Applications: Move to Userland/Applications/

Userland/Applications/HexEditor/CMakeLists.txt

@@ -0,0 +1,8 @@
+set(SOURCES
+    HexEditor.cpp
+    HexEditorWidget.cpp
+    main.cpp
+)
+
+serenity_app(HexEditor ICON app-hexeditor)
+target_link_libraries(HexEditor LibGUI)

Userland/Applications/HexEditor/HexEditor.cpp

@@ -0,0 +1,583 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "HexEditor.h"
+#include <AK/StringBuilder.h>
+#include <LibGUI/Action.h>
+#include <LibGUI/Clipboard.h>
+#include <LibGUI/Menu.h>
+#include <LibGUI/Painter.h>
+#include <LibGUI/ScrollBar.h>
+#include <LibGUI/TextEditor.h>
+#include <LibGUI/Window.h>
+#include <LibGfx/FontDatabase.h>
+#include <LibGfx/Palette.h>
+#include <ctype.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+
+HexEditor::HexEditor()
+{
+    set_focus_policy(GUI::FocusPolicy::StrongFocus);
+    set_scrollbars_enabled(true);
+    set_font(Gfx::FontDatabase::default_fixed_width_font());
+    set_background_role(ColorRole::Base);
+    set_foreground_role(ColorRole::BaseText);
+    vertical_scrollbar().set_step(line_height());
+}
+
+HexEditor::~HexEditor()
+{
+}
+
+void HexEditor::set_readonly(bool readonly)
+{
+    if (m_readonly == readonly)
+        return;
+    m_readonly = readonly;
+}
+
+void HexEditor::set_buffer(const ByteBuffer& buffer)
+{
+    m_buffer = buffer;
+    set_content_length(buffer.size());
+    m_tracked_changes.clear();
+    m_position = 0;
+    m_byte_position = 0;
+    update();
+    update_status();
+}
+
+void HexEditor::fill_selection(u8 fill_byte)
+{
+    if (!has_selection())
+        return;
+
+    for (int i = m_selection_start; i <= m_selection_end; i++) {
+        m_tracked_changes.set(i, m_buffer.data()[i]);
+        m_buffer.data()[i] = fill_byte;
+    }
+
+    update();
+    did_change();
+}
+
+void HexEditor::set_position(int position)
+{
+    if (position > static_cast<int>(m_buffer.size()))
+        return;
+
+    m_position = position;
+    m_byte_position = 0;
+    scroll_position_into_view(position);
+    update_status();
+}
+
+bool HexEditor::write_to_file(const StringView& path)
+{
+    if (m_buffer.is_empty())
+        return true;
+
+    int fd = open_with_path_length(path.characters_without_null_termination(), path.length(), O_WRONLY | O_CREAT | O_TRUNC, 0666);
+    if (fd < 0) {
+        perror("open");
+        return false;
+    }
+
+    int rc = ftruncate(fd, m_buffer.size());
+    if (rc < 0) {
+        perror("ftruncate");
+        return false;
+    }
+
+    ssize_t nwritten = write(fd, m_buffer.data(), m_buffer.size());
+    if (nwritten < 0) {
+        perror("write");
+        close(fd);
+        return false;
+    }
+
+    if (static_cast<size_t>(nwritten) == m_buffer.size()) {
+        m_tracked_changes.clear();
+        update();
+    }
+
+    close(fd);
+    return true;
+}
+
+bool HexEditor::copy_selected_hex_to_clipboard()
+{
+    if (!has_selection())
+        return false;
+
+    StringBuilder output_string_builder;
+    for (int i = m_selection_start; i <= m_selection_end; i++)
+        output_string_builder.appendff("{:02X} ", m_buffer.data()[i]);
+
+    GUI::Clipboard::the().set_plain_text(output_string_builder.to_string());
+    return true;
+}
+
+bool HexEditor::copy_selected_text_to_clipboard()
+{
+    if (!has_selection())
+        return false;
+
+    StringBuilder output_string_builder;
+    for (int i = m_selection_start; i <= m_selection_end; i++)
+        output_string_builder.append(isprint(m_buffer.data()[i]) ? m_buffer[i] : '.');
+
+    GUI::Clipboard::the().set_plain_text(output_string_builder.to_string());
+    return true;
+}
+
+bool HexEditor::copy_selected_hex_to_clipboard_as_c_code()
+{
+    if (!has_selection())
+        return false;
+
+    StringBuilder output_string_builder;
+    output_string_builder.appendff("unsigned char raw_data[{}] = {{\n", (m_selection_end - m_selection_start) + 1);
+    output_string_builder.append("    ");
+    for (int i = m_selection_start, j = 1; i <= m_selection_end; i++, j++) {
+        output_string_builder.appendff("{:#02X}", m_buffer.data()[i]);
+        if (i != m_selection_end)
+            output_string_builder.append(", ");
+        if ((j % 12) == 0) {
+            output_string_builder.append("\n");
+            output_string_builder.append("    ");
+        }
+    }
+    output_string_builder.append("\n};\n");
+
+    GUI::Clipboard::the().set_plain_text(output_string_builder.to_string());
+    return true;
+}
+
+void HexEditor::set_bytes_per_row(int bytes_per_row)
+{
+    m_bytes_per_row = bytes_per_row;
+    set_content_size({ offset_margin_width() + (m_bytes_per_row * (character_width() * 3)) + 10 + (m_bytes_per_row * character_width()) + 20, total_rows() * line_height() + 10 });
+    update();
+}
+
+void HexEditor::set_content_length(int length)
+{
+    if (length == m_content_length)
+        return;
+    m_content_length = length;
+    set_content_size({ offset_margin_width() + (m_bytes_per_row * (character_width() * 3)) + 10 + (m_bytes_per_row * character_width()) + 20, total_rows() * line_height() + 10 });
+}
+
+void HexEditor::mousedown_event(GUI::MouseEvent& event)
+{
+    if (event.button() != GUI::MouseButton::Left) {
+        return;
+    }
+
+    auto absolute_x = horizontal_scrollbar().value() + event.x();
+    auto absolute_y = vertical_scrollbar().value() + event.y();
+
+    auto hex_start_x = frame_thickness() + 90;
+    auto hex_start_y = frame_thickness() + 5;
+    auto hex_end_x = hex_start_x + (bytes_per_row() * (character_width() * 3));
+    auto hex_end_y = hex_start_y + 5 + (total_rows() * line_height());
+
+    auto text_start_x = frame_thickness() + 100 + (bytes_per_row() * (character_width() * 3));
+    auto text_start_y = frame_thickness() + 5;
+    auto text_end_x = text_start_x + (bytes_per_row() * character_width());
+    auto text_end_y = text_start_y + 5 + (total_rows() * line_height());
+
+    if (absolute_x >= hex_start_x && absolute_x <= hex_end_x && absolute_y >= hex_start_y && absolute_y <= hex_end_y) {
+        auto byte_x = (absolute_x - hex_start_x) / (character_width() * 3);
+        auto byte_y = (absolute_y - hex_start_y) / line_height();
+        auto offset = (byte_y * m_bytes_per_row) + byte_x;
+
+        if (offset < 0 || offset >= static_cast<int>(m_buffer.size()))
+            return;
+
+#ifdef HEX_DEBUG
+        outln("HexEditor::mousedown_event(hex): offset={}", offset);
+#endif
+
+        m_edit_mode = EditMode::Hex;
+        m_byte_position = 0;
+        m_position = offset;
+        m_in_drag_select = true;
+        m_selection_start = offset;
+        m_selection_end = offset;
+        update();
+        update_status();
+    }
+
+    if (absolute_x >= text_start_x && absolute_x <= text_end_x && absolute_y >= text_start_y && absolute_y <= text_end_y) {
+        auto byte_x = (absolute_x - text_start_x) / character_width();
+        auto byte_y = (absolute_y - text_start_y) / line_height();
+        auto offset = (byte_y * m_bytes_per_row) + byte_x;
+
+        if (offset < 0 || offset >= static_cast<int>(m_buffer.size()))
+            return;
+
+#ifdef HEX_DEBUG
+        outln("HexEditor::mousedown_event(text): offset={}", offset);
+#endif
+
+        m_position = offset;
+        m_byte_position = 0;
+        m_in_drag_select = true;
+        m_selection_start = offset;
+        m_selection_end = offset;
+        m_edit_mode = EditMode::Text;
+        update();
+        update_status();
+    }
+}
+
+void HexEditor::mousemove_event(GUI::MouseEvent& event)
+{
+    auto absolute_x = horizontal_scrollbar().value() + event.x();
+    auto absolute_y = vertical_scrollbar().value() + event.y();
+
+    auto hex_start_x = frame_thickness() + 90;
+    auto hex_start_y = frame_thickness() + 5;
+    auto hex_end_x = hex_start_x + (bytes_per_row() * (character_width() * 3));
+    auto hex_end_y = hex_start_y + 5 + (total_rows() * line_height());
+
+    auto text_start_x = frame_thickness() + 100 + (bytes_per_row() * (character_width() * 3));
+    auto text_start_y = frame_thickness() + 5;
+    auto text_end_x = text_start_x + (bytes_per_row() * character_width());
+    auto text_end_y = text_start_y + 5 + (total_rows() * line_height());
+
+    if ((absolute_x >= hex_start_x && absolute_x <= hex_end_x
+            && absolute_y >= hex_start_y && absolute_y <= hex_end_y)
+        || (absolute_x >= text_start_x && absolute_x <= text_end_x
+            && absolute_y >= text_start_y && absolute_y <= text_end_y)) {
+        set_override_cursor(Gfx::StandardCursor::IBeam);
+    } else {
+        set_override_cursor(Gfx::StandardCursor::None);
+    }
+
+    if (m_in_drag_select) {
+        if (absolute_x >= hex_start_x && absolute_x <= hex_end_x && absolute_y >= hex_start_y && absolute_y <= hex_end_y) {
+            auto byte_x = (absolute_x - hex_start_x) / (character_width() * 3);
+            auto byte_y = (absolute_y - hex_start_y) / line_height();
+            auto offset = (byte_y * m_bytes_per_row) + byte_x;
+
+            if (offset < 0 || offset > static_cast<int>(m_buffer.size()))
+                return;
+
+            m_selection_end = offset;
+            scroll_position_into_view(offset);
+        }
+
+        if (absolute_x >= text_start_x && absolute_x <= text_end_x && absolute_y >= text_start_y && absolute_y <= text_end_y) {
+            auto byte_x = (absolute_x - text_start_x) / character_width();
+            auto byte_y = (absolute_y - text_start_y) / line_height();
+            auto offset = (byte_y * m_bytes_per_row) + byte_x;
+            if (offset < 0 || offset > static_cast<int>(m_buffer.size()))
+                return;
+
+            m_selection_end = offset;
+            scroll_position_into_view(offset);
+        }
+        update_status();
+        update();
+        return;
+    }
+}
+
+void HexEditor::mouseup_event(GUI::MouseEvent& event)
+{
+    if (event.button() == GUI::MouseButton::Left) {
+        if (m_in_drag_select) {
+            if (m_selection_end < m_selection_start) {
+                // lets flip these around
+                auto start = m_selection_end;
+                m_selection_end = m_selection_start;
+                m_selection_start = start;
+            }
+            m_in_drag_select = false;
+        }
+        update();
+        update_status();
+    }
+}
+
+void HexEditor::scroll_position_into_view(int position)
+{
+    int y = position / bytes_per_row();
+    int x = position % bytes_per_row();
+    Gfx::IntRect rect {
+        frame_thickness() + offset_margin_width() + (x * (character_width() * 3)) + 10,
+        frame_thickness() + 5 + (y * line_height()),
+        (character_width() * 3),
+        line_height() - m_line_spacing
+    };
+    scroll_into_view(rect, true, true);
+}
+
+void HexEditor::keydown_event(GUI::KeyEvent& event)
+{
+#ifdef HEX_DEBUG
+    outln("HexEditor::keydown_event key={}", static_cast<u8>(event.key()));
+#endif
+
+    if (event.key() == KeyCode::Key_Up) {
+        if (m_position - bytes_per_row() >= 0) {
+            m_position -= bytes_per_row();
+            m_byte_position = 0;
+            scroll_position_into_view(m_position);
+            update();
+            update_status();
+        }
+        return;
+    }
+
+    if (event.key() == KeyCode::Key_Down) {
+        if (m_position + bytes_per_row() < static_cast<int>(m_buffer.size())) {
+            m_position += bytes_per_row();
+            m_byte_position = 0;
+            scroll_position_into_view(m_position);
+            update();
+            update_status();
+        }
+        return;
+    }
+
+    if (event.key() == KeyCode::Key_Left) {
+        if (m_position - 1 >= 0) {
+            m_position--;
+            m_byte_position = 0;
+            scroll_position_into_view(m_position);
+            update();
+            update_status();
+        }
+        return;
+    }
+
+    if (event.key() == KeyCode::Key_Right) {
+        if (m_position + 1 < static_cast<int>(m_buffer.size())) {
+            m_position++;
+            m_byte_position = 0;
+            scroll_position_into_view(m_position);
+            update();
+            update_status();
+        }
+        return;
+    }
+
+    if (event.key() == KeyCode::Key_Backspace) {
+        if (m_position > 0) {
+            m_position--;
+            m_byte_position = 0;
+            scroll_position_into_view(m_position);
+            update();
+            update_status();
+        }
+        return;
+    }
+
+    if (!is_readonly() && !event.ctrl() && !event.alt() && !event.text().is_empty()) {
+        if (m_edit_mode == EditMode::Hex) {
+            hex_mode_keydown_event(event);
+        } else {
+            text_mode_keydown_event(event);
+        }
+    }
+}
+
+void HexEditor::hex_mode_keydown_event(GUI::KeyEvent& event)
+{
+    if ((event.key() >= KeyCode::Key_0 && event.key() <= KeyCode::Key_9) || (event.key() >= KeyCode::Key_A && event.key() <= KeyCode::Key_F)) {
+        if (m_buffer.is_empty())
+            return;
+        ASSERT(m_position >= 0);
+        ASSERT(m_position < static_cast<int>(m_buffer.size()));
+
+        // yes, this is terrible... but it works.
+        auto value = (event.key() >= KeyCode::Key_0 && event.key() <= KeyCode::Key_9)
+            ? event.key() - KeyCode::Key_0
+            : (event.key() - KeyCode::Key_A) + 0xA;
+
+        if (m_byte_position == 0) {
+            m_tracked_changes.set(m_position, m_buffer.data()[m_position]);
+            m_buffer.data()[m_position] = value << 4 | (m_buffer.data()[m_position] & 0xF); // shift new value left 4 bits, OR with existing last 4 bits
+            m_byte_position++;
+        } else {
+            m_buffer.data()[m_position] = (m_buffer.data()[m_position] & 0xF0) | value; // save the first 4 bits, OR the new value in the last 4
+            if (m_position + 1 < static_cast<int>(m_buffer.size()))
+                m_position++;
+            m_byte_position = 0;
+        }
+
+        update();
+        update_status();
+        did_change();
+    }
+}
+
+void HexEditor::text_mode_keydown_event(GUI::KeyEvent& event)
+{
+    if (m_buffer.is_empty())
+        return;
+    ASSERT(m_position >= 0);
+    ASSERT(m_position < static_cast<int>(m_buffer.size()));
+
+    if (event.code_point() == 0) // This is a control key
+        return;
+
+    m_tracked_changes.set(m_position, m_buffer.data()[m_position]);
+    m_buffer.data()[m_position] = event.code_point();
+    if (m_position + 1 < static_cast<int>(m_buffer.size()))
+        m_position++;
+    m_byte_position = 0;
+
+    update();
+    update_status();
+    did_change();
+}
+
+void HexEditor::update_status()
+{
+    if (on_status_change)
+        on_status_change(m_position, m_edit_mode, m_selection_start, m_selection_end);
+}
+
+void HexEditor::did_change()
+{
+    if (on_change)
+        on_change();
+}
+
+void HexEditor::paint_event(GUI::PaintEvent& event)
+{
+    GUI::Frame::paint_event(event);
+
+    GUI::Painter painter(*this);
+    painter.add_clip_rect(widget_inner_rect());
+    painter.add_clip_rect(event.rect());
+    painter.fill_rect(event.rect(), palette().color(background_role()));
+
+    if (m_buffer.is_empty())
+        return;
+
+    painter.translate(frame_thickness(), frame_thickness());
+    painter.translate(-horizontal_scrollbar().value(), -vertical_scrollbar().value());
+
+    Gfx::IntRect offset_clip_rect {
+        0,
+        vertical_scrollbar().value(),
+        85,
+        height() - height_occupied_by_horizontal_scrollbar() //(total_rows() * line_height()) + 5
+    };
+    painter.fill_rect(offset_clip_rect, palette().ruler());
+    painter.draw_line(offset_clip_rect.top_right(), offset_clip_rect.bottom_right(), palette().ruler_border());
+
+    auto margin_and_hex_width = offset_margin_width() + (m_bytes_per_row * (character_width() * 3)) + 15;
+    painter.draw_line({ margin_and_hex_width, 0 },
+        { margin_and_hex_width, vertical_scrollbar().value() + (height() - height_occupied_by_horizontal_scrollbar()) },
+        palette().ruler_border());
+
+    auto view_height = (height() - height_occupied_by_horizontal_scrollbar());
+    auto min_row = max(0, vertical_scrollbar().value() / line_height());              // if below 0 then use 0
+    auto max_row = min(total_rows(), min_row + ceil_div(view_height, line_height())); // if above calculated rows, use calculated rows
+
+    // paint offsets
+    for (int i = min_row; i < max_row; i++) {
+        Gfx::IntRect side_offset_rect {
+            frame_thickness() + 5,
+            frame_thickness() + 5 + (i * line_height()),
+            width() - width_occupied_by_vertical_scrollbar(),
+            height() - height_occupied_by_horizontal_scrollbar()
+        };
+
+        bool is_current_line = (m_position / bytes_per_row()) == i;
+        auto line = String::formatted("{:#08X}", i * bytes_per_row());
+        painter.draw_text(
+            side_offset_rect,
+            line,
+            is_current_line ? Gfx::FontDatabase::default_bold_font() : font(),
+            Gfx::TextAlignment::TopLeft,
+            is_current_line ? palette().ruler_active_text() : palette().ruler_inactive_text());
+    }
+
+    for (int i = min_row; i < max_row; i++) {
+        for (int j = 0; j < bytes_per_row(); j++) {
+            auto byte_position = (i * bytes_per_row()) + j;
+            if (byte_position >= static_cast<int>(m_buffer.size()))
+                return;
+
+            Color text_color = palette().color(foreground_role());
+            if (m_tracked_changes.contains(byte_position)) {
+                text_color = Color::Red;
+            }
+
+            auto highlight_flag = false;
+            if (m_selection_start > -1 && m_selection_end > -1) {
+                if (byte_position >= m_selection_start && byte_position <= m_selection_end) {
+                    highlight_flag = true;
+                }
+                if (byte_position >= m_selection_end && byte_position <= m_selection_start) {
+                    highlight_flag = true;
+                }
+            }
+
+            Gfx::IntRect hex_display_rect {
+                frame_thickness() + offset_margin_width() + (j * (character_width() * 3)) + 10,
+                frame_thickness() + 5 + (i * line_height()),
+                (character_width() * 3),
+                line_height() - m_line_spacing
+            };
+            if (highlight_flag) {
+                painter.fill_rect(hex_display_rect, palette().selection());
+                text_color = text_color == Color::Red ? Color::from_rgb(0xFFC0CB) : palette().selection_text();
+            } else if (byte_position == m_position) {
+                painter.fill_rect(hex_display_rect, palette().inactive_selection());
+                text_color = palette().inactive_selection_text();
+            }
+
+            auto line = String::formatted("{:02X}", m_buffer[byte_position]);
+            painter.draw_text(hex_display_rect, line, Gfx::TextAlignment::TopLeft, text_color);
+
+            Gfx::IntRect text_display_rect {
+                frame_thickness() + offset_margin_width() + (bytes_per_row() * (character_width() * 3)) + (j * character_width()) + 20,
+                frame_thickness() + 5 + (i * line_height()),
+                character_width(),
+                line_height() - m_line_spacing
+            };
+            // selection highlighting.
+            if (highlight_flag) {
+                painter.fill_rect(text_display_rect, palette().selection());
+            } else if (byte_position == m_position) {
+                painter.fill_rect(text_display_rect, palette().inactive_selection());
+            }
+
+            painter.draw_text(text_display_rect, String::formatted("{:c}", isprint(m_buffer[byte_position]) ? m_buffer[byte_position] : '.'), Gfx::TextAlignment::TopLeft, text_color);
+        }
+    }
+}

Userland/Applications/HexEditor/HexEditor.h

@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/ByteBuffer.h>
+#include <AK/Function.h>
+#include <AK/HashMap.h>
+#include <AK/NonnullOwnPtrVector.h>
+#include <AK/NonnullRefPtrVector.h>
+#include <AK/StdLibExtras.h>
+#include <LibGUI/ScrollableWidget.h>
+#include <LibGfx/Font.h>
+#include <LibGfx/TextAlignment.h>
+
+class HexEditor : public GUI::ScrollableWidget {
+    C_OBJECT(HexEditor)
+public:
+    enum EditMode {
+        Hex,
+        Text
+    };
+
+    virtual ~HexEditor() override;
+
+    bool is_readonly() const { return m_readonly; }
+    void set_readonly(bool);
+
+    void set_buffer(const ByteBuffer&);
+    void fill_selection(u8 fill_byte);
+    bool write_to_file(const StringView& path);
+
+    bool has_selection() const { return !(m_selection_start == -1 || m_selection_end == -1 || (m_selection_end - m_selection_start) < 0 || m_buffer.is_empty()); }
+    bool copy_selected_text_to_clipboard();
+    bool copy_selected_hex_to_clipboard();
+    bool copy_selected_hex_to_clipboard_as_c_code();
+
+    int bytes_per_row() const { return m_bytes_per_row; }
+    void set_bytes_per_row(int);
+
+    void set_position(int position);
+
+    Function<void(int, EditMode, int, int)> on_status_change; // position, edit mode, selection start, selection end
+    Function<void()> on_change;
+
+protected:
+    HexEditor();
+
+    virtual void paint_event(GUI::PaintEvent&) override;
+    virtual void mousedown_event(GUI::MouseEvent&) override;
+    virtual void mouseup_event(GUI::MouseEvent&) override;
+    virtual void mousemove_event(GUI::MouseEvent&) override;
+    virtual void keydown_event(GUI::KeyEvent&) override;
+
+private:
+    bool m_readonly { false };
+    int m_line_spacing { 4 };
+    int m_content_length { 0 };
+    int m_bytes_per_row { 16 };
+    ByteBuffer m_buffer;
+    bool m_in_drag_select { false };
+    int m_selection_start { 0 };
+    int m_selection_end { 0 };
+    HashMap<int, u8> m_tracked_changes;
+    int m_position { 0 };
+    int m_byte_position { 0 }; // 0 or 1
+    EditMode m_edit_mode { Hex };
+
+    void scroll_position_into_view(int position);
+
+    int total_rows() const { return ceil_div(m_content_length, m_bytes_per_row); }
+    int line_height() const { return font().glyph_height() + m_line_spacing; }
+    int character_width() const { return font().glyph_width('W'); }
+    int offset_margin_width() const { return 80; }
+
+    void hex_mode_keydown_event(GUI::KeyEvent&);
+    void text_mode_keydown_event(GUI::KeyEvent&);
+
+    void set_content_length(int); // I might make this public if I add fetching data on demand.
+    void update_status();
+    void did_change();
+};

Userland/Applications/HexEditor/HexEditorWidget.cpp

@@ -0,0 +1,241 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "HexEditorWidget.h"
+#include <AK/Optional.h>
+#include <AK/StringBuilder.h>
+#include <LibCore/File.h>
+#include <LibGUI/Action.h>
+#include <LibGUI/BoxLayout.h>
+#include <LibGUI/Button.h>
+#include <LibGUI/FilePicker.h>
+#include <LibGUI/InputBox.h>
+#include <LibGUI/Menu.h>
+#include <LibGUI/MenuBar.h>
+#include <LibGUI/MessageBox.h>
+#include <LibGUI/StatusBar.h>
+#include <LibGUI/TextBox.h>
+#include <LibGUI/TextEditor.h>
+#include <LibGUI/ToolBar.h>
+#include <stdio.h>
+#include <string.h>
+
+HexEditorWidget::HexEditorWidget()
+{
+    set_fill_with_background_color(true);
+    set_layout<GUI::VerticalBoxLayout>();
+    layout()->set_spacing(2);
+
+    m_editor = add<HexEditor>();
+
+    m_editor->on_status_change = [this](int position, HexEditor::EditMode edit_mode, int selection_start, int selection_end) {
+        m_statusbar->set_text(0, String::formatted("Offset: {:#08X}", position));
+        m_statusbar->set_text(1, String::formatted("Edit Mode: {}", edit_mode == HexEditor::EditMode::Hex ? "Hex" : "Text"));
+        m_statusbar->set_text(2, String::formatted("Selection Start: {}", selection_start));
+        m_statusbar->set_text(3, String::formatted("Selection End: {}", selection_end));
+        m_statusbar->set_text(4, String::formatted("Selected Bytes: {}", abs(selection_end - selection_start) + 1));
+    };
+
+    m_editor->on_change = [this] {
+        bool was_dirty = m_document_dirty;
+        m_document_dirty = true;
+        if (!was_dirty)
+            update_title();
+    };
+
+    m_statusbar = add<GUI::StatusBar>(5);
+
+    m_new_action = GUI::Action::create("New", { Mod_Ctrl, Key_N }, Gfx::Bitmap::load_from_file("/res/icons/16x16/new.png"), [this](const GUI::Action&) {
+        if (m_document_dirty) {
+            if (GUI::MessageBox::show(window(), "Save changes to current file first?", "Warning", GUI::MessageBox::Type::Warning, GUI::MessageBox::InputType::OKCancel) != GUI::Dialog::ExecResult::ExecOK)
+                return;
+            m_save_action->activate();
+        }
+
+        String value;
+        if (GUI::InputBox::show(value, window(), "Enter new file size:", "New file size") == GUI::InputBox::ExecOK && !value.is_empty()) {
+            auto file_size = value.to_int();
+            if (file_size.has_value() && file_size.value() > 0) {
+                m_document_dirty = false;
+                m_editor->set_buffer(ByteBuffer::create_zeroed(file_size.value()));
+                set_path(LexicalPath());
+                update_title();
+            } else {
+                GUI::MessageBox::show(window(), "Invalid file size entered.", "Error", GUI::MessageBox::Type::Error);
+            }
+        }
+    });
+
+    m_open_action = GUI::CommonActions::make_open_action([this](auto&) {
+        Optional<String> open_path = GUI::FilePicker::get_open_filepath(window());
+
+        if (!open_path.has_value())
+            return;
+
+        open_file(open_path.value());
+    });
+
+    m_save_action = GUI::CommonActions::make_save_action([&](auto&) {
+        if (!m_path.is_empty()) {
+            if (!m_editor->write_to_file(m_path)) {
+                GUI::MessageBox::show(window(), "Unable to save file.\n", "Error", GUI::MessageBox::Type::Error);
+            } else {
+                m_document_dirty = false;
+                update_title();
+            }
+            return;
+        }
+
+        m_save_as_action->activate();
+    });
+
+    m_save_as_action = GUI::CommonActions::make_save_as_action([&](auto&) {
+        Optional<String> save_path = GUI::FilePicker::get_save_filepath(window(), m_name.is_null() ? "Untitled" : m_name, m_extension.is_null() ? "bin" : m_extension);
+        if (!save_path.has_value())
+            return;
+
+        if (!m_editor->write_to_file(save_path.value())) {
+            GUI::MessageBox::show(window(), "Unable to save file.\n", "Error", GUI::MessageBox::Type::Error);
+            return;
+        }
+
+        m_document_dirty = false;
+        set_path(LexicalPath(save_path.value()));
+        dbgln("Wrote document to {}", save_path.value());
+    });
+
+    auto menubar = GUI::MenuBar::construct();
+    auto& app_menu = menubar->add_menu("Hex Editor");
+    app_menu.add_action(*m_new_action);
+    app_menu.add_action(*m_open_action);
+    app_menu.add_action(*m_save_action);
+    app_menu.add_action(*m_save_as_action);
+    app_menu.add_separator();
+    app_menu.add_action(GUI::CommonActions::make_quit_action([this](auto&) {
+        if (!request_close())
+            return;
+        GUI::Application::the()->quit();
+    }));
+
+    m_goto_decimal_offset_action = GUI::Action::create("Go To Offset (Decimal)...", { Mod_Ctrl | Mod_Shift, Key_G }, Gfx::Bitmap::load_from_file("/res/icons/16x16/go-forward.png"), [this](const GUI::Action&) {
+        String value;
+        if (GUI::InputBox::show(value, window(), "Enter Decimal offset:", "Go To") == GUI::InputBox::ExecOK && !value.is_empty()) {
+            auto new_offset = value.to_int();
+            if (new_offset.has_value())
+                m_editor->set_position(new_offset.value());
+        }
+    });
+
+    m_goto_hex_offset_action = GUI::Action::create("Go To Offset (Hex)...", { Mod_Ctrl, Key_G }, Gfx::Bitmap::load_from_file("/res/icons/16x16/go-forward.png"), [this](const GUI::Action&) {
+        String value;
+        if (GUI::InputBox::show(value, window(), "Enter Hex offset:", "Go To") == GUI::InputBox::ExecOK && !value.is_empty()) {
+            auto new_offset = strtol(value.characters(), nullptr, 16);
+            m_editor->set_position(new_offset);
+        }
+    });
+
+    auto& edit_menu = menubar->add_menu("Edit");
+    edit_menu.add_action(GUI::Action::create("Fill selection...", { Mod_Ctrl, Key_B }, [&](const GUI::Action&) {
+        String value;
+        if (GUI::InputBox::show(value, window(), "Fill byte (hex):", "Fill Selection") == GUI::InputBox::ExecOK && !value.is_empty()) {
+            auto fill_byte = strtol(value.characters(), nullptr, 16);
+            m_editor->fill_selection(fill_byte);
+        }
+    }));
+    edit_menu.add_separator();
+    edit_menu.add_action(*m_goto_decimal_offset_action);
+    edit_menu.add_action(*m_goto_hex_offset_action);
+    edit_menu.add_separator();
+    edit_menu.add_action(GUI::Action::create("Copy Hex", { Mod_Ctrl, Key_C }, [&](const GUI::Action&) {
+        m_editor->copy_selected_hex_to_clipboard();
+    }));
+    edit_menu.add_action(GUI::Action::create("Copy Text", { Mod_Ctrl | Mod_Shift, Key_C }, [&](const GUI::Action&) {
+        m_editor->copy_selected_text_to_clipboard();
+    }));
+    edit_menu.add_separator();
+    edit_menu.add_action(GUI::Action::create("Copy As C Code", { Mod_Alt | Mod_Shift, Key_C }, [&](const GUI::Action&) {
+        m_editor->copy_selected_hex_to_clipboard_as_c_code();
+    }));
+
+    auto& view_menu = menubar->add_menu("View");
+    auto& bytes_per_row_menu = view_menu.add_submenu("Bytes per row");
+    for (int i = 8; i <= 32; i += 8) {
+        bytes_per_row_menu.add_action(GUI::Action::create(String::number(i), [this, i](auto&) {
+            m_editor->set_bytes_per_row(i);
+            m_editor->update();
+        }));
+    }
+
+    auto& help_menu = menubar->add_menu("Help");
+    help_menu.add_action(GUI::CommonActions::make_about_action("Hex Editor", GUI::Icon::default_icon("Hex Editor"), window()));
+
+    GUI::Application::the()->set_menubar(move(menubar));
+
+    m_editor->set_focus(true);
+}
+
+HexEditorWidget::~HexEditorWidget()
+{
+}
+
+void HexEditorWidget::set_path(const LexicalPath& lexical_path)
+{
+    m_path = lexical_path.string();
+    m_name = lexical_path.title();
+    m_extension = lexical_path.extension();
+    update_title();
+}
+
+void HexEditorWidget::update_title()
+{
+    StringBuilder builder;
+    builder.append(m_path);
+    if (m_document_dirty)
+        builder.append(" (*)");
+    builder.append(" - Hex Editor");
+    window()->set_title(builder.to_string());
+}
+
+void HexEditorWidget::open_file(const String& path)
+{
+    auto file = Core::File::construct(path);
+    if (!file->open(Core::IODevice::ReadOnly)) {
+        GUI::MessageBox::show(window(), String::formatted("Opening \"{}\" failed: {}", path, strerror(errno)), "Error", GUI::MessageBox::Type::Error);
+        return;
+    }
+
+    m_document_dirty = false;
+    m_editor->set_buffer(file->read_all()); // FIXME: On really huge files, this is never going to work. Should really create a framework to fetch data from the file on-demand.
+    set_path(LexicalPath(path));
+}
+
+bool HexEditorWidget::request_close()
+{
+    if (!m_document_dirty)
+        return true;
+    auto result = GUI::MessageBox::show(window(), "The file has been modified. Quit without saving?", "Quit without saving?", GUI::MessageBox::Type::Warning, GUI::MessageBox::InputType::OKCancel);
+    return result == GUI::MessageBox::ExecOK;
+}

Userland/Applications/HexEditor/HexEditorWidget.h

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include "HexEditor.h"
+#include <AK/Function.h>
+#include <AK/LexicalPath.h>
+#include <LibGUI/Application.h>
+#include <LibGUI/TextEditor.h>
+#include <LibGUI/Widget.h>
+#include <LibGUI/Window.h>
+
+class HexEditor;
+
+class HexEditorWidget final : public GUI::Widget {
+    C_OBJECT(HexEditorWidget)
+public:
+    virtual ~HexEditorWidget() override;
+    void open_file(const String& path);
+    bool request_close();
+
+private:
+    HexEditorWidget();
+    void set_path(const LexicalPath& file);
+    void update_title();
+
+    RefPtr<HexEditor> m_editor;
+    String m_path;
+    String m_name;
+    String m_extension;
+    RefPtr<GUI::Action> m_new_action;
+    RefPtr<GUI::Action> m_open_action;
+    RefPtr<GUI::Action> m_save_action;
+    RefPtr<GUI::Action> m_save_as_action;
+    RefPtr<GUI::Action> m_goto_decimal_offset_action;
+    RefPtr<GUI::Action> m_goto_hex_offset_action;
+
+    RefPtr<GUI::StatusBar> m_statusbar;
+
+    bool m_document_dirty { false };
+};

Userland/Applications/HexEditor/main.cpp

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "HexEditorWidget.h"
+#include <LibGUI/Icon.h>
+#include <LibGfx/Bitmap.h>
+#include <stdio.h>
+
+int main(int argc, char** argv)
+{
+    if (pledge("stdio shared_buffer accept rpath unix cpath wpath fattr thread", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
+    auto app = GUI::Application::construct(argc, argv);
+
+    if (pledge("stdio shared_buffer accept rpath cpath wpath thread", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
+    auto app_icon = GUI::Icon::default_icon("app-hexeditor");
+
+    auto window = GUI::Window::construct();
+    window->set_title("Hex Editor");
+    window->resize(640, 400);
+
+    auto& hex_editor_widget = window->set_main_widget<HexEditorWidget>();
+
+    window->on_close_request = [&]() -> GUI::Window::CloseRequestDecision {
+        if (hex_editor_widget.request_close())
+            return GUI::Window::CloseRequestDecision::Close;
+        return GUI::Window::CloseRequestDecision::StayOpen;
+    };
+
+    window->show();
+    window->set_icon(app_icon.bitmap_for_size(16));
+
+    if (argc >= 2)
+        hex_editor_widget.open_file(argv[1]);
+
+    return app->exec();
+}