hothouse-mon/Core/Src/terminal.c

/*
 * terminal.c
 *
 *  Created on: Aug 2, 2022
 *      Author: daniel.chokola
 */

/* Includes */
#include <string.h>
#include <stdarg.h>
#include "config.h"
#include "terminal.h"

/* Private Variables */
static char wbuf[TERM_RXBUF_LEN]; /* working buffer */
static char rxbuf[TERM_RXBUF_LEN]; /* receive buffer */
static uint32_t rxlen;
static int8_t rxline;

/* Function Prototypes */
__attribute__((always_inline)) inline int8_t term_is_whitespace(char c)
{
	if(c == '\n' ||
	   c == '\r' ||
	   c == '\t' ||
	   c == '\v' ||
	   c == '\f' ||
	   c == ' ')
	{
		return !0;
	}

	return 0;
}
static int32_t term_stripn(char *buf, int32_t n);

/* Function Definitions */
void term_prompt()
{
	term_printf("\r%s-g%s $ ", APP_NAME, GIT_REV);
}

void term_rx(char *buf, uint32_t len)
{
	uint32_t i;
	char c;

	for(i = 0; i < len; i++)
	{
		c = buf[i];

		/* ignore null bytes */
		if(c == '\0')
		{
			continue;
		}
		/* handle backspace */
		if(c == '\b')
		{
			if(rxlen)
			{
				rxlen--;
			}
			rxbuf[rxlen] = '\0';
			if(rxlen)
			{
				/* term_printf("\b\x1b[0K"); */
			}

			continue;
		}
		/* handle escape sequences */
		if(c == '\x1b')
		{
			c = '^';
		}

		rxbuf[rxlen++] = (char) c;
		/* local echo */
		/* term_printf("%c", c); */
		if(c == '\n' || c == '\r')
		{
			/* EOL */
			rxbuf[rxlen - 1] = '\0';
			rxline = 1;
		}
	}
}

void term_printf(const char *fmt, ...)
{
	va_list args;
	int32_t len;
	uint8_t res;

	va_start(args, fmt);
	len = vsprintf(wbuf, fmt, args);
	va_end(args);

	/* FIXME: this will lock up if there's too much Tx/Rx traffic */
	do
	{
		res = CDC_Transmit_FS((uint8_t *) wbuf, (uint16_t) len);
	}
	while(res == USBD_BUSY);
}

/* strip trailing whitespace from a string of length n */
static int32_t term_stripn(char *buf, int32_t n)
{
	int32_t i = n - 1;

	while(i >= 0)
	{
		if(term_is_whitespace(buf[i]))
		{
			buf[i--] = '\0';
		}
		else if(buf[i] == '\0')
		{
			i--;
			continue;
		}
		else
		{
			break;
		}
	}

	return i + 1;
}