From 6e6fbc5ad3a026b346198aefb7e187ff2c44d2ff Mon Sep 17 00:00:00 2001
From: twinaphex <libretro@gmail.com>
Date: Fri, 3 Jan 2020 14:19:31 +0100
Subject: [PATCH] (Dsound) Split up dsound_write (XAudio) Optimize
 xa_write_nonblock

---
 audio/drivers/dsound.c | 40 +++++++++++++++++++++++++++++++++++++++-
 audio/drivers/xaudio.c | 14 +++++---------
 2 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/audio/drivers/dsound.c b/audio/drivers/dsound.c
index 948792c460..23676b419d 100644
--- a/audio/drivers/dsound.c
+++ b/audio/drivers/dsound.c
@@ -53,6 +53,10 @@
 #pragma comment(lib, "dxguid")
 #endif
 
+/* Forward declarations */
+static ssize_t dsound_write_nonblock(void *data, const void *buf_, size_t size);
+static ssize_t dsound_write(void *data, const void *buf_, size_t size);
+
 typedef struct dsound
 {
    LPDIRECTSOUND ds;
@@ -485,6 +489,40 @@ static void dsound_set_nonblock_state(void *data, bool state)
    dsound_t *ds = (dsound_t*)data;
    if (ds)
       ds->nonblock = state;
+
+   if (ds->nonblock)
+      audio_dsound.write = dsound_write_nonblock;
+   else
+      audio_dsound.write = dsound_write;
+}
+
+static ssize_t dsound_write_nonblock(void *data, const void *buf_, size_t size)
+{
+   size_t     written = 0;
+   dsound_t       *ds = (dsound_t*)data;
+   const uint8_t *buf = (const uint8_t*)buf_;
+
+   if (!ds->thread_alive)
+      return -1;
+
+   if (size > 0)
+   {
+      size_t avail;
+
+      EnterCriticalSection(&ds->crit);
+      avail = fifo_write_avail(ds->buffer);
+      if (avail > size)
+         avail = size;
+
+      fifo_write(ds->buffer, buf, avail);
+      LeaveCriticalSection(&ds->crit);
+
+      buf     += avail;
+      size    -= avail;
+      written += avail;
+   }
+
+   return written;
 }
 
 static ssize_t dsound_write(void *data, const void *buf_, size_t size)
@@ -512,7 +550,7 @@ static ssize_t dsound_write(void *data, const void *buf_, size_t size)
       size    -= avail;
       written += avail;
 
-      if (ds->nonblock || !ds->thread_alive)
+      if (!ds->thread_alive)
          break;
 
       if (avail == 0)
diff --git a/audio/drivers/xaudio.c b/audio/drivers/xaudio.c
index 07e725e12c..3f5ab74fbe 100644
--- a/audio/drivers/xaudio.c
+++ b/audio/drivers/xaudio.c
@@ -328,16 +328,12 @@ static ssize_t xa_write_nonblock(void *data, const void *buf, size_t size)
    xa_t *xa              = (xa_t*)data;
    xaudio2_t *handle     = xa->xa;
    const uint8_t *buffer = (const uint8_t*)buf;
+   size_t avail          = XAUDIO2_WRITE_AVAILABLE(xa->xa);
 
-   if (xa->nonblock)
-   {
-      size_t avail = XAUDIO2_WRITE_AVAILABLE(xa->xa);
-
-      if (avail == 0)
-         return 0;
-      if (avail < size)
-         size = avail;
-   }
+   if (avail == 0)
+      return 0;
+   if (avail < size)
+      size = avail;
 
    bytes = size;