Add an example of saving 10 images on a b2nd frame

examples/b2nd/stack_images.c

@@ -0,0 +1,79 @@
+/*********************************************************************
+  Blosc - Blocked Shuffling and Compression Library
+
+  Copyright (c) 2021  The Blosc Development Team <blosc@blosc.org>
+  https://blosc.org
+  License: BSD 3-Clause (see LICENSE.txt)
+
+  See LICENSE.txt for details about copyright and rights to use.
+**********************************************************************/
+
+// This is an example that saves a stack of images in a b2nd frame.
+
+#include <blosc2.h>
+#include <b2nd.h>
+
+
+int main() {
+  blosc2_init();
+  const int32_t width = 4 * 512;
+  const int32_t height = 4 * 272;
+  const int64_t buffershape[] = {1, height, width};
+  // Determine the buffer size of the image (in bytes)
+  const int64_t buffersize = width * height * (int64_t)sizeof(uint16_t);
+  uint16_t* image = malloc(buffersize);
+  int64_t N_images = 10;
+
+  char *urlpath = "test_image_dataset.b2nd";
+  blosc2_remove_urlpath(urlpath);
+
+  blosc2_cparams cparams = BLOSC2_CPARAMS_DEFAULTS;
+  cparams.typesize = sizeof(uint16_t);
+  cparams.compcode = BLOSC_BLOSCLZ;
+  cparams.clevel = 5;
+  cparams.nthreads = 4;
+
+  blosc2_storage storage = BLOSC2_STORAGE_DEFAULTS;
+  storage.contiguous = true;  // for a single file in output
+  storage.cparams = &cparams;
+  storage.urlpath = urlpath;
+
+  // shape, chunkshape and blockshape of the ndarray
+  int64_t shape[] = {N_images, height, width};
+  int32_t chunkshape[] = {1, height, width};
+  int32_t blockshape[] = {1, height, width};
+
+  b2nd_context_t *ctx = b2nd_create_ctx(&storage, 3,
+                                        shape, chunkshape, blockshape,
+                                        "|u2", DTYPE_NUMPY_FORMAT,
+                                        NULL, 0);
+  b2nd_array_t *src;
+  if (b2nd_empty(ctx, &src) < 0) {
+    printf("Error in b2nd_empty\n");
+    return -1;
+  }
+
+  // loop through all images
+  for (int64_t i = 0; i < N_images; i++) {
+    printf("Saving image #: %lld\n", i);
+    int64_t start[] = {i, 0, 0};
+    int64_t stop[] = {i + 1, height, width};
+    // Generate random image data
+    for (int j = 0; j < width * height; j++) {
+      image[j] = rand() % 65536; // generate random pixels (uncompressible data)
+    }
+
+    if (b2nd_set_slice_cbuffer(image, buffershape, buffersize, start, stop, src) < 0) {
+      printf("Error in b2nd_append\n");
+      return -1;
+    }
+  }
+
+  // Clean resources
+  b2nd_free(src);
+  b2nd_free_ctx(ctx);
+  blosc2_destroy();
+  free(image);
+
+  return 0;
+}