RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 08:08:12 +00:00
Code Issues Activity Actions

LibCore: Add {Big,Little}EndianOutputBitStream

Browse source 
Also add some tests that ensure that the input and output streams match
each other, because I can't wrap my head around what the internal
representation looks like.
This commit is contained in:
Tim Schumacher 2022-12-26 14:32:01 +01:00 • committed by Andreas Kling
parent 0bdbe27d6b
commit b4b80b7ec6
2 changed files with 281 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

115
Tests/LibCore/TestLibCoreStream.cpp
View file

@ -6,6 +6,7 @@
#include <AK/Format.h>
#include <AK/String.h>
#include <LibCore/BitStream.h>
#include <LibCore/EventLoop.h>
#include <LibCore/LocalServer.h>
#include <LibCore/MemoryStream.h>
@ -559,3 +560,117 @@ TEST_CASE(allocating_memory_stream_10kb)
offset += file_span.size();
}
}
// Bit stream tests
// Note: This does not do any checks on the internal representation, it just ensures that the behavior of the input and output streams match.
TEST_CASE(little_endian_bit_stream_input_output_match)
{
auto memory_stream = make<Core::Stream::AllocatingMemoryStream>();
// Note: The bit stream only ever reads from/writes to the underlying stream in one byte chunks,
// so testing with sizes that will not trigger a write will yield unexpected results.
auto bit_write_stream = MUST(Core::Stream::LittleEndianOutputBitStream::construct(Core::Stream::Handle<Core::Stream::Stream>(*memory_stream)));
auto bit_read_stream = MUST(Core::Stream::LittleEndianInputBitStream::construct(Core::Stream::Handle<Core::Stream::Stream>(*memory_stream)));
// Test two mirrored chunks of a fully mirrored pattern to check that we are not dropping bits.
{
MUST(bit_write_stream->write_bits(0b1111u, 4));
MUST(bit_write_stream->write_bits(0b1111u, 4));
auto result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b1111u, result);
result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b1111u, result);
}
{
MUST(bit_write_stream->write_bits(0b0000u, 4));
MUST(bit_write_stream->write_bits(0b0000u, 4));
auto result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b0000u, result);
result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b0000u, result);
}
// Test two mirrored chunks of a non-mirrored pattern to check that we are writing bits within a pattern in the correct order.
{
MUST(bit_write_stream->write_bits(0b1000u, 4));
MUST(bit_write_stream->write_bits(0b1000u, 4));
auto result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b1000u, result);
result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b1000u, result);
}
// Test two different chunks to check that we are not confusing their order.
{
MUST(bit_write_stream->write_bits(0b1000u, 4));
MUST(bit_write_stream->write_bits(0b0100u, 4));
auto result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b1000u, result);
result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b0100u, result);
}
// Test a pattern that spans multiple bytes.
{
MUST(bit_write_stream->write_bits(0b1101001000100001u, 16));
auto result = MUST(bit_read_stream->read_bits(16));
EXPECT_EQ(0b1101001000100001u, result);
}
}
// Note: This does not do any checks on the internal representation, it just ensures that the behavior of the input and output streams match.
TEST_CASE(big_endian_bit_stream_input_output_match)
{
auto memory_stream = make<Core::Stream::AllocatingMemoryStream>();
// Note: The bit stream only ever reads from/writes to the underlying stream in one byte chunks,
// so testing with sizes that will not trigger a write will yield unexpected results.
auto bit_write_stream = MUST(Core::Stream::BigEndianOutputBitStream::construct(Core::Stream::Handle<Core::Stream::Stream>(*memory_stream)));
auto bit_read_stream = MUST(Core::Stream::BigEndianInputBitStream::construct(Core::Stream::Handle<Core::Stream::Stream>(*memory_stream)));
// Test two mirrored chunks of a fully mirrored pattern to check that we are not dropping bits.
{
MUST(bit_write_stream->write_bits(0b1111u, 4));
MUST(bit_write_stream->write_bits(0b1111u, 4));
auto result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b1111u, result);
result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b1111u, result);
}
{
MUST(bit_write_stream->write_bits(0b0000u, 4));
MUST(bit_write_stream->write_bits(0b0000u, 4));
auto result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b0000u, result);
result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b0000u, result);
}
// Test two mirrored chunks of a non-mirrored pattern to check that we are writing bits within a pattern in the correct order.
{
MUST(bit_write_stream->write_bits(0b1000u, 4));
MUST(bit_write_stream->write_bits(0b1000u, 4));
auto result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b1000u, result);
result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b1000u, result);
}
// Test two different chunks to check that we are not confusing their order.
{
MUST(bit_write_stream->write_bits(0b1000u, 4));
MUST(bit_write_stream->write_bits(0b0100u, 4));
auto result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b1000u, result);
result = MUST(bit_read_stream->read_bits(4));
EXPECT_EQ(0b0100u, result);
}
// Test a pattern that spans multiple bytes.
{
MUST(bit_write_stream->write_bits(0b1101001000100001u, 16));
auto result = MUST(bit_read_stream->read_bits(16));
EXPECT_EQ(0b1101001000100001u, result);
}
}