c - HDF5:如何将数据附加到数据集(可扩展数组)

Question

关注this tutorial ，我试图扩展我的 HDF5 数据集。代码如下，但是数据未正确写入数据集(数据集具有正确的最终大小但仅包含零)。与教程的唯一区别是我必须使用动态数组。有什么想法吗？

int main()
{    
    hsize_t dims[1], max_dims[1], newdims[1], chunk_dims[1], offset[1];
    hid_t file, file_space, plist, dataset, mem_space;
    int32_t *buffer1, *buffer2;

    file = H5Fcreate("test.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);

    // Create dataspace with initial dim = 0 and final = UNLIMITED
    dims[0] = 0;
    max_dims[0] = H5S_UNLIMITED;
    file_space = H5Screate_simple(RANK, dims, max_dims);

    // Create dataset creation property list to have chunks
    plist = H5Pcreate(H5P_DATASET_CREATE);
    H5Pset_layout(plist, H5D_CHUNKED);
    chunk_dims[0] = 2;
    H5Pset_chunk(plist, RANK, chunk_dims);

    // Create the dataset
    dataset = H5Dcreate(file, "Test", H5T_NATIVE_INT32, file_space, H5P_DEFAULT, plist, H5P_DEFAULT);

    H5Pclose(plist);
    H5Sclose(file_space);

    //## FIRST BUFFER

    int length = 6;
    buffer1 = new int32_t[length];
    for (hsize_t i = 0; i < length; i++)
        buffer1[i] = i;

    // Extend the dataset by getting previous size and adding current length
    file_space = H5Dget_space(dataset);
    H5Sget_simple_extent_dims(file_space, dims, NULL);
    newdims[0] = dims[0] + length;
    H5Dset_extent(dataset, newdims);

    // Select hyperslab on the file dataset
    offset[0] = dims[0];
    dims[0] = length;
    H5Sselect_hyperslab(file_space, H5S_SELECT_SET, offset, NULL, dims, NULL);

    // Dataspace for buffer in memory
    mem_space = H5Screate_simple(RANK, dims, NULL);

    // Append buffer to dataset
    H5Dwrite(dataset, H5T_NATIVE_INT32, mem_space, file_space, H5P_DEFAULT, buffer1);

    H5Sclose(file_space);
    H5Sclose(mem_space);

    //## SECOND BUFFER

    length = 4;
    buffer2 = new int32_t[length];
    for (hsize_t i = 0; i < length; i++)
        buffer2[i] = i;

    // Extend the dataset by getting previous size and adding current length
    file_space = H5Dget_space(dataset);
    H5Sget_simple_extent_dims(file_space, dims, NULL);
    newdims[0] = dims[0] + length;
    H5Dset_extent(dataset, newdims);

    // Select hyperslab on the file dataset
    offset[0] = dims[0];
    dims[0] = length;
    H5Sselect_hyperslab(file_space, H5S_SELECT_SET, offset, NULL, dims, NULL);

    // Dataspace for buffer in memory
    mem_space = H5Screate_simple(RANK, dims, NULL);

    // Append buffer to dataset
    H5Dwrite(dataset, H5T_NATIVE_INT32, mem_space, file_space, H5P_DEFAULT, buffer2);

    H5Sclose(file_space);
    H5Sclose(mem_space);

    H5Dclose(dataset);
    H5Fclose(file);

   delete[] buffer1;
   delete[] buffer2;
}

Answer 1

我已经找到解决问题的方法了。它与动态数组无关。问题是，在调用 H5Sget_simple_extent_dims 之后，数据空间 ID 会以某种方式失效(我不明白为什么......一个错误？)并且您需要在重新使用它之前再次获取它，例如在选择 hyperslab 之前:

// Select hyperslab on the file dataset
offset[0] = dims[0];
dims[0] = length;
H5Dclose(file_space); // --ADDED-- CLOSE THE PREVIOUSLY OPENED
file_space = H5Dget_space(dataset); // --ADDED-- REOPEN
H5Sselect_hyperslab(file_space, H5S_SELECT_SET, offset, NULL, dims, NULL);