Merge pull request #62 from segfault-bilibili/fix-loop-off-by-one

Fix off-by-one error in loop support
OpenCGSS · Feb 24, 2022 · c364976 · c364976
2 parents 31c316a + 9b8911f
commit c364976
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Showing 3 changed files with 9 additions and 9 deletions.
diff --git a/Exchange/DereTore.Exchange.Audio.HCA/HcaAudioStream.cs b/Exchange/DereTore.Exchange.Audio.HCA/HcaAudioStream.cs
@@ -143,7 +143,7 @@ public override long Length {
                 var waveDataBlockSize = _decoder.GetMinWaveDataBufferSize();
                 totalLength += waveDataBlockSize * hcaInfo.BlockCount;
                 if (HasLoop && audioParams.SimulatedLoopCount > 0) {
-                    var loopedBlockCount = hcaInfo.LoopEnd - hcaInfo.LoopStart + 1;
+                    var loopedBlockCount = hcaInfo.LoopEnd - hcaInfo.LoopStart;
                     totalLength += waveDataBlockSize * loopedBlockCount * audioParams.SimulatedLoopCount;
                 }
                 _length = totalLength;
@@ -201,7 +201,7 @@ private void EnsureSoundDataDecodedWithLoops(long waveDataOffset, int byteCount)
             var audioParams = _audioParams;
             var decodedSize = (waveDataOffset - headerSize) / waveBlockSize * waveBlockSize;
             // For those before or in the loop range...
-            if (audioParams.InfiniteLoop || startBlockIndex <= hcaInfo.LoopEnd + (hcaInfo.LoopEnd - hcaInfo.LoopStart + 1) * audioParams.SimulatedLoopCount) {
+            if (audioParams.InfiniteLoop || startBlockIndex <= hcaInfo.LoopEnd - 1 + (hcaInfo.LoopEnd - hcaInfo.LoopStart) * audioParams.SimulatedLoopCount) {
                 var blockIndex = startBlockIndex;
                 var executed = false;
                 while (true) {
@@ -218,7 +218,7 @@ private void EnsureSoundDataDecodedWithLoops(long waveDataOffset, int byteCount)
                     EnsureDecodeOneBlock(blockIndex);
                     decodedSize += waveBlockSize;
                     ++blockIndex;
-                    if (blockIndex > hcaInfo.LoopEnd) {
+                    if (blockIndex > hcaInfo.LoopEnd - 1) {
                         blockIndex = hcaInfo.LoopStart;
                     }
                     executed = true;
@@ -228,10 +228,10 @@ private void EnsureSoundDataDecodedWithLoops(long waveDataOffset, int byteCount)
             if (audioParams.InfiniteLoop) {
                 return;
             }
-            var endBlockIndex = hcaInfo.LoopEnd + (hcaInfo.LoopEnd - hcaInfo.LoopStart + 1) * audioParams.SimulatedLoopCount;
+            var endBlockIndex = hcaInfo.LoopEnd - 1 + (hcaInfo.LoopEnd - hcaInfo.LoopStart) * audioParams.SimulatedLoopCount;
             var startOfAfterLoopRegion = endBlockIndex * waveBlockSize;
             if (waveDataEnd >= startOfAfterLoopRegion) {
-                for (var blockIndex = hcaInfo.LoopEnd + 1; blockIndex < hcaInfo.BlockCount && decodedSize < waveDataEnd; ++blockIndex) {
+                for (var blockIndex = hcaInfo.LoopEnd; blockIndex < hcaInfo.BlockCount && decodedSize < waveDataEnd; ++blockIndex) {
                     EnsureDecodeOneBlock(blockIndex);
                     decodedSize += waveBlockSize;
                 }
@@ -261,7 +261,7 @@ private long MapPosToNonLoopedWaveStreamPos(long requestedPosition) {
             var waveBlockSize = _decoder.GetMinWaveDataBufferSize();
             var headerSize = _headerSize;
             var relativeDataPosition = requestedPosition - headerSize;
-            var endLoopDataPosition = (hcaInfo.LoopEnd + 1) * waveBlockSize;
+            var endLoopDataPosition = (hcaInfo.LoopEnd) * waveBlockSize;
             if (relativeDataPosition < endLoopDataPosition) {
                 return requestedPosition;
             }

diff --git a/Exchange/DereTore.Exchange.Audio.HCA/HcaDecoder.cs b/Exchange/DereTore.Exchange.Audio.HCA/HcaDecoder.cs
@@ -88,7 +88,7 @@ public int WriteWaveHeader(byte[] stream, AudioParams audioParams) {
 
             var totalBlockCount = hcaInfo.BlockCount;
             if (hcaInfo.LoopFlag) {
-                totalBlockCount += (hcaInfo.LoopEnd - hcaInfo.LoopStart + 1) * audioParams.SimulatedLoopCount;
+                totalBlockCount += (hcaInfo.LoopEnd - hcaInfo.LoopStart) * audioParams.SimulatedLoopCount;
             }
             wavData.DataSize = totalBlockCount * 0x80 * 8 * wavRiff.FmtSamplingSize;
             wavRiff.RiffSize = (uint)(0x1c + (hcaInfo.Comment != null ? wavNote.NoteSize : 0) + Marshal.SizeOf(wavData) + wavData.DataSize);

diff --git a/Exchange/DereTore.Exchange.Audio.HCA/HcaHelper.cs b/Exchange/DereTore.Exchange.Audio.HCA/HcaHelper.cs
@@ -91,7 +91,7 @@ public static uint CalculateLengthInSamples(HcaInfo hcaInfo, uint loopCount, boo
                 return uint.MaxValue;
             }
             var totalBlockCount = hcaInfo.BlockCount;
-            totalBlockCount += (hcaInfo.LoopEnd - hcaInfo.LoopStart + 1) * loopCount;
+            totalBlockCount += (hcaInfo.LoopEnd - hcaInfo.LoopStart) * loopCount;
             return totalBlockCount * hcaInfo.ChannelCount * 0x80 * 8;
         }
 
@@ -104,7 +104,7 @@ public static float CalculateLengthInSeconds(HcaInfo hcaInfo, uint loopCount, bo
                 return float.MaxValue;
             }
             var totalBlockCount = hcaInfo.BlockCount;
-            totalBlockCount += (hcaInfo.LoopEnd - hcaInfo.LoopStart + 1) * loopCount;
+            totalBlockCount += (hcaInfo.LoopEnd - hcaInfo.LoopStart) * loopCount;
             return totalBlockCount * 0x80 * 8 / (float)hcaInfo.SamplingRate;
         }