Merge pull request #15516 from opensourcerouting/freebsd-printf-sync-20240310

lib/printf: pick up ISO C23 / N2680 from FreeBSD

doc/developer/logging.rst

@@ -77,7 +77,14 @@ are available:
 
 .. note::
 
-   ``printfrr()`` does not support the ``%n`` format.
+   ``printfrr()`` does not support the ``%n`` format.  It does support ISO C23
+   ``%b``, ``%w99d`` and ``%wf99d`` additions, but the latter two are not
+   supported by the ``frr-format`` plugin yet, and all 3 aren't supported by
+   the older compilers still in use on some supported platforms.
+
+   ``%b`` can be used with ``FMT_NSTD``, but ``%w99d`` and ``%wf99d`` require
+   work in the ``frr-format`` plugin before they are really usable.
+
 
 AS-Safety
 ^^^^^^^^^
@@ -557,8 +564,9 @@ Integer formats
    cause compiler warnings when used without the plugin.  Use with
    :c:macro:`FMT_NSTD` if necessary.
 
-   It is possible ISO C23 may introduce another format for these, possibly
-   ``%w64d`` discussed in `JTC 1/SC 22/WG 14/N2680 <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2680.pdf>`_.
+   As anticipated, ISO C23 has introduced new modifiers for this, specifically
+   ``%w64d`` (= ``%Ld``) and ``%w64u`` (= ``%Lu``).  Unfortunately, these new
+   modifiers are not supported by ``frr-format`` yet.
 
 .. frrfmt:: %Lu (uint64_t)
 

lib/printf/README

@@ -1,6 +1,7 @@
 This is the printf implementation from FreeBSD.  The history of this code is:
 - imported on 2019-05-12, from SVN revision 347514
 - resynced on 2023-09-03, to pick up `%b` implementation
+- resynced on 2024-03-10, to pick up `%w[f](8|16|32|64)d` implementation
 
 Please don't reindent or otherwise mangle the files to make importing fixes
 easy (not that there are significant changes likely to happen...)

lib/printf/printflocal.h

@@ -52,6 +52,7 @@
 #define	PTRDIFFT	0x800		/* ptrdiff_t */
 #define	INTMAXT		0x1000		/* intmax_t */
 #define	CHARINT		0x2000		/* print char using int format */
+#define	FASTINT		0x4000		/* int_fastN_t */
 
 /*
  * Macros for converting digits to letters and vice versa

lib/printf/vfprintf.c

@@ -416,6 +416,49 @@ reswitch:	switch (ch) {
 		case 't':
 			flags |= PTRDIFFT;
 			goto rflag;
+		case 'w':
+			/*
+			 * Fixed-width integer types.  On all platforms we
+			 * support, int8_t is equivalent to char, int16_t
+			 * is equivalent to short, int32_t is equivalent
+			 * to int, int64_t is equivalent to long long int.
+			 * Furthermore, int_fast8_t, int_fast16_t and
+			 * int_fast32_t are equivalent to int, and
+			 * int_fast64_t is equivalent to long long int.
+			 */
+			flags &= ~(CHARINT|SHORTINT|LONGINT|LLONGINT|INTMAXT);
+			if (fmt[0] == 'f') {
+				flags |= FASTINT;
+				fmt++;
+			} else {
+				flags &= ~FASTINT;
+			}
+			if (fmt[0] == '8') {
+				if (!(flags & FASTINT))
+					flags |= CHARINT;
+				else
+					(void) 0;	/* no flag set = 32 */
+				fmt += 1;
+			} else if (fmt[0] == '1' && fmt[1] == '6') {
+				if (!(flags & FASTINT))
+					flags |= SHORTINT;
+				else
+					(void) 0;	/* no flag set = 32 */
+				fmt += 2;
+			} else if (fmt[0] == '3' && fmt[1] == '2') {
+				/* no flag set = 32 */
+				fmt += 2;
+			} else if (fmt[0] == '6' && fmt[1] == '4') {
+				flags |= LLONGINT;
+				fmt += 2;
+			} else {
+				if (flags & FASTINT) {
+					flags &= ~FASTINT;
+					fmt--;
+				}
+				goto invalid;
+			}
+			goto rflag;
 		case 'z':
 			flags |= SIZET;
 			goto rflag;
@@ -684,6 +727,7 @@ number:			if ((dprec = prec) >= 0)
 		default:	/* "%?" prints ?, unless ? is NUL */
 			if (ch == '\0')
 				goto done;
+invalid:
 			/* pretend it was %c with argument ch */
 			buf[0] = ch;
 			cp = buf;

tests/lib/test_printfrr.c

@@ -143,6 +143,8 @@ int main(int argc, char **argv)
 		NAN,
 	};
 	uint64_t ui64 = 0xfeed1278cafef00d;
+	uint16_t i16 = -23456;
+	int_fast8_t if8 = 123;
 	struct in_addr ip;
 	char *p;
 	char buf[256];
@@ -169,6 +171,16 @@ int main(int argc, char **argv)
 	FMT_NSTD(printchk("11110000000011111010010111000011", "%b", 0xf00fa5c3));
 	FMT_NSTD(printchk("0b01011010", "%#010b", 0x5a));
 
+/* FMT_NSTD is conditional on the frr-format plugin being NOT enabled.
+ * However, the frr-format plugin does not support %wd/%wfd yet, so this needs
+ * to be unconditional.
+ */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat"
+	printchk("123 -23456 feed1278cafef00d 9876", "%wf8d %w16d %w64x %d",
+		 if8, i16, ui64, 9876);
+#pragma GCC diagnostic pop
+
 	inet_aton("192.168.1.2", &ip);
 	printchk("192.168.1.2", "%pI4", &ip);
 	printchk("         192.168.1.2", "%20pI4", &ip);