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/*
* Unit tests for class CircularBuffer.
*/
#include "util/CircularBuffer.hxx"
#include <gtest/gtest.h>
TEST(CircularBuffer, Basic)
{
constexpr size_t N = 8;
int data[N];
CircularBuffer<int> buffer(data, N);
EXPECT_EQ(size_t(N), buffer.GetCapacity());
/* '.' = empty; 'O' = occupied; 'X' = blocked */
/* checks on empty buffer */
/* [.......X] */
EXPECT_TRUE(buffer.empty());
EXPECT_FALSE(buffer.IsFull());
EXPECT_EQ(size_t(0), buffer.GetSize());
EXPECT_EQ(size_t(7), buffer.GetSpace());
EXPECT_TRUE(buffer.Read().empty());
EXPECT_FALSE(buffer.Write().empty());
EXPECT_EQ(&data[0], buffer.Write().data);
EXPECT_EQ(size_t(7), buffer.Write().size);
/* append one element */
/* [O......X] */
buffer.Append(1);
EXPECT_FALSE(buffer.empty());
EXPECT_FALSE(buffer.IsFull());
EXPECT_FALSE(buffer.Read().empty());
EXPECT_EQ(size_t(1), buffer.GetSize());
EXPECT_EQ(size_t(6), buffer.GetSpace());
EXPECT_EQ(size_t(1), buffer.Read().size);
EXPECT_EQ(&data[0], buffer.Read().data);
EXPECT_FALSE(buffer.Write().empty());
EXPECT_EQ(&data[1], buffer.Write().data);
EXPECT_EQ(size_t(6), buffer.Write().size);
/* append 6 elements, buffer is now full */
/* [OOOOOOOX] */
buffer.Append(6);
EXPECT_FALSE(buffer.empty());
EXPECT_TRUE(buffer.IsFull());
EXPECT_FALSE(buffer.Read().empty());
EXPECT_EQ(size_t(7), buffer.GetSize());
EXPECT_EQ(size_t(0), buffer.GetSpace());
EXPECT_EQ(size_t(7), buffer.Read().size);
EXPECT_EQ(&data[0], buffer.Read().data);
EXPECT_TRUE(buffer.Write().empty());
/* consume [0]; can append one at [7] */
/* [XOOOOOO.] */
buffer.Consume(1);
EXPECT_FALSE(buffer.empty());
EXPECT_FALSE(buffer.IsFull());
EXPECT_FALSE(buffer.Read().empty());
EXPECT_EQ(size_t(6), buffer.GetSize());
EXPECT_EQ(size_t(1), buffer.GetSpace());
EXPECT_EQ(size_t(6), buffer.Read().size);
EXPECT_EQ(&data[1], buffer.Read().data);
EXPECT_FALSE(buffer.Write().empty());
EXPECT_EQ(&data[7], buffer.Write().data);
EXPECT_EQ(size_t(1), buffer.Write().size);
/* append one element; [0] is still empty but cannot
be written to because head==1 */
/* [XOOOOOOO] */
buffer.Append(1);
EXPECT_FALSE(buffer.empty());
EXPECT_TRUE(buffer.IsFull());
EXPECT_FALSE(buffer.Read().empty());
EXPECT_EQ(size_t(7), buffer.GetSize());
EXPECT_EQ(size_t(0), buffer.GetSpace());
EXPECT_EQ(size_t(7), buffer.Read().size);
EXPECT_EQ(&data[1], buffer.Read().data);
EXPECT_TRUE(buffer.Write().empty());
/* consume [1..3]; can append [0..2] */
/* [...XOOOO] */
buffer.Consume(3);
EXPECT_FALSE(buffer.empty());
EXPECT_FALSE(buffer.IsFull());
EXPECT_FALSE(buffer.Read().empty());
EXPECT_EQ(size_t(4), buffer.GetSize());
EXPECT_EQ(size_t(3), buffer.GetSpace());
EXPECT_EQ(size_t(4), buffer.Read().size);
EXPECT_EQ(&data[4], buffer.Read().data);
EXPECT_FALSE(buffer.Write().empty());
EXPECT_EQ(&data[0], buffer.Write().data);
EXPECT_EQ(size_t(3), buffer.Write().size);
/* append [0..1] */
/* [OO.XOOOO] */
buffer.Append(2);
EXPECT_FALSE(buffer.empty());
EXPECT_FALSE(buffer.IsFull());
EXPECT_FALSE(buffer.Read().empty());
EXPECT_EQ(size_t(6), buffer.GetSize());
EXPECT_EQ(size_t(1), buffer.GetSpace());
EXPECT_EQ(size_t(4), buffer.Read().size);
EXPECT_EQ(&data[4], buffer.Read().data);
EXPECT_FALSE(buffer.Write().empty());
EXPECT_EQ(&data[2], buffer.Write().data);
EXPECT_EQ(size_t(1), buffer.Write().size);
/* append [2] */
/* [OOOXOOOO] */
buffer.Append(1);
EXPECT_FALSE(buffer.empty());
EXPECT_TRUE(buffer.IsFull());
EXPECT_FALSE(buffer.Read().empty());
EXPECT_EQ(size_t(7), buffer.GetSize());
EXPECT_EQ(size_t(0), buffer.GetSpace());
EXPECT_EQ(size_t(4), buffer.Read().size);
EXPECT_EQ(&data[4], buffer.Read().data);
EXPECT_TRUE(buffer.Write().empty());
/* consume [4..7] */
/* [OOO....X] */
buffer.Consume(4);
EXPECT_FALSE(buffer.empty());
EXPECT_FALSE(buffer.IsFull());
EXPECT_FALSE(buffer.Read().empty());
EXPECT_EQ(size_t(3), buffer.GetSize());
EXPECT_EQ(size_t(4), buffer.GetSpace());
EXPECT_EQ(size_t(3), buffer.Read().size);
EXPECT_EQ(&data[0], buffer.Read().data);
EXPECT_FALSE(buffer.Write().empty());
EXPECT_EQ(&data[3], buffer.Write().data);
EXPECT_EQ(size_t(4), buffer.Write().size);
/* consume [0..2]; after that, we can only write 5,
because the CircularBuffer class doesn't have
special code to rewind/reset an empty buffer */
/* [..X.....] */
buffer.Consume(3);
EXPECT_TRUE(buffer.empty());
EXPECT_FALSE(buffer.IsFull());
EXPECT_EQ(size_t(0), buffer.GetSize());
EXPECT_EQ(size_t(7), buffer.GetSpace());
EXPECT_TRUE(buffer.Read().empty());
EXPECT_FALSE(buffer.Write().empty());
EXPECT_EQ(&data[3], buffer.Write().data);
EXPECT_EQ(size_t(5), buffer.Write().size);
}
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