From aa5a89951c65a19ee80ac50bac12a1d78dd491f4 Mon Sep 17 00:00:00 2001
From: lc6464 <64722907+lc6464@users.noreply.github.com>
Date: Wed, 13 Sep 2023 23:23:15 +0800
Subject: [PATCH] v2.0.0-RC.1

---
 LC6464.Base16384.csproj |  4 ++--
 Shared.cs               |  5 +++++
 Text.cs                 | 11 +++++++----
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/LC6464.Base16384.csproj b/LC6464.Base16384.csproj
index 7001997..d5fb807 100644
--- a/LC6464.Base16384.csproj
+++ b/LC6464.Base16384.csproj
@@ -17,8 +17,8 @@
 		<PackageLicenseExpression>GPL-3.0-only</PackageLicenseExpression>
 		<PackageRequireLicenseAcceptance>True</PackageRequireLicenseAcceptance>
 		<Authors>LC</Authors>
-		<Version>2.0.0-Preview.2</Version>
-		<PackageReleaseNotes>修复一些高级 API 逻辑错误以及 Span 访问越界等致命问题。</PackageReleaseNotes>
+		<Version>2.0.0-RC.1</Version>
+		<PackageReleaseNotes>完成了 ToUtf8BOMBytes 方法。</PackageReleaseNotes>
 	</PropertyGroup>
 	<ItemGroup>
 		<Using Include="System.Runtime.InteropServices" />
diff --git a/Shared.cs b/Shared.cs
index cbe49e7..98cbd3f 100644
--- a/Shared.cs
+++ b/Shared.cs
@@ -57,6 +57,11 @@ private static void EncodeLengthInternal(long dataLength, out long outLength, ou
 	/// </summary>
 	public static ReadOnlySpan<byte> Utf16LEPreamble => new byte[] { 0xFF, 0xFE };
 
+	/// <summary>
+	/// UTF-8 with BOM 编码的 BOM，应在文件头部出现。
+	/// </summary>
+	public static ReadOnlySpan<byte> Utf8Preamble => new byte[] { 0xEF, 0xBB, 0xBF };
+
 
 	/// <summary>
 	/// 计算编码指针需要的长度。
diff --git a/Text.cs b/Text.cs
index 6498015..22c5f99 100644
--- a/Text.cs
+++ b/Text.cs
@@ -14,15 +14,18 @@ public static partial class Base16384 {
 	public static ReadOnlySpan<byte> ConvertFromUtf16BEBytesToUtf8Bytes(this ReadOnlySpan<byte> data) =>
 		Encoding.Convert(Encoding.BigEndianUnicode, Encoding.UTF8, data.ToArray());
 
-#if DEBUG // 此处仍有问题，暂时不使用
 	/// <summary>
 	/// 将 UTF-16 BE 编码的数据转换为 UTF-8 with BOM 编码的数据。
 	/// </summary>
 	/// <param name="data">UTF-16 BE 编码的数据</param>
 	/// <returns>UTF-8 with BOM 编码的数据</returns>
-	public static ReadOnlySpan<byte> ConvertFromUtf16BEBytesToUtf8BOMBytes(this ReadOnlySpan<byte> data) =>
-		Encoding.Convert(Encoding.BigEndianUnicode, new UTF8Encoding(true), data.ToArray());
-#endif
+	public static ReadOnlySpan<byte> ConvertFromUtf16BEBytesToUtf8BOMBytes(this ReadOnlySpan<byte> data) {
+		Span<byte> buffer = new byte[data.Length + 3];
+		Utf8Preamble.CopyTo(buffer);
+		data.ConvertFromUtf16BEBytesToUtf8Bytes().CopyTo(buffer[3..]);
+		return buffer;
+	}
+
 
 	/// <summary>
 	/// 将 UTF-16 BE 编码的数据转换为字符串。