Add command parsing and echo commandadd-shell

1 files changed, 103 insertions, 3 deletions

diff --git a/os/shell/shell.c b/os/shell/shell.c
index 933b19c..4fb5488 100644
--- a/os/shell/shell.c
+++ b/os/shell/shell.c
@@ -1,17 +1,116 @@
 #include "../../os/main.h"
 #include "../../kernel/gpu/text_mode/display.h"
+#include "../stdlib/sdtlib.h"
+#include "../commands/echo.h"
+
+#define CMD_BUFFER_SIZE 80
+
+// TODO history buffer
+unsigned char cmd_buffer[CMD_BUFFER_SIZE];
+int cmd_buffer_p = 0;
+
+// cant malloc yet so just store locally
+unsigned char cmd[CMD_BUFFER_SIZE];
+unsigned char args[CMD_BUFFER_SIZE];
+
+void shell_set_prompt() {
+  scrn_print("$> ");
+}
+
+void shell_clear_cmd_buffer() {
+  for(int i = 0; i < CMD_BUFFER_SIZE; i++) {
+    cmd_buffer[i] = 0;
+  }
+  cmd_buffer_p = 0;
+}
+
+void shell_clear_cmd() {
+  for(int i = 0; i < CMD_BUFFER_SIZE; i++) {
+    cmd[i] = 0;
+  }
+}
+
+void shell_clear_args() {
+  for(int i = 0; i < CMD_BUFFER_SIZE; i++) {
+    args[i] = 0;
+  }
+}
+
+unsigned char* shell_parse_cmd() {
+  shell_clear_cmd();
+  for(int i = 0; i < CMD_BUFFER_SIZE; i++) {
+    if (cmd_buffer[i] == ' ') {
+      break;
+    }
+    cmd[i] = cmd_buffer[i];
+  }
+  return cmd;
+}
+
+unsigned char* shell_parse_args() {
+  shell_clear_args();
+  int arg_idx = 0;
+  for(int i = 0; i < CMD_BUFFER_SIZE; i++) {
+    if (cmd_buffer[i] == ' ') {
+      arg_idx = i + 1;
+      break;
+    }
+  }
+
+  if (arg_idx == 0) {
+    return args;
+  }
+  else {
+    for(int i = arg_idx; i < CMD_BUFFER_SIZE; i++) {
+      args[i - arg_idx] = cmd_buffer[i];
+    }
+    return args;
+  }
+}
+
+void shell_exec_cmd(unsigned char* cmd_name, unsigned char* args) {
+  // TODO lookup string to funciton pointer
+  if (strcmp(cmd_name, "echo") == 0) {
+    echo(args);
+  }
+  else if (strcmp(cmd_name, "") != 0) {
+    scrn_print(cmd_name);
+    scrn_println(": command not found");
+  }
+}
+
+void shell_process_cmd_buffer() {
+  scrn_newline();
+
+  shell_exec_cmd(shell_parse_cmd(), shell_parse_args());
+
+  shell_clear_cmd_buffer();
+  shell_set_prompt();  
+}
+
+void shell_handle_backspace() {
+  if (cmd_buffer_p != 0) {
+    cmd_buffer[--cmd_buffer_p] = 0;
+    scrn_backspace();
+  }
+}
+
+void shell_handle_keypress(unsigned char key) {
+  cmd_buffer[cmd_buffer_p++] = key;
+  scrn_putchar(key);
+}
 
 void keypress_handler(unsigned char key) {
   switch(key)
     {
       case '\b':
-        scrn_backspace();
+        shell_handle_backspace();
         break;
       case '\n':
-        scrn_newline();
+        shell_process_cmd_buffer();
         break;
       default:
-        scrn_putchar(key);
+        shell_handle_keypress(key);
     }
 }
 
@@ -19,5 +118,6 @@ Program_t shell_run() {
   Program_t this;
   this.keypress_handler = keypress_handler;
   this.name = "shell";
+  shell_set_prompt();
   return this;
 }
\ No newline at end of file