[PATCH v4 10/34] lib/pretty-printers: prt_string_option(), prt_bitflags()

[Kent Overstreet <kent.overstreet@gmail.com>]

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
---
 include/linux/pretty-printers.h | 10 ++++++
 lib/Makefile                    |  2 +-
 lib/pretty-printers.c           | 60 +++++++++++++++++++++++++++++++++
 3 files changed, 71 insertions(+), 1 deletion(-)
 create mode 100644 include/linux/pretty-printers.h
 create mode 100644 lib/pretty-printers.c

diff --git a/include/linux/pretty-printers.h b/include/linux/pretty-printers.h
new file mode 100644
index 0000000000..f39d8edfba
--- /dev/null
+++ b/include/linux/pretty-printers.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+/* Copyright (C) 2022 Kent Overstreet */
+
+#ifndef _LINUX_PRETTY_PRINTERS_H
+#define _LINUX_PRETTY_PRINTERS_H
+
+void prt_string_option(struct printbuf *, const char * const[], size_t);
+void prt_bitflags(struct printbuf *, const char * const[], u64);
+
+#endif /* _LINUX_PRETTY_PRINTERS_H */
diff --git a/lib/Makefile b/lib/Makefile
index b4609a4258..b520024852 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -34,7 +34,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 is_single_threaded.o plist.o decompress.o kobject_uevent.o \
 	 earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
 	 nmi_backtrace.o nodemask.o win_minmax.o memcat_p.o \
-	 buildid.o printbuf.o
+	 buildid.o printbuf.o pretty-printers.o
 
 lib-$(CONFIG_PRINTK) += dump_stack.o
 lib-$(CONFIG_SMP) += cpumask.o
diff --git a/lib/pretty-printers.c b/lib/pretty-printers.c
new file mode 100644
index 0000000000..addbac95e0
--- /dev/null
+++ b/lib/pretty-printers.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: LGPL-2.1+
+/* Copyright (C) 2022 Kent Overstreet */
+
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/printbuf.h>
+#include <linux/pretty-printers.h>
+
+/**
+ * prt_string_option - Given a list of strings, print out the list and indicate
+ * which option is selected, with square brackets (sysfs style)
+ *
+ * @out: The printbuf to output to
+ * @list: List of strings to choose from
+ * @selected: The option to highlight, with square brackets
+ */
+void prt_string_option(struct printbuf *out,
+		       const char * const list[],
+		       size_t selected)
+{
+	size_t i;
+
+	for (i = 0; list[i]; i++) {
+		if (i)
+			prt_char(out, ' ');
+		if (i == selected)
+			prt_char(out, '[');
+		prt_str(out, list[i]);
+		if (i == selected)
+			prt_char(out, ']');
+	}
+}
+EXPORT_SYMBOL(prt_string_option);
+
+/**
+ * prt_bitflags: Given a bitmap and a list of names for each bit, print out which
+ * bits are on, comma separated
+ *
+ * @out: The printbuf to output to
+ * @list: List of names for each bit
+ * @flags: Bits to print
+ */
+void prt_bitflags(struct printbuf *out,
+		  const char * const list[], u64 flags)
+{
+	unsigned bit, nr = 0;
+	bool first = true;
+
+	while (list[nr])
+		nr++;
+
+	while (flags && (bit = __ffs(flags)) < nr) {
+		if (!first)
+			prt_char(out, ',');
+		first = false;
+		prt_str(out, list[bit]);
+		flags ^= 1 << bit;
+	}
+}
+EXPORT_SYMBOL(prt_bitflags);
-- 
2.36.1