/[svn]/libgig/trunk/src/gig.cpp

Diff of /libgig/trunk/src/gig.cpp

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-revision 2922 by schoenebeck,
Wed May 18 18:04:49 2016 UTC
+revision 2989 by schoenebeck,
Sat Sep 24 14:00:46 2016 UTC
 Line 338 
 namespace {
       *                         ('wvpl') list chunk
       * @param fileNo         - number of an extension file where this sample
       *                         is located, 0 otherwise
+      * @param index          - wave pool index of sample (may be -1 on new sample)
       */
-     Sample::Sample(File* pFile, RIFF::List* waveList, file_offset_t WavePoolOffset, unsigned long fileNo) : DLS::Sample((DLS::File*) pFile, waveList, WavePoolOffset) {
+     Sample::Sample(File* pFile, RIFF::List* waveList, file_offset_t WavePoolOffset, unsigned long fileNo, int index)
+         : DLS::Sample((DLS::File*) pFile, waveList, WavePoolOffset)
+     {
          static const DLS::Info::string_length_t fixedStringLengths[] = {
              { CHUNK_ID_INAM, 64 },
              { 0, 0 }
-Line 349 
 namespace {
+Line 352 
 namespace {
          FileNo = fileNo;
          __resetCRC(crc);
+         // if this is not a new sample, try to get the sample's already existing
+         // CRC32 checksum from disk, this checksum will reflect the sample's CRC32
+         // checksum of the time when the sample was consciously modified by the
+         // user for the last time (by calling Sample::Write() that is).
+         if (index >= 0) { // not a new file ...
+             try {
+                 uint32_t crc = pFile->GetSampleChecksumByIndex(index);
+                 this->crc = crc;
+             } catch (...) {}
+         }
          pCk3gix = waveList->GetSubChunk(CHUNK_ID_3GIX);
          if (pCk3gix) {
-Line 1341 
 namespace {
+Line 1354 
 namespace {
          return pGroup;
      }
+     /**
+      * Returns the CRC-32 checksum of the sample's raw wave form data at the
+      * time when this sample's wave form data was modified for the last time
+      * by calling Write(). This checksum only covers the raw wave form data,
+      * not any meta informations like i.e. bit depth or loop points. Since
+      * this method just returns the checksum stored for this sample i.e. when
+      * the gig file was loaded, this method returns immediately. So it does no
+      * recalcuation of the checksum with the currently available sample wave
+      * form data.
+      *
+      * @see VerifyWaveData()
+      */
+     uint32_t Sample::GetWaveDataCRC32Checksum() {
+         return crc;
+     }
+     /**
+      * Checks the integrity of this sample's raw audio wave data. Whenever a
+      * Sample's raw wave data is intentionally modified (i.e. by calling
+      * Write() and supplying the new raw audio wave form data) a CRC32 checksum
+      * is calculated and stored/updated for this sample, along to the sample's
+      * meta informations.
+      *
+      * Now by calling this method the current raw audio wave data is checked
+      * against the already stored CRC32 check sum in order to check whether the
+      * sample data had been damaged unintentionally for some reason. Since by
+      * calling this method always the entire raw audio wave data has to be
+      * read, verifying all samples this way may take a long time accordingly.
+      * And that's also the reason why the sample integrity is not checked by
+      * default whenever a gig file is loaded. So this method must be called
+      * explicitly to fulfill this task.
+      *
+      * @param pActually - (optional) if provided, will be set to the actually
+      *                    calculated checksum of the current raw wave form data,
+      *                    you can get the expected checksum instead by calling
+      *                    GetWaveDataCRC32Checksum()
+      * @returns true if sample is OK or false if the sample is damaged
+      * @throws Exception if no checksum had been stored to disk for this
+      *         sample yet, or on I/O issues
+      * @see GetWaveDataCRC32Checksum()
+      */
+     bool Sample::VerifyWaveData(uint32_t* pActually) {
+         File* pFile = static_cast<File*>(GetParent());
+         uint32_t crc = CalculateWaveDataChecksum();
+         if (pActually) *pActually = crc;
+         return crc == this->crc;
+     }
+     uint32_t Sample::CalculateWaveDataChecksum() {
+         const size_t sz = 20*1024; // 20kB buffer size
+         std::vector<uint8_t> buffer(sz);
+         buffer.resize(sz);
+         const size_t n = sz / FrameSize;
+         SetPos(0);
+         uint32_t crc = 0;
+         __resetCRC(crc);
+         while (true) {
+             file_offset_t nRead = Read(&buffer[0], n);
+             if (nRead <= 0) break;
+             __calculateCRC(&buffer[0], nRead * FrameSize, crc);
+         }
+         __encodeCRC(crc);
+         return crc;
+     }
      Sample::~Sample() {
          Instances--;
          if (!Instances && InternalDecompressionBuffer.Size) {
-Line 3106 
 namespace {
+Line 3185 
 namespace {
          int step = 1;
          for (int i = 0 ; i < veldim ; i++) step <<= pDimensionDefinitions[i].bits;
          int skipveldim = (step << pDimensionDefinitions[veldim].bits) - step;
-         int end = step * pDimensionDefinitions[veldim].zones;
          // loop through all dimension regions for all dimensions except the velocity dimension
          int dim[8] = { 0 };
          for (int i = 0 ; i < DimensionRegions ; i++) {
+             const int end = i + step * pDimensionDefinitions[veldim].zones;
+             // create a velocity table for all cases where the velocity zone is zero
              if (pDimensionRegions[i]->DimensionUpperLimits[veldim] ||
                  pDimensionRegions[i]->VelocityUpperLimit) {
                  // create the velocity table
-Line 3142 
 namespace {
+Line 3222 
 namespace {
                  }
              }
+             // jump to the next case where the velocity zone is zero
              int j;
              int shift = 0;
              for (j = 0 ; j < Dimensions ; j++) {
-Line 5375 
 namespace {
+Line 5456 
 namespace {
                          __notify_progress(pProgress, subprogress);
                          file_offset_t waveFileOffset = wave->GetFilePos();
-                         pSamples->push_back(new Sample(this, wave, waveFileOffset - wvplFileOffset, fileNo));
+                         pSamples->push_back(new Sample(this, wave, waveFileOffset - wvplFileOffset, fileNo, iSampleIndex));
                          iSampleIndex++;
                      }
-Line 5613 
 namespace {
+Line 5694 
 namespace {
          if (!_3crc) return;
          // get the index of the sample
-         int iWaveIndex = -1;
+         int iWaveIndex = GetWaveTableIndexOf(pSample);
-         File::SampleList::iterator iter = pSamples->begin();
-         File::SampleList::iterator end  = pSamples->end();
-         for (int index = 0; iter != end; ++iter, ++index) {
-             if (*iter == pSample) {
-                 iWaveIndex = index;
-                 break;
-             }
-         }
          if (iWaveIndex < 0) throw gig::Exception("Could not update crc, could not find sample");
          // write the CRC-32 checksum to disk
          _3crc->SetPos(iWaveIndex * 8);
-         uint32_t tmp = 1;
+         uint32_t one = 1;
-         _3crc->WriteUint32(&tmp); // unknown, always 1?
+         _3crc->WriteUint32(&one); // always 1
          _3crc->WriteUint32(&crc);
      }
+     uint32_t File::GetSampleChecksum(Sample* pSample) {
+         // get the index of the sample
+         int iWaveIndex = GetWaveTableIndexOf(pSample);
+         if (iWaveIndex < 0) throw gig::Exception("Could not retrieve reference crc of sample, could not resolve sample's wave table index");
+         return GetSampleChecksumByIndex(iWaveIndex);
+     }
+     uint32_t File::GetSampleChecksumByIndex(int index) {
+         if (index < 0) throw gig::Exception("Could not retrieve reference crc of sample, invalid wave pool index of sample");
+         RIFF::Chunk* _3crc = pRIFF->GetSubChunk(CHUNK_ID_3CRC);
+         if (!_3crc) throw gig::Exception("Could not retrieve reference crc of sample, no checksums stored for this file yet");
+         uint8_t* pData = (uint8_t*) _3crc->LoadChunkData();
+         if (!pData) throw gig::Exception("Could not retrieve reference crc of sample, no checksums stored for this file yet");
+         // read the CRC-32 checksum directly from disk
+         size_t pos = index * 8;
+         if (pos + 8 > _3crc->GetNewSize())
+             throw gig::Exception("Could not retrieve reference crc of sample, could not seek to required position in crc chunk");
+         uint32_t one = load32(&pData[pos]); // always 1
+         if (one != 1)
+             throw gig::Exception("Could not retrieve reference crc of sample, because reference checksum table is damaged");
+         return load32(&pData[pos+4]);
+     }
+     int File::GetWaveTableIndexOf(gig::Sample* pSample) {
+         if (!pSamples) GetFirstSample(); // make sure sample chunks were scanned
+         File::SampleList::iterator iter = pSamples->begin();
+         File::SampleList::iterator end  = pSamples->end();
+         for (int index = 0; iter != end; ++iter, ++index)
+             if (*iter == pSample)
+                 return index;
+         return -1;
+     }
+     /**
+      * Checks whether the file's "3CRC" chunk was damaged. This chunk contains
+      * the CRC32 check sums of all samples' raw wave data.
+      *
+      * @return true if 3CRC chunk is OK, or false if 3CRC chunk is damaged
+      */
+     bool File::VerifySampleChecksumTable() {
+         RIFF::Chunk* _3crc = pRIFF->GetSubChunk(CHUNK_ID_3CRC);
+         if (!_3crc) return false;
+         if (_3crc->GetNewSize() <= 0) return false;
+         if (_3crc->GetNewSize() % 8) return false;
+         if (!pSamples) GetFirstSample(); // make sure sample chunks were scanned
+         if (_3crc->GetNewSize() != pSamples->size() * 8) return false;
+         const int n = _3crc->GetNewSize() / 8;
+         uint32_t* pData = (uint32_t*) _3crc->LoadChunkData();
+         if (!pData) return false;
+         for (int i = 0; i < n; ++i) {
+             uint32_t one = pData[i*2];
+             if (one != 1) return false;
+         }
+         return true;
+     }
+     /**
+      * Recalculates CRC32 checksums for all samples and rebuilds this gig
+      * file's checksum table with those new checksums. This might usually
+      * just be necessary if the checksum table was damaged.
+      *
+      * @e IMPORTANT: The current implementation of this method only works
+      * with files that have not been modified since it was loaded, because
+      * it expects that no externally caused file structure changes are
+      * required!
+      *
+      * Due to the expectation above, this method is currently protected
+      * and actually only used by the command line tool "gigdump" yet.
+      *
+      * @returns true if Save() is required to be called after this call,
+      *          false if no further action is required
+      */
+     bool File::RebuildSampleChecksumTable() {
+         // make sure sample chunks were scanned
+         if (!pSamples) GetFirstSample();
+         bool bRequiresSave = false;
+         // make sure "3CRC" chunk exists with required size
+         RIFF::Chunk* _3crc = pRIFF->GetSubChunk(CHUNK_ID_3CRC);
+         if (!_3crc) {
+             _3crc = pRIFF->AddSubChunk(CHUNK_ID_3CRC, pSamples->size() * 8);
+             // the order of einf and 3crc is not the same in v2 and v3
+             RIFF::Chunk* einf = pRIFF->GetSubChunk(CHUNK_ID_EINF);
+             if (einf && pVersion && pVersion->major == 3) pRIFF->MoveSubChunk(_3crc, einf);
+             bRequiresSave = true;
+         } else if (_3crc->GetNewSize() != pSamples->size() * 8) {
+             _3crc->Resize(pSamples->size() * 8);
+             bRequiresSave = true;
+         }
+         if (bRequiresSave) { // refill CRC table for all samples in RAM ...
+             uint32_t* pData = (uint32_t*) _3crc->LoadChunkData();
+             {
+                 File::SampleList::iterator iter = pSamples->begin();
+                 File::SampleList::iterator end  = pSamples->end();
+                 for (; iter != end; ++iter) {
+                     gig::Sample* pSample = (gig::Sample*) *iter;
+                     int index = GetWaveTableIndexOf(pSample);
+                     if (index < 0) throw gig::Exception("Could not rebuild crc table for samples, wave table index of a sample could not be resolved");
+                     pData[index*2]   = 1; // always 1
+                     pData[index*2+1] = pSample->CalculateWaveDataChecksum();
+                 }
+             }
+         } else { // no file structure changes necessary, so directly write to disk and we are done ...
+             // make sure file is in write mode
+             pRIFF->SetMode(RIFF::stream_mode_read_write);
+             {
+                 File::SampleList::iterator iter = pSamples->begin();
+                 File::SampleList::iterator end  = pSamples->end();
+                 for (; iter != end; ++iter) {
+                     gig::Sample* pSample = (gig::Sample*) *iter;
+                     int index = GetWaveTableIndexOf(pSample);
+                     if (index < 0) throw gig::Exception("Could not rebuild crc table for samples, wave table index of a sample could not be resolved");
+                     pSample->crc  = pSample->CalculateWaveDataChecksum();
+                     SetSampleChecksum(pSample, pSample->crc);
+                 }
+             }
+         }
+         return bRequiresSave;
+     }
      Group* File::GetFirstGroup() {
          if (!pGroups) LoadGroups();
          // there must always be at least one group
-Line 6046 
 namespace {
+Line 6251 
 namespace {
          // update 3crc chunk
          // The 3crc chunk contains CRC-32 checksums for the
-         // samples. The actual checksum values will be filled in
+         // samples. When saving a gig file to disk, we first update the 3CRC
-         // later, by Sample::Write.
+         // chunk here (in RAM) with the old crc values which we read from the
+         // 3CRC chunk when we opened the file (available with gig::Sample::crc
+         // member variable). This step is required, because samples might have
+         // been deleted by the user since the file was opened, which in turn
+         // changes the order of the (i.e. old) checksums within the 3crc chunk.
+         // If a sample was conciously modified by the user (that is if
+         // Sample::Write() was called later on) then Sample::Write() will just
+         // update the respective individual checksum(s) directly on disk and
+         // leaves all other sample checksums untouched.
          RIFF::Chunk* _3crc = pRIFF->GetSubChunk(CHUNK_ID_3CRC);
          if (_3crc) {
              _3crc->Resize(pSamples->size() * 8);
-         } else if (newFile) {
+         } else /*if (newFile)*/ {
              _3crc = pRIFF->AddSubChunk(CHUNK_ID_3CRC, pSamples->size() * 8);
-             _3crc->LoadChunkData();
              // the order of einf and 3crc is not the same in v2 and v3
              if (einf && pVersion && pVersion->major == 3) pRIFF->MoveSubChunk(_3crc, einf);
          }
+         { // must be performed in RAM here ...
+             uint32_t* pData = (uint32_t*) _3crc->LoadChunkData();
+             if (pData) {
+                 File::SampleList::iterator iter = pSamples->begin();
+                 File::SampleList::iterator end  = pSamples->end();
+                 for (int index = 0; iter != end; ++iter, ++index) {
+                     gig::Sample* pSample = (gig::Sample*) *iter;
+                     pData[index*2]   = 1; // always 1
+                     pData[index*2+1] = pSample->crc;
+                 }
+             }
+         }
      }
      void File::UpdateFileOffsets() {

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