From a0df8384279a9540faf6ba5a529cac5839b2dd8a Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Sun, 29 Oct 2023 03:38:51 -0500
Subject: [PATCH] fix crash when loading song with no chips

---
 src/engine/engine.cpp  |  6 +++---
 src/engine/fileOps.cpp | 20 +++++++++++++++-----
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 76a307f5b..ae1f63930 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -1081,7 +1081,7 @@ bool DivEngine::addSystem(DivSystem which) {
           song.patchbay.push_back((i<<20)|j);
         }
       } else {
-        song.patchbay.reserve(outs);
+        if (outs>0) song.patchbay.reserve(outs);
         for (unsigned int j=0; j<outs; j++) {
           song.patchbay.push_back((i<<20)|(j<<16)|j);
         }
@@ -1189,11 +1189,11 @@ bool DivEngine::swapSystem(int src, int dest, bool preserveOrder) {
 
     // prepare swap list
     int index=0;
-    swapList.reserve(song.systemLen);
+    if (song.systemLen>0) swapList.reserve(song.systemLen);
     for (int i=0; i<song.systemLen; i++) {
       chanList.clear();
       const int channelCount=getChannelCount(song.system[i]);
-      chanList.reserve(channelCount);
+      if (channelCount>0) chanList.reserve(channelCount);
       for (int j=0; j<channelCount; j++) {
         chanList.push_back(index);
         index++;
diff --git a/src/engine/fileOps.cpp b/src/engine/fileOps.cpp
index d7815ffa9..2d27d8b52 100644
--- a/src/engine/fileOps.cpp
+++ b/src/engine/fileOps.cpp
@@ -343,7 +343,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
       ds.insLen=16;
     }
     logI("reading instruments (%d)...",ds.insLen);
-    ds.ins.reserve(ds.insLen);
+    if (ds.insLen>0) ds.ins.reserve(ds.insLen);
     for (int i=0; i<ds.insLen; i++) {
       DivInstrument* ins=new DivInstrument;
       unsigned char mode=0;
@@ -679,7 +679,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
     if (ds.version>0x0b) {
       ds.waveLen=(unsigned char)reader.readC();
       logI("reading wavetables (%d)...",ds.waveLen);
-      ds.wave.reserve(ds.waveLen);
+      if (ds.waveLen>0) ds.wave.reserve(ds.waveLen);
       for (int i=0; i<ds.waveLen; i++) {
         DivWavetable* wave=new DivWavetable;
         wave->len=(unsigned char)reader.readI();
@@ -849,7 +849,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
       // it appears this byte stored the YMU759 sample rate
       ymuSampleRate=reader.readC();
     }
-    ds.sample.reserve(ds.sampleLen);
+    if (ds.sampleLen>0) ds.sample.reserve(ds.sampleLen);
     for (int i=0; i<ds.sampleLen; i++) {
       DivSample* sample=new DivSample;
       int length=reader.readI();
@@ -1961,6 +1961,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
     }
 
     logD("systems:");
+    ds.systemLen=0;
     for (int i=0; i<DIV_MAX_CHIPS; i++) {
       unsigned char sysID=reader.readC();
       ds.system[i]=systemFromFileFur(sysID);
@@ -1981,6 +1982,13 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
       tchans=DIV_MAX_CHANS;
       logW("too many channels!");
     }
+    logV("system len: %d",ds.systemLen);
+    if (ds.systemLen<1) {
+      logE("zero chips!");
+      lastError="zero chips!";
+      delete[] file;
+      return false;
+    }
 
     // system volume
     for (int i=0; i<DIV_MAX_CHIPS; i++) {
@@ -2369,7 +2377,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
 
       // patchbay
       unsigned int conns=reader.readI();
-      ds.patchbay.reserve(conns);
+      if (conns>0) ds.patchbay.reserve(conns);
       for (unsigned int i=0; i<conns; i++) {
         ds.patchbay.push_back((unsigned int)reader.readI());
       }
@@ -6074,7 +6082,6 @@ SafeWriter* DivEngine::saveDMF(unsigned char version) {
       if (sys!=DIV_SYSTEM_GB) {
         int realVolMacroLen=i->std.volMacro.len;
         if (realVolMacroLen>127) realVolMacroLen=127;
-        w->writeC(realVolMacroLen);
         if (sys==DIV_SYSTEM_C64_6581 || sys==DIV_SYSTEM_C64_8580) {
           if (i->std.algMacro.len>0) volIsCutoff=true;
           if (volIsCutoff) {
@@ -6083,15 +6090,18 @@ SafeWriter* DivEngine::saveDMF(unsigned char version) {
             }
             realVolMacroLen=i->std.algMacro.len;
             if (realVolMacroLen>127) realVolMacroLen=127;
+            w->writeC(realVolMacroLen);
             for (int j=0; j<realVolMacroLen; j++) {
               w->writeI((-i->std.algMacro.val[j])+18);
             }
           } else {
+            w->writeC(realVolMacroLen);
             for (int j=0; j<realVolMacroLen; j++) {
               w->writeI(i->std.volMacro.val[j]);
             }
           }
         } else {
+          w->writeC(realVolMacroLen);
           for (int j=0; j<realVolMacroLen; j++) {
             w->writeI(i->std.volMacro.val[j]);
           }