lib/bitops_test.c

   1 /*
   2  *      BIRD Library -- Generic Bit Operations Tests
   3  *
   4  *      (c) 2015 CZ.NIC z.s.p.o.
   5  *
   6  *      Can be freely distributed and used under the terms of the GNU GPL.
   7  */
   8
   9 #include "test/birdtest.h"
  10 #include "test/bt-utils.h" /* naive_pow() */
  11
  12 #include "lib/bitops.h"
  13
  14 #define MAX_NUM 1000
  15 #define CHECK_BIT(var,pos) ((var) & (u32)(1<<(pos)))
  16
  17 static int
  18 t_mkmask(void)
  19 {
  20   int i;
  21   u32 compute, expect;
  22
  23   bt_assert(u32_mkmask(0) == 0x00000000);
  24   for (i = 1; i <= 32; i++)
  25   {
  26     compute = u32_mkmask(i);
  27     expect  = (u32) (0xffffffff << (32-i));
  28     bt_assert_msg(compute == expect, "u32_mkmask(%d) = 0x%08X, expected 0x%08X", i, compute, expect);
  29   }
  30
  31   return 1;
  32 }
  33
  34 static int
  35 u32_masklen_expected(u32 mask)
  36 {
  37   int j, expect = 0;
  38
  39   int valid = 0;
  40   for (j = 0; j <= 32; j++)
  41     if (mask == (j ? (0xffffffff << (32-j)) : 0)) /* Shifting 32-bit value by 32 bits is undefined behavior */
  42         valid = 1;
  43
  44   if (!valid && mask != 0)
  45     expect = 255;
  46   else
  47     for (j = 0; j <= 31; j++)
  48       if (CHECK_BIT(mask, (31-j)))
  49         expect = j+1;
  50       else
  51         break;
  52   return expect;
  53 }
  54
  55 static void
  56 check_mask(u32 mask)
  57 {
  58   int expected, masklen;
  59
  60   expected = u32_masklen_expected(mask);
  61   masklen = u32_masklen(mask);
  62   int ok = (expected == masklen);
  63   bt_debug("u32_masklen(Ox%08x) = %d, expected %d  %s\n", mask, masklen, expected, ok ? "OK" : "FAIL!");
  64   bt_assert(ok);
  65 }
  66
  67 static int
  68 t_masklen(void)
  69 {
  70   u32 i;
  71
  72   check_mask(0x82828282);
  73   check_mask(0x00000000);
  74
  75   for (i = 0; i <= 32; i++)
  76     check_mask(((u32) (i ? (0xffffffff << (32-i)) : 0)) & 0xffffffff); /* Shifting 32-bit value by 32 bits is undefined behavior */
  77
  78   for (i = 0; i <= MAX_NUM; i++)
  79     check_mask(bt_random());
  80
  81   return 1;
  82 }
  83
  84 static void
  85 check_log2(u32 n)
  86 {
  87   u32 log  = u32_log2(n);
  88   u32 low  = bt_naive_pow(2, log);
  89   u32 high = bt_naive_pow(2, log+1);
  90
  91   bt_assert_msg(n >= low && n < high,
  92                 "u32_log2(%u) = %u, %u should be in the range <%u, %u)",
  93                 n, log, n, low, high);
  94 }
  95
  96 static int
  97 t_log2(void)
  98 {
  99   u32 i;
 100
 101   for (i = 0; i < 31; i++)
 102     bt_assert(u32_log2(bt_naive_pow(2, i+1)) == i+1);
 103
 104   for (i = 1; i < MAX_NUM; i++)
 105     check_log2(i);
 106
 107   for (i = 1; i < MAX_NUM; i++)
 108     check_log2(((u32) bt_random()) % 0x0fffffff);
 109
 110   return 1;
 111 }
 112
 113 int
 114 main(int argc, char *argv[])
 115 {
 116   bt_init(argc, argv);
 117
 118   bt_test_suite(t_mkmask, "u32_mkmask()");
 119   bt_test_suite(t_masklen, "u32_masklen()");
 120   bt_test_suite(t_log2, "u32_log2()");
 121
 122   return bt_exit_value();
 123 }