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Merged
ProgramMax merged 1 commit into from
May 14, 2025
Merged

Use std::variant for actions #77

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808 changes: 321 additions & 487 deletions Code/png_cicp_editor/Actions.cpp
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149 changes: 56 additions & 93 deletions Code/png_cicp_editor/Actions.hpp
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@@ -1,93 +1,56 @@
// Copyright 2025, The png_cicp_editor Contributors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef PNG_CICP_EDITOR_ACTIONS_HPP
#define PNG_CICP_EDITOR_ACTIONS_HPP

#include <string>

#include "CICP.hpp"

namespace PNG_CICP_Editor {

enum class Actions {
Version,
Help,
License,
Add,
Overwrite,
Remove,
};

struct VersionAction {
void operator()() const noexcept;
};

struct HelpAction {
void operator()() const noexcept;
};

struct LicenseAction {
void operator()() const noexcept;
};

struct AddAction {
explicit AddAction(CICP cicp, std::string file_path) noexcept;

void operator()() const noexcept;

CICP cicp_;
std::string file_path_;
};

struct OverwriteAction {
explicit OverwriteAction(CICP cicp, std::string file_path) noexcept;

void operator()() const noexcept;

CICP cicp_;
std::string file_path_;
};

struct RemoveAction {
explicit RemoveAction(std::string file_path) noexcept;

void operator()() const noexcept;

std::string file_path_;
};

struct Action {

explicit Action(VersionAction version) noexcept;
explicit Action(HelpAction help) noexcept;
explicit Action(LicenseAction license) noexcept;
explicit Action(AddAction add) noexcept;
explicit Action(OverwriteAction overwrite) noexcept;
explicit Action(RemoveAction remove) noexcept;

Action(const Action& rhs) noexcept;
Action(Action&& rhs) noexcept;

~Action() noexcept;

Action& operator =(const Action& rhs) noexcept;
Action& operator =(Action&& rhs) noexcept;

Actions action_type_;
union A {
VersionAction version_;
HelpAction help_;
LicenseAction license_;
AddAction add_;
OverwriteAction overwrite_;
RemoveAction remove_;

~A() noexcept;
} action_;
};

} // namespace PNG_CICP_Editor

#endif // #ifndef PNG_CICP_EDITOR_ACTIONS_HPP
// Copyright 2025, The png_cicp_editor Contributors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef PNG_CICP_EDITOR_ACTIONS_HPP
#define PNG_CICP_EDITOR_ACTIONS_HPP

#include <string>
#include <variant>

#include "CICP.hpp"

namespace PNG_CICP_Editor {

struct VersionAction {};

struct HelpAction {};

struct LicenseAction {};

struct AddAction {
explicit AddAction(CICP cicp, std::string file_path) noexcept;

CICP cicp_;
std::string file_path_;
};

struct OverwriteAction {
explicit OverwriteAction(CICP cicp, std::string file_path) noexcept;

CICP cicp_;
std::string file_path_;
};

struct RemoveAction {
explicit RemoveAction(std::string file_path) noexcept;

std::string file_path_;
};

using Action = std::variant<VersionAction, HelpAction, LicenseAction, AddAction, OverwriteAction, RemoveAction>;

struct ActionExecutor {

void operator()(const PNG_CICP_Editor::VersionAction& action) const noexcept;
void operator()(const PNG_CICP_Editor::HelpAction& action) const noexcept;
void operator()(const PNG_CICP_Editor::LicenseAction& action) const noexcept;
void operator()(const PNG_CICP_Editor::AddAction& action) const noexcept;
void operator()(const PNG_CICP_Editor::OverwriteAction& action) const noexcept;
void operator()(const PNG_CICP_Editor::RemoveAction& action) const noexcept;

};

} // namespace PNG_CICP_Editor

#endif // #ifndef PNG_CICP_EDITOR_ACTIONS_HPP
196 changes: 108 additions & 88 deletions Code/png_cicp_editor/CICPCreator.cpp
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// Copyright 2025, The png_cicp_editor Contributors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "CICPCreator.hpp"

namespace {

// TODO: This implementation is ripped directly from the example CRC implementation in the spec:
// https://w3c.github.io/png/#samplecrc
// Surely, there is a better way for this use case.
unsigned long crc_table[256];
int crc_table_computed = 0;

void make_crc_table() noexcept {
unsigned long c;
int n, k;

for (n = 0; n < 256; n++) {
c = (unsigned long)n;
for (k = 0; k < 8; k++) {
if (c & 1) {
c = 0xedb88320L ^ (c >> 1);
}
else {
c = c >> 1;
}
}
crc_table[n] = c;
}
crc_table_computed = 1;
}

unsigned long update_crc(unsigned long crc, char* buf, int len) noexcept {
unsigned long c = crc;
int n;

if (!crc_table_computed) {
make_crc_table();
}

for (n = 0; n < len; n++) {
c = crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
}

return c;
}

unsigned long crc(char* buf, int len) noexcept {
return update_crc(0xffffffffL, buf, len) ^ 0xffffffffL;
}

} // anonymous namespace

namespace PNG_CICP_Editor {

std::array<char, 16> create_cicp_buffer(const CICP& cicp) noexcept {
std::array<char, 16> buffer;

// length
buffer[0] = 0;
buffer[1] = 0;
buffer[2] = 0;
buffer[3] = 4;

// chunk type
buffer[4] = 'c';
buffer[5] = 'I';
buffer[6] = 'C';
buffer[7] = 'P';

// chunk data
buffer[8] = cicp.color_primaries_;
buffer[9] = cicp.transfer_function_;
buffer[10] = cicp.matrix_coefficients_;
buffer[11] = cicp.video_full_range_flag_;

// crc
unsigned long calculated_crc = crc(&buffer[4], 8);
buffer[12] = static_cast<char>(calculated_crc >> 24);
buffer[13] = static_cast<char>(calculated_crc >> 16);
buffer[14] = static_cast<char>(calculated_crc >> 8);
buffer[15] = static_cast<char>(calculated_crc >> 0);

return buffer;
}

} // namespace PNG_CICP_Editor
// Copyright 2025, The png_cicp_editor Contributors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "CICPCreator.hpp"

namespace {

// TODO: This implementation is ripped directly from the example CRC implementation in the spec:
// https://w3c.github.io/png/#samplecrc
// Surely, there is a better way for this use case.
unsigned long crc_table[256];
int crc_table_computed = 0;

void make_crc_table() noexcept {
unsigned long c;
int n, k;

for (n = 0; n < 256; n++) {
c = (unsigned long)n;
for (k = 0; k < 8; k++) {
if (c & 1) {
c = 0xedb88320L ^ (c >> 1);
}
else {
c = c >> 1;
}
}
crc_table[n] = c;
}
crc_table_computed = 1;
}

unsigned long update_crc(unsigned long crc, char* buf, int len) noexcept {
unsigned long c = crc;
int n;

if (!crc_table_computed) {
make_crc_table();
}

for (n = 0; n < len; n++) {
c = crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
}

return c;
}

unsigned long crc(char* buf, int len) noexcept {
return update_crc(0xffffffffL, buf, len) ^ 0xffffffffL;
}

// https://www.youtube.com/watch?v=m7PVZixO35c
unsigned computer_crc32(unsigned char* data, int length, int* zerop) noexcept {
uint32_t crc = 0xffffffff;
const uint32_t polynomial = 0xedb88320;

int zeroes = 0;
int i, j;
for (i = 0; i < length; i++) {
crc ^= data[i];
for (j = 0; j < 8; j++) {
// Do it without branching, use boolean operations to xor with the
// polynomial or zero depending on whether last bit is set
//zeroes += (1-(crc & 1));
crc = (crc >> 1) ^ ((0-(crc & 1)) & polynomial);
}
}
*zerop = zeroes;
return crc;
}

} // anonymous namespace

namespace PNG_CICP_Editor {

std::array<char, 16> create_cicp_buffer(const CICP& cicp) noexcept {
std::array<char, 16> buffer;

// length
buffer[0] = 0;
buffer[1] = 0;
buffer[2] = 0;
buffer[3] = 4;

// chunk type
buffer[4] = 'c';
buffer[5] = 'I';
buffer[6] = 'C';
buffer[7] = 'P';

// chunk data
buffer[8] = cicp.color_primaries_;
buffer[9] = cicp.transfer_function_;
buffer[10] = cicp.matrix_coefficients_;
buffer[11] = cicp.video_full_range_flag_;

// crc
unsigned long calculated_crc = crc(&buffer[4], 8);
buffer[12] = static_cast<char>(calculated_crc >> 24);
buffer[13] = static_cast<char>(calculated_crc >> 16);
buffer[14] = static_cast<char>(calculated_crc >> 8);
buffer[15] = static_cast<char>(calculated_crc >> 0);

return buffer;
}

} // namespace PNG_CICP_Editor
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