[Veritas] Implement file operations.

Aaru.Filesystems/VxFS/File.cs

@@ -29,6 +29,7 @@
 using System;
 using System.Collections.Generic;
 using Aaru.CommonTypes.Enums;
+using Aaru.CommonTypes.Interfaces;
 using Aaru.CommonTypes.Structs;
 using Aaru.Helpers;
 
@@ -54,6 +55,100 @@ public sealed partial class VxFS
         return ErrorNumber.NoError;
     }
 
+    /// <inheritdoc />
+    public ErrorNumber OpenFile(string path, out IFileNode node)
+    {
+        node = null;
+
+        if(!_mounted) return ErrorNumber.AccessDenied;
+
+        if(string.IsNullOrEmpty(path) || path == "/") return ErrorNumber.IsDirectory;
+
+        ErrorNumber errno = LookupInode(path, out DiskInode inode, out uint inodeNumber);
+
+        if(errno != ErrorNumber.NoError) return errno;
+
+        var fileType = (VxfsFileType)(inode.vdi_mode & VXFS_TYPE_MASK);
+
+        if(fileType == VxfsFileType.Dir) return ErrorNumber.IsDirectory;
+
+        node = new VxFsFileNode
+        {
+            Path        = path,
+            Length      = (long)inode.vdi_size,
+            Offset      = 0,
+            InodeNumber = inodeNumber,
+            Inode       = inode
+        };
+
+        return ErrorNumber.NoError;
+    }
+
+    /// <inheritdoc />
+    public ErrorNumber CloseFile(IFileNode node)
+    {
+        if(!_mounted) return ErrorNumber.AccessDenied;
+
+        if(node is not VxFsFileNode) return ErrorNumber.InvalidArgument;
+
+        return ErrorNumber.NoError;
+    }
+
+    /// <inheritdoc />
+    public ErrorNumber ReadFile(IFileNode node, long length, byte[] buffer, out long read)
+    {
+        read = 0;
+
+        if(!_mounted) return ErrorNumber.AccessDenied;
+
+        if(node is not VxFsFileNode fileNode) return ErrorNumber.InvalidArgument;
+
+        if(buffer == null) return ErrorNumber.InvalidArgument;
+
+        if(fileNode.Offset < 0 || fileNode.Offset >= fileNode.Length) return ErrorNumber.InvalidArgument;
+
+        long toRead = length;
+
+        if(fileNode.Offset + toRead > fileNode.Length) toRead = fileNode.Length - fileNode.Offset;
+
+        if(toRead <= 0) return ErrorNumber.NoError;
+
+        if(toRead > buffer.Length) toRead = buffer.Length;
+
+        int  blockSize     = _superblock.vs_bsize;
+        long bytesRead     = 0;
+        long currentOffset = fileNode.Offset;
+
+        while(bytesRead < toRead)
+        {
+            var blockNum      = (uint)(currentOffset / blockSize);
+            var offsetInBlock = (int)(currentOffset  % blockSize);
+
+            byte[] blockData = ReadInodeBlock(fileNode.Inode, blockNum);
+
+            if(blockData == null)
+            {
+                // Sparse block / hole — fill with zeros
+                long bytesToZero = Math.Min(blockSize - offsetInBlock, toRead - bytesRead);
+                Array.Clear(buffer, (int)bytesRead, (int)bytesToZero);
+                bytesRead     += bytesToZero;
+                currentOffset += bytesToZero;
+
+                continue;
+            }
+
+            long bytesToCopy = Math.Min(blockSize - offsetInBlock, toRead - bytesRead);
+            Array.Copy(blockData, offsetInBlock, buffer, bytesRead, bytesToCopy);
+            bytesRead     += bytesToCopy;
+            currentOffset += bytesToCopy;
+        }
+
+        read            =  bytesRead;
+        fileNode.Offset += bytesRead;
+
+        return ErrorNumber.NoError;
+    }
+
     /// <summary>Resolves a path to its inode</summary>
     /// <param name="path">Path to resolve</param>
     /// <param name="inode">Output inode</param>

Aaru.Filesystems/VxFS/Internal.cs

@@ -46,4 +46,23 @@ public sealed partial class VxFS
         /// <inheritdoc />
         public string Path { get; init; }
     }
+
+    /// <summary>File node for reading file contents</summary>
+    sealed class VxFsFileNode : IFileNode
+    {
+        /// <summary>The inode number</summary>
+        internal uint InodeNumber { get; init; }
+
+        /// <summary>The file's disk inode containing metadata and extent pointers</summary>
+        internal DiskInode Inode { get; init; }
+
+        /// <inheritdoc />
+        public string Path { get; init; }
+
+        /// <inheritdoc />
+        public long Length { get; init; }
+
+        /// <inheritdoc />
+        public long Offset { get; set; }
+    }
 }

Aaru.Filesystems/VxFS/Unimplemented.cs

@@ -28,7 +28,6 @@
 
 using System;
 using Aaru.CommonTypes.Enums;
-using Aaru.CommonTypes.Interfaces;
 using Aaru.CommonTypes.Structs;
 
 namespace Aaru.Filesystems;
@@ -40,14 +39,4 @@ public sealed partial class VxFS
 
     /// <inheritdoc />
     public ErrorNumber ReadLink(string path, out string dest) => throw new NotImplementedException();
-
-    /// <inheritdoc />
-    public ErrorNumber OpenFile(string path, out IFileNode node) => throw new NotImplementedException();
-
-    /// <inheritdoc />
-    public ErrorNumber CloseFile(IFileNode node) => throw new NotImplementedException();
-
-    /// <inheritdoc />
-    public ErrorNumber ReadFile(IFileNode node, long length, byte[] buffer, out long read) =>
-        throw new NotImplementedException();
 }