From 1aa8a4d46ffbf019f6bb4bccb81cc89bec07bb38 Mon Sep 17 00:00:00 2001
From: ssdsnake <id4-ssdsnake@proxyid.net>
Date: Fri, 3 Dec 2021 15:40:19 -0600
Subject: DolphinTool: CLI utility interface and disc image tools

---
 Source/Core/DiscIO/DiscUtils.cpp | 47 ++++++++++++++++++++++++++++++++++++++++
 Source/Core/DiscIO/DiscUtils.h   | 29 +++++++++++++++++++++++++
 2 files changed, 76 insertions(+)

(limited to 'Source/Core/DiscIO')

diff --git a/Source/Core/DiscIO/DiscUtils.cpp b/Source/Core/DiscIO/DiscUtils.cpp
index 84cf7ed7c4..002ce066db 100644
--- a/Source/Core/DiscIO/DiscUtils.cpp
+++ b/Source/Core/DiscIO/DiscUtils.cpp
@@ -12,6 +12,8 @@
 #include <fmt/format.h>
 
 #include "Common/CommonTypes.h"
+#include "Common/MathUtil.h"
+#include "DiscIO/Blob.h"
 #include "DiscIO/Filesystem.h"
 #include "DiscIO/Volume.h"
 
@@ -198,4 +200,49 @@ u64 GetBiggestReferencedOffset(const Volume& volume, const std::vector<Partition
   return biggest_offset;
 }
 
+bool IsGCZBlockSizeLegacyCompatible(int block_size, u64 file_size)
+{
+  // In order for versions of Dolphin prior to 5.0-11893 to be able to convert a GCZ file
+  // to ISO without messing up the final part of the file in some way, the file size
+  // must be an integer multiple of the block size (fixed in 3aa463c) and must not be
+  // an integer multiple of the block size multiplied by 32 (fixed in 26b21e3).
+  return file_size % block_size == 0 && file_size % (block_size * 32) != 0;
+}
+
+bool IsDiscImageBlockSizeValid(int block_size, DiscIO::BlobType format)
+{
+  switch (format)
+  {
+  case DiscIO::BlobType::GCZ:
+    // Block size "must" be a power of 2
+    if (!MathUtil::IsPow2(block_size))
+      return false;
+
+    break;
+  case DiscIO::BlobType::WIA:
+    // Block size must not be less than the minimum, and must be a multiple of it
+    if (block_size < WIA_MIN_BLOCK_SIZE || block_size % WIA_MIN_BLOCK_SIZE != 0)
+      return false;
+
+    break;
+  case DiscIO::BlobType::RVZ:
+    // Block size must not be smaller than the minimum
+    // Block sizes smaller than the large block size threshold must be a power of 2
+    // Block sizes larger than that threshold must be a multiple of the threshold
+    if (block_size < RVZ_MIN_BLOCK_SIZE ||
+        (block_size < RVZ_BIG_BLOCK_SIZE_LCM && !MathUtil::IsPow2(block_size)) ||
+        (block_size > RVZ_BIG_BLOCK_SIZE_LCM && block_size % RVZ_BIG_BLOCK_SIZE_LCM != 0))
+    {
+      return false;
+    }
+
+    break;
+  default:
+    ASSERT(false);
+    break;
+  }
+
+  return true;
+}
+
 }  // namespace DiscIO
diff --git a/Source/Core/DiscIO/DiscUtils.h b/Source/Core/DiscIO/DiscUtils.h
index 0b0cb80684..5baf5fcafa 100644
--- a/Source/Core/DiscIO/DiscUtils.h
+++ b/Source/Core/DiscIO/DiscUtils.h
@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "Common/CommonTypes.h"
+#include "DiscIO/Blob.h"
 
 namespace DiscIO
 {
@@ -49,6 +50,31 @@ constexpr u32 WII_NONPARTITION_DISCHEADER_SIZE = 0x100;
 constexpr u32 WII_REGION_DATA_ADDRESS = 0x4E000;
 constexpr u32 WII_REGION_DATA_SIZE = 0x20;
 
+// 128 KiB (0x20000) is the default block size for GCZ/RVZ images
+constexpr int GCZ_RVZ_PREFERRED_BLOCK_SIZE = 0x20000;
+
+// 32 KiB (0x8000) was picked because DVD timings are emulated as if we can't read less than
+// an entire ECC block at once. Therefore, little reason to choose a smaller block size.
+constexpr int PREFERRED_MIN_BLOCK_SIZE = 0x8000;
+
+// 2 MiB (0x200000) was picked because it is the smallest block size supported by WIA.
+// For performance reasons, blocks shouldn't be too large.
+constexpr int PREFERRED_MAX_BLOCK_SIZE = 0x200000;
+
+// If we didn't find a good GCZ block size, pick the block size which was hardcoded
+// in legacy versions. That way, at least we're not worse than older versions.
+// 16 KiB (0x4000) for supporting GCZs in versions of Dolphin prior to 5.0-11893
+constexpr int GCZ_FALLBACK_BLOCK_SIZE = 0x4000;
+
+// 2 MiB (0x200000) is the smallest block size supported by WIA.
+constexpr int WIA_MIN_BLOCK_SIZE = 0x200000;
+
+// 32 KiB (0x8000) is the smallest block size supported by RVZ.
+constexpr int RVZ_MIN_BLOCK_SIZE = 0x8000;
+
+// 2 MiB (0x200000): for RVZ, block sizes larger than 2 MiB must be an integer multiple of 2 MiB.
+constexpr int RVZ_BIG_BLOCK_SIZE_LCM = 0x200000;
+
 std::string NameForPartitionType(u32 partition_type, bool include_prefix);
 
 std::optional<u64> GetApploaderSize(const Volume& volume, const Partition& partition);
@@ -59,4 +85,7 @@ std::optional<u64> GetFSTSize(const Volume& volume, const Partition& partition);
 
 u64 GetBiggestReferencedOffset(const Volume& volume);
 u64 GetBiggestReferencedOffset(const Volume& volume, const std::vector<Partition>& partitions);
+
+bool IsGCZBlockSizeLegacyCompatible(int block_size, u64 file_size);
+bool IsDiscImageBlockSizeValid(int block_size, DiscIO::BlobType format);
 }  // namespace DiscIO
-- 
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