From 3a6d24b1d99df6233baf3370aacadd25a437e590 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 29 Nov 2025 13:36:01 +0000
Subject: [PATCH] Add ZStandard frame and dictionary types

Co-authored-by: adamhathcock <527620+adamhathcock@users.noreply.github.com>
---
 .../ZStandard/Unsafe/ZSTD_ResetDirective.cs   |  8 +++++++
 .../Unsafe/ZSTD_dictContentType_e.cs          | 13 ++++++++++++
 .../ZStandard/Unsafe/ZSTD_dictLoadMethod_e.cs | 10 +++++++++
 .../ZStandard/Unsafe/ZSTD_frameHeader.cs      | 21 +++++++++++++++++++
 .../ZStandard/Unsafe/ZSTD_frameType_e.cs      |  7 +++++++
 5 files changed, 59 insertions(+)
 create mode 100644 src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_ResetDirective.cs
 create mode 100644 src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_dictContentType_e.cs
 create mode 100644 src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_dictLoadMethod_e.cs
 create mode 100644 src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_frameHeader.cs
 create mode 100644 src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_frameType_e.cs

diff --git a/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_ResetDirective.cs b/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_ResetDirective.cs
new file mode 100644
index 00000000..df0bd035
--- /dev/null
+++ b/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_ResetDirective.cs
@@ -0,0 +1,8 @@
+namespace SharpCompress.Compressors.ZStandard.Unsafe;
+
+public enum ZSTD_ResetDirective
+{
+    ZSTD_reset_session_only = 1,
+    ZSTD_reset_parameters = 2,
+    ZSTD_reset_session_and_parameters = 3,
+}
diff --git a/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_dictContentType_e.cs b/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_dictContentType_e.cs
new file mode 100644
index 00000000..18e7172f
--- /dev/null
+++ b/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_dictContentType_e.cs
@@ -0,0 +1,13 @@
+namespace SharpCompress.Compressors.ZStandard.Unsafe;
+
+public enum ZSTD_dictContentType_e
+{
+    /// <summary>dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent"</summary>
+    ZSTD_dct_auto = 0,
+
+    /// <summary>ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY</summary>
+    ZSTD_dct_rawContent = 1,
+
+    /// <summary>refuses to load a dictionary if it does not respect Zstandard's specification</summary>
+    ZSTD_dct_fullDict = 2,
+}
diff --git a/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_dictLoadMethod_e.cs b/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_dictLoadMethod_e.cs
new file mode 100644
index 00000000..5d1ee309
--- /dev/null
+++ b/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_dictLoadMethod_e.cs
@@ -0,0 +1,10 @@
+namespace SharpCompress.Compressors.ZStandard.Unsafe;
+
+public enum ZSTD_dictLoadMethod_e
+{
+    /// <summary>Copy dictionary content internally</summary>
+    ZSTD_dlm_byCopy = 0,
+
+    /// <summary>Reference dictionary content -- the dictionary buffer must outlive its users</summary>
+    ZSTD_dlm_byRef = 1,
+}
diff --git a/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_frameHeader.cs b/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_frameHeader.cs
new file mode 100644
index 00000000..3caa2787
--- /dev/null
+++ b/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_frameHeader.cs
@@ -0,0 +1,21 @@
+namespace SharpCompress.Compressors.ZStandard.Unsafe;
+
+public struct ZSTD_frameHeader
+{
+    /// <summary>if == ZSTD_CONTENTSIZE_UNKNOWN, it means this field is not available. 0 means "empty"</summary>
+    public ulong frameContentSize;
+
+    /// <summary>can be very large, up to frameContentSize</summary>
+    public ulong windowSize;
+    public uint blockSizeMax;
+
+    /// <summary>if == ZSTD_skippableFrame, frameContentSize is the size of skippable content</summary>
+    public ZSTD_frameType_e frameType;
+    public uint headerSize;
+
+    /// <summary>for ZSTD_skippableFrame, contains the skippable magic variant [0-15]</summary>
+    public uint dictID;
+    public uint checksumFlag;
+    public uint _reserved1;
+    public uint _reserved2;
+}
diff --git a/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_frameType_e.cs b/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_frameType_e.cs
new file mode 100644
index 00000000..a399748f
--- /dev/null
+++ b/src/SharpCompress/Compressors/ZStandard/Unsafe/ZSTD_frameType_e.cs
@@ -0,0 +1,7 @@
+namespace SharpCompress.Compressors.ZStandard.Unsafe;
+
+public enum ZSTD_frameType_e
+{
+    ZSTD_frame,
+    ZSTD_skippableFrame,
+}