From 4209b88459bce25a7a0a80f28163838dc21595e8 Mon Sep 17 00:00:00 2001
From: GaryOderNichts <12049776+GaryOderNichts@users.noreply.github.com>
Date: Sun, 25 Jul 2021 12:02:35 +0200
Subject: [PATCH] Add back audio buffering

---
 src/audio/oal/stream.cpp | 35 ++++++++++++++++++++++++++++++++---
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/audio/oal/stream.cpp b/src/audio/oal/stream.cpp
index 7e68f042..a4f45272 100644
--- a/src/audio/oal/stream.cpp
+++ b/src/audio/oal/stream.cpp
@@ -679,6 +679,21 @@ public:
 #endif
 
 #ifdef AUDIO_OAL_USE_MPG123
+static ssize_t mpg123_read_replacement(void* handle, void* data, size_t size)
+{
+	return fread(data, 1, size, (FILE*)handle);
+}
+
+static off_t mpg123_seek_replacement(void* handle, off_t offset, int whence)
+{
+	fseek((FILE*)handle, offset, whence);
+	return ftell((FILE*)handle);
+}
+
+static void mpg123_close_replacement(void* handle)
+{
+	fclose((FILE*)handle);
+}
 
 class CMP3File : public IDecoder
 {
@@ -689,13 +704,15 @@ protected:
 	uint32 m_nChannels;
 	const char* m_pPath;
 	bool m_bFileNotOpenedYet;
+	char* m_buffer;
 
 	CMP3File() :
 		m_pMH(nil),
 		m_bOpened(false),
 		m_nRate(0),
 		m_bFileNotOpenedYet(false),
-		m_nChannels(0) {}
+		m_nChannels(0),
+		m_buffer(NULL) {}
 public:
 	CMP3File(const char *path) :
 		m_pMH(nil),
@@ -703,7 +720,8 @@ public:
 		m_nRate(0),
 		m_nChannels(0),
 		m_pPath(path),
-		m_bFileNotOpenedYet(false)
+		m_bFileNotOpenedYet(false),
+		m_buffer(NULL)
 	{
 		m_pMH = mpg123_new(nil, nil);
 		if ( m_pMH )
@@ -723,10 +741,16 @@ public:
 	{
 		if(!m_bFileNotOpenedYet) return;
 
+		FILE* f = fopen(m_pPath, "rb");
+
+		m_buffer = (char*) memalign(0x40, IO_BUFFER_SIZE);
+		setvbuf(f, m_buffer, _IOFBF, IO_BUFFER_SIZE);
+
 		long rate = 0;
 		int channels = 0;
 		int encoding = 0;
-		m_bOpened = mpg123_open(m_pMH, m_pPath) == MPG123_OK
+		m_bOpened =  mpg123_replace_reader_handle(m_pMH, mpg123_read_replacement, mpg123_seek_replacement, mpg123_close_replacement) == MPG123_OK 
+				&& mpg123_open_handle(m_pMH, f) == MPG123_OK
 		        && mpg123_getformat(m_pMH, &rate, &channels, &encoding) == MPG123_OK;
 
 		m_nRate = rate;
@@ -746,6 +770,8 @@ public:
 			mpg123_close(m_pMH);
 			mpg123_delete(m_pMH);
 
+			free(m_buffer);
+
 			m_pMH = nil;
 		}
 	}
@@ -852,6 +878,9 @@ public:
 
 		FILE *f = fopen(m_pPath, "rb");
 
+		m_buffer = (char*) memalign(0x40, IO_BUFFER_SIZE);
+		setvbuf(f, m_buffer, _IOFBF, IO_BUFFER_SIZE);
+
 		m_bOpened = f && mpg123_replace_reader_handle(m_pMH, r_read, r_seek, r_close) == MPG123_OK
 			&& mpg123_open_handle(m_pMH, f) == MPG123_OK && mpg123_getformat(m_pMH, &rate, &channels, &encoding) == MPG123_OK;