Implement 'H' and 'J' escape sequences.

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/8289a5c93ca

AK/Vector.h

@@ -87,6 +87,9 @@ public:
     size_t size() const { return m_impl ? m_impl->size() : 0; }
     size_t capacity() const { return m_impl ? m_impl->capacity() : 0; }
 
+    T* data() { return m_impl ? &at(0) : nullptr; }
+    const T* data() const { return m_impl ? &at(0) : nullptr; }
+
     const T& at(size_t i) const { return m_impl->at(i); }
     T& at(size_t i) { return m_impl->at(i); }
 

Kernel/Console.cpp

@@ -1,6 +1,8 @@
 #include "Console.h"
 #include "VGA.h"
 #include "IO.h"
+#include "kprintf.h"
+#include <AK/String.h>
 
 // Bytes output to 0xE9 end up on the Bochs console. It's very handy.
 #define CONSOLE_OUT_TO_E9
@@ -34,21 +36,153 @@ ssize_t Console::read(byte* buffer, size_t bufferSize)
     return 0;
 }
 
+inline bool isParameter(byte ch)
+{
+    return ch >= 0x30 && ch <= 0x3f;
+}
+
+inline bool isIntermediate(byte ch)
+{
+    return ch >= 0x20 && ch <= 0x2f;
+}
+
+inline bool isFinal(byte ch)
+{
+    return ch >= 0x40 && ch <= 0x7e;
+}
+
+unsigned parseUInt(const String& str, bool& ok)
+{
+    unsigned value = 0;
+    for (size_t i = 0; i < str.length(); ++i) {
+        if (str[i] < '0' || str[i] > '9') {
+            ok = false;
+            return 0;
+        }
+        value = value * 10;
+        value += str[i] - '0';
+    }
+    ok = true;
+    return value;
+}
+
+void Console::escape$H(const Vector<unsigned>& params)
+{
+    unsigned row = 1;
+    unsigned col = 1;
+
+    if (params.size() >= 1)
+        row = params[0];
+    if (params.size() >= 2)
+        col = params[1];
+    m_cursorRow = row - 1;
+    m_cursorColumn = col - 1;
+    vga_set_cursor(row - 1, col - 1);
+}
+
+void Console::escape$J(const Vector<unsigned>& params)
+{
+    int mode = 0;
+    if (params.size() >= 1)
+        mode = params[0];
+    switch (mode) {
+    case 0:
+        // FIXME: Clear from cursor to end of screen.
+        notImplemented();
+        break;
+    case 1:
+        // FIXME: Clear from cursor to beginning of screen.
+        notImplemented();
+        break;
+    case 2:
+        vga_clear();
+        break;
+    case 3:
+        // FIXME: <esc>[3J should also clear the scrollback buffer.
+        vga_clear();
+        break;
+    }
+}
+
+void Console::executeEscapeSequence(byte final)
+{
+    auto paramparts = String((const char*)m_parameters.data(), m_parameters.size()).split(';');
+    Vector<unsigned> params;
+    for (auto& parampart : paramparts) {
+        bool ok;
+        unsigned value = parseUInt(parampart, ok);
+        if (!ok) {
+            // FIXME: Should we do something else?
+            return;
+        }
+        params.append(value);
+    }
+    switch (final) {
+    case 'H': escape$H(params); break;
+    case 'J': escape$J(params); break;
+    default: break;
+    }
+
+    m_parameters.clear();
+    m_intermediates.clear();
+}
+
 void Console::putChar(char ch)
 {
 #ifdef CONSOLE_OUT_TO_E9
+    //if (ch != 27)
     IO::out8(0xe9, ch);
 #endif
-    switch (ch) {
-    case '\0':
-        return;
-    case '\n':
-        m_cursorColumn = 0;
+    auto scrollup = [&] {
         if (m_cursorRow == (m_rows - 1)) {
             vga_scroll_up();
         } else {
             ++m_cursorRow;
         }
+        m_cursorColumn = 0;
+    };
+
+    switch (m_escState) {
+    case ExpectBracket:
+        if (ch == '[')
+            m_escState = ExpectParameter;
+        else
+            m_escState = Normal;
+        return;
+    case ExpectParameter:
+        if (isParameter(ch)) {
+            m_parameters.append(ch);
+            return;
+        }
+        m_escState = ExpectIntermediate;
+        // fall through
+    case ExpectIntermediate:
+        if (isIntermediate(ch)) {
+            m_intermediates.append(ch);
+            return;
+        }
+        m_escState = ExpectFinal;
+        // fall through
+    case ExpectFinal:
+        if (isFinal(ch)) {
+            m_escState = Normal;
+            executeEscapeSequence(ch);
+            return;
+        }
+        m_escState = Normal;
+        return;
+    case Normal:
+        break;
+    }
+
+    switch (ch) {
+    case '\0':
+        return;
+    case '\033':
+        m_escState = ExpectBracket;
+        return;
+    case '\n':
+        scrollup();
         vga_set_cursor(m_cursorRow, m_cursorColumn);
         return;
     }
@@ -56,14 +190,8 @@ void Console::putChar(char ch)
     vga_putch_at(m_cursorRow, m_cursorColumn, ch);
 
     ++m_cursorColumn;
-    if (m_cursorColumn >= m_columns) {
-        if (m_cursorRow == (m_rows - 1)) {
-            vga_scroll_up();
-        } else {
-            ++m_cursorRow;
-        }
-        m_cursorColumn = 0;
-    }
+    if (m_cursorColumn >= m_columns)
+        scrollup();
     vga_set_cursor(m_cursorRow, m_cursorColumn);
 }
 

Kernel/Console.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <AK/Compiler.h>
+#include <AK/Vector.h>
 #include <VirtualFileSystem/CharacterDevice.h>
 
 class Console final : public CharacterDevice {
@@ -17,6 +18,9 @@ public:
     void putChar(char);
 
 private:
+    void escape$H(const Vector<unsigned>&);
+    void escape$J(const Vector<unsigned>&);
+
     const byte m_rows { 25 };
     const byte m_columns { 80 };
     byte m_cursorRow { 0 };
@@ -24,6 +28,19 @@ private:
 
     byte m_currentAttribute { 0x07 };
 
+    void executeEscapeSequence(byte final);
+
+    enum EscapeState {
+        Normal,
+        ExpectBracket,
+        ExpectParameter,
+        ExpectIntermediate,
+        ExpectFinal,
+    };
+    EscapeState m_escState { Normal };
+    Vector<byte> m_parameters;
+    Vector<byte> m_intermediates;
+
     const byte* s_vgaMemory { (const byte*)0xb8000 };
 };
 

Kernel/VGA.cpp

@@ -15,6 +15,12 @@ void vga_scroll_up()
     memset(vga_mem + (160 * 24), 0, 160);
 }
 
+void vga_clear()
+{
+    InterruptDisabler disabler;
+    memset(vga_mem, 0, 160 * 25);
+}
+
 void vga_putch_at(byte row, byte column, byte ch)
 {
     word cur = (row * 160) + (column * 2);

Kernel/VGA.h

@@ -10,4 +10,4 @@ void vga_set_cursor(BYTE row, BYTE column);
 WORD vga_get_cursor();
 void vga_putch_at(byte row, byte column, byte ch);
 void vga_scroll_up();
-
+void vga_clear();