ISSUE: Can't read data from grb file

.gitignore

@@ -11,3 +11,6 @@ artifacts/
 *.sln.ide
 .vs/
 .idea/
+/src/NGrib/nuget/*.log
+/src/NGrib/nuget/20250313-165204.log
+/src/NGrib/nuget/20250313-165310.log

src/NGrib/BufferedBinaryReader.cs

@@ -196,6 +196,21 @@ public int ReadUIntN(int nbBit)
 			}
 		}
 
+		public void ReadUIntN(int nbBit, int[] buffer, int nbValues, int skip = 0)
+		{
+			NextUIntN();
+
+			if (skip > 0)
+            {
+                ReadUIntN(skip);
+            }
+
+            for (int i = 0;	i < nbValues; i++)
+			{
+				buffer[i] = ReadUIntN(nbBit);
+			}
+		}
+
 		public int ReadIntN(int nbBit)
 		{
 			var result = ReadUIntN(nbBit);

src/NGrib/Grib1/Grib1ProductDefinitionSection.cs

@@ -401,36 +401,41 @@ public Grib1WaveSpectra2DDirFreq WaveSpectra2DDirFreq
 		/// </remarks>
 		public int[] CustomData { get; }
 
-		// *** constructors *******************************************************
-
-		/// <summary> Constructs a <tt>Grib1ProductDefinitionSection</tt> object from a raf.
-		/// 
-		/// </summary>
-		/// <param name="raf">with PDS content
-		/// 
-		/// </param>
-		/// <throws>  NotSupportedException  if raf contains no valid GRIB file </throws>
-		//UPGRADE_TODO: Class 'java.io.RandomAccessFile' was converted to 'System.IO.FileStream' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javaioRandomAccessFile'"
-		internal Grib1ProductDefinitionSection(System.IO.Stream raf)
-		{
-			// octets 1-3 PDS length
-			length = (int) GribNumbers.uint3(raf);
-
-
-			// Paramter table octet 4
-			table_version = raf.ReadByte();
-
-			// Center  octet 5
-			center_id = raf.ReadByte();
-
-			// octet 6 Generating Process - See Table A
-			process_id = raf.ReadByte();
-
-			// octet 7 (id of grid type) - not supported yet
-			grid_id = raf.ReadByte();
-
-			//octet 8 (flag for presence of GDS and BMS)
-			int exists = raf.ReadByte();
+        // *** constructors *******************************************************
+
+        /// <summary> Constructs a <tt>Grib1ProductDefinitionSection</tt> object from a raf.
+        /// 
+        /// </summary>
+        /// <param name="raf">with PDS content
+        /// 
+        /// </param>
+        /// <throws>  NotSupportedException  if raf contains no valid GRIB file </throws>
+        //UPGRADE_TODO: Class 'java.io.RandomAccessFile' was converted to 'System.IO.FileStream' which has a different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1073_javaioRandomAccessFile'"
+        internal Grib1ProductDefinitionSection(System.IO.Stream raf)
+        {
+            // octets 1-3 PDS length
+            length = (int)GribNumbers.uint3(raf);
+
+            if (length <= 0)
+            {
+                lengthErr = true;
+                return;
+            }
+
+            // Paramter table octet 4
+            table_version = raf.ReadByte();
+
+            // Center  octet 5
+            center_id = raf.ReadByte();
+
+            // octet 6 Generating Process - See Table A
+            process_id = raf.ReadByte();
+
+            // octet 7 (id of grid type) - not supported yet
+            grid_id = raf.ReadByte();
+
+            //octet 8 (flag for presence of GDS and BMS)
+            int exists = raf.ReadByte();
 			//BKSystem.IO.BitStream s = new BKSystem.IO.BitStream(8);
 //            s.WriteByte((byte)raf.ReadByte());
 //            s.Position = 0;

src/NGrib/Grib2/CodeTables/4_1_ParameterCategory.cs

@@ -2,17 +2,17 @@
  * This file is part of NGrib.
  *
  * Copyright © 2020 Nicolas Mangué
- * 
+ *
  * NGrib 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 3 of the License, or (at your option) any later version.
- * 
+ *
  * NGrib 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 NGrib.  If not, see <https://www.gnu.org/licenses/>.
  */
@@ -120,8 +120,12 @@ private ParameterCategory(Discipline discipline, int code, string description)
 			new ParameterCategory(Discipline.MeteorologicalProducts, 18, "Nuclear/radiology");
 
 		///<summary>Physical atmospheric properties</summary>
-		public static ParameterCategory PhysicalAtmosphericProperties { get; } = new ParameterCategory(Discipline.MeteorologicalProducts,
-			19, "Physical atmospheric properties");
+		public static ParameterCategory PhysicalAtmosphericProperties { get; } =
+			new ParameterCategory(Discipline.MeteorologicalProducts, 19, "Physical atmospheric properties");
+
+		///<summary>Atmospheric Chemical Constituents</summary>
+		public static ParameterCategory AtmosphericChemicalConstituents { get; } =
+			new ParameterCategory(Discipline.MeteorologicalProducts, 20, "Atmospheric Chemical Constituents");
 
 		///<summary>CCITT IA5 string</summary>
 		public static ParameterCategory CcittIa5String { get; } =
@@ -208,6 +212,7 @@ private ParameterCategory(Discipline discipline, int code, string description)
 				.Add(Electrodynamics)
 				.Add(NuclearRadiology)
 				.Add(PhysicalAtmosphericProperties)
+				.Add(AtmosphericChemicalConstituents)
 				.Add(CcittIa5String)
 				.Add(Miscellaneous)
 				.Add(HydrologyBasicProducts)
@@ -225,6 +230,6 @@ private ParameterCategory(Discipline discipline, int code, string description)
 				.Add(SurfaceProperties)
 				.Add(SubSurfaceProperties)
 				.GroupBy(c => c.Discipline)
-				.ToDictionary(g => g.Key, g => (IReadOnlyCollection<ParameterCategory>) g.ToImmutableList());
+				.ToDictionary(g => g.Key, g => (IReadOnlyCollection<ParameterCategory>)g.ToImmutableList());
 	}
 }