t/helper/test-genzeros.c

   1 #include "test-tool.h"
   2 #include "git-compat-util.h"
   3
   4 int cmd__genzeros(int argc, const char **argv)
   5 {
   6         /* static, so that it is NUL-initialized */
   7         static const char zeros[256 * 1024];
   8         intmax_t count;
   9         ssize_t n;
  10
  11         if (argc > 2) {
  12                 fprintf(stderr, "usage: %s [<count>]\n", argv[0]);
  13                 return 1;
  14         }
  15
  16         count = argc > 1 ? strtoimax(argv[1], NULL, 0) : -1;
  17
  18         /* Writing out individual NUL bytes is slow... */
  19         while (count < 0)
  20                 if (write(1, zeros, ARRAY_SIZE(zeros)) < 0)
  21                         return -1;
  22
  23         while (count > 0) {
  24                 n = write(1, zeros, count < ARRAY_SIZE(zeros) ?
  25                           count : ARRAY_SIZE(zeros));
  26
  27                 if (n < 0)
  28                         return -1;
  29
  30                 count -= n;
  31         }
  32
  33         return 0;
  34 }