Add support for UP and DOWN history navigation

bootloader/bootloader.asm

@@ -134,7 +134,7 @@ second_step:
     ; Loading the assembly kernel from floppy
 
     KERNEL_BASE equ 0x100      ; 0x100:0x0 = 0x1000
-    sectors equ 0x40           ; sectors to read
+    sectors equ 0x42           ; sectors to read
     bootdev equ 0x0
 
     mov ax, KERNEL_BASE

fill.bash

@@ -1,5 +1,5 @@
 #!/bin/bash
 
 size=`stat -c%s kernel/kernel.bin`
-let filler_size=16384-$size
+let filler_size=17408-$size
 dd if=/dev/zero of=filler.bin bs=1 count=$filler_size

kernel/include/keyboard.hpp

@@ -15,6 +15,7 @@ namespace keyboard {
 const char KEY_ENTER = 0x1C;
 const char KEY_BACKSPACE = 0x0E;
 const char KEY_UP = 0x48;
+const char KEY_DOWN = 0x50;
 
 void install_driver();
 char get_char();

kernel/include/vector.hpp

@@ -60,6 +60,14 @@ public:
         return _capacity;
     }
 
+    const value_type& operator[](size_type pos) const {
+        return data[pos];
+    }
+
+    value_type& operator[](size_type pos){
+        return data[pos];
+    }
+
     //Modifiers
 
     void push_back(value_type& element){

kernel/src/shell.cpp

@@ -88,8 +88,42 @@ void start_shell(){
                 }
 
                 k_print("thor> ");
-            } else if(key == keyboard::KEY_UP){
-                //TODO
+            } else if(key == keyboard::KEY_UP || key == keyboard::KEY_DOWN){
+                if(history.size() > 0){
+                    if(key == keyboard::KEY_UP){
+                        if(history_index == 0){
+                            continue;
+                        }
+
+                        --history_index;
+                    } else { //KEY_DOWN
+                        if(history_index == history.size()){
+                            continue;
+                        }
+
+                        ++history_index;
+                    }
+
+                    set_column(6);
+
+                    for(uint64_t i = 0; i < current_input_length; ++i){
+                        k_print(' ');
+                    }
+
+                    set_column(6);
+
+                    current_input_length = 0;
+
+                    if(history_index < history.size()){
+                        auto saved = history[history_index];
+                        while(*saved){
+                            current_input[current_input_length++] = *saved;
+                            k_print(*saved);
+
+                            ++saved;
+                        }
+                    }
+                }
             } else if(key == keyboard::KEY_BACKSPACE){
                 if(current_input_length > 0){
                     k_print('\b');
@@ -111,6 +145,13 @@ void start_shell(){
 void exec_command(){
     char buffer[50];
 
+    auto saved = new char[current_input_length + 1];
+    memcopy(saved, current_input, current_input_length);
+    saved[current_input_length] = '\0';
+
+    history.push_back(saved);
+    history_index = history.size();
+
     for(auto& command : commands){
         const char* input_command = current_input;
         if(str_contains(current_input, ' ')){