Fix overflow in octal formatting in echo, add support for hexadecimal input, add tests for octal and hexadecimal formatting

1 files changed, 26 insertions, 12 deletions

diff --git a/toys/echo.c b/toys/echo.c
index 5feb9899..f7c423cf 100644
--- a/toys/echo.c
+++ b/toys/echo.c
@@ -17,17 +17,19 @@ config ECHO
 	  Write each argument to stdout, with one space between each, followed
 	  by a newline.
 
-	  -n	No trailing newline.
-	  -e	Process the following escape sequences:
-	  	\\	backslash
-	  	\a	alert (beep/flash)
-	  	\b	backspace
-	  	\c	Stop output here (avoids trailing newline)
-	  	\f	form feed
-	  	\n	newline
-	  	\r	carriage return
-	  	\t	horizontal tab
-	  	\v	vertical tab
+	  -n    No trailing newline.
+	  -e    Process the following escape sequences:
+	   \\     backslash
+	   \0NNN octal values (1 to 3 digits)
+	   \a    alert (beep/flash)
+	   \b    backspace
+	   \c    stop output here (avoids trailing newline)
+	   \f    form feed
+	   \n    newline
+	   \r    carriage return
+	   \t    horizontal tab
+	   \v    vertical tab
+	   \xHH  hexadecimal values (1 to 2 digits)
 */
 
 #include "toys.h"
@@ -60,10 +62,22 @@ void echo_main(void)
 						if (found) c = to[found-from];
 						else if (d == 'c') goto done;
 						else if (d == '0') {
+							int n = 0;
 							c = 0;
-							while (arg[j]>='0' && arg[j]<='7')
+							while (arg[j]>='0' && arg[j]<='7' && n++<3)
 								c = (c*8)+arg[j++]-'0';
 						}
+						else if (d == 'x') {
+							int n = 0;
+							c = 0;							
+							while (n++<2)
+								if (arg[j]>='0' && arg[j]<='9')
+									c = (c*16)+arg[j++]-'0';
+								else if (tolower(arg[j])>='a' && tolower(arg[j])<='f')
+									c = (c*16)+tolower(arg[j++])-'a'+10;
+								else
+									break;							
+						}
 					}
 				}
 				xputc(c);