better arg checking for hist_find_ndim

we were not checking the number of input bands

move checks to _build

thanks travisbell

see https://github.com/libvips/libvips/issues/2634

ChangeLog

@@ -1,3 +1,6 @@
+26/11/21 started 8.12.3
+- better arg checking for hist_find_ndim [travisbell]
+
 26/11/21 started 8.12.2
 - make exif resuint optional and default to inch
 - win: don't set create time on inappropriate file descriptors [lovell]

configure.ac

@@ -2,7 +2,7 @@
 
 # also update the version number in the m4 macros below
 
-AC_INIT([vips], [8.12.2], [vipsip@jiscmail.ac.uk])
+AC_INIT([vips], [8.12.3], [vipsip@jiscmail.ac.uk])
 # required for gobject-introspection
 AC_PREREQ([2.69])
 
@@ -18,7 +18,7 @@ AC_CONFIG_MACRO_DIR([m4])
 # user-visible library versioning
 m4_define([vips_major_version], [8])
 m4_define([vips_minor_version], [12])
-m4_define([vips_micro_version], [2])
+m4_define([vips_micro_version], [3])
 m4_define([vips_version],
           [vips_major_version.vips_minor_version.vips_micro_version])
 
@@ -41,7 +41,7 @@ VIPS_LIBS=""
 # binary interface changed: increment current, reset revision to 0
 #   binary interface changes backwards compatible?: increment age
 #   binary interface changes not backwards compatible?: reset age to 0
-LIBRARY_REVISION=2
+LIBRARY_REVISION=3
 LIBRARY_CURRENT=56
 LIBRARY_AGE=14
 

libvips/arithmetic/hist_find_ndim.c

@@ -8,6 +8,8 @@
  * 	- small celanups
  * 17/8/13
  * 	- redo as a class
+ * 28/1/22 travisbell 
+ * 	- better arg checking
  */
 
 /*
@@ -57,8 +59,6 @@ struct _VipsHistFindNDim;
 typedef struct {
 	struct _VipsHistFindNDim *ndim;
 
-	int bins;
-	int max_val;
 	unsigned int ***data;		
 } Histogram;
 
@@ -69,6 +69,10 @@ typedef struct _VipsHistFindNDim {
 	 */
 	int bins;
 
+	/* Max pixel value for this format.
+	 */
+	int max_val;
+
 	/* Main image histogram. Subhists accumulate to this.
 	 */
 	Histogram *hist;
@@ -89,7 +93,6 @@ static Histogram *
 histogram_new( VipsHistFindNDim *ndim )
 {
 	VipsImage *in = VIPS_STATISTIC( ndim )->ready;
-	VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( ndim );
 	int bins = ndim->bins;
 
 	/* How many dimensions do we need to allocate?
@@ -104,14 +107,6 @@ histogram_new( VipsHistFindNDim *ndim )
 		return( NULL );
 
 	hist->ndim = ndim;
-	hist->bins = bins;
-	hist->max_val = in->BandFmt == VIPS_FORMAT_UCHAR ? 256 : 65536;
-	if( bins < 1 || 
-		bins > hist->max_val ) {
-		vips_error( class->nickname, 
-			_( "bins out of range [1,%d]" ), hist->max_val );
-		return( NULL );
-	}
 
 	if( !(hist->data = VIPS_ARRAY( ndim, bins, unsigned int ** )) )
 		return( NULL );
@@ -147,6 +142,25 @@ vips_hist_find_ndim_build( VipsObject *object )
 		"out", vips_image_new(),
 		NULL );
 
+	if( statistic->in ) {
+		VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( ndim );
+
+		if( statistic->in->Bands > 3 ) {
+			vips_error( class->nickname, 
+				"%s", _( "image is not 1 - 3 bands" ) );
+			return( -1 );
+		}
+
+		ndim->max_val = 
+			statistic->in->BandFmt == VIPS_FORMAT_UCHAR ? 256 : 65536;
+		if( ndim->bins < 1 || 
+			ndim->bins > ndim->max_val ) {
+			vips_error( class->nickname, 
+				_( "bins out of range [1,%d]" ), ndim->max_val );
+			return( -1 );
+		}
+	}
+
 	/* main hist made on first thread start.
 	 */
 
@@ -204,9 +218,9 @@ vips_hist_find_ndim_stop( VipsStatistic *statistic, void *seq )
 
 	int i, j, k;
 
-	for( i = 0; i < hist->bins; i++ )
-		for( j = 0; j < hist->bins; j++ )
-			for( k = 0; k < hist->bins; k++ )
+	for( i = 0; i < ndim->bins; i++ )
+		for( j = 0; j < ndim->bins; j++ )
+			for( k = 0; k < ndim->bins; k++ )
 				if( hist->data[i] && hist->data[i][j] ) {
 					hist->data[i][j][k] += 
 						sub_hist->data[i][j][k];
@@ -236,9 +250,10 @@ vips_hist_find_ndim_scan( VipsStatistic *statistic, void *seq,
 	int x, int y, void *in, int n )
 {
 	Histogram *hist = (Histogram *) seq;
+	VipsHistFindNDim *ndim = (VipsHistFindNDim *) statistic;
 	VipsImage *im = statistic->ready;
 	int nb = im->Bands;
-	double scale = (double) (hist->max_val + 1) / hist->bins;
+	double scale = (double) (ndim->max_val + 1) / ndim->bins;
 	int i, j, k; 
 	int index[3];