Round numbers, add more icc profiles for testing, add ComputeProfileId() and ValidateProfile() methods (#1)

Author: BobLd

IccProfileNet.Tests/D50_XYZ.cs

@@ -49,7 +49,8 @@ public void Header()
 
             Assert.Equal("none", header.ProfileCreatorSignature);
 
-            Assert.NotNull(header.ProfileId); // TODO
+            Assert.NotNull(header.ProfileId);
+            Assert.False(header.IsProfileIdComputed());
         }
 
         [Fact]

IccProfileNet.Tests/D55_XYZ.cs

@@ -49,7 +49,8 @@ public void Header()
 
             Assert.Equal("none", header.ProfileCreatorSignature);
 
-            Assert.NotNull(header.ProfileId); // TODO
+            Assert.NotNull(header.ProfileId);
+            Assert.False(header.IsProfileIdComputed());
         }
 
         [Fact]

IccProfileNet.Tests/D65_XYZ.cs

@@ -49,7 +49,8 @@ public void Header()
 
             Assert.Equal("none", header.ProfileCreatorSignature);
 
-            Assert.NotNull(header.ProfileId); // TODO
+            Assert.NotNull(header.ProfileId);
+            Assert.False(header.IsProfileIdComputed());
         }
 
         [Fact]

IccProfileNet.Tests/ICC_Profile_no_created_date.cs

@@ -52,7 +52,8 @@ public void Header()
 
             Assert.Equal("appl", header.ProfileCreatorSignature);
 
-            Assert.NotNull(header.ProfileId); // TODO
+            Assert.NotNull(header.ProfileId);
+            Assert.False(header.IsProfileIdComputed());
         }
 
         [Fact]

IccProfileNet.Tests/ICC_v2_LutType.cs

@@ -51,7 +51,8 @@ public void Header()
 
             Assert.Equal("ADBE", header.ProfileCreatorSignature);
 
-            Assert.NotNull(header.ProfileId); // TODO
+            Assert.NotNull(header.ProfileId);
+            Assert.False(header.IsProfileIdComputed());
         }
 
         [Fact]

IccProfileNet.Tests/ISO22028_2_ROMM_RGB.cs

@@ -49,7 +49,10 @@ public void Header()
 
             Assert.Equal("none", header.ProfileCreatorSignature);
 
-            Assert.NotNull(header.ProfileId); // TODO
+            Assert.NotNull(header.ProfileId);
+            Assert.True(header.IsProfileIdComputed());
+            var profileIDCheck = _profile.ComputeProfileId();
+            Assert.Equal(profileIDCheck, header.ProfileId);
         }
 
         [Fact]

IccProfileNet.Tests/PRMG_v201_MR.cs

@@ -51,7 +51,10 @@ public void Header()
 
             Assert.Equal("KODA", header.ProfileCreatorSignature);
 
-            Assert.NotNull(header.ProfileId); // TODO
+            Assert.NotNull(header.ProfileId);
+            Assert.True(header.IsProfileIdComputed());
+            var profileIDCheck = _profile.ComputeProfileId();
+            Assert.Equal(profileIDCheck, header.ProfileId);
         }
 
         [Fact]

IccProfileNet.Tests/Profiles/tftcentral/ASUS_PB278QV_user.icm

@@ -0,0 +1 @@
+http://tftcentral.co.uk/articles/icc_profiles

IccProfileNet.Tests/Profiles/tftcentral/SOURCES.txt

@@ -53,7 +53,10 @@ public void Header()
 
             Assert.Equal("", header.ProfileCreatorSignature);
 
-            Assert.NotNull(header.ProfileId); // TODO
+            Assert.NotNull(header.ProfileId);
+            Assert.True(header.IsProfileIdComputed());
+            var profileIDCheck = _profile.ComputeProfileId();
+            Assert.Equal(profileIDCheck, header.ProfileId);
         }
 
         [Fact]

IccProfileNet.Tests/Profiles/tftcentral/aoc_agon_pro_ag344uxm.icm

@@ -55,7 +55,10 @@ public void Header()
 
             Assert.Equal("none", header.ProfileCreatorSignature);
 
-            Assert.NotNull(header.ProfileId); // TODO
+            Assert.NotNull(header.ProfileId);
+            Assert.True(header.IsProfileIdComputed());
+            var profileIDCheck = _profile.ComputeProfileId();
+            Assert.Equal(profileIDCheck, header.ProfileId);
         }
 
         [Fact]

IccProfileNet.Tests/Profiles/tftcentral/asrock_PG34WQ15R3A.icm

@@ -4,7 +4,7 @@
 
 namespace IccProfileNet
 {
-    internal static class IccHelper
+    public static class IccHelper
     {
         internal static double[] Lookup(double[] input, double[][] clut, byte[] clutGridPoints)
         {
@@ -43,6 +43,36 @@ internal static double[] Lookup(double[] input, double[][] clut, int clutGridPoi
             return clut[(int)index];
         }
 
+        public static byte[] ComputeProfileId(byte[] profileBytes)
+        {
+            // Compute profile id
+            // This field, if not zero (00h), shall hold the Profile ID. The Profile ID shall be calculated using the MD5
+            // fingerprinting method as defined in Internet RFC 1321.The entire profile, whose length is given by the size field
+            // in the header, with the profile flags field (bytes 44 to 47, see 7.2.11), rendering intent field (bytes 64 to 67, see
+            // 7.2.15), and profile ID field (bytes 84 to 99) in the profile header temporarily set to zeros (00h), shall be used to
+            // calculate the ID. A profile ID field value of zero (00h) shall indicate that a profile ID has not been calculated.
+            // Profile creators should compute and record a profile ID.
+
+            // with the profile flags field (bytes 44 to 47, see 7.2.11)
+            for (int i = IccProfileHeader.ProfileFlagsOffset; i < IccProfileHeader.ProfileFlagsOffset + IccProfileHeader.ProfileFlagsLength; i++)
+            {
+                profileBytes[i] = 0;
+            }
+
+            // rendering intent field (bytes 64 to 67, see 7.2.15)
+            for (int i = IccProfileHeader.RenderingIntentOffset; i < IccProfileHeader.RenderingIntentOffset + IccProfileHeader.RenderingIntentLength; i++)
+            {
+                profileBytes[i] = 0;
+            }
+
+            for (int i = IccProfileHeader.ProfileIdOffset; i < IccProfileHeader.ProfileIdOffset + IccProfileHeader.ProfileIdLength; i++)
+            {
+                profileBytes[i] = 0;
+            }
+
+            return System.Security.Cryptography.MD5.HashData(profileBytes);
+        }
+
         internal static string GetString(byte[] bytes, int index, int count)
         {
             return Encoding.ASCII.GetString(bytes, index, count).Replace("\0", string.Empty);
@@ -102,22 +132,25 @@ internal static IccXyz ReadXyz(byte[] bytes)
 
         internal static double ReadU8Fixed8Number(byte[] bytes)
         {
+            // TODO - use ReadUInt16 instead of BitConverter.ToInt16 ????
             if (BitConverter.IsLittleEndian)
             {
                 Array.Reverse(bytes);
             }
 
-            return BitConverter.ToInt16(bytes, 0) / ((double)byte.MaxValue + 1);
+            return Math.Round(BitConverter.ToInt16(bytes, 0) / ((double)byte.MaxValue + 1), 4, MidpointRounding.AwayFromZero);
         }
 
         internal static double Reads15Fixed16Number(byte[] bytes)
         {
+            // TODO - use ReadUInt32 instead of BitConverter.ToInt32 ????
+
             if (BitConverter.IsLittleEndian)
             {
                 Array.Reverse(bytes);
             }
 
-            return (BitConverter.ToInt32(bytes) - 0.5f) / ((double)ushort.MaxValue + 1);
+            return Math.Round((BitConverter.ToInt32(bytes) - 0.5f) / ((double)ushort.MaxValue + 1), 4, MidpointRounding.AwayFromZero);
         }
 
         internal static double[] Reads15Fixed16Array(byte[] bytes)

IccProfileNet.Tests/Profiles/tftcentral/asus_rog_strix_xg27aq_rtings.icm

@@ -41,6 +41,39 @@ public IccProfile(byte[] data)
             _tags = new Lazy<IReadOnlyDictionary<string, IccTagTypeBase>>(() => GetTags());
         }
 
+        public byte[] GetOrComputeProfileId()
+        {
+            if (Header.IsProfileIdComputed())
+            {
+                return Header.ProfileId;
+            }
+
+            return ComputeProfileId();
+        }
+
+        public byte[] ComputeProfileId()
+        {
+            return IccHelper.ComputeProfileId(Data);
+        }
+
+        /// <summary>
+        /// Validates the profile against the profile id.
+        /// </summary>
+        /// <returns>
+        /// <c>true</c> if the profile id contained in the header matches the re-computed profile id.
+        /// <c>false</c> if they don't match.
+        /// <c>null</c> if the profile id is not set in the header.
+        /// </returns>
+        public bool? ValidateProfile()
+        {
+            if (Header.IsProfileIdComputed())
+            {
+                return null;
+            }
+
+            return Header.ProfileId.SequenceEqual(ComputeProfileId());
+        }
+
         private static IccTagTableItem[] ParseTagTable(byte[] bytes)
         {
             // Tag count (n)

IccProfileNet.Tests/Profiles/tftcentral/asus_rog_swift_pg42uq.icm

@@ -159,6 +159,11 @@ public struct IccProfileHeader
         /// </summary>
         public byte[] ProfileId => _profileId.Value;
 
+        public bool IsProfileIdComputed()
+        {
+            return !ProfileId.All(v => v == 0);
+        }
+
         public IccProfileHeader(byte[] profile)
         {
             // Profile version number
@@ -299,21 +304,7 @@ public IccProfileHeader(byte[] profile)
             {
                 // Profile ID
                 // 84 to 99
-                byte[] profileId = profile.Skip(ProfileIdOffset).Take(ProfileIdLength).ToArray();
-
-                if (profileId.All(b => b == 0))
-                {
-                    // Compute profile id
-                    // This field, if not zero (00h), shall hold the Profile ID. The Profile ID shall be calculated using the MD5
-                    // fingerprinting method as defined in Internet RFC 1321.The entire profile, whose length is given by the size field
-                    // in the header, with the profile flags field (bytes 44 to 47, see 7.2.11), rendering intent field (bytes 64 to 67, see
-                    // 7.2.15), and profile ID field (bytes 84 to 99) in the profile header temporarily set to zeros (00h), shall be used to
-                    // calculate the ID. A profile ID field value of zero (00h) shall indicate that a profile ID has not been calculated.
-                    // Profile creators should compute and record a profile ID.
-
-                    profileId = System.Security.Cryptography.MD5.HashData(profile);
-                }
-                return profileId;
+                return profile.Skip(ProfileIdOffset).Take(ProfileIdLength).ToArray();
             });
         }