From 8b3f318f60d8ad945c7b5c316bc5de1f20bb4c8a Mon Sep 17 00:00:00 2001
From: Andy Sloane <andy@a1k0n.net>
Date: Fri, 20 Nov 2015 17:28:39 -0800
Subject: [PATCH] [#19] handle loops of length 0

also more robust way to find sample offsets to load in the file
---
 xm.js | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/xm.js b/xm.js
index b6dcfeb..dbc89bc 100644
--- a/xm.js
+++ b/xm.js
@@ -787,8 +787,8 @@ function load(arrayBuf) {
       // FIXME: ignoring keymaps for now and assuming 1 sample / instrument
       // var keymap = getarray(dv, idx+0x21);
       var samphdrsiz = dv.getUint32(idx+0x1d, true);
-      console.log("hdrsiz %d; instrument %d: '%s' %d samples, samphdrsiz %d",
-          hdrsiz, i, instname, nsamp, samphdrsiz);
+      console.log("hdrsiz %d; instrument %s: '%s' %d samples, samphdrsiz %d",
+          hdrsiz, (i+1).toString(16), instname, nsamp, samphdrsiz);
       idx += hdrsiz;
       var totalsamples = 0;
       var samps = [];
@@ -802,7 +802,10 @@ function load(arrayBuf) {
         var samppan = dv.getUint8(idx+15);
         var sampnote = dv.getInt8(idx+16);
         var sampname = getstring(dv, idx+18, 22);
-        var sampleoffset = idx + nsamp * samphdrsiz + totalsamples;
+        var sampleoffset = totalsamples;
+        if (samplooplen === 0) {
+          samptype &= ~3;
+        }
         console.log("sample %d: len %d name '%s' loop %d/%d vol %d offset %s",
             j, samplen, sampname, samploop, samplooplen, sampvol, sampleoffset.toString(16));
         console.log("           type %d note %s(%d) finetune %d pan %d",
@@ -816,24 +819,26 @@ function load(arrayBuf) {
           'len': samplen, 'loop': samploop,
           'looplen': samplooplen, 'note': sampnote, 'fine': sampfinetune,
           'pan': samppan, 'type': samptype, 'vol': sampvol,
-          'sampledata': ConvertSample(
-              new Uint8Array(arrayBuf, sampleoffset, samplen), samptype & 16),
+          'fileoffset': sampleoffset
         };
         // length / pointers are all specified in bytes; fixup for 16-bit samples
-        if (samptype & 16) {
+        samps.push(samp);
+        idx += samphdrsiz;
+        totalsamples += samplen;
+      }
+      for (j = 0; j < nsamp; j++) {
+        var samp = samps[j];
+        samp.sampledata = ConvertSample(
+            new Uint8Array(arrayBuf, idx + samp.fileoffset, samp.len), samp.type & 16);
+        if (samp.type & 16) {
           samp.len /= 2;
           samp.loop /= 2;
           samp.looplen /= 2;
         }
-
         // unroll short loops and any pingpong loops
         if ((samp.type & 3) && (samp.looplen < 2048 || (samp.type & 2))) {
           UnrollSampleLoop(samp);
         }
-        samps.push(samp);
-
-        idx += samphdrsiz;
-        totalsamples += samplen;
       }
       idx += totalsamples;
       inst.samplemap = samplemap;