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LibGfx: Use ByteBuffer instead of Vector<u8> in PNGWriter

Browse source 
This is the first step towards reducing the number of copies in
PNGWriter by switching to ByteBuffer as underlying storage.
This commit is contained in:
Aziz Berkay Yesilyurt 2021-07-11 18:39:17 +02:00 • committed by Andreas Kling
parent d78a007b5d
commit 97859aaff1
1 changed files with 50 additions and 54 deletions
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104
Userland/Libraries/LibGfx/PNGWriter.cpp
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@ -5,6 +5,7 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Concepts.h>
#include <AK/String.h>
#include <LibCrypto/Checksum/CRC32.h>
#include <LibGfx/Bitmap.h>
@ -15,16 +16,22 @@ namespace Gfx {
class PNGChunk {
public:
explicit PNGChunk(String);
Vector<u8> const& data() const { return m_data; };
auto const& data() const { return m_data; };
String const& type() const { return m_type; };
template<typename T>
void add_as_big_endian(T);
template<typename T>
void add_as_little_endian(T);
void add_u8(u8);
void add_u16_big(u16);
void add_u32_big(u32);
void add_u16_little(u16);
void add_u32_little(u32);
private:
Vector<u8> m_data;
template<typename T>
requires(IsUnsigned<T>) void add(T);
ByteBuffer m_data;
String m_type;
};
@ -41,8 +48,8 @@ private:
void update_adler(u8);
bool full() { return m_non_compressible_data.size() == 65535; }
Vector<u8> m_non_compressible_data;
u32 m_adler_s1 { 1 };
u32 m_adler_s2 { 0 };
u16 m_adler_s1 { 1 };
u16 m_adler_s2 { 0 };
};
PNGChunk::PNGChunk(String type)
@ -50,37 +57,29 @@ PNGChunk::PNGChunk(String type)
{
}
template<typename T>
requires(IsUnsigned<T>) void PNGChunk::add(T data)
{
m_data.append(&data, sizeof(T));
}
template<typename T>
void PNGChunk::add_as_little_endian(T data)
{
auto data_out = AK::convert_between_host_and_little_endian(data);
add(data_out);
}
template<typename T>
void PNGChunk::add_as_big_endian(T data)
{
auto data_out = AK::convert_between_host_and_big_endian(data);
add(data_out);
}
void PNGChunk::add_u8(u8 data)
{
m_data.append(data);
}
void PNGChunk::add_u16_little(u16 data)
{
m_data.append(data & 0xff);
m_data.append((data >> 8) & 0xff);
}
void PNGChunk::add_u32_little(u32 data)
{
m_data.append(data & 0xff);
m_data.append((data >> 8) & 0xff);
m_data.append((data >> 16) & 0xff);
m_data.append((data >> 24) & 0xff);
}
void PNGChunk::add_u32_big(u32 data)
{
m_data.append((data >> 24) & 0xff);
m_data.append((data >> 16) & 0xff);
m_data.append((data >> 8) & 0xff);
m_data.append(data & 0xff);
}
void PNGChunk::add_u16_big(u16 data)
{
m_data.append((data >> 8) & 0xff);
m_data.append(data & 0xff);
add(data);
}
void NonCompressibleBlock::add_byte_to_block(u8 data, PNGChunk& chunk)
@ -95,17 +94,13 @@ void NonCompressibleBlock::add_byte_to_block(u8 data, PNGChunk& chunk)
void NonCompressibleBlock::add_block_to_chunk(PNGChunk& png_chunk, bool last)
{
if (last) {
png_chunk.add_u8(1);
} else {
png_chunk.add_u8(0);
}
png_chunk.add_u8(last);
auto len = m_non_compressible_data.size();
auto nlen = ~len;
u16 len = m_non_compressible_data.size();
u16 nlen = ~len;
png_chunk.add_u16_little(len);
png_chunk.add_u16_little(nlen);
png_chunk.add_as_little_endian(len);
png_chunk.add_as_little_endian(nlen);
for (auto non_compressed_byte : m_non_compressible_data) {
png_chunk.add_u8(non_compressed_byte);
@ -125,11 +120,12 @@ void NonCompressibleBlock::update_adler(u8 data)
void PNGWriter::add_chunk(PNGChunk const& png_chunk)
{
Vector<u8> combined;
ByteBuffer combined;
for (auto character : png_chunk.type()) {
combined.append(character);
combined.append(&character, sizeof(character));
}
combined.extend(png_chunk.data());
combined.append(png_chunk.data().data(), png_chunk.data().size());
auto crc = BigEndian(Crypto::Checksum::CRC32({ (const u8*)combined.data(), combined.size() }).digest());
auto data_len = BigEndian(png_chunk.data().size());
@ -151,8 +147,8 @@ void PNGWriter::add_png_header()
void PNGWriter::add_IHDR_chunk(u32 width, u32 height, u8 bit_depth, u8 color_type, u8 compression_method, u8 filter_method, u8 interlace_method)
{
PNGChunk png_chunk { "IHDR" };
png_chunk.add_u32_big(width);
png_chunk.add_u32_big(height);
png_chunk.add_as_big_endian(width);
png_chunk.add_as_big_endian(height);
png_chunk.add_u8(bit_depth);
png_chunk.add_u8(color_type);
png_chunk.add_u8(compression_method);
@ -172,7 +168,7 @@ void PNGWriter::add_IDAT_chunk(Gfx::Bitmap const& bitmap)
PNGChunk png_chunk { "IDAT" };
u16 CMF_FLG = 0x81d;
png_chunk.add_u16_big(CMF_FLG);
png_chunk.add_as_big_endian(CMF_FLG);
NonCompressibleBlock non_compressible_block;
@ -189,8 +185,8 @@ void PNGWriter::add_IDAT_chunk(Gfx::Bitmap const& bitmap)
}
non_compressible_block.finalize(png_chunk);
png_chunk.add_u16_big(non_compressible_block.adler_s2());
png_chunk.add_u16_big(non_compressible_block.adler_s1());
png_chunk.add_as_big_endian(non_compressible_block.adler_s2());
png_chunk.add_as_big_endian(non_compressible_block.adler_s1());
add_chunk(png_chunk);
}