commit: 46ec041c11acdc8a5bdac738685a45e84941cfc0
parent 24930bf695d343c6644504f63769e9ed881d040c
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date: Tue, 3 Sep 2024 21:42:31 +0200
cmd/printf: add support for \xHH backslash-escape
Diffstat:
2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/cmd/printf.1 b/cmd/printf.1
@@ -99,15 +99,22 @@ Write a <vertical tab> character.
Write a <single quote> character.
.It Cm \e\e
Write a backslash character.
+.It Cm \ex Ns Ar hex-num
+Write a byte whose
+value is the 1- or 2-digits
+hexadecimal number
+.Ar hex-num .
.It Cm \e Ns Ar num
Write a byte whose
value is the 1-, 2-, or 3-digit
octal number
.Ar num .
+.El
Multibyte characters can be constructed using multiple
+.Cm \ex Ns Ar hex-num
+or
.Cm \e Ns Ar num
sequences.
-.El
.Pp
Each format specification is introduced by the percent character
(``%'').
@@ -368,6 +375,9 @@ The
command is expected to be compatible with the
.St -p1003.2
specification.
+The
+.Cm \ex Ns Ar hex-num
+backslash-escape is an extension.
.Sh HISTORY
The
.Nm
diff --git a/cmd/printf.c b/cmd/printf.c
@@ -568,6 +568,22 @@ escape(char *fmt, int percent, size_t *len)
*store = '\v';
break;
/* octal constant */
+ case 'x': /* hex */
+ c = 2;
+ fmt++;
+ for(value = 0; c-- && isxdigit(*fmt); ++fmt)
+ {
+ value <<= 4;
+ if(*fmt <= '9')
+ value += *fmt - '0';
+ else if(*fmt <= 'F')
+ value += *fmt - 'A' + 10;
+ else
+ value += *fmt - 'a' + 10;
+ }
+ --fmt;
+ *store = (char)value;
+ break;
case '0':
case '1':
case '2':
