libcolord: Add cd_mat33_is_finite

Move the logic to check whether any entries in a matrix are NaN or infinite from
cd_it8_utils_calculate_ccmx into a helper function in cd-math.c.

In addition, fix a bug in this code: if any entries of the matrix are exactly
zero, then fpclassify will return FP_ZERO instead of FP_NORMAL. Don't treat this
as a failure: only FP_NAN and FP_INFINITE are errors.

3 files changed, 31 insertions, 10 deletions

diff --git a/lib/colord/cd-it8-utils.c b/lib/colord/cd-it8-utils.c
index 90f57f0..38ae042 100644
--- a/lib/colord/cd-it8-utils.c
+++ b/lib/colord/cd-it8-utils.c
@@ -183,10 +183,8 @@ cd_it8_utils_calculate_ccmx (CdIt8 *it8_reference,
 	CdMat3x3 m_rgb;
 	CdMat3x3 m_rgb_inv;
 	CdMat3x3 n_rgb;
-	const gdouble *data;
 	gdouble m_lumi = 0.0f;
 	gdouble n_lumi = 0.0f;
-	guint i;
 	g_autofree gchar *tmp = NULL;
 
 	/* read reference matrix */
@@ -217,14 +215,8 @@ cd_it8_utils_calculate_ccmx (CdIt8 *it8_reference,
 	g_debug ("device calibration = %s", tmp);
 
 	/* check there are no nan's or inf's */
-	data = cd_mat33_get_data (&calibration);
-	for (i = 0; i < 9; i++) {
-		if (fpclassify (data[i]) != FP_NORMAL) {
-			g_set_error (error, 1, 0,
-				     "Matrix value %u non-normal: %f", i, data[i]);
-			return FALSE;
-		}
-	}
+	if (!cd_mat33_is_finite (&calibration, error))
+		return FALSE;
 
 	/* save to ccmx file */
 	cd_it8_set_matrix (it8_ccmx, &calibration);
diff --git a/lib/colord/cd-math.c b/lib/colord/cd-math.c
index 2eacaae..db98b08 100644
--- a/lib/colord/cd-math.c
+++ b/lib/colord/cd-math.c
@@ -453,3 +453,30 @@ cd_mat33_copy (const CdMat3x3 *src, CdMat3x3 *dest)
 	g_return_if_fail (src != dest);
 	memcpy (dest, src, sizeof (CdMat3x3));
 }
+
+/**
+ * cd_mat33_is_finite:
+ * @mat: the matrix to test
+ * @error: (out): A #GError, or %NULL
+ *
+ * Determine whether all entries in the specified matrix are finite and not
+ * NaNs.
+ *
+ * Return value: %TRUE if isfinite() returns %TRUE for all values.
+ */
+gboolean
+cd_mat33_is_finite (const CdMat3x3 *mat, GError **error)
+{
+	const gdouble *data = cd_mat33_get_data (mat);
+
+	for (guint i = 0; i < 9; i++) {
+		if (!isfinite (data[i])) {
+			g_set_error (error, 1, 0,
+				     "Matrix value %u non-normal: %f",
+				     i, data[i]);
+			return FALSE;
+		}
+	}
+
+	return TRUE;
+}
diff --git a/lib/colord/cd-math.h b/lib/colord/cd-math.h
index 5f6c39c..70492b4 100644
--- a/lib/colord/cd-math.h
+++ b/lib/colord/cd-math.h
@@ -88,6 +88,8 @@ void		 cd_mat33_normalize		(const CdMat3x3		*src,
 						 CdMat3x3		*dest);
 void		 cd_mat33_copy			(const CdMat3x3		*src,
 						 CdMat3x3		*dest);
+gboolean	 cd_mat33_is_finite		(const CdMat3x3		*mat,
+						 GError			**error);
 
 #undef __CD_MATH_H_INSIDE__