//

// SPDX-License-Identifier: BSD-3-Clause

// Copyright (c) Contributors to the OpenEXR Project.

//

//-----------------------------------------------------------------------------

//

//      class DeepTiledInputFile

//

//-----------------------------------------------------------------------------

#include "ImfDeepTiledInputFile.h"

#include "Iex.h"

#include "IlmThreadPool.h"

#if ILMTHREAD_THREADING_ENABLED

#    include "IlmThreadProcessGroup.h"

#    include <mutex>

#endif

#include "ImfDeepFrameBuffer.h"

#include "ImfInputPartData.h"

// TODO: remove once TiledOutput is converted

#include "ImfTileOffsets.h"

#include "ImfTiledMisc.h"

#include <algorithm>

#include <string>

#include <vector>

OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_ENTER

namespace {

// TODO: similarities to tiled input file...

struct TileProcess

{

    ~TileProcess ()

    {

        if (!first)

            exr_decoding_destroy (decoder.context, &decoder);

    }

    void run_decode (

        exr_const_context_t ctxt,

        int pn,

        const DeepFrameBuffer *outfb,

        const std::vector<DeepSlice> &filllist);

    void update_pointers (

        const DeepFrameBuffer *outfb,

        int fb_absX, int fb_absY,

        int t_absX, int t_absY);

    void run_fill (

        const DeepFrameBuffer *outfb,

        int fb_absX, int fb_absY,

        int t_absX, int t_absY,

        const std::vector<DeepSlice> &filllist);

    void copy_sample_count (

        const DeepFrameBuffer *outfb,

        int fb_absX, int fb_absY,

        int t_absX, int t_absY);

    exr_result_t          last_decode_err = EXR_ERR_UNKNOWN;

    bool                  first = true;

    bool                  counts_only = false;

    exr_chunk_info_t      cinfo;

    exr_decode_pipeline_t decoder;

    TileProcess*          next;

};

#if ILMTHREAD_THREADING_ENABLED

using TileProcessGroup = ILMTHREAD_NAMESPACE::ProcessGroup<TileProcess>;

#endif

} // empty namespace

//

// struct TiledInputFile::Data stores things that will be

// needed between calls to readTile()

//

struct DeepTiledInputFile::Data

{

    Data (Context *ctxt, int pN, int nT)

    : _ctxt (ctxt)

    , partNumber (pN)

    , numThreads (nT)

    {}

    void initialize ()

    {

        if (_ctxt->storage (partNumber) != EXR_STORAGE_DEEP_TILED)

            throw IEX_NAMESPACE::ArgExc ("File part is not a tiled part");

        if (EXR_ERR_SUCCESS != exr_get_tile_descriptor (

                *_ctxt,

                partNumber,

                &tile_x_size,

                &tile_y_size,

                &tile_level_mode,

                &tile_round_mode))

            throw IEX_NAMESPACE::ArgExc ("Unable to query tile descriptor");

        if (EXR_ERR_SUCCESS != exr_get_tile_levels (

                *_ctxt,

                partNumber,

                &num_x_levels,

                &num_y_levels))

            throw IEX_NAMESPACE::ArgExc ("Unable to query number of tile levels");

    }

    // TODO: generalize to have async framebuffer path

    void readTiles (int dx1, int dx2, int dy1, int dy2, int lx, int ly, bool countsOnly);

    Context* _ctxt;

    int partNumber;

    int numThreads;

    Header header;

    bool header_filled = false;

    uint32_t tile_x_size = 0;

    uint32_t tile_y_size = 0;

    exr_tile_level_mode_t tile_level_mode = EXR_TILE_LAST_TYPE;

    exr_tile_round_mode_t tile_round_mode = EXR_TILE_ROUND_LAST_TYPE;

    int32_t num_x_levels = 0;

    int32_t num_y_levels = 0;

    bool frameBufferValid = false;

    DeepFrameBuffer frameBuffer;

    std::vector<DeepSlice> fill_list;

#if ILMTHREAD_THREADING_ENABLED

    std::mutex _mx;

    class TileBufferTask final : public ILMTHREAD_NAMESPACE::Task

    {

    public:

        TileBufferTask (

            ILMTHREAD_NAMESPACE::TaskGroup* group,

            Data*                   ifd,

            TileProcessGroup*       tileg,

            const DeepFrameBuffer*  outfb,

            const exr_chunk_info_t& cinfo,

            bool                    countsOnly)

            : Task (group)

            , _outfb (outfb)

            , _ifd (ifd)

            , _tile (tileg->pop ())

            , _tile_group (tileg)

        {

            _tile->cinfo = cinfo;

            _tile->counts_only = countsOnly;

        }

        ~TileBufferTask () override

        {

            _tile_group->push (_tile);

        }

        void execute () override;

    private:

        void run_decode ();

        const DeepFrameBuffer* _outfb;

        Data*                  _ifd;

        TileProcess*       _tile;

        TileProcessGroup*  _tile_group;

    };

#endif

};

DeepTiledInputFile::DeepTiledInputFile (

    const char*               filename,

    const ContextInitializer& ctxtinit,

    int                       numThreads)

    : _ctxt (filename, ctxtinit, Context::read_mode_t{})

    , _data (std::make_shared<Data> (&_ctxt, 0, numThreads))

{

    _data->initialize ();

}

DeepTiledInputFile::DeepTiledInputFile (const char fileName[], int numThreads)

    : DeepTiledInputFile (

        fileName,

        ContextInitializer ()

        .silentHeaderParse (true)

        .strictHeaderValidation (false),

        numThreads)

{

}

DeepTiledInputFile::DeepTiledInputFile (

    OPENEXR_IMF_INTERNAL_NAMESPACE::IStream& is, int numThreads)

    : DeepTiledInputFile (

        is.fileName (),

        ContextInitializer ()

        .silentHeaderParse (true)

        .strictHeaderValidation (false)

        .setInputStream (&is),

        numThreads)

{

}

DeepTiledInputFile::DeepTiledInputFile (InputPartData* part)

    : _ctxt (part->context),

      _data (std::make_shared<Data> (&_ctxt, part->partNumber, part->numThreads))

{

    _data->initialize ();

}

const char*

DeepTiledInputFile::fileName () const

{

    return _ctxt.fileName ();

}

const Header&

DeepTiledInputFile::header () const

{

#if ILMTHREAD_THREADING_ENABLED

    std::lock_guard<std::mutex> lock (_data->_mx);

#endif

    if (!_data->header_filled)

    {

        _data->header = _ctxt.header (_data->partNumber);

        _data->header_filled = true;

    }

    return _data->header;

}

int

DeepTiledInputFile::version () const

{

    return _ctxt.version ();

}

void

DeepTiledInputFile::setFrameBuffer (const DeepFrameBuffer& frameBuffer)

{

#if ILMTHREAD_THREADING_ENABLED

    std::lock_guard<std::mutex> lock (_data->_mx);

#endif

    _data->fill_list.clear ();

    for (DeepFrameBuffer::ConstIterator j = frameBuffer.begin ();

         j != frameBuffer.end ();

         ++j)

    {

        const exr_attr_chlist_entry_t* curc = _ctxt.findChannel (

            _data->partNumber, j.name ());

        if (!curc)

        {

            _data->fill_list.push_back (j.slice ());

            continue;

        }

        if (curc->x_sampling != j.slice ().xSampling ||

            curc->y_sampling != j.slice ().ySampling)

            THROW (

                IEX_NAMESPACE::ArgExc,

                "X and/or y subsampling factors "

                "of \""

                    << j.name ()

                    << "\" channel "

                       "of input file \""

                    << fileName ()

                    << "\" are "

                       "not compatible with the frame buffer's "

                       "subsampling factors.");

    }

    _data->frameBuffer = frameBuffer;

    _data->frameBufferValid = true;

}

const DeepFrameBuffer&

DeepTiledInputFile::frameBuffer () const

{

#if ILMTHREAD_THREADING_ENABLED

    std::lock_guard<std::mutex> lock (_data->_mx);

#endif

    return _data->frameBuffer;

}

bool

DeepTiledInputFile::isComplete () const

{

    return _ctxt.chunkTableValid (_data->partNumber);

}

void

DeepTiledInputFile::readTiles (

    int dx1, int dx2, int dy1, int dy2, int lx, int ly)

{

    //

    // Read a range of tiles from the file into the framebuffer

    //

    try

    {

        if (!_data->frameBufferValid)

        {

            throw IEX_NAMESPACE::ArgExc (

                "readTiles called with no valid frame buffer");

        }

        if (!isValidLevel (lx, ly))

            THROW (

                IEX_NAMESPACE::ArgExc,

                "Level coordinate "

                "(" << lx

                    << ", " << ly

                    << ") "

                       "is invalid.");

        if (dx1 > dx2) std::swap (dx1, dx2);

        if (dy1 > dy2) std::swap (dy1, dy2);

        _data->readTiles (dx1, dx2, dy1, dy2, lx, ly, false);

    }

    catch (IEX_NAMESPACE::BaseExc& e)

    {

        REPLACE_EXC (

            e,

            "Error reading deep tiled data from image "

            "file \""

                << fileName () << "\". " << e.what ());

        throw;

    }

}

void

DeepTiledInputFile::readTiles (int dx1, int dx2, int dy1, int dy2, int l)

{

    readTiles (dx1, dx2, dy1, dy2, l, l);

}

void

DeepTiledInputFile::readTile (int dx, int dy, int lx, int ly)

{

    readTiles (dx, dx, dy, dy, lx, ly);

}

void

DeepTiledInputFile::readTile (int dx, int dy, int l)

{

    readTile (dx, dy, l, l);

}

#pragma pack(push, 1)

struct DeepTileChunkHeader

{

    int32_t dx;

    int32_t dy;

    int32_t lx;

    int32_t ly;

    uint64_t packedCountSize;

    uint64_t packedDataSize;

    uint64_t unpackedDataSize;

};

#pragma pack(pop)

void

DeepTiledInputFile::rawTileData (

    int&      dx,

    int&      dy,

    int&      lx,

    int&      ly,

    char*     pixelData,

    uint64_t& pixelDataSize) const

{

    exr_chunk_info_t cinfo;

    static_assert (sizeof(DeepTileChunkHeader) == 40, "Expect a 40-byte tiled chunk header");

    if (EXR_ERR_SUCCESS == exr_read_tile_chunk_info (

            _ctxt, _data->partNumber, dx, dy, lx, ly, &cinfo))

    {

        uint64_t cbytes;

        cbytes = sizeof (DeepTileChunkHeader);

        cbytes += cinfo.sample_count_table_size;

        cbytes += cinfo.packed_size;

        if (!pixelData || cbytes > pixelDataSize)

        {

            pixelDataSize = cbytes;

            return;

        }

        pixelDataSize = cbytes;

        DeepTileChunkHeader* dch = reinterpret_cast<DeepTileChunkHeader*> (pixelData);

        dch->dx = cinfo.start_x;

        dch->dy = cinfo.start_y;

        dch->lx = cinfo.level_x;

        dch->ly = cinfo.level_y;

        dch->packedCountSize = cinfo.sample_count_table_size;

        dch->packedDataSize = cinfo.packed_size;

        dch->unpackedDataSize = cinfo.unpacked_size;

        pixelData += sizeof(DeepTileChunkHeader);

        if (EXR_ERR_SUCCESS !=

            exr_read_deep_chunk (

                _ctxt,

                _data->partNumber,

                &cinfo,

                pixelData + cinfo.sample_count_table_size,

                pixelData))

        {

            THROW (

                IEX_NAMESPACE::ArgExc,

                "Error reading deep tiled data from image "

                "file \""

                << fileName () << "\". Unable to read raw tile data of "

                << pixelDataSize << " bytes.");

        }

    }

    else

    {

        THROW (

            IEX_NAMESPACE::ArgExc,

            "Error reading deep tile data from image "

            "file \""

            << fileName ()

            << "\". Unable to query data block information.");

    }

}

unsigned int

DeepTiledInputFile::tileXSize () const

{

    return _data->tile_x_size;

}

unsigned int

DeepTiledInputFile::tileYSize () const

{

    return _data->tile_y_size;

}

LevelMode

DeepTiledInputFile::levelMode () const

{

    return (LevelMode)_data->tile_level_mode;

}

LevelRoundingMode

DeepTiledInputFile::levelRoundingMode () const

{

    return (LevelRoundingMode)_data->tile_round_mode;

}

int

DeepTiledInputFile::numLevels () const

{

    if (levelMode () == RIPMAP_LEVELS)

        THROW (

            IEX_NAMESPACE::LogicExc,

            "Error calling numLevels() on image "

            "file \""

                << fileName ()

                << "\" "

                   "(numLevels() is not defined for files "

                   "with RIPMAP level mode).");

    return _data->num_x_levels;

}

int

DeepTiledInputFile::numXLevels () const

{

    return _data->num_x_levels;

}

int

DeepTiledInputFile::numYLevels () const

{

    return _data->num_y_levels;

}

bool

DeepTiledInputFile::isValidLevel (int lx, int ly) const

{

    if (lx < 0 || ly < 0) return false;

    if (levelMode () == MIPMAP_LEVELS && lx != ly) return false;

    if (lx >= numXLevels () || ly >= numYLevels ()) return false;

    return true;

}

int

DeepTiledInputFile::levelWidth (int lx) const

{

    int32_t levw = 0;

    if (EXR_ERR_SUCCESS != exr_get_level_sizes (

            _ctxt, _data->partNumber, lx, 0, &levw, nullptr))

    {

        THROW (

            IEX_NAMESPACE::ArgExc,

            "Error calling levelWidth() on image "

            "file \""

                << fileName () << "\".");

    }

    return levw;

}

int

DeepTiledInputFile::levelHeight (int ly) const

{

    int32_t levh = 0;

    if (EXR_ERR_SUCCESS != exr_get_level_sizes (

            _ctxt, _data->partNumber, 0, ly, nullptr, &levh))

    {

        THROW (

            IEX_NAMESPACE::ArgExc,

            "Error calling levelWidth() on image "

            "file \""

                << fileName () << "\".");

    }

    return levh;

}

int

DeepTiledInputFile::numXTiles (int lx) const

{

    int32_t countx = 0;

    if (EXR_ERR_SUCCESS != exr_get_tile_counts (

            _ctxt, _data->partNumber, lx, 0, &countx, nullptr))

    {

        THROW (

            IEX_NAMESPACE::ArgExc,

            "Error calling numXTiles() on image "

            "file \""

                << fileName () << "\".");

    }

    return countx;

}

int

DeepTiledInputFile::numYTiles (int ly) const

{

    int32_t county = 0;

    if (EXR_ERR_SUCCESS != exr_get_tile_counts (

            _ctxt, _data->partNumber, 0, ly, nullptr, &county))

    {

        THROW (

            IEX_NAMESPACE::ArgExc,

            "Error calling numYTiles() on image "

            "file \""

                << fileName () << "\".");

    }

    return county;

}

IMATH_NAMESPACE::Box2i

DeepTiledInputFile::dataWindowForLevel (int l) const

{

    return dataWindowForLevel (l, l);

}

IMATH_NAMESPACE::Box2i

DeepTiledInputFile::dataWindowForLevel (int lx, int ly) const

{

    int32_t levw = 0, levh = 0;

    if (EXR_ERR_SUCCESS != exr_get_level_sizes (

            _ctxt, _data->partNumber, lx, ly, &levw, &levh))

    {

        THROW (

            IEX_NAMESPACE::ArgExc,

            "Error calling dataWindowForLevel() on image "

            "file \""

                << fileName () << "\".");

    }

    exr_attr_box2i_t dw = _ctxt.dataWindow (_data->partNumber);

    return IMATH_NAMESPACE::Box2i (

        IMATH_NAMESPACE::V2i (dw.min.x, dw.min.y),

        IMATH_NAMESPACE::V2i (dw.min.x + levw - 1, dw.min.y + levh - 1));

}

IMATH_NAMESPACE::Box2i

DeepTiledInputFile::dataWindowForTile (int dx, int dy, int l) const

{

    return dataWindowForTile (dx, dy, l, l);

}

IMATH_NAMESPACE::Box2i

DeepTiledInputFile::dataWindowForTile (int dx, int dy, int lx, int ly) const

{

    try

    {

        if (!isValidTile (dx, dy, lx, ly))

            throw IEX_NAMESPACE::ArgExc ("Arguments not in valid range.");

        //exr_attr_box2i_t dw = _ctxt.dataWindow (_data->partNumber);

        auto dw = dataWindowForLevel (lx, ly);

        int32_t tileSizeX, tileSizeY;

        if (EXR_ERR_SUCCESS !=

            exr_get_tile_sizes (_ctxt, _data->partNumber, lx, ly, &tileSizeX, &tileSizeY))

          throw IEX_NAMESPACE::ArgExc ("Unable to query the data window.");

        dw.min.x += dx * tileSizeX;

        dw.min.y += dy * tileSizeY;

        int limX = dw.min.x + tileSizeX - 1;

        int limY = dw.min.y + tileSizeY - 1;

        limX = std::min (limX, dw.max.x);

        limY = std::min (limY, dw.max.y);

        return IMATH_NAMESPACE::Box2i (

            IMATH_NAMESPACE::V2i (dw.min.x, dw.min.y),

            IMATH_NAMESPACE::V2i (limX, limY));

    }

    catch (IEX_NAMESPACE::BaseExc& e)

    {

        REPLACE_EXC (

            e,

            "Error calling dataWindowForTile() on image "

            "file \""

                << fileName () << "\". " << e.what ());

        throw;

    }

}

bool

DeepTiledInputFile::isValidTile (int dx, int dy, int lx, int ly) const

{

    int32_t countx = 0, county = 0;

    if (EXR_ERR_SUCCESS == exr_get_tile_counts (

            _ctxt, _data->partNumber, lx, ly, &countx, &county))

    {

        // get tile counts will check lx, ly for us

        return ((dx < countx && dx >= 0) &&

                (dy < county && dy >= 0));

    }

    return false;

}

void

DeepTiledInputFile::readPixelSampleCounts (

    int dx1, int dx2, int dy1, int dy2, int lx, int ly)

{

    //

    // Read a range of tiles from the file into the framebuffer

    //

    try

    {

        if (!_data->frameBufferValid)

        {

            throw IEX_NAMESPACE::ArgExc (

                "readPixelSampleCounts called with no valid frame buffer");

        }

        if (!isValidLevel (lx, ly))

            THROW (

                IEX_NAMESPACE::ArgExc,

                "Level coordinate "

                "(" << lx

                    << ", " << ly

                    << ") "

                       "is invalid.");

        if (dx1 > dx2) std::swap (dx1, dx2);

        if (dy1 > dy2) std::swap (dy1, dy2);

        _data->readTiles (dx1, dx2, dy1, dy2, lx, ly, true);

    }

    catch (IEX_NAMESPACE::BaseExc& e)

    {

        REPLACE_EXC (

            e,

            "Error reading deep pixel sample counts data from image "

            "file \""

                << fileName () << "\". " << e.what ());

        throw;

    }

}

void

DeepTiledInputFile::readPixelSampleCount (int dx, int dy, int l)

{

    readPixelSampleCount (dx, dy, l, l);

}

void

DeepTiledInputFile::readPixelSampleCount (int dx, int dy, int lx, int ly)

{

    readPixelSampleCounts (dx, dx, dy, dy, lx, ly);

}

void

DeepTiledInputFile::readPixelSampleCounts (

    int dx1, int dx2, int dy1, int dy2, int l)

{

    readPixelSampleCounts (dx1, dx2, dy1, dy2, l, l);

}

size_t

DeepTiledInputFile::totalTiles () const

{

    //

    // Calculate the total number of tiles in the file

    //

    int numAllTiles = 0;

    switch (levelMode ())

    {

        case ONE_LEVEL:

        case MIPMAP_LEVELS:

            for (int i_l = 0; i_l < numLevels (); ++i_l)

                numAllTiles += numXTiles (i_l) * numYTiles (i_l);

            break;

        case RIPMAP_LEVELS:

            for (int i_ly = 0; i_ly < numYLevels (); ++i_ly)

                for (int i_lx = 0; i_lx < numXLevels (); ++i_lx)

                    numAllTiles += numXTiles (i_lx) * numYTiles (i_ly);

            break;

        default: throw IEX_NAMESPACE::ArgExc ("Unknown LevelMode format.");

    }

    return numAllTiles;

}

namespace

{

struct tilepos

{

    uint64_t filePos;

    int      dx;

    int      dy;

    int      lx;

    int      ly;

    bool     operator< (const tilepos& other) const

    {

        return filePos < other.filePos;

    }

};

} // namespace

void

DeepTiledInputFile::getTileOrder (int dx[], int dy[], int lx[], int ly[]) const

{

    // TODO: remove once TiledOutputFile copy is converted

    switch (_ctxt.lineOrder (_data->partNumber))

    {

        case EXR_LINEORDER_RANDOM_Y:

            // calc below outside the nest

            break;

        case EXR_LINEORDER_DECREASING_Y:

        {

            dx[0] = 0;

            dy[0] = numYTiles (0) - 1;

            lx[0] = 0;

            ly[0] = 0;

            return;

        }

        case EXR_LINEORDER_INCREASING_Y:

            dx[0] = 0;

            dy[0] = 0;

            lx[0] = 0;

            ly[0] = 0;

            return;

        case EXR_LINEORDER_LAST_TYPE: /* invalid but should never be here */

        default:

            throw IEX_NAMESPACE::ArgExc ("Unknown LineOrder.");

    }

    size_t numAllTiles = 0;

    int numX = numXLevels ();

    int numY = numYLevels ();

    switch (levelMode ())

    {

        case ONE_LEVEL:

        case MIPMAP_LEVELS:

            for (int i_l = 0; i_l < numY; ++i_l)

                numAllTiles += size_t (numXTiles (i_l)) * size_t (numYTiles (i_l));

            break;

        case RIPMAP_LEVELS:

            for (int i_ly = 0; i_ly < numY; ++i_ly)

                for (int i_lx = 0; i_lx < numX; ++i_lx)

                    numAllTiles += size_t (numXTiles (i_lx)) * size_t (numYTiles (i_ly));

            break;

        default:

            throw IEX_NAMESPACE::ArgExc ("Unknown LevelMode format.");

    }

    std::vector<tilepos> table;

    table.resize (numAllTiles);

    size_t tIdx = 0;

    switch (levelMode ())

    {

        case ONE_LEVEL:

        case MIPMAP_LEVELS:

            for (int i_l = 0; i_l < numY; ++i_l)

            {

                int nY = numYTiles (i_l);

                int nX = numXTiles (i_l);

                for ( int y = 0; y < nY; ++y )

                    for ( int x = 0; x < nX; ++x )

                    {

                        exr_chunk_info_t cinfo;

                        if (EXR_ERR_SUCCESS == exr_read_tile_chunk_info (

                                _ctxt, _data->partNumber, x, y, i_l, i_l, &cinfo))

                        {

                            tilepos &tp = table[tIdx++];

                            tp.filePos = cinfo.data_offset;

                            tp.dx = x;

                            tp.dy = y;

                            tp.lx = i_l;

                            tp.ly = i_l;

                        }

                        else

                        {

                            throw IEX_NAMESPACE::ArgExc ("Unable to get tile offset.");

                        }

                    }

            }

            break;

        case RIPMAP_LEVELS:

            for (int i_ly = 0; i_ly < numY; ++i_ly)

            {

                int nY = numYTiles (i_ly);

                for (int i_lx = 0; i_lx < numX; ++i_lx)

                {

                    int nX = numXTiles (i_lx);

                    for ( int y = 0; y < nY; ++y )

                        for ( int x = 0; x < nX; ++x )

                        {

                            exr_chunk_info_t cinfo;

                            if (EXR_ERR_SUCCESS == exr_read_tile_chunk_info (

                                    _ctxt, _data->partNumber, x, y, i_lx, i_ly, &cinfo))

                            {

                                tilepos &tp = table[tIdx++];

                                tp.filePos = cinfo.data_offset;

                                tp.dx = x;

                                tp.dy = y;

                                tp.lx = i_lx;

                                tp.ly = i_ly;

                            }

                            else

                            {

                                throw IEX_NAMESPACE::ArgExc ("Unable to get tile offset.");

                            }

                        }

                }

            }

            break;

        default: throw IEX_NAMESPACE::ArgExc ("Unknown LevelMode format.");

    }

    std::sort (table.begin(), table.end ());

    for (size_t i = 0; i < numAllTiles; ++i)

    {

        const auto& tp = table[i];

        dx[i] = tp.dx;

        dy[i] = tp.dy;

        lx[i] = tp.lx;

        ly[i] = tp.ly;

    }

}

void DeepTiledInputFile::Data::readTiles (

    int dx1, int dx2, int dy1, int dy2, int lx, int ly, bool countsOnly)

{

    int nTiles = dx2 - dx1 + 1;

    nTiles *= dy2 - dy1 + 1;

    exr_chunk_info_t      cinfo;

#if ILMTHREAD_THREADING_ENABLED

    if (nTiles > 1 && numThreads > 1)

    {

        // we need the lifetime of this to last longer than the

        // lifetime of the task group below such that we don't get use

        // after free type error, so use scope rules to accomplish

        // this

        TileProcessGroup tpg (numThreads);

        {

            ILMTHREAD_NAMESPACE::TaskGroup tg;

            for (int ty = dy1; ty <= dy2; ++ty)

            {

                for (int tx = dx1; tx <= dx2; ++tx)

                {

                    exr_result_t rv = exr_read_tile_chunk_info (

                        *_ctxt, partNumber, tx, ty, lx, ly, &cinfo);

                    if (EXR_ERR_INCOMPLETE_CHUNK_TABLE == rv)

                    {

                        THROW (

                            IEX_NAMESPACE::InputExc,

                            "Tile (" << tx << ", " << ty << ", " << lx << ", " << ly

                            << ") is missing.");

                    }

                    else if (EXR_ERR_SUCCESS != rv)

                        throw IEX_NAMESPACE::InputExc ("Unable to query tile information");

                    ILMTHREAD_NAMESPACE::ThreadPool::addGlobalTask (

                        new TileBufferTask (&tg, this, &tpg, &frameBuffer, cinfo, countsOnly) );