circlebuf.test.cc

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 * Authors: Andreas Sandberg
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#include <gtest/gtest.h>

#include "base/circlebuf.hh"

const char data[] = {
    0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7,
    0x8, 0x9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf,
};

// Basic non-overflow functionality
TEST(CircleBufTest, BasicReadWriteNoOverflow)
{
    CircleBuf<char> buf(8);
    char foo[16];

    // Write empty buffer, no overflow
    buf.write(data, 8);
    EXPECT_EQ(buf.size(), 8);
    buf.peek(foo, 8);
    EXPECT_EQ(memcmp(foo, data, 8), 0);

    // Read 2
    buf.read(foo, 2);
    EXPECT_EQ(memcmp(foo, data, 2), 0);
    EXPECT_EQ(buf.size(), 6);
    buf.read(foo, 6);
    EXPECT_EQ(memcmp(foo, data + 2, 6), 0);
    EXPECT_EQ(buf.size(), 0);
}

// Basic single write overflow functionality
TEST(CircleBufTest, SingleWriteOverflow)
{
    CircleBuf<char> buf(8);
    char foo[16];

    buf.write(data, 16);
    EXPECT_EQ(buf.size(), 8);
    buf.peek(foo, 8);
    EXPECT_EQ(memcmp(data + 8, foo, 8), 0);
}


// Multi-write overflow functionality
TEST(CircleBufTest, MultiWriteOverflow)
{
    CircleBuf<char> buf(8);
    char foo[16];

    // Write, no overflow, write overflow
    buf.write(data, 6);
    buf.write(data + 8, 6);
    EXPECT_EQ(buf.size(), 8);
    buf.peek(foo, 8);
    EXPECT_EQ(memcmp(data + 4, foo, 2), 0);
    EXPECT_EQ(memcmp(data + 8, foo + 2, 6), 0);
}

// Pointer wrap around
TEST(CircleBufTest, PointerWrapAround)
{
    CircleBuf<char> buf(8);
    char foo[16];

    // _start == 0, _stop = 8
    buf.write(data, 8);
    // _start == 4, _stop = 8
    buf.read(foo, 4);
    // _start == 4, _stop = 12
    buf.write(data + 8, 4);
    EXPECT_EQ(buf.size(), 8);
    // _start == 10, _stop = 12
    // Normalized: _start == 2, _stop = 4
    buf.read(foo + 4, 6);
    EXPECT_EQ(buf.size(), 2);
    EXPECT_EQ(memcmp(data, foo, 10), 0);
    // Normalized: _start == 4, _stop = 4
    buf.read(foo + 10, 2);
    EXPECT_EQ(buf.size(), 0);
    EXPECT_EQ(memcmp(data, foo, 12), 0);
}