From 37b36ef33202cae3afbdd864b2cf29f7e6fe4d3c Mon Sep 17 00:00:00 2001
From: rakslice <rakslice@gmail.com>
Date: Mon, 21 Sep 2020 20:33:26 -0700
Subject: [PATCH] actually use dynamically detected cdroms; if read via
 cdenable doesn't work use the logical drive handle instead

---
 BasiliskII/src/Windows/sys_windows.cpp | 47 +++++++++++++++++++-------
 BasiliskII/src/cdrom.cpp               | 17 +++++-----
 2 files changed, 42 insertions(+), 22 deletions(-)

diff --git a/BasiliskII/src/Windows/sys_windows.cpp b/BasiliskII/src/Windows/sys_windows.cpp
index 8e876307..264ee366 100755
--- a/BasiliskII/src/Windows/sys_windows.cpp
+++ b/BasiliskII/src/Windows/sys_windows.cpp
@@ -84,7 +84,7 @@ static char *sector_buffer = NULL;
 
 // Prototypes
 static bool is_cdrom_readable(file_handle *fh);
-
+static DWORD file_offset_read(HANDLE fh, loff_t offset, int count, char *buf);
 
 /*
  *  Initialization
@@ -266,12 +266,42 @@ void SysAddSerialPrefs(void)
  *  Can't give too much however, would be annoying, this is difficult..
  */
 
-static inline int cd_read_with_retry(file_handle *fh, ULONG LBA, int count, char *buf )
+static inline int cd_read_with_retry(file_handle *fh, ULONG offset, int count, char *buf )
 {
 	if (!fh || !fh->fh)
 		return 0;
 
-	return CdenableSysReadCdBytes(fh->fh, LBA, count, buf);
+	DWORD bytes_read = CdenableSysReadCdBytes(fh->fh, offset, count, buf);
+
+	if (bytes_read == 0) {
+		// fall back to logical volume handle read in the case where there's no cdenable
+		bytes_read = file_offset_read(fh->fh, offset, count, buf);
+	}
+
+	return bytes_read;
+}
+
+/*
+ * Generic offset read function for a file or a device that behaves like one
+ */
+ 
+static DWORD file_offset_read(HANDLE fh, loff_t offset, int count, char *buf)
+{
+	// Seek to position
+	LONG lo = (LONG)offset;
+	LONG hi = (LONG)(offset >> 32);
+	DWORD r = SetFilePointer(fh, lo, &hi, FILE_BEGIN);
+	if (r == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
+		return 0;
+	}
+
+	DWORD bytes_read;
+
+	// Read data
+	if (ReadFile(fh, buf, count, &bytes_read, NULL) == 0)
+		bytes_read = 0;
+
+	return bytes_read;
 }
 
 static int cd_read(file_handle *fh, cachetype *cptr, ULONG LBA, int count, char *buf)
@@ -581,16 +611,7 @@ size_t Sys_read(void *arg, void *buffer, loff_t offset, size_t length)
 	DWORD bytes_read = 0;
 
 	if (fh->is_file) {
-		// Seek to position
-		LONG lo = (LONG)offset;
-		LONG hi = (LONG)(offset >> 32);
-		DWORD r = SetFilePointer(fh->fh, lo, &hi, FILE_BEGIN);
-		if (r == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR)
-			return 0;
-
-		// Read data
-		if (ReadFile(fh->fh, buffer, length, &bytes_read, NULL) == 0)
-			bytes_read = 0;
+		bytes_read = file_offset_read(fh->fh, offset, length, (char *)buffer);
 	}
 	else if (fh->is_cdrom) {
 		int bytes_left, try_bytes, got_bytes;
diff --git a/BasiliskII/src/cdrom.cpp b/BasiliskII/src/cdrom.cpp
index ee8d2350..ce2a398a 100644
--- a/BasiliskII/src/cdrom.cpp
+++ b/BasiliskII/src/cdrom.cpp
@@ -303,15 +303,14 @@ void CDROMInit(void)
 	if (PrefsFindString("cdrom", 0) == NULL) {
 		SysAddCDROMPrefs();
 	}
-	else {
-		// Add drives specified in preferences
-		int index = 0;
-		const char *str;
-		while ((str = PrefsFindString("cdrom", index++)) != NULL) {
-			void *fh = Sys_open(str, true);
-			if (fh)
-				drives.push_back(cdrom_drive_info(fh));
-		}
+	
+	// Add drives specified in preferences
+	int index = 0;
+	const char *str;
+	while ((str = PrefsFindString("cdrom", index++)) != NULL) {
+		void *fh = Sys_open(str, true);
+		if (fh)
+			drives.push_back(cdrom_drive_info(fh));
 	}
 	
 	if (!drives.empty()) { // set to first drive by default