From 07b767bee15491b3323d02c0c7ed7ac46843f0c3 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Wed, 2 Feb 2022 23:17:16 -0500
Subject: [PATCH] prepare for ADPCM-B

---
 src/engine/engine.h | 6 +++++-
 src/engine/sample.h | 8 ++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/engine/engine.h b/src/engine/engine.h
index 32542c54..a8fe7d04 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -523,6 +523,8 @@ class DivEngine {
 
     unsigned char* adpcmMem;
     size_t adpcmMemLen;
+    unsigned char* adpcmBMem;
+    size_t adpcmBMemLen;
 
     DivEngine():
       output(NULL),
@@ -573,6 +575,8 @@ class DivEngine {
       oscBuf{NULL,NULL},
       oscSize(1),
       adpcmMem(NULL),
-      adpcmMemLen(0) {}
+      adpcmMemLen(0),
+      adpcmBMem(NULL),
+      adpcmBMemLen(0) {}
 };
 #endif
diff --git a/src/engine/sample.h b/src/engine/sample.h
index 7afb011e..b0d7f267 100644
--- a/src/engine/sample.h
+++ b/src/engine/sample.h
@@ -4,6 +4,14 @@ struct DivSample {
   String name;
   int length, rate, centerRate, loopStart, loopOffP;
   signed char vol, pitch;
+  // valid values are:
+  // - 0: ZX Spectrum overlay drum (1-bit PCM)
+  // - 1: 1-bit NES DPCM
+  // - 4: BRR
+  // - 5: raw ADPCM-A
+  // - 6: raw ADPCM-B
+  // - 8: 8-bit PCM
+  // - 16: 16-bit PCM
   unsigned char depth;
   short* data;
   unsigned int rendLength, adpcmRendLength, rendOff, rendOffP, rendOffContiguous;