Initial commit - get by Span

RocksDbSharp/Native.Marshaled.cs

@@ -1,10 +1,11 @@
-/*
+/*
     The functions in this file provide some wrappers around the lowest level C API to aid in marshalling.
     This is kept separate so that the lowest level imports can be kept as close as possible to c.h from rocksdb.
     See Native.Raw.cs for more information.
 */
 using System;
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
 using Transitional;
@@ -155,7 +156,37 @@ public byte[] rocksdb_get(
             rocksdb_free(resultPtr);
             return result;
         }
-
+
+        public unsafe Span<byte> rocksdb_get_span(
+            IntPtr db,
+            IntPtr read_options,
+            byte[] key,
+            long keyLength,
+            out IntPtr errptr,
+            ColumnFamilyHandle cf = null)
+        {
+            UIntPtr skLength = (UIntPtr)keyLength;
+            var resultPtr = cf == null
+                ? rocksdb_get(db, read_options, key, skLength, out UIntPtr valueLength, out errptr)
+                : rocksdb_get_cf(db, read_options, cf.Handle, key, skLength, out valueLength, out errptr);
+            if (errptr != IntPtr.Zero)
+                return null;
+            if (resultPtr == IntPtr.Zero)
+                return null;
+            Span<byte> span = new Span<byte>((void*)resultPtr, (int)valueLength);
+            //MemoryMarshal.GetReference(span);
+
+
+            return span;
+        }
+
+        public unsafe void rocksdb_release_span(in Span<byte> span)
+        {
+            ref byte ptr = ref MemoryMarshal.GetReference(span);
+            IntPtr intPtr = new IntPtr(Unsafe.AsPointer(ref ptr));
+            rocksdb_free(intPtr);
+        }
+
         /// <summary>
         /// Executes a multi_get with automatic marshalling
         /// </summary>

RocksDbSharp/Native.Wrap.cs

@@ -182,6 +182,19 @@ public byte[] rocksdb_get(
                 throw new RocksDbException(errptr);
             return result;
         }
+
+        public Span<byte> rocksdb_get_span(
+            IntPtr db,
+            IntPtr read_options,
+            byte[] key,
+            long keyLength = 0,
+            ColumnFamilyHandle cf = null)
+        {
+            var result = rocksdb_get_span(db, read_options, key, keyLength == 0 ? key.Length : keyLength, out IntPtr errptr, cf);
+            if (errptr != IntPtr.Zero)
+                throw new RocksDbException(errptr);
+            return result;
+        }
 
         public KeyValuePair<string, string>[] rocksdb_multi_get(
             IntPtr db,

RocksDbSharp/RocksDb.cs

@@ -119,12 +119,22 @@ public byte[] Get(byte[] key, ColumnFamilyHandle cf = null, ReadOptions readOpti
         {
             return Get(key, key.GetLongLength(0), cf, readOptions);
         }
-
+        
         public byte[] Get(byte[] key, long keyLength, ColumnFamilyHandle cf = null, ReadOptions readOptions = null)
         {
             return Native.Instance.rocksdb_get(Handle, (readOptions ?? DefaultReadOptions).Handle, key, keyLength, cf);
         }
 
+        public Span<byte> GetSpan(byte[] key, ColumnFamilyHandle cf = null, ReadOptions readOptions = null)
+        {
+            return GetSpan(key, key.GetLongLength(0), cf, readOptions);
+        }
+
+        public Span<byte> GetSpan(byte[] key, long keyLength, ColumnFamilyHandle cf = null, ReadOptions readOptions = null)
+        {
+            return Native.Instance.rocksdb_get_span(Handle, (readOptions ?? DefaultReadOptions).Handle, key, keyLength, cf);
+        }
+
         /// <summary>
         /// Reads the contents of the database value associated with <paramref name="key"/>, if present, into the supplied
         /// <paramref name="buffer"/> at <paramref name="offset"/> up to <paramref name="length"/> bytes, returning the
@@ -306,5 +316,10 @@ public void CompactRange(string start, string limit, ColumnFamilyHandle cf = nul
                 encoding = Encoding.UTF8;
             CompactRange(encoding.GetBytes(start), encoding.GetBytes(limit), cf);
         }
+
+        public void DangerousReleaseMemory(in Span<byte> span)
+        {
+            Native.Instance.rocksdb_release_span(in span);
+        }
     }
 }

RocksDbSharp/RocksDbSharp.csproj

@@ -1,5 +1,5 @@
 <Project Sdk="Microsoft.NET.Sdk">
-  <Import Project="..\Versions.targets.include"/>
+  <Import Project="..\Versions.targets.include" />
   <PropertyGroup>
     <Title>RocksDbSharp</Title>
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
@@ -40,5 +40,6 @@
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.CSharp" Version="4.5.0" />
+    <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="4.5.2" />
   </ItemGroup>
 </Project>