From 2aad23c443d7286a42f99e55c13ad165817963da Mon Sep 17 00:00:00 2001
From: TheLastRar <TheLastRar@users.noreply.github.com>
Date: Mon, 16 Dec 2024 18:46:21 +0000
Subject: [PATCH] ChdFileReader: Migrate libchdr patch into PCSX2

Added function didn't need to be in libchdr
---
 3rdparty/libchdr/include/libchdr/chd.h |  1 -
 3rdparty/libchdr/src/libchdr_chd.c     | 21 ------------------
 pcsx2/CDVD/ChdFileReader.cpp           | 30 +++++++++++++++++++++++---
 3 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/3rdparty/libchdr/include/libchdr/chd.h b/3rdparty/libchdr/include/libchdr/chd.h
index d1e7a81dd16bc..1092d40b4327f 100644
--- a/3rdparty/libchdr/include/libchdr/chd.h
+++ b/3rdparty/libchdr/include/libchdr/chd.h
@@ -407,7 +407,6 @@ CHD_EXPORT const chd_header *chd_get_header(chd_file *chd);
 CHD_EXPORT chd_error chd_read_header_core_file(core_file *file, chd_header *header);
 CHD_EXPORT chd_error chd_read_header_file(FILE *file, chd_header *header);
 CHD_EXPORT chd_error chd_read_header(const char *filename, chd_header *header);
-CHD_EXPORT bool chd_is_matching_parent(const chd_header* header, const chd_header* parent_header);
 
 
 
diff --git a/3rdparty/libchdr/src/libchdr_chd.c b/3rdparty/libchdr/src/libchdr_chd.c
index cac9720a172e1..aa1ec8b9dc67c 100644
--- a/3rdparty/libchdr/src/libchdr_chd.c
+++ b/3rdparty/libchdr/src/libchdr_chd.c
@@ -2281,27 +2281,6 @@ CHD_EXPORT chd_error chd_read_header(const char *filename, chd_header *header)
 	return err;
 }
 
-CHD_EXPORT bool chd_is_matching_parent(const chd_header* header, const chd_header* parent_header)
-{
-  /* check MD5 if it isn't empty */
-  if (memcmp(nullmd5, header->parentmd5, sizeof(header->parentmd5)) != 0 &&
-      memcmp(nullmd5, parent_header->md5, sizeof(parent_header->md5)) != 0 &&
-      memcmp(parent_header->md5, header->parentmd5, sizeof(header->parentmd5)) != 0)
-	{
-		return false;
-	}
-
-  /* check SHA1 if it isn't empty */
-  if (memcmp(nullsha1, header->parentsha1, sizeof(header->parentsha1)) != 0 &&
-      memcmp(nullsha1, parent_header->sha1, sizeof(parent_header->sha1)) != 0 &&
-      memcmp(parent_header->sha1, header->parentsha1, sizeof(header->parentsha1)) != 0)
-	{
-		return false;
-	}
-
-	return true;
-}
-
 /***************************************************************************
     CORE DATA READ/WRITE
 ***************************************************************************/
diff --git a/pcsx2/CDVD/ChdFileReader.cpp b/pcsx2/CDVD/ChdFileReader.cpp
index fbf2c642aa6b0..b58095c2897e4 100644
--- a/pcsx2/CDVD/ChdFileReader.cpp
+++ b/pcsx2/CDVD/ChdFileReader.cpp
@@ -95,6 +95,30 @@ ChdFileReader::~ChdFileReader()
 	pxAssert(!ChdFile);
 }
 
+static bool IsHeaderParentCHD(const chd_header& header, const chd_header& parent_header)
+{
+	static const u8 nullmd5[CHD_MD5_BYTES]{};
+	static const u8 nullsha1[CHD_SHA1_BYTES]{};
+
+	// Check MD5 if it isn't empty.
+	if (std::memcmp(nullmd5, header.parentmd5, CHD_MD5_BYTES) != 0 &&
+		std::memcmp(nullmd5, parent_header.md5, CHD_MD5_BYTES) != 0 &&
+		std::memcmp(parent_header.md5, header.parentmd5, CHD_MD5_BYTES) != 0)
+	{
+		return false;
+	}
+
+	// Check SHA1 if it isn't empty.
+	if (std::memcmp(nullsha1, header.parentsha1, CHD_SHA1_BYTES) != 0 &&
+		std::memcmp(nullsha1, parent_header.sha1, CHD_SHA1_BYTES) != 0 &&
+		std::memcmp(parent_header.sha1, header.parentsha1, CHD_SHA1_BYTES) != 0)
+	{
+		return false;
+	}
+
+	return true;
+}
+
 static chd_file* OpenCHD(const std::string& filename, FileSystem::ManagedCFilePtr fp, Error* error, u32 recursion_level)
 {
 	chd_file* chd;
@@ -144,14 +168,14 @@ static chd_file* OpenCHD(const std::string& filename, FileSystem::ManagedCFilePt
 		if (!StringUtil::compareNoCase(parent_dir, Path::GetDirectory(it->first)))
 			continue;
 
-		if (!chd_is_matching_parent(&header, &it->second))
+		if (!IsHeaderParentCHD(header, it->second))
 			continue;
 
 		// Re-check the header, it might have changed since we last opened.
 		chd_header parent_header;
 		auto parent_fp = FileSystem::OpenManagedSharedCFile(it->first.c_str(), "rb", FileSystem::FileShareMode::DenyWrite);
 		if (parent_fp && chd_read_header_file(parent_fp.get(), &parent_header) == CHDERR_NONE &&
-			chd_is_matching_parent(&header, &parent_header))
+			IsHeaderParentCHD(header, parent_header))
 		{
 			// Need to take a copy of the string, because the parent might add to the list and invalidate the iterator.
 			const std::string filename_to_open = it->first;
@@ -192,7 +216,7 @@ static chd_file* OpenCHD(const std::string& filename, FileSystem::ManagedCFilePt
 			else
 				s_chd_hash_cache.emplace_back(fd.FileName, parent_header);
 
-			if (!chd_is_matching_parent(&header, &parent_header))
+			if (!IsHeaderParentCHD(header, parent_header))
 				continue;
 
 			// Match! Open this one.