blosc2-src 0.1.4

FFI bindings for c-blosc2
Documentation
/*********************************************************************
    Blosc - Blocked Shuffling and Compression Library

    Copyright (c) 2021  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.

    Test program demonstrating use of the Blosc codec from C code.
    To compile this program:

    $ gcc -O test_zfp_prec_float.c -o test_zfp_prec_float -lblosc2


**********************************************************************/

#include "blosc-private.h"
#include "b2nd.h"
#include "blosc2/codecs-registry.h"
#include "blosc2.h"

#include <inttypes.h>
#include <math.h>
#include <stdio.h>

static int test_zfp_prec_float(blosc2_schunk *schunk) {

  if (schunk->typesize != 4) {
    printf("Error: This test is only for doubles.\n");
    return 0;
  }
  int64_t nchunks = schunk->nchunks;
  int32_t chunksize = (int32_t) (schunk->chunksize);
  float *data_in = malloc(chunksize);
  int decompressed;
  int64_t csize;
  int64_t dsize;
  int64_t csize_f = 0;
  uint8_t *data_out = malloc(chunksize + BLOSC2_MAX_OVERHEAD);
  float *data_dest = malloc(chunksize);

  /* Create a context for compression */
  int8_t zfp_prec = 25;
  blosc2_cparams cparams = BLOSC2_CPARAMS_DEFAULTS;
  cparams.splitmode = BLOSC_NEVER_SPLIT;
  cparams.typesize = schunk->typesize;
  cparams.compcode = BLOSC_CODEC_ZFP_FIXED_PRECISION;
  cparams.compcode_meta = zfp_prec;
  cparams.filters[BLOSC2_MAX_FILTERS - 1] = BLOSC_NOFILTER;
  cparams.clevel = 5;
  cparams.nthreads = 1;
  cparams.blocksize = schunk->blocksize;
  cparams.schunk = schunk;
  blosc2_context *cctx;
  cctx = blosc2_create_cctx(cparams);

  blosc2_dparams dparams = BLOSC2_DPARAMS_DEFAULTS;
  dparams.nthreads = 1;
  dparams.schunk = schunk;
  blosc2_context *dctx;
  dctx = blosc2_create_dctx(dparams);

  for (int ci = 0; ci < nchunks; ci++) {

    decompressed = blosc2_schunk_decompress_chunk(schunk, ci, data_in, chunksize);
    if (decompressed < 0) {
      printf("Error decompressing chunk \n");
      return -1;
    }

    /* Compress with clevel=5 and shuffle active  */
    csize = blosc2_compress_ctx(cctx, data_in, chunksize, data_out, chunksize + BLOSC2_MAX_OVERHEAD);
    if (csize == 0) {
      printf("Buffer is incompressible.  Giving up.\n");
      return 0;
    } else if (csize < 0) {
      printf("Compression error.  Error code: %" PRId64 "\n", csize);
      return (int) csize;
    }
    csize_f += csize;


    /* Decompress  */
    dsize = blosc2_decompress_ctx(dctx, data_out, chunksize + BLOSC2_MAX_OVERHEAD, data_dest, chunksize);
    if (dsize <= 0) {
      printf("Decompression error.  Error code: %" PRId64 "\n", dsize);
      return (int) dsize;
    }
    double tolerance = 0.01;
    for (int i = 0; i < (chunksize / cparams.typesize); i++) {
      if ((data_in[i] == 0) || (data_dest[i] == 0)) {
        if (fabsf(data_in[i] - data_dest[i]) > tolerance) {
          printf("i: %d, data %.8f, dest %.8f", i, data_in[i], data_dest[i]);
          printf("\n Decompressed data differs from original!\n");
          return -1;
        }
      } else if (fabsf(data_in[i] - data_dest[i]) > tolerance * fmaxf(fabsf(data_in[i]), fabsf(data_dest[i]))) {
        printf("i: %d, data %.8f, dest %.8f", i, data_in[i], data_dest[i]);
        printf("\n Decompressed data differs from original!\n");
        return -1;
      }
    }
  }
  csize_f = csize_f / nchunks;

  free(data_in);
  free(data_out);
  free(data_dest);
  blosc2_free_ctx(cctx);
  blosc2_free_ctx(dctx);

  printf("Successful roundtrip!\n");
  printf("Compression: %d -> %" PRId64 " (%.1fx)\n", chunksize, csize_f, (1. * chunksize) / (double) csize_f);
  return (int) (chunksize - csize_f);
}

static int test_zfp_prec_double(blosc2_schunk *schunk) {

  if (schunk->typesize != 8) {
    printf("Error: This test is only for doubles.\n");
    return 0;
  }
  int64_t nchunks = schunk->nchunks;
  int32_t chunksize = (int32_t) (schunk->chunksize);
  double *data_in = malloc(chunksize);
  int decompressed;
  int64_t csize;
  int64_t dsize;
  int64_t csize_f = 0;
  uint8_t *data_out = malloc(chunksize + BLOSC2_MAX_OVERHEAD);
  double *data_dest = malloc(chunksize);

  /* Create a context for compression */
  int zfp_prec = 25;
  blosc2_cparams cparams = BLOSC2_CPARAMS_DEFAULTS;
  cparams.splitmode = BLOSC_NEVER_SPLIT;
  cparams.typesize = schunk->typesize;
  cparams.compcode = BLOSC_CODEC_ZFP_FIXED_PRECISION;
  cparams.compcode_meta = zfp_prec;
  cparams.filters[BLOSC2_MAX_FILTERS - 1] = BLOSC_NOFILTER;
  cparams.clevel = 5;
  cparams.nthreads = 1;
  cparams.blocksize = schunk->blocksize;
  cparams.schunk = schunk;
  blosc2_context *cctx;
  cctx = blosc2_create_cctx(cparams);

  blosc2_dparams dparams = BLOSC2_DPARAMS_DEFAULTS;
  dparams.nthreads = 1;
  dparams.schunk = schunk;
  blosc2_context *dctx;
  dctx = blosc2_create_dctx(dparams);

  for (int ci = 0; ci < nchunks; ci++) {

    decompressed = blosc2_schunk_decompress_chunk(schunk, ci, data_in, chunksize);
    if (decompressed < 0) {
      printf("Error decompressing chunk \n");
      return -1;
    }

    /* Compress with clevel=5 and shuffle active  */
    csize = blosc2_compress_ctx(cctx, data_in, chunksize, data_out, chunksize + BLOSC2_MAX_OVERHEAD);
    if (csize == 0) {
      printf("Buffer is incompressible.  Giving up.\n");
      return 0;
    } else if (csize < 0) {
      printf("Compression error.  Error code: %" PRId64 "\n", csize);
      return (int) csize;
    }
    csize_f += csize;


    /* Decompress  */
    dsize = blosc2_decompress_ctx(dctx, data_out, chunksize + BLOSC2_MAX_OVERHEAD, data_dest, chunksize);
    if (dsize <= 0) {
      printf("Decompression error.  Error code: %" PRId64 "\n", dsize);
      return (int) dsize;
    }
    double tolerance = 0.01;
    for (int i = 0; i < (chunksize / cparams.typesize); i++) {
      if ((data_in[i] == 0) || (data_dest[i] == 0)) {
        if (fabs(data_in[i] - data_dest[i]) > tolerance) {
          printf("i: %d, data %.16f, dest %.16f", i, data_in[i], data_dest[i]);
          printf("\n Decompressed data differs from original!\n");
          return -1;
        }
      } else if (fabs(data_in[i] - data_dest[i]) > tolerance * fmax(fabs(data_in[i]), fabs(data_dest[i]))) {
        printf("i: %d, data %.16f, dest %.16f", i, data_in[i], data_dest[i]);
        printf("\n Decompressed data differs from original!\n");
        return -1;
      }
    }
  }
  csize_f = csize_f / nchunks;

  free(data_in);
  free(data_out);
  free(data_dest);
  blosc2_free_ctx(cctx);
  blosc2_free_ctx(dctx);

  printf("Successful roundtrip!\n");
  printf("Compression: %d -> %" PRId64 " (%.1fx)\n", chunksize, csize_f, (1. * chunksize) / (double) csize_f);
  return (int) (chunksize - csize_f);
}


int float_cyclic() {
  int8_t ndim = 3;
  int64_t shape[] = {40, 60, 20};
  int32_t chunkshape[] = {20, 30, 16};
  int32_t blockshape[] = {11, 14, 7};
  int32_t typesize = sizeof(float);
  int64_t nelem = 1;
  for (int i = 0; i < ndim; ++i) {
    nelem *= shape[i];
  }
  int64_t size = nelem * typesize;

  float *data = malloc(size);
  for (int i = 0; i < nelem; i += 2) {
    float j = (float) i;
    data[i] = (j + j / 10 + j / 100);
    data[i + 1] = (2 + j / 10 + j / 1000);
  }

  blosc2_cparams cparams = BLOSC2_CPARAMS_DEFAULTS;
  cparams.typesize = typesize;
  blosc2_storage b2_storage = {.cparams=&cparams};
  b2_storage.contiguous = true;

  b2nd_context_t *ctx = b2nd_create_ctx(&b2_storage, ndim, shape, chunkshape, blockshape, NULL, 0,
                                        NULL, 0);

  b2nd_array_t *arr;
  BLOSC_ERROR(b2nd_from_cbuffer(ctx, &arr, data, size));
  blosc2_schunk *schunk = arr->sc;

  /* Run the test. */
  int result = test_zfp_prec_float(schunk);
  BLOSC_ERROR(b2nd_free_ctx(ctx));
  BLOSC_ERROR(b2nd_free(arr));
  return result;
}

int double_same_cells() {
  int8_t ndim = 2;
  int64_t shape[] = {40, 60};
  int32_t chunkshape[] = {20, 30};
  int32_t blockshape[] = {16, 16};
  int32_t typesize = sizeof(double);
  int64_t nelem = 1;
  for (int i = 0; i < ndim; ++i) {
    nelem *= shape[i];
  }
  int64_t size = nelem * typesize;

  double *data = malloc(size);
  for (int i = 0; i < nelem; i += 4) {
    data[i] = 1.5;
    data[i + 1] = 14.7;
    data[i + 2] = 23.6;
    data[i + 3] = 3.2;
  }

  blosc2_cparams cparams = BLOSC2_CPARAMS_DEFAULTS;
  cparams.typesize = typesize;
  blosc2_storage b2_storage = {.cparams=&cparams};
  b2_storage.contiguous = true;

  b2nd_context_t *ctx = b2nd_create_ctx(&b2_storage, ndim, shape, chunkshape, blockshape, NULL, 0,
                                        NULL, 0);

  b2nd_array_t *arr;
  BLOSC_ERROR(b2nd_from_cbuffer(ctx, &arr, data, size));
  blosc2_schunk *schunk = arr->sc;

  /* Run the test. */
  int result = test_zfp_prec_double(schunk);
  BLOSC_ERROR(b2nd_free_ctx(ctx));
  BLOSC_ERROR(b2nd_free(arr));
  return result;
}

int item_prices() {
  blosc2_schunk *schunk = blosc2_schunk_open("example_item_prices.b2nd");
  BLOSC_ERROR_NULL(schunk, BLOSC2_ERROR_FILE_OPEN);

  /* Run the test. */
  int result = test_zfp_prec_float(schunk);
  blosc2_schunk_free(schunk);
  return result;
}


int main(void) {

  int result;
  blosc2_init();   // this is mandatory for initializing the plugin mechanism
  result = float_cyclic();
  printf("float_cyclic: %d obtained \n \n", result);
  if (result < 0)
    return result;
  result = double_same_cells();
  printf("double_same_cells: %d obtained \n \n", result);
  if (result < 0)
    return result;
  result = item_prices();
  printf("item_prices: %d obtained \n \n", result);
  if (result < 0)
    return result;
  blosc2_destroy();

  return BLOSC2_ERROR_SUCCESS;
}