/* Function to handle system calls for reading from the terminal
* PARAMETERS: fd - not used in this function
* buf - a pointer to a buffer in which to write the data
* nbytes - not used by this function
* RETURNS: the number of bytes successfully read into the buffer
* INFO: This function reads bytes from the line buffer up until the
* newline character (\n). If no newline character is present
* than the entire buffer is read. This function also clears
* the line buffer. It is intended to be called mainly
* by the shell.
*/
int32_t terminal_read(int32_t fd, void * buf, int32_t nbytes)
{
cli();
clear_line_buffer(current_process->terminal);
current_process->terminal->term_read = 1;
sti();
while(current_process->terminal->term_read == 1)
{
}
current_process->terminal->terminal_read_ret = current_process->terminal->line_buf_index;
memcpy(buf,(void*)current_process->terminal->line_buf,BUFFER_SIZE);
clear_line_buffer(current_process->terminal);
return current_process->terminal->terminal_read_ret;
}
/* Function to handle system calls for writing to the terminal
* PARAMETERS: fd - not used in this function
buf - a pointer to a buffer which contains the data to write
nbytes - the number of bytes to write from the buffer
* RETURNS: the number of bytes successfully written, or -1 on failure
* INFO: This function sets the write_lock to 1 at the beginning of
* exec
ution, and clears it before returning. This will
* allow user programs to block keyboard echoes while trying
* to output information to the terminal.
*/
int32_t terminal_write(int32_t fd, const void * buf, int32_t nbytes)
{
int32_t i;
uint8_t* _buf = (uint8_t*)buf;
//Check for valid pointer and valid n_bytes
if(buf == NULL || nbytes < 0)
return -1;
else
{
current_process->terminal->write_lock = 1;
for(i=0; i<nbytes; i++)
{
if(current_process->terminal == curr_terminal)
{
screen_add_char(_buf[i],current_process->terminal);
}
storage_add_char(_buf[i],current_process->terminal);
}
clear_line_buffer(current_process->terminal);
current_process->terminal->write_lock = 0;
return i;
}
}
// Clear line of length len
void clear_line_buffer(int len){
clear_line_buffer(len,len);
}
int main()
{
std::vector<std::string> history;
std::string line;
char c;
unsigned int hist_idx;
unsigned int cursor;
// For every line
while (true) {
printf("> ");
line.clear();
hist_idx = history.size();
cursor = 0;
// For every char
while (true) {
c = getch();
// Handle backspace key
if (c == 127 && cursor > 0) {
clear_line_buffer(line.size(),cursor);
line.erase(--cursor,1);
printf("%s",line.c_str());
back_up_buffer(line.size()-cursor);
continue;
}
// Handle arrow keys
if (c == 27 && getch() == 91) {
switch (getch()) {
//Down Arrow
case 65:
if (hist_idx > 0){
clear_line_buffer(line.size(),cursor);
line = history.at(--hist_idx);
printf("%s",line.c_str());
cursor = line.size();
}
break;
// Up Arrow
case 66:
if (hist_idx+1 < history.size() ){
clear_line_buffer(line.size(),cursor);
line = history.at(++hist_idx);
printf("%s",line.c_str());
cursor = line.size();
}
break;
// Right Arrow
case 67:
if (cursor < line.size()) putchar(line.at(cursor++));
break;
// Left Arrow
case 68:
if (cursor > 0) {
putchar('\b');
cursor--;
}
break;
}
continue;
}
// Handle Enter key
if (c == 10){
putchar(10);
history.push_back(line);
line.clear();
break;
}
// Everything else
clear_line_buffer(line.size(),cursor);
line.insert(cursor++, 1, c);
printf("%s",line.c_str());
back_up_buffer(line.size()-cursor);
}
}
}
