hint, IMAGE **in )
{
int i, len, nany;
/* How many input images are there? And how many are IM_ANY?
*/
for( i = 0, len = 0, nany = 0; in[i]; i++, len++ )
if( in[i]->dhint == IM_ANY )
nany++;
if( len == 0 )
/* No input images? Just set the requested hint. We don't
* force ANY, since the operation might be something like
* tiled read of an EXR image, where we certainly don't want
* ANY.
*/
;
else if( nany == len )
/* Special case: if all the inputs are IM_ANY, then output can
* be IM_ANY regardless of what this function wants.
*/
hint = IM_ANY;
else
/* Find the most restrictive of all the hints available to us.
*/
for( i = 0; i < len; i++ )
hint = find_least( hint, in[i]->dhint );
im->dhint = hint;
#ifdef DEBUG
printf( "im_demand_hint_array: set dhint for \"%s\" to %s\n",
im->filename, im_dhint2char( im->dhint ) );
#endif /*DEBUG*/
/* im depends on all these ims.
*/
for( i = 0; i < len; i++ )
im__link_make( im, in[i] );
return( 0 );
}
/* Build an array, and call the above.
*/
int
im_demand_hint( IMAGE *im, im_demand_type hint, ... )
{
va_list ap;
int i;
IMAGE *ar[MAX_IMAGES];
va_start( ap, hint );
for( i = 0; i < MAX_IMAGES && (ar[i] = va_arg( ap, IMAGE * )); i++ )
;
va_end( ap );
if( i == MAX_IMAGES ) {
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im_error( "im_demand_hint",
"%s", _( "too many images" ) );
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return( -1 );
}
return( im_demand_hint_array( im, hint, ar ) );
}