diff --git a/src/engine/sample.cpp b/src/engine/sample.cpp
index 19768fcf7..d5e1844c8 100644
--- a/src/engine/sample.cpp
+++ b/src/engine/sample.cpp
@@ -32,6 +32,10 @@ extern "C" {
 #include "../../extern/adpcm/ymz_codec.h"
 }
 
+DivSampleHistory::~DivSampleHistory() {
+  if (data!=NULL) delete[] data;
+}
+
 bool DivSample::save(const char* path) {
   SNDFILE* f;
   SF_INFO si;
@@ -786,7 +790,48 @@ unsigned int DivSample::getCurBufLen() {
   return 0;
 }
 
+DivSampleHistory* DivSample::prepareUndo(bool data) {
+  DivSampleHistory* h;
+  if (data) {
+    unsigned char* duplicate;
+    if (getCurBuf()==NULL) {
+      duplicate=NULL;
+    } else {
+      duplicate=new unsigned char[getCurBufLen()];
+      memcpy(duplicate,getCurBuf(),getCurBufLen());
+    }
+    h=new DivSampleHistory(duplicate,getCurBufLen(),samples,depth,rate,centerRate,loopStart);
+  } else {
+    h=new DivSampleHistory(depth,rate,centerRate,loopStart);
+  }
+  while (!redoHist.empty()) {
+    DivSampleHistory* h=redoHist.front();
+    delete h;
+    redoHist.pop_front();
+  }
+  undoHist.push_back(h);
+  return h;
+}
+
+int DivSample::undo() {
+  return 0;
+}
+
+int DivSample::redo() {
+  return 0;
+}
+
 DivSample::~DivSample() {
+  while (!undoHist.empty()) {
+    DivSampleHistory* h=undoHist.front();
+    delete h;
+    undoHist.pop_front();
+  }
+  while (!redoHist.empty()) {
+    DivSampleHistory* h=redoHist.front();
+    delete h;
+    redoHist.pop_front();
+  }
   if (data8) delete[] data8;
   if (data16) delete[] data16;
   if (data1) delete[] data1;
diff --git a/src/engine/sample.h b/src/engine/sample.h
index c697a9951..f07c7ef91 100644
--- a/src/engine/sample.h
+++ b/src/engine/sample.h
@@ -18,6 +18,7 @@
  */
 
 #include "../ta-utils.h"
+#include <deque>
 
 enum DivResampleFilters {
   DIV_RESAMPLE_NONE=0,
@@ -28,6 +29,33 @@ enum DivResampleFilters {
   DIV_RESAMPLE_BEST
 };
 
+struct DivSampleHistory {
+  unsigned char* data;
+  unsigned int length, samples;
+  unsigned char depth;
+  int rate, centerRate, loopStart;
+  bool hasSample;
+  DivSampleHistory(void* d, unsigned int l, unsigned int s, unsigned char de, int r, int cr, int ls):
+    data((unsigned char*)d),
+    length(l),
+    samples(s),
+    depth(de),
+    rate(r),
+    centerRate(cr),
+    loopStart(ls),
+    hasSample(true) {}
+  DivSampleHistory(unsigned char de, int r, int cr, int ls):
+    data(NULL),
+    length(0),
+    samples(0),
+    depth(de),
+    rate(r),
+    centerRate(cr),
+    loopStart(ls),
+    hasSample(false) {}
+  ~DivSampleHistory();
+};
+
 struct DivSample {
   String name;
   int rate, centerRate, loopStart, loopOffP;
@@ -62,6 +90,9 @@ struct DivSample {
 
   unsigned int samples;
 
+  std::deque<DivSampleHistory*> undoHist;
+  std::deque<DivSampleHistory*> redoHist;
+
   /**
    * @warning DO NOT USE - internal functions
    */
@@ -154,6 +185,27 @@ struct DivSample {
    * @return the sample data length.
    */
   unsigned int getCurBufLen();
+
+  /**
+   * prepare an undo step for this sample.
+   * @param data whether to include sample data.
+   * @return the undo step.
+   */
+  DivSampleHistory* prepareUndo(bool data);
+
+  /**
+   * undo. you may need to call DivEngine::renderSamples afterwards.
+   * @warning do not attempt to undo outside of a synchronized block!
+   * @return 0 on failure; 1 on success and 2 on success (data changed).
+   */
+  int undo();
+
+  /**
+   * redo. you may need to call DivEngine::renderSamples afterwards.
+   * @warning do not attempt to redo outside of a synchronized block!
+   * @return 0 on failure; 1 on success and 2 on success (data changed).
+   */
+  int redo();
   DivSample():
     name(""),
     rate(32000),