Add a UDF reader and wrapper

SabreTools.Data.Extensions.Test/UDFExtensionsTests.cs

@@ -0,0 +1,199 @@
+using SabreTools.Data.Models.UDF;
+using Xunit;
+
+namespace SabreTools.Data.Extensions.Test
+{
+    public class UDFExtensionsTests
+    {
+        #region DecodeDCharacters
+
+        [Fact]
+        public void DecodeDCharacters_Null_Empty()
+        {
+            byte[]? data = null;
+            Assert.Equal(string.Empty, data.DecodeDCharacters());
+        }
+
+        [Fact]
+        public void DecodeDCharacters_8Bit_Decoded()
+        {
+            byte[] data = [8, 0x41, 0x62, 0xE4];
+            Assert.Equal("Abä", data.DecodeDCharacters());
+        }
+
+        [Fact]
+        public void DecodeDCharacters_16Bit_Decoded()
+        {
+            byte[] data = [16, 0x00, 0x41, 0x30, 0x42];
+            Assert.Equal("Aあ", data.DecodeDCharacters());
+        }
+
+        [Fact]
+        public void DecodeDCharacters_UnknownCompression_Null()
+        {
+            byte[] data = [1, 0x41];
+            Assert.Null(data.DecodeDCharacters());
+        }
+
+        [Fact]
+        public void DecodeDString_UsesLengthByte()
+        {
+            byte[] data = [8, 0x41, 0x42, 0x43, 0x00, 3];
+            Assert.Equal("AB", data.DecodeDString());
+        }
+
+        [Fact]
+        public void DecodeDString_ZeroLength_Empty()
+        {
+            byte[] data = [8, 0x41, 0x00, 0];
+            Assert.Equal(string.Empty, data.DecodeDString());
+        }
+
+        #endregion
+
+        #region TryGetSector
+
+        [Fact]
+        public void TryGetSector_Type1_StartPlusBlock()
+        {
+            var volume = CreateVolume(new Type1PartitionMap { PartitionNumber = 0 });
+            bool actual = volume.TryGetSector(UDFExtensions.GetKey(0, 10), out long sector);
+            Assert.True(actual);
+            Assert.Equal(1010, sector);
+        }
+
+        [Fact]
+        public void TryGetSector_Type1_OutsidePartition_False()
+        {
+            var volume = CreateVolume(new Type1PartitionMap { PartitionNumber = 0 });
+            bool actual = volume.TryGetSector(UDFExtensions.GetKey(0, 100), out _);
+            Assert.False(actual);
+        }
+
+        [Fact]
+        public void TryGetSector_UnknownPartitionReference_False()
+        {
+            var volume = CreateVolume(new Type1PartitionMap { PartitionNumber = 0 });
+            bool actual = volume.TryGetSector(UDFExtensions.GetKey(1, 0), out _);
+            Assert.False(actual);
+        }
+
+        [Fact]
+        public void TryGetSector_Metadata_ThroughMetadataFile()
+        {
+            // Metadata File at block 5 of partition 0: blocks 0-1 of the metadata partition are blocks 20-21,
+            // blocks 2-3 are blocks 40-41
+            var volume = CreateVolume(
+                new Type1PartitionMap { PartitionNumber = 0 },
+                new MetadataPartitionMap { PartitionNumber = 0, MetadataFileLocation = 5, MetadataMirrorFileLocation = 6 });
+            volume.FileEntries[UDFExtensions.GetKey(0, 5)] = CreateShortAdEntry((4096, 20), (4096, 40));
+
+            Assert.True(volume.TryGetSector(UDFExtensions.GetKey(1, 1), out long first));
+            Assert.Equal(1021, first);
+            Assert.True(volume.TryGetSector(UDFExtensions.GetKey(1, 2), out long second));
+            Assert.Equal(1040, second);
+            Assert.False(volume.TryGetSector(UDFExtensions.GetKey(1, 4), out _));
+        }
+
+        [Fact]
+        public void TryGetSector_Metadata_FallsBackToMirror()
+        {
+            var volume = CreateVolume(
+                new Type1PartitionMap { PartitionNumber = 0 },
+                new MetadataPartitionMap { PartitionNumber = 0, MetadataFileLocation = 5, MetadataMirrorFileLocation = 6 });
+            volume.FileEntries[UDFExtensions.GetKey(0, 6)] = CreateShortAdEntry((2048, 30));
+
+            Assert.True(volume.TryGetSector(UDFExtensions.GetKey(1, 0), out long sector));
+            Assert.Equal(1030, sector);
+        }
+
+        #endregion
+
+        #region GetAllocationDescriptors
+
+        [Fact]
+        public void GetAllocationDescriptors_Embedded_Empty()
+        {
+            var entry = new FileEntry();
+            entry.ICBTag.Flags = (ushort)AllocationDescriptorType.EMBEDDED;
+            entry.AllocationDescriptors = [1, 2, 3];
+
+            var actual = new Volume().GetAllocationDescriptors(0, entry);
+            Assert.NotNull(actual);
+            Assert.Empty(actual);
+        }
+
+        [Fact]
+        public void GetAllocationDescriptors_ZeroLengthTerminates()
+        {
+            var entry = CreateShortAdEntry((2048, 20), (0, 99), (2048, 40));
+
+            var actual = new Volume().GetAllocationDescriptors(UDFExtensions.GetKey(2, 7), entry);
+            Assert.NotNull(actual);
+            var ad = Assert.Single(actual);
+            Assert.Equal(20u, ad.ExtentLocation.LogicalBlockNumber);
+            Assert.Equal((ushort)2, ad.ExtentLocation.PartitionReferenceNumber);
+        }
+
+        [Fact]
+        public void GetAllocationDescriptors_MissingAllocationExtent_NullWithKey()
+        {
+            var entry = CreateShortAdEntry((2048, 20), ((3u << 30) | 2048, 50));
+
+            var actual = new Volume().GetAllocationDescriptors(UDFExtensions.GetKey(0, 7), entry, out long missingKey);
+            Assert.Null(actual);
+            Assert.Equal(UDFExtensions.GetKey(0, 50), missingKey);
+        }
+
+        [Fact]
+        public void GetAllocationDescriptors_AllocationExtentLoop_Null()
+        {
+            var volume = new Volume();
+            var entry = CreateShortAdEntry(((3u << 30) | 2048, 50));
+            volume.AllocationExtentDescriptors[UDFExtensions.GetKey(0, 50)] = new AllocationExtentDescriptor
+            {
+                AllocationDescriptors = CreateShortAdEntry(((3u << 30) | 2048, 50)).AllocationDescriptors,
+            };
+
+            var actual = volume.GetAllocationDescriptors(UDFExtensions.GetKey(0, 7), entry);
+            Assert.Null(actual);
+        }
+
+        #endregion
+
+        /// <summary>
+        /// Volume with partition 0 at sector 1000 (length 50) and the given partition maps
+        /// </summary>
+        private static Volume CreateVolume(params PartitionMap[] maps)
+        {
+            return new Volume
+            {
+                VolumeDescriptorSequence =
+                [
+                    new PartitionDescriptor { PartitionNumber = 0, PartitionStartingLocation = 1000, PartitionLength = 50 },
+                    new LogicalVolumeDescriptor { LogicalBlockSize = 2048, PartitionMaps = maps },
+                ],
+            };
+        }
+
+        /// <summary>
+        /// File Entry with the given short allocation descriptors (extent length, position)
+        /// </summary>
+        private static FileEntry CreateShortAdEntry(params (uint Length, uint Position)[] extents)
+        {
+            var data = new byte[extents.Length * 8];
+            for (int i = 0; i < extents.Length; i++)
+            {
+                for (int b = 0; b < 4; b++)
+                {
+                    data[(i * 8) + b] = (byte)(extents[i].Length >> (8 * b));
+                    data[(i * 8) + 4 + b] = (byte)(extents[i].Position >> (8 * b));
+                }
+            }
+
+            var entry = new FileEntry { AllocationDescriptors = data };
+            entry.ICBTag.Flags = (ushort)AllocationDescriptorType.SHORT;
+            return entry;
+        }
+    }
+}