libcruft-util/test/bitwise.cpp

#include "bitwise.hpp"
#include "std.hpp"
#include "tap.hpp"


//-----------------------------------------------------------------------------
static void
test_rotate (cruft::TAP::logger &tap)
{
    tap.expect_eq (cruft::rotatel (uint8_t (0x0F), 0), 0x0Fu, "rotate-left u8");
    tap.expect_eq (cruft::rotatel (uint8_t (0x0F), 4), 0xF0u, "rotate-left u8");
    tap.expect_eq (cruft::rotatel (uint8_t (0xF0), 4), 0x0Fu, "rotate-left u8");

    tap.expect_eq (cruft::rotater (uint8_t (0x0F), 0), 0x0Fu, "rotate-right u8");
    tap.expect_eq (cruft::rotater (uint8_t (0x0F), 4), 0xF0u, "rotate-right u8");
    tap.expect_eq (cruft::rotater (uint8_t (0xF0), 4), 0x0Fu, "rotate-right u8");

    tap.expect_eq (cruft::rotatel (uint16_t (0xABCD),  0), 0xABCDu, "rotate-left u16");
    tap.expect_eq (cruft::rotatel (uint16_t (0xABCD),  4), 0xBCDAu, "rotate-left u16");
    tap.expect_eq (cruft::rotatel (uint16_t (0xABCD),  8), 0xCDABu, "rotate-left u16");
    tap.expect_eq (cruft::rotatel (uint16_t (0xABCD), 12), 0xDABCu, "rotate-left u16");

    tap.expect_eq (cruft::rotater (uint16_t (0xABCD),  0), 0xABCDu, "rotate-right u16");
    tap.expect_eq (cruft::rotater (uint16_t (0xABCD),  4), 0xDABCu, "rotate-right u16");
    tap.expect_eq (cruft::rotater (uint16_t (0xABCD),  8), 0xCDABu, "rotate-right u16");
    tap.expect_eq (cruft::rotater (uint16_t (0xABCD), 12), 0xBCDAu, "rotate-right u16");

    tap.expect_eq (cruft::rotatel (uint32_t (0x12345670), 12), 0x45670123u, "rotate-left u32");
    tap.expect_eq (cruft::rotater (uint32_t (0x12345670), 12), 0x67012345u, "rotate-right u32");

    tap.expect_eq (cruft::rotatel (uint64_t (0x1234567890ABCDEF), 12), 0x4567890ABCDEF123u, "rotate-left u64");
    tap.expect_eq (cruft::rotater (uint64_t (0x1234567890ABCDEF), 12), 0xDEF1234567890ABCu, "rotate-right u64");
}


//-----------------------------------------------------------------------------
void
test_reverse (cruft::TAP::logger &tap)
{
    size_t matches = 0;
    for (unsigned i = 0; i < 256; ++i) {
        auto first = cruft::reverse<uint8_t> (i);
        auto last  = cruft::reverse<uint8_t> (first);
        if (last == i)
            matches++;
    }

    tap.expect_eq (matches, 256u, "exhaustive 8 bit reverse");
}


//-----------------------------------------------------------------------------
void
test_bitfield (cruft::TAP::logger &tap)
{
    union {
        /// * lo is set to 1 and hi is set to 0 to establish bit ordering
        /// * mid pattern tests behaviour across byte boundaries
        u16 raw = 0b0111'0011'0000'0001;
        //          |  |mid^---^      |
        //   highest^  |        lowest^
        //      high^--^
        cruft::bitfield<u16, 0,1> lowest;
        cruft::bitfield<u16,15,1> highest;
        cruft::bitfield<u16,12,4> high;
        cruft::bitfield<u16, 6,4> mid;
    };

    tap.expect_eq (lowest,  u16 {   0b1}, "bitfield lowest bit");
    tap.expect_eq (highest, u16 {   0b0}, "bitfield highest bit");
    tap.expect_eq (high,    u16 {0b0111}, "bitfield high bits");
    tap.expect_eq (mid,     u16 {0b1100}, "bitfield byte boundary bits");
}


//-----------------------------------------------------------------------------
int
main (int, char**)
{
    cruft::TAP::logger tap;

    test_rotate (tap);
    test_reverse (tap);
    test_bitfield (tap);

    tap.expect_eq (cruft::ctz (0b11110000u), 4u, "count-trailing-zero trivial test");

    return tap.status ();
}