gdaldefaultasync.cpp

/******************************************************************************
 *
 * Project:  GDAL Core
 * Purpose:  Implementation of GDALDefaultAsyncReader and the
 *           GDALAsyncReader base class.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 2010, Frank Warmerdam
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#include "cpl_port.h"
#include "gdal_priv.h"

#include <cstring>

#include "cpl_conv.h"
#include "cpl_error.h"
#include "cpl_string.h"
#include "gdal.h"

CPL_C_START
GDALAsyncReader *GDALGetDefaultAsyncReader(GDALDataset *poDS, int nXOff,
                                           int nYOff, int nXSize, int nYSize,
                                           void *pBuf, int nBufXSize,
                                           int nBufYSize, GDALDataType eBufType,
                                           int nBandCount, int *panBandMap,
                                           int nPixelSpace, int nLineSpace,
                                           int nBandSpace, char **papszOptions);
CPL_C_END

/************************************************************************/
/* ==================================================================== */
/*                         GDALAsyncReader                              */
/* ==================================================================== */
/************************************************************************/

/************************************************************************/
/*                          GDALAsyncReader()                           */
/************************************************************************/

GDALAsyncReader::GDALAsyncReader()
    : poDS(nullptr), nXOff(0), nYOff(0), nXSize(0), nYSize(0), pBuf(nullptr),
      nBufXSize(0), nBufYSize(0), eBufType(GDT_Unknown), nBandCount(0),
      panBandMap(nullptr), nPixelSpace(0), nLineSpace(0), nBandSpace(0)
{
}

/************************************************************************/
/*                         ~GDALAsyncReader()                           */
/************************************************************************/
GDALAsyncReader::~GDALAsyncReader() = default;

/************************************************************************/
/*                        GetNextUpdatedRegion()                        */
/************************************************************************/

/**
 * \fn GDALAsyncStatusType GDALAsyncReader::GetNextUpdatedRegion( double
 * dfTimeout, int* pnBufXOff, int* pnBufYOff, int* pnBufXSize, int* pnBufYSize)
 * = 0;
 *
 * \brief Get async IO update
 *
 * Provide an opportunity for an asynchronous IO request to update the
 * image buffer and return an indication of the area of the buffer that
 * has been updated.
 *
 * The dfTimeout parameter can be used to wait for additional data to
 * become available.  The timeout does not limit the amount
 * of time this method may spend actually processing available data.
 *
 * The following return status are possible.
 * - GARIO_PENDING: No imagery was altered in the buffer, but there is still
 * activity pending, and the application should continue to call
 * GetNextUpdatedRegion() as time permits.
 * - GARIO_UPDATE: Some of the imagery has been updated, but there is still
 * activity pending.
 * - GARIO_ERROR: Something has gone wrong. The asynchronous request should
 * be ended.
 * - GARIO_COMPLETE: An update has occurred and there is no more pending work
 * on this request. The request should be ended and the buffer used.
 *
 * @param dfTimeout the number of seconds to wait for additional updates.  Use
 * -1 to wait indefinitely, or zero to not wait at all if there is no data
 * available.
 * @param pnBufXOff location to return the X offset of the area of the
 * request buffer that has been updated.
 * @param pnBufYOff location to return the Y offset of the area of the
 * request buffer that has been updated.
 * @param pnBufXSize location to return the X size of the area of the
 * request buffer that has been updated.
 * @param pnBufYSize location to return the Y size of the area of the
 * request buffer that has been updated.
 *
 * @return GARIO_ status, details described above.
 */

/************************************************************************/
/*                     GDALARGetNextUpdatedRegion()                     */
/************************************************************************/

/**
 * \brief Get async IO update
 *
 * Provide an opportunity for an asynchronous IO request to update the
 * image buffer and return an indication of the area of the buffer that
 * has been updated.
 *
 * The dfTimeout parameter can be used to wait for additional data to
 * become available.  The timeout does not limit the amount
 * of time this method may spend actually processing available data.
 *
 * The following return status are possible.
 * - GARIO_PENDING: No imagery was altered in the buffer, but there is still
 * activity pending, and the application should continue to call
 * GetNextUpdatedRegion() as time permits.
 * - GARIO_UPDATE: Some of the imagery has been updated, but there is still
 * activity pending.
 * - GARIO_ERROR: Something has gone wrong. The asynchronous request should
 * be ended.
 * - GARIO_COMPLETE: An update has occurred and there is no more pending work
 * on this request. The request should be ended and the buffer used.
 *
 * This is the same as GDALAsyncReader::GetNextUpdatedRegion()
 *
 * @param hARIO handle to the async reader.
 * @param dfTimeout the number of seconds to wait for additional updates.  Use
 * -1 to wait indefinitely, or zero to not wait at all if there is no data
 * available.
 * @param pnBufXOff location to return the X offset of the area of the
 * request buffer that has been updated.
 * @param pnBufYOff location to return the Y offset of the area of the
 * request buffer that has been updated.
 * @param pnBufXSize location to return the X size of the area of the
 * request buffer that has been updated.
 * @param pnBufYSize location to return the Y size of the area of the
 * request buffer that has been updated.
 *
 * @return GARIO_ status, details described above.
 */

GDALAsyncStatusType CPL_STDCALL GDALARGetNextUpdatedRegion(
    GDALAsyncReaderH hARIO, double dfTimeout, int *pnBufXOff, int *pnBufYOff,
    int *pnBufXSize, int *pnBufYSize)
{
    VALIDATE_POINTER1(hARIO, "GDALARGetNextUpdatedRegion", GARIO_ERROR);
    return static_cast<GDALAsyncReader *>(hARIO)->GetNextUpdatedRegion(
        dfTimeout, pnBufXOff, pnBufYOff, pnBufXSize, pnBufYSize);
}

/************************************************************************/
/*                             LockBuffer()                             */
/************************************************************************/

/**
 * \fn GDALAsyncReader::LockBuffer(double)
 * \brief Lock image buffer.
 *
 * Locks the image buffer passed into GDALDataset::BeginAsyncReader().
 * This is useful to ensure the image buffer is not being modified while
 * it is being used by the application.  UnlockBuffer() should be used
 * to release this lock when it is no longer needed.
 *
 * @param dfTimeout the time in seconds to wait attempting to lock the buffer.
 * -1.0 to wait indefinitely and 0 to not wait at all if it can't be
 * acquired immediately.  Default is -1.0 (infinite wait).
 *
 * @return TRUE if successful, or FALSE on an error.
 */

/**/
/**/

int GDALAsyncReader::LockBuffer(double /* dfTimeout */)
{
    return TRUE;
}

/************************************************************************/
/*                          GDALARLockBuffer()                          */
/************************************************************************/

/**
 * \brief Lock image buffer.
 *
 * Locks the image buffer passed into GDALDataset::BeginAsyncReader().
 * This is useful to ensure the image buffer is not being modified while
 * it is being used by the application.  UnlockBuffer() should be used
 * to release this lock when it is no longer needed.
 *
 * This is the same as GDALAsyncReader::LockBuffer()
 *
 * @param hARIO handle to async reader.
 * @param dfTimeout the time in seconds to wait attempting to lock the buffer.
 * -1.0 to wait indefinitely and 0 to not wait at all if it can't be
 * acquired immediately.  Default is -1.0 (infinite wait).
 *
 * @return TRUE if successful, or FALSE on an error.
 */

int CPL_STDCALL GDALARLockBuffer(GDALAsyncReaderH hARIO, double dfTimeout)
{
    VALIDATE_POINTER1(hARIO, "GDALARLockBuffer", FALSE);
    return static_cast<GDALAsyncReader *>(hARIO)->LockBuffer(dfTimeout);
}

/************************************************************************/
/*                            UnlockBuffer()                            */
/************************************************************************/

/**
 * \brief Unlock image buffer.
 *
 * Releases a lock on the image buffer previously taken with LockBuffer().
 */

void GDALAsyncReader::UnlockBuffer()

{
}

/************************************************************************/
/*                          GDALARUnlockBuffer()                        */
/************************************************************************/

/**
 * \brief Unlock image buffer.
 *
 * Releases a lock on the image buffer previously taken with LockBuffer().
 *
 * This is the same as GDALAsyncReader::UnlockBuffer()
 *
 * @param hARIO handle to async reader.
 */

void CPL_STDCALL GDALARUnlockBuffer(GDALAsyncReaderH hARIO)
{
    VALIDATE_POINTER0(hARIO, "GDALARUnlockBuffer");
    static_cast<GDALAsyncReader *>(hARIO)->UnlockBuffer();
}

/************************************************************************/
/* ==================================================================== */
/*                     GDALDefaultAsyncReader                           */
/* ==================================================================== */
/************************************************************************/

class GDALDefaultAsyncReader : public GDALAsyncReader
{
  private:
    char **papszOptions = nullptr;

    CPL_DISALLOW_COPY_ASSIGN(GDALDefaultAsyncReader)

  public:
    GDALDefaultAsyncReader(GDALDataset *poDS, int nXOff, int nYOff, int nXSize,
                           int nYSize, void *pBuf, int nBufXSize, int nBufYSize,
                           GDALDataType eBufType, int nBandCount,
                           int *panBandMap, int nPixelSpace, int nLineSpace,
                           int nBandSpace, char **papszOptions);
    ~GDALDefaultAsyncReader() override;

    GDALAsyncStatusType GetNextUpdatedRegion(double dfTimeout, int *pnBufXOff,
                                             int *pnBufYOff, int *pnBufXSize,
                                             int *pnBufYSize) override;
};

/************************************************************************/
/*                     GDALGetDefaultAsyncReader()                      */
/************************************************************************/

GDALAsyncReader *GDALGetDefaultAsyncReader(GDALDataset *poDS, int nXOff,
                                           int nYOff, int nXSize, int nYSize,
                                           void *pBuf, int nBufXSize,
                                           int nBufYSize, GDALDataType eBufType,
                                           int nBandCount, int *panBandMap,
                                           int nPixelSpace, int nLineSpace,
                                           int nBandSpace, char **papszOptions)

{
    return new GDALDefaultAsyncReader(poDS, nXOff, nYOff, nXSize, nYSize, pBuf,
                                      nBufXSize, nBufYSize, eBufType,
                                      nBandCount, panBandMap, nPixelSpace,
                                      nLineSpace, nBandSpace, papszOptions);
}

/************************************************************************/
/*                       GDALDefaultAsyncReader()                       */
/************************************************************************/

GDALDefaultAsyncReader::GDALDefaultAsyncReader(
    GDALDataset *poDSIn, int nXOffIn, int nYOffIn, int nXSizeIn, int nYSizeIn,
    void *pBufIn, int nBufXSizeIn, int nBufYSizeIn, GDALDataType eBufTypeIn,
    int nBandCountIn, int *panBandMapIn, int nPixelSpaceIn, int nLineSpaceIn,
    int nBandSpaceIn, char **papszOptionsIn)

{
    poDS = poDSIn;
    nXOff = nXOffIn;
    nYOff = nYOffIn;
    nXSize = nXSizeIn;
    nYSize = nYSizeIn;
    pBuf = pBufIn;
    nBufXSize = nBufXSizeIn;
    nBufYSize = nBufYSizeIn;
    eBufType = eBufTypeIn;
    nBandCount = nBandCountIn;
    panBandMap = static_cast<int *>(CPLMalloc(sizeof(int) * nBandCountIn));

    if (panBandMapIn != nullptr)
        memcpy(panBandMap, panBandMapIn, sizeof(int) * nBandCount);
    else
    {
        for (int i = 0; i < nBandCount; i++)
            panBandMap[i] = i + 1;
    }

    nPixelSpace = nPixelSpaceIn;
    nLineSpace = nLineSpaceIn;
    nBandSpace = nBandSpaceIn;

    papszOptions = CSLDuplicate(papszOptionsIn);
}

/************************************************************************/
/*                      ~GDALDefaultAsyncReader()                       */
/************************************************************************/

GDALDefaultAsyncReader::~GDALDefaultAsyncReader()

{
    CPLFree(panBandMap);
    CSLDestroy(papszOptions);
}

/************************************************************************/
/*                        GetNextUpdatedRegion()                        */
/************************************************************************/

GDALAsyncStatusType
GDALDefaultAsyncReader::GetNextUpdatedRegion(double /*dfTimeout*/,
                                             int *pnBufXOff, int *pnBufYOff,
                                             int *pnBufXSize, int *pnBufYSize)
{
    CPLErr eErr;

    eErr =
        poDS->RasterIO(GF_Read, nXOff, nYOff, nXSize, nYSize, pBuf, nBufXSize,
                       nBufYSize, eBufType, nBandCount, panBandMap, nPixelSpace,
                       nLineSpace, nBandSpace, nullptr);

    *pnBufXOff = 0;
    *pnBufYOff = 0;
    *pnBufXSize = nBufXSize;
    *pnBufYSize = nBufYSize;

    if (eErr == CE_None)
        return GARIO_COMPLETE;
    else
        return GARIO_ERROR;
}