Add freeBuffers() function to InputFile classes

The idea here is to provide a way to get InputFile objects back to their
initial state after pixels have been read, which involves the allocating
of various memory buffers that usually aren't freed until the objects
are destroyed.  This can be useful if an application wants to keep an
object around for additional reading, but doesn't want unnecessary
memory overhead in the meantime.

Also provided is a bufferSize() function that the application might
use to determine if freeing the buffers is enough of a memory savings
to be worth the trouble.

Signed-off-by: Brendan Bolles <brendan@fnord.com>

src/lib/OpenEXR/ImfDeepScanLineInputFile.cpp

@@ -80,6 +80,16 @@ struct ScanLineProcess
         const DeepFrameBuffer *outfb,
         int fbY);
 
+    size_t get_buffer_size ()
+    {
+        return exr_decoding_get_buffer_size (&decoder);
+    }
+
+    void free_buffers ()
+    {
+        exr_decoding_free_buffers (&decoder);
+    }
+
     exr_result_t          last_decode_err = EXR_ERR_UNKNOWN;
     bool                  first = true;
     bool                  counts_only = false;
@@ -458,6 +468,44 @@ DeepScanLineInputFile::lastScanLineInChunk (int y) const
     return _data->getChunkRange (y).second;
 }
 
+////////////////////////////////////////
+
+size_t
+DeepScanLineInputFile::bufferSize () const
+{
+#if ILMTHREAD_THREADING_ENABLED
+    std::lock_guard<std::mutex> lock (_data->_mx);
+#endif
+    size_t retval = 0;
+
+    std::shared_ptr<ScanLineProcess> sp = _data->processStack;
+
+    while (sp)
+    {
+        retval += sp->get_buffer_size();
+
+        sp = sp->next;
+    }
+
+    return retval;
+}
+
+void
+DeepScanLineInputFile::freeBuffers ()
+{
+#if ILMTHREAD_THREADING_ENABLED
+    std::lock_guard<std::mutex> lock (_data->_mx);
+#endif
+    std::shared_ptr<ScanLineProcess> sp = _data->processStack;
+
+    while (sp)
+    {
+        sp->free_buffers();
+
+        sp = sp->next;
+    }
+}
+
 std::pair<int, int> DeepScanLineInputFile::Data::getChunkRange (int y) const
 {
     exr_attr_box2i_t dw = _ctxt->dataWindow (partNumber);
@@ -612,8 +660,6 @@ DeepScanLineInputFile::Data::readData (
 #endif
 }
 
-////////////////////////////////////////
-
 void
 DeepScanLineInputFile::Data::readMemData (
         const DeepFrameBuffer &fb,

src/lib/OpenEXR/ImfDeepScanLineInputFile.h

@@ -233,6 +233,12 @@ class IMF_EXPORT_TYPE DeepScanLineInputFile
         int                    scanLine1,
         int                    scanLine2) const;
 
+    IMF_EXPORT
+    size_t bufferSize () const;
+
+    IMF_EXPORT
+    void freeBuffers ();
+
 private:
     Context _ctxt;
     struct IMF_HIDDEN Data;

src/lib/OpenEXR/ImfDeepScanLineInputPart.cpp

@@ -116,4 +116,16 @@ DeepScanLineInputPart::readPixelSampleCounts (
         rawdata, frameBuffer, scanLine1, scanLine2);
 }
 
+unsigned long long
+DeepScanLineInputPart::bufferSize () const
+{
+    return file->bufferSize ();
+}
+
+void
+DeepScanLineInputPart::freeBuffers ()
+{
+    file->freeBuffers ();
+}
+
 OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_EXIT

src/lib/OpenEXR/ImfDeepScanLineInputPart.h

@@ -145,6 +145,11 @@ class IMF_EXPORT_TYPE DeepScanLineInputPart
     int firstScanLineInChunk (int y) const;
     IMF_EXPORT
     int lastScanLineInChunk (int y) const;
+
+    IMF_EXPORT
+    unsigned long long bufferSize () const;
+    IMF_EXPORT
+    void freeBuffers ();
 
 private:
     DeepScanLineInputFile* file;

src/lib/OpenEXR/ImfDeepTiledInputFile.cpp

@@ -65,6 +65,16 @@ struct TileProcess
         int fb_absX, int fb_absY,
         int t_absX, int t_absY);
 
+    size_t get_buffer_size ()
+    {
+        return exr_decoding_get_buffer_size (&decoder);
+    }
+
+    void free_buffers ()
+    {
+        exr_decoding_free_buffers (&decoder);
+    }
+
     exr_result_t          last_decode_err = EXR_ERR_UNKNOWN;
     bool                  first = true;
     bool                  counts_only = false;
@@ -914,6 +924,42 @@ DeepTiledInputFile::getTileOrder (int dx[], int dy[], int lx[], int ly[]) const
     }
 }
 
+size_t
+DeepTiledInputFile::bufferSize () const
+{
+#if ILMTHREAD_THREADING_ENABLED
+    std::lock_guard<std::mutex> lock (_data->_mx);
+#endif
+    size_t retval = 0;
+
+    std::shared_ptr<TileProcess> sp = _data->processStack;
+
+    while (sp)
+    {
+        retval += sp->get_buffer_size();
+
+        sp = sp->next;
+    }
+
+    return retval;
+}
+
+void
+DeepTiledInputFile::freeBuffers ()
+{
+#if ILMTHREAD_THREADING_ENABLED
+    std::lock_guard<std::mutex> lock (_data->_mx);
+#endif
+    std::shared_ptr<TileProcess> sp = _data->processStack;
+
+    while (sp)
+    {
+        sp->free_buffers();
+
+        sp = sp->next;
+    }
+}
+
 void DeepTiledInputFile::Data::readTiles (
     int dx1, int dx2, int dy1, int dy2, int lx, int ly, bool countsOnly)
 {

src/lib/OpenEXR/ImfDeepTiledInputFile.h

@@ -377,6 +377,12 @@ class IMF_EXPORT_TYPE DeepTiledInputFile
     IMF_EXPORT
     void readPixelSampleCounts (int dx1, int dx2, int dy1, int dy2, int l = 0);
 
+    IMF_EXPORT
+    size_t bufferSize () const;
+
+    IMF_EXPORT
+    void freeBuffers ();
+
 private:
     Context _ctxt;
     struct IMF_HIDDEN Data;

src/lib/OpenEXR/ImfDeepTiledInputPart.cpp

@@ -207,4 +207,16 @@ DeepTiledInputPart::readPixelSampleCounts (
     file->readPixelSampleCounts (dx1, dx2, dy1, dy2, l);
 }
 
+unsigned long long
+DeepTiledInputPart::bufferSize () const
+{
+    return file->bufferSize ();
+}
+
+void
+DeepTiledInputPart::freeBuffers ()
+{
+    file->freeBuffers ();
+}
+
 OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_EXIT

src/lib/OpenEXR/ImfDeepTiledInputPart.h

@@ -334,6 +334,11 @@ class IMF_EXPORT_TYPE DeepTiledInputPart
     IMF_EXPORT
     void readPixelSampleCounts (int dx1, int dx2, int dy1, int dy2, int l = 0);
 
+    IMF_EXPORT
+    unsigned long long bufferSize () const;
+    IMF_EXPORT
+    void freeBuffers ();
+
 private:
     DeepTiledInputFile* file;
 

src/lib/OpenEXR/ImfInputFile.cpp

@@ -5,7 +5,7 @@
 
 //-----------------------------------------------------------------------------
 //
-//	class InputFile
+//  class InputFile
 //
 //-----------------------------------------------------------------------------
 
@@ -271,6 +271,60 @@ InputFile::rawTileData (
     }
 }
 
+size_t
+InputFile::bufferSize () const
+{
+    if (_data->_storage == EXR_STORAGE_DEEP_SCANLINE)
+    {
+        return _data->_dsFile->bufferSize ();
+    }
+    else if (
+        _data->_storage == EXR_STORAGE_DEEP_TILED ||
+        _data->_storage == EXR_STORAGE_TILED)
+    {
+        return _data->_tFile->bufferSize ();
+    }
+    else if (_data->_storage == EXR_STORAGE_SCANLINE)
+    {
+        return _data->_sFile->bufferSize ();
+    }
+    else
+    {
+        THROW (
+            IEX_NAMESPACE::ArgExc,
+            "Unable to handle data storage type in file '" << fileName ()
+                                                           << "'");
+    }
+}
+
+void
+InputFile::freeBuffers ()
+{
+    _data->deleteCachedBuffer ();
+
+    if (_data->_storage == EXR_STORAGE_DEEP_SCANLINE)
+    {
+        _data->_dsFile->freeBuffers ();
+    }
+    else if (
+        _data->_storage == EXR_STORAGE_DEEP_TILED ||
+        _data->_storage == EXR_STORAGE_TILED)
+    {
+        _data->_tFile->freeBuffers ();
+    }
+    else if (_data->_storage == EXR_STORAGE_SCANLINE)
+    {
+        _data->_sFile->freeBuffers ();
+    }
+    else
+    {
+        THROW (
+            IEX_NAMESPACE::ArgExc,
+            "Unable to handle data storage type in file '" << fileName ()
+                                                           << "'");
+    }
+}
+
 TiledInputFile&
 InputFile::asTiledInput (void) const
 {

src/lib/OpenEXR/ImfInputFile.h

@@ -245,6 +245,12 @@ class IMF_EXPORT_TYPE InputFile
         const char*& pixelData,
         int&         pixelDataSize);
 
+    IMF_EXPORT
+    size_t bufferSize () const;
+
+    IMF_EXPORT
+    void freeBuffers ();
+
 private:
     IMF_HIDDEN void initialize (void);
 

src/lib/OpenEXR/ImfInputPart.cpp

@@ -96,4 +96,16 @@ InputPart::rawTileData (
     file->rawTileData (dx, dy, lx, ly, pixelData, pixelDataSize);
 }
 
+unsigned long long
+InputPart::bufferSize () const
+{
+    return file->bufferSize ();
+}
+
+void
+InputPart::freeBuffers ()
+{
+    file->freeBuffers ();
+}
+
 OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_EXIT

src/lib/OpenEXR/ImfInputPart.h

@@ -57,6 +57,12 @@ class IMF_EXPORT_TYPE InputPart
         const char*& pixelData,
         int&         pixelDataSize);
 
+    IMF_EXPORT
+    unsigned long long bufferSize () const;
+
+    IMF_EXPORT
+    void freeBuffers ();
+
 private:
     InputFile* file;
     // for internal use - give OutputFile and TiledOutputFile access to file for copyPixels

src/lib/OpenEXR/ImfScanLineInputFile.cpp

@@ -5,7 +5,7 @@
 
 //-----------------------------------------------------------------------------
 //
-//	class ScanLineInputFile
+//  class ScanLineInputFile
 //
 //-----------------------------------------------------------------------------
 
@@ -61,6 +61,16 @@ struct ScanLineProcess
         const FrameBuffer *outfb,
         int fbY,
         const std::vector<Slice> &filllist);
+
+    size_t get_buffer_size ()
+    {
+        return exr_decoding_get_buffer_size (&decoder);
+    }
+
+    void free_buffers ()
+    {
+        exr_decoding_free_buffers (&decoder);
+    }
 
     exr_result_t          last_decode_err = EXR_ERR_UNKNOWN;
     bool                  first = true;
@@ -408,6 +418,44 @@ ScanLineInputFile::rawPixelDataToBuffer (
 
 ////////////////////////////////////////
 
+size_t
+ScanLineInputFile::bufferSize () const
+{
+#if ILMTHREAD_THREADING_ENABLED
+    std::lock_guard<std::mutex> lock (_data->_mx);
+#endif
+    size_t retval = 0;
+
+    std::shared_ptr<ScanLineProcess> sp = _data->processStack;
+
+    while (sp)
+    {
+        retval += sp->get_buffer_size();
+
+        sp = sp->next;
+    }
+
+    return retval;
+}
+
+void
+ScanLineInputFile::freeBuffers ()
+{
+#if ILMTHREAD_THREADING_ENABLED
+    std::lock_guard<std::mutex> lock (_data->_mx);
+#endif
+    std::shared_ptr<ScanLineProcess> sp = _data->processStack;
+
+    while (sp)
+    {
+        sp->free_buffers();
+
+        sp = sp->next;
+    }
+}
+
+////////////////////////////////////////
+
 void ScanLineInputFile::Data::readPixels (
     const FrameBuffer &fb, int scanLine1, int scanLine2)
 {