lib/fletcher16_test.c

   1 /*
   2  *      BIRD Library -- Fletcher-16 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 "lib/fletcher16.h"
  11
  12 static u16
  13 straightforward_fletcher16_compute(const char *data)
  14 {
  15   int count = strlen(data);
  16
  17   u16 sum1 = 0;
  18   u16 sum2 = 0;
  19   int index;
  20
  21   for (index = 0; index < count; ++index)
  22   {
  23     sum1 = (sum1 + data[index]) % 255;
  24     sum2 = (sum2 + sum1) % 255;
  25   }
  26
  27   sum2 = (sum2 + sum1) % 255;
  28   sum2 = (sum2 + sum1) % 255;
  29
  30   return (sum1 << 8) | sum2;
  31 }
  32
  33 static u16
  34 straightforward_fletcher16_checksum(const char *data)
  35 {
  36   u16 csum;
  37   u16 c0,c1,x,y;
  38
  39   csum = straightforward_fletcher16_compute(data);
  40   c0 = (csum >> 8) & 0xff;
  41   c1 = csum & 0xff;
  42
  43   x = (255 +   c0 - c1) % 255;
  44   y = (510 - 2*c0 + c1) % 255;
  45
  46   if (!x) x = 255;
  47   if (!y) y = 255;
  48
  49   return (x << 8) | y;
  50 }
  51
  52 const u8 zero16[2] = {};
  53
  54 static int
  55 test_fletcher16(void *out_, const void *in_, const void *expected_out_)
  56 {
  57   u16 *out = out_;
  58   const char *in = in_;
  59   const u16 *expected_out = expected_out_;
  60
  61   struct fletcher16_context ctxt;
  62
  63   fletcher16_init(&ctxt);
  64   fletcher16_update(&ctxt, in, strlen(in));
  65   fletcher16_update(&ctxt, zero16, 2);
  66   *out = fletcher16_compute(&ctxt);
  67
  68   return *out == *expected_out;
  69 }
  70
  71 static int
  72 test_fletcher16_checksum(void *out_, const void *in_, const void *expected_out_)
  73 {
  74   u16 *out = out_;
  75   const char *in = in_;
  76   const u16 *expected_out = expected_out_;
  77
  78   struct fletcher16_context ctxt;
  79   int len = strlen(in);
  80
  81   fletcher16_init(&ctxt);
  82   fletcher16_update(&ctxt, in, len);
  83   fletcher16_update(&ctxt, zero16, 2);
  84   *out = fletcher16_final(&ctxt, len+2, len);
  85
  86   return *out == *expected_out;
  87 }
  88
  89 static int
  90 t_fletcher16_compute(void)
  91 {
  92   struct bt_pair test_vectors[] = {
  93     {
  94       .in  = "\001\002",
  95       .out = & ((const u16) { straightforward_fletcher16_compute("\001\002") }),
  96     },
  97     {
  98       .in  = "",
  99       .out = & ((const u16) { straightforward_fletcher16_compute("") }),
 100     },
 101     {
 102       .in  = "a",
 103       .out = & ((const u16) { straightforward_fletcher16_compute("a") }),
 104     },
 105     {
 106       .in  = "abcd",
 107       .out = & ((const u16) { straightforward_fletcher16_compute("abcd") }),
 108     },
 109     {
 110       .in  = "message digest",
 111       .out = & ((const u16) { straightforward_fletcher16_compute("message digest") }),
 112     },
 113     {
 114       .in  = "abcdefghijklmnopqrstuvwxyz",
 115       .out = & ((const u16) { straightforward_fletcher16_compute("abcdefghijklmnopqrstuvwxyz") }),
 116     },
 117     {
 118       .in  = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
 119       .out = & ((const u16) { straightforward_fletcher16_compute("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") }),
 120     },
 121     {
 122       .in  = "12345678901234567890123456789012345678901234567890123456789012345678901234567890",
 123       .out = & ((const u16) { straightforward_fletcher16_compute("12345678901234567890123456789012345678901234567890123456789012345678901234567890") }),
 124     },
 125   };
 126
 127   return bt_assert_batch(test_vectors, test_fletcher16, bt_fmt_str, bt_fmt_unsigned);
 128 }
 129
 130 static int
 131 t_fletcher16_checksum(void)
 132 {
 133   struct bt_pair test_vectors[] = {
 134     {
 135       .in  = "\001\002",
 136       .out =  & ((const u16) { straightforward_fletcher16_checksum("\001\002") }),
 137     },
 138     {
 139       .in  = "",
 140       .out =  & ((const u16) { straightforward_fletcher16_checksum("") }),
 141     },
 142     {
 143       .in  = "a",
 144       .out =  & ((const u16) { straightforward_fletcher16_checksum("a") }),
 145     },
 146     {
 147       .in  = "abcd",
 148       .out =  & ((const u16) { straightforward_fletcher16_checksum("abcd") }),
 149     },
 150     {
 151       .in  = "message digest",
 152       .out =  & ((const u16) { straightforward_fletcher16_checksum("message digest") }),
 153     },
 154     {
 155       .in  = "abcdefghijklmnopqrstuvwxyz",
 156       .out =  & ((const u16) { straightforward_fletcher16_checksum("abcdefghijklmnopqrstuvwxyz") }),
 157     },
 158     {
 159       .in  = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
 160       .out =  & ((const u16) { straightforward_fletcher16_checksum("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") }),
 161     },
 162     {
 163       .in  = "12345678901234567890123456789012345678901234567890123456789012345678901234567890",
 164       .out =  & ((const u16) { straightforward_fletcher16_checksum("12345678901234567890123456789012345678901234567890123456789012345678901234567890") }),
 165     },
 166   };
 167
 168   return bt_assert_batch(test_vectors, test_fletcher16_checksum, bt_fmt_str, bt_fmt_unsigned);
 169 }
 170
 171 int
 172 main(int argc, char *argv[])
 173 {
 174   bt_init(argc, argv);
 175
 176   bt_test_suite(t_fletcher16_compute, "Fletcher-16 Compute Tests");
 177   bt_test_suite(t_fletcher16_checksum, "Fletcher-16 Checksum Tests");
 178
 179   return bt_exit_value();
 180 }