From 6a27983f179695c263ebc95f52b8ef81008fb4bb Mon Sep 17 00:00:00 2001
From: SarahW <pcem@pcem-emulator.co.uk>
Date: Wed, 8 May 2019 21:49:47 +0100
Subject: [PATCH] In Windows IOCTL CD-ROM code, only try reading via SPTI if
 ReadFile returned success but didn't read all requested data. Fixes Red Alert
 2 installer.

---
 src/cdrom-ioctl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cdrom-ioctl.c b/src/cdrom-ioctl.c
index 3ae7a23..8c8eb2b 100644
--- a/src/cdrom-ioctl.c
+++ b/src/cdrom-ioctl.c
@@ -451,8 +451,8 @@ static int ioctl_readsector(uint8_t *b, int sector, int count)
         status = ReadFile(hIOCTL, b, count*2048, (LPDWORD)&size, NULL);
         ioctl_close();
 
-        /*If the read failed, try again using SPTI*/
-        if (!status || size != count*2048)
+        /*If the read 'succeeded' but didn't read all required data, try again using SPTI*/
+        if (status && size != count*2048)
         {
                 uint8_t cmd[12] = { 0xbe, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0 };
                 SCSI_PASS_THROUGH_DIRECT_WITH_BUFFER swb;