flatland.c

   1 /*
   2
   3   Example of FFI extension I started from:
   4
   5     https://github.com/pytorch/extension-ffi.git
   6
   7   There is this tutorial
   8
   9     https://github.com/pytorch/tutorials/blob/master/Creating%20Extensions%20using%20FFI.md
  10
  11   And TH's Tensor definition are here in my install:
  12
  13     anaconda3/lib/python3.5/site-packages/torch/lib/include/TH/generic/THTensor.h
  14
  15  */
  16
  17 #include <TH/TH.h>
  18
  19 #include "sequence_generator.h"
  20
  21 THByteTensor *generate_sequence(long nb_sequences,
  22                                 long nb_images,
  23                                 long image_height, long image_width,
  24                                 int nb_shapes,
  25                                 int random_shape_size, int random_colors) {
  26
  27   long nb_channels = 3;
  28   unsigned char *a, *b;
  29   long s, c, k, i, j, st0, st1, st2, st3, st4;
  30
  31   THLongStorage *size = THLongStorage_newWithSize(5);
  32   size->data[0] = nb_sequences;
  33   size->data[1] = nb_images;
  34   size->data[2] = nb_channels;
  35   size->data[3] = image_height;
  36   size->data[4] = image_width;
  37   THByteTensor *result = THByteTensor_newWithSize(size, NULL);
  38   THLongStorage_free(size);
  39
  40   st0 = THByteTensor_stride(result, 0);
  41   st1 = THByteTensor_stride(result, 1);
  42   st2 = THByteTensor_stride(result, 2);
  43   st3 = THByteTensor_stride(result, 3);
  44   st4 = THByteTensor_stride(result, 4);
  45
  46   unsigned char tmp_buffer[nb_images * nb_channels * image_width * image_height];
  47
  48   for(s = 0; s < nb_sequences; s++) {
  49     a = THByteTensor_storage(result)->data + THByteTensor_storageOffset(result) + s * st0;
  50     fl_generate_sequence(nb_images, image_width, image_height, nb_shapes,
  51                          random_shape_size, random_colors,
  52                          tmp_buffer);
  53     unsigned char *r = tmp_buffer;
  54     for(k = 0; k < nb_images; k++) {
  55       for(c = 0; c < nb_channels; c++) {
  56         for(i = 0; i < image_height; i++) {
  57           b = a + k * st1 + c * st2 + i * st3;
  58           for(j = 0; j < image_width; j++) {
  59             *b = (unsigned char) (*r);
  60             r++;
  61             b += st4;
  62           }
  63         }
  64       }
  65     }
  66   }
  67
  68   return result;
  69 }