Fix commit 63fdd08

Author: flanglet

src/entropy/HuffmanDecoder.cpp

@@ -219,10 +219,14 @@ bool HuffmanDecoder::decodeChunk(kanzi::byte block[], uint count)
     if ((szBits0 > maxFragBits) || (szBits1 > maxFragBits) || (szBits2 > maxFragBits) || (szBits3 > maxFragBits))
         return false;
 
-    int idx0 = 0 * fragStride;
-    int idx1 = 1 * fragStride;
-    int idx2 = 2 * fragStride;
-    int idx3 = 3 * fragStride;
+    const int base0 = 0 * fragStride;
+    const int base1 = 1 * fragStride;
+    const int base2 = 2 * fragStride;
+    const int base3 = 3 * fragStride;
+    int idx0 = base0;
+    int idx1 = base1;
+    int idx2 = base2;
+    int idx3 = base3;
 
     // Read all compressed data from bitstream
     _bitstream.readBits(&_buffer[idx0], szBits0);
@@ -333,10 +337,13 @@ bool HuffmanDecoder::decodeChunk(kanzi::byte block[], uint count)
     for (uint i = count4; i < count; i++)
         block[i] = kanzi::byte(_bitstream.readBits(8));
 
-    return ((idx0 << 3) - (bits0 + DECODING_BATCH_SIZE) == szBits0) &&
-           ((idx1 << 3) - (bits1 + DECODING_BATCH_SIZE) == szBits1) &&
-           ((idx2 << 3) - (bits2 + DECODING_BATCH_SIZE) == szBits2) &&
-           ((idx3 << 3) - (bits3 + DECODING_BATCH_SIZE) == szBits3);
+    const int used0 = ((idx0 - base0) << 3) - (bits0 + DECODING_BATCH_SIZE);
+    const int used1 = ((idx1 - base1) << 3) - (bits1 + DECODING_BATCH_SIZE);
+    const int used2 = ((idx2 - base2) << 3) - (bits2 + DECODING_BATCH_SIZE);
+    const int used3 = ((idx3 - base3) << 3) - (bits3 + DECODING_BATCH_SIZE);
+
+    return (used0 == szBits0) && (used1 == szBits1) &&
+           (used2 == szBits2) && (used3 == szBits3);
 }
 
 int HuffmanDecoder::decodeV5(kanzi::byte block[], uint blkptr, uint count)

src/test/TestEntropyCodec.cpp

@@ -255,6 +255,53 @@ int testDeclaredPayloadConsumption()
     return 0;
 }
 
+int testHuffmanFragmentedRoundTrip()
+{
+    cout << endl
+         << "=== Huffman fragmented round-trip test ===" << endl;
+    const uint size = 1 << 20;
+    vector<kanzi::byte> values(size);
+    vector<kanzi::byte> decoded(size, kanzi::byte(0));
+    uint32 state = 0x12345678;
+
+    for (uint i = 0; i < size; i++) {
+        state = (state * 1103515245U) + 12345U;
+        values[i] = kanzi::byte(state >> 24);
+    }
+
+    stringbuf buffer;
+    iostream ios(&buffer);
+    DefaultOutputBitStream obs(ios, 1 << 15);
+    HuffmanEncoder encoder(obs);
+
+    if (encoder.encode(&values[0], 0, size) != int(size)) {
+        cout << "Encoding error in Huffman fragmented round-trip test" << endl;
+        return 1;
+    }
+
+    encoder.dispose();
+    obs.close();
+    ios.rdbuf()->pubseekpos(0);
+    DefaultInputBitStream ibs(ios, 1 << 15);
+    HuffmanDecoder decoder(ibs);
+
+    if (decoder.decode(&decoded[0], 0, size) != int(size)) {
+        cout << "Decoding error in Huffman fragmented round-trip test" << endl;
+        return 1;
+    }
+
+    decoder.dispose();
+    ibs.close();
+
+    if (memcmp(&values[0], &decoded[0], size) != 0) {
+        cout << "Mismatch in Huffman fragmented round-trip test" << endl;
+        return 1;
+    }
+
+    cout << "Huffman fragmented round-trip test passed" << endl;
+    return 0;
+}
+
 class ConstantPredictor FINAL : public Predictor
 {
 public:
@@ -614,6 +661,7 @@ int TestEntropyCodec_main(int argc, const char* argv[])
     try {
         res |= testBinaryEntropyBufferGrowth();
         res |= testDeclaredPayloadConsumption();
+        res |= testHuffmanFragmentedRoundTrip();
         vector<string> codecs;
         bool doPerf = true;