use print library instead of stdio

main.c

@@ -20,11 +20,8 @@
 
 /* standard libraries */
 #include <stdint.h> // standard integer types
-#include <stdio.h> // standard I/O facilities
 #include <stdlib.h> // standard utilities
-#include <unistd.h> // standard streams
 #include <string.h> // string utilities
-#include <math.h> // mathematical utilities
 
 /* STM32 (including CM3) libraries */
 #include <libopencmsis/core_cm3.h> // Cortex M3 utilities
@@ -40,6 +37,7 @@
 
 /* own libraries */
 #include "global.h" // board definitions
+#include "print.h" // printing utilities
 #include "usart.h" // USART utilities
 #include "usb_cdcacm.h" // USB CDC ACM utilities
 
@@ -51,33 +49,31 @@
 volatile bool rtc_internal_tick_flag = false; /**< flag set when internal RTC ticked */
 /** @} */
 
-int _write(int file, char *ptr, int len)
-{
-	int i; // how much data has been sent
-	static char newline = 0; // what newline has been sent
 
-	if (file == STDOUT_FILENO || file == STDERR_FILENO) {
-		for (i = 0; i < len; i++) {
-			if (ptr[i] == '\r' || ptr[i] == '\n') { // send CR+LF newline for most carriage return and line feed combination
-				if (newline==0 || (newline==ptr[i])) { // newline has already been detected
-					usart_putchar_nonblocking('\r'); // send newline over USART
-					usart_putchar_nonblocking('\n'); // send newline over USART
-					cdcacm_putchar('\r'); // send newline over USB
-					cdcacm_putchar('\n'); // send newline over USB
-					newline = ptr[i]; // remember the newline
-				}
-				if (ptr[i] == '\n') { // line feed are always considered to end a line (the LF+CR combination is not supported to better support the others)
-					newline = 0; // clear new line
-				}
-			} else { // non-newline character
-				usart_putchar_nonblocking(ptr[i]); // send byte over USART
-				cdcacm_putchar(ptr[i]); // send byte over USB
-				newline = 0; // clear new line
-			}
+size_t putc(char c)
+{
+	size_t length = 0; // number of characters printed
+	static char newline = 0; // to remember on which character we sent the newline
+	if (0==c) {
+		length = 0; // don't print string termination character
+	} else if ('\r' == c || '\n' == c) { // send CR+LF newline for most carriage return and line feed combination
+		if (0==newline || c==newline) { // send newline only if not already send (and only once on \r\n or \n\r)
+			usart_putchar_nonblocking('\r'); // send CR over USART
+			cdcacm_putchar('\r'); // send CR over USB
+			usart_putchar_nonblocking('\n'); // send LF over USART
+			cdcacm_putchar('\n'); // send LF over USB
+			length += 2; // remember we printed 2 characters
+			newline = c; // remember on which character we sent the newline
+		} else {
+			length = 0; // the \r or \n of \n\r or \r\n has already been printed
 		}
-		return i;
+	} else {
+		usart_putchar_nonblocking(c); // send byte over USART
+		cdcacm_putchar(c); // send byte over USB
+		newline = 0; // clear new line
+		length++; // remember we printed 1 character
 	}
-	return -1;
+	return length; // return number of characters printed   
 }
 
 /** user input command */
@@ -149,16 +145,9 @@ void main(void)
 	iwdg_start(); // start independent watchdog
 #endif
 
-	// setup board
-	board_setup();
-	
-	// setup USART and USB for user communication
+	board_setup(); // setup board
     usart_setup(); // setup USART (for printing)
 	cdcacm_setup(); // setup USB CDC ACM (for printing)
-	setbuf(stdout, NULL); // set standard out buffer to NULL to immediately print
-	setbuf(stderr, NULL); // set standard error buffer to NULL to immediately print
-
-	// minimal setup ready	
 	printf("welcome to the STM32F1 CuVoodoo example code\n"); // print welcome message
 
 #if !(DEBUG)