From 531aebb54fc78fd88fbed76c83ec5313f4de2e46 Mon Sep 17 00:00:00 2001
From: YoshiRulz <OSSYoshiRulz@gmail.com>
Date: Sun, 4 Dec 2022 09:42:35 +1000
Subject: [PATCH] Expose `MemoryDomain.ReadByteRange`'s `Span` overload via
 `IMemoryApi`

---
 .../Api/Classes/MemoryApi.cs                  | 20 +++++++++++++++++++
 .../Api/Interfaces/IMemoryApi.cs              |  9 +++++++++
 2 files changed, 29 insertions(+)

diff --git a/src/BizHawk.Client.Common/Api/Classes/MemoryApi.cs b/src/BizHawk.Client.Common/Api/Classes/MemoryApi.cs
index 3c6725d42d..d8d0ebe100 100644
--- a/src/BizHawk.Client.Common/Api/Classes/MemoryApi.cs
+++ b/src/BizHawk.Client.Common/Api/Classes/MemoryApi.cs
@@ -260,6 +260,26 @@ namespace BizHawk.Client.Common
 			return newBytes;
 		}
 
+		public bool ReadByteRange(ulong srcStartOffset, Span<byte> dstBuffer, string domain = null)
+		{
+			var d = NamedDomainOrCurrent(domain);
+			if (srcStartOffset >= (ulong) d.Size)
+			{
+				LogCallback($"Warning: attempted read of {srcStartOffset} outside the memory size of {d.Size}");
+				return false;
+			}
+			try
+			{
+				d.BulkPeekByte(srcStartOffset, dstBuffer);
+				return true;
+			}
+			catch (Exception e)
+			{
+				LogCallback($"bulk-peek threw {e.GetType().Name}: {e.Message}");
+				return false;
+			}
+		}
+
 		public void WriteByteRange(long addr, IReadOnlyList<byte> memoryblock, string domain = null)
 		{
 			var d = NamedDomainOrCurrent(domain);
diff --git a/src/BizHawk.Client.Common/Api/Interfaces/IMemoryApi.cs b/src/BizHawk.Client.Common/Api/Interfaces/IMemoryApi.cs
index ae644937a0..08a082c3c3 100644
--- a/src/BizHawk.Client.Common/Api/Interfaces/IMemoryApi.cs
+++ b/src/BizHawk.Client.Common/Api/Interfaces/IMemoryApi.cs
@@ -17,6 +17,15 @@ namespace BizHawk.Client.Common
 
 		uint ReadByte(long addr, string domain = null);
 		IReadOnlyList<byte> ReadByteRange(long addr, int length, string domain = null);
+
+		/// <summary>copies a region of memory into <paramref name="dstBuffer"/>, starting at <paramref name="srcStartOffset"/> and taking as many bytes as will fit in the buffer</summary>
+		/// <returns>
+		/// <see langword="false"/> iff the internal API call threw an exception (for example, if you request bytes beyond the end of the domain).<br/>
+		/// If this happens, the state of <paramref name="dstBuffer"/> is undefined. Anywhere from <c>0</c> bytes to all of them could have been copied.
+		/// The exception is when <paramref name="srcStartOffset"/> falls outside the domain, as that is checked first and results in a no-op.
+		/// </returns>
+		bool ReadByteRange(ulong srcStartOffset, Span<byte> dstBuffer, string domain = null);
+
 		float ReadFloat(long addr, string domain = null);
 
 		int ReadS8(long addr, string domain = null);