diff options
Diffstat (limited to 'lib/fletcher16_test.c')
| -rw-r--r-- | lib/fletcher16_test.c | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/lib/fletcher16_test.c b/lib/fletcher16_test.c index 1020e6ec..3cd4c302 100644 --- a/lib/fletcher16_test.c +++ b/lib/fletcher16_test.c @@ -24,24 +24,33 @@ straightforward_fletcher16_compute(const char *data) sum2 = (sum2 + sum1) % 255; } - return (sum2 << 8) | sum1; + sum2 = (sum2 + sum1) % 255; + sum2 = (sum2 + sum1) % 255; + + return (sum1 << 8) | sum2; } static u16 straightforward_fletcher16_checksum(const char *data) { u16 csum; - u8 c0,c1,f0,f1; + u16 c0,c1,x,y; csum = straightforward_fletcher16_compute(data); - f0 = csum & 0xff; - f1 = (csum >> 8) & 0xff; - c0 = 0xff - ((f0 + f1) % 0xff); - c1 = 0xff - ((f0 + c0) % 0xff); + c0 = (csum >> 8) & 0xff; + c1 = csum & 0xff; + + x = (255 + c0 - c1) % 255; + y = (510 - 2*c0 + c1) % 255; - return (c1 << 8) | c0; + if (!x) x = 255; + if (!y) y = 255; + + return (x << 8) | y; } +const u8 zero16[2] = {}; + static int test_fletcher16(void *out_, const void *in_, const void *expected_out_) { @@ -53,7 +62,8 @@ test_fletcher16(void *out_, const void *in_, const void *expected_out_) fletcher16_init(&ctxt); fletcher16_update(&ctxt, in, strlen(in)); - put_u16(out, fletcher16_compute(&ctxt)); + fletcher16_update(&ctxt, zero16, 2); + *out = fletcher16_compute(&ctxt); return *out == *expected_out; } @@ -70,7 +80,8 @@ test_fletcher16_checksum(void *out_, const void *in_, const void *expected_out_) fletcher16_init(&ctxt); fletcher16_update(&ctxt, in, len); - put_u16(out, fletcher16_final(&ctxt, len, len)); + fletcher16_update(&ctxt, zero16, 2); + *out = fletcher16_final(&ctxt, len+2, len); return *out == *expected_out; } @@ -81,7 +92,7 @@ t_fletcher16_compute(void) struct bt_pair test_vectors[] = { { .in = "\001\002", - .out = & (const u16) { 0x0403 }, + .out = & ((const u16) { straightforward_fletcher16_compute("\001\002") }), }, { .in = "", |