From be32dc0e046ba1ada831a0f006ed8a5c89fd9fc8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Pol=C3=A1k?= <456647@muni.cz>
Date: Fri, 2 Sep 2022 12:26:06 +0200
Subject: [PATCH] Fix UB when there are no audio devices

When there are no capture nor playback devices, pContext->pDeviceInfos
is NULL and pContext->playbackDeviceInfoCount is 0.
Unfortunately, any arithmetic on NULL is UB, including trivial +0,
which triggers UB sanitizer. This can lead to crashes,
for example when compiling with Zig, which enables UBsan by default.
---
 miniaudio.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/miniaudio.h b/miniaudio.h
index a05b086c..c4b156a7 100644
--- a/miniaudio.h
+++ b/miniaudio.h
@@ -39913,7 +39913,12 @@ MA_API ma_result ma_context_get_devices(ma_context* pContext, ma_device_info** p
 
             /* Capture devices. */
             if (ppCaptureDeviceInfos != NULL) {
-                *ppCaptureDeviceInfos = pContext->pDeviceInfos + pContext->playbackDeviceInfoCount; /* Capture devices come after playback devices. */
+                *ppCaptureDeviceInfos = pContext->pDeviceInfos;
+                /* Capture devices come after playback devices. */
+                if (pContext->playbackDeviceInfoCount > 0) {
+                    /* Conditional, because NULL+0 is undefined behavior. */
+                    *ppCaptureDeviceInfos += pContext->playbackDeviceInfoCount;
+                }
             }
             if (pCaptureDeviceCount != NULL) {
                 *pCaptureDeviceCount = pContext->captureDeviceInfoCount;