[COMMIT seastar master] util/print_safe: dedup convert_hex_safe()

[Commit Bot]

From: Kefu Chai <kefu...@scylladb.com>
Committer: Kefu Chai <kefu...@scylladb.com>
Branch: master

util/print_safe: dedup convert_hex_safe()

* consolidate the implementation of `convert_hex_safe()` and
`convert_zero_padded_hex_safe()`. less repeatings this way.
* include used headers.

Signed-off-by: Kefu Chai <kefu...@scylladb.com>

---
diff --git a/include/seastar/util/print_safe.hh b/include/seastar/util/print_safe.hh
--- a/include/seastar/util/print_safe.hh
+++ b/include/seastar/util/print_safe.hh
@@ -22,10 +22,13 @@
#pragma once

#include <seastar/util/concepts.hh>
-#include <stdio.h>
+#include <cassert>
+#include <cstring>
#if __cplusplus > 201703L
#include <concepts>
#endif
+#include <stdio.h>
+#include <unistd.h>

namespace seastar {

@@ -64,11 +67,11 @@ void print_safe(const char *str) noexcept {
// Fills a buffer with a hexadecimal representation of an integer
// and returns a pointer to the first character.
// For example, convert_hex_safe(buf, 4, uint16_t(12)) fills the buffer with " c".
-template<typename Integral>
-SEASTAR_CONCEPT( requires std::is_integral_v<Integral> )
+template<typename Integral, char Padding = ' '>
+SEASTAR_CONCEPT( requires std::integral<Integral> )
char* convert_hex_safe(char *buf, size_t bufsz, Integral n) noexcept {
const char *digits = "0123456789abcdef";
- memset(buf, ' ', bufsz);
+ memset(buf, Padding, bufsz);
auto* p = buf + bufsz;
do {
assert(p > buf);
@@ -83,14 +86,7 @@ char* convert_hex_safe(char *buf, size_t bufsz, Integral n) noexcept {
template<typename Integral>
SEASTAR_CONCEPT( requires std::integral<Integral> )
void convert_zero_padded_hex_safe(char *buf, size_t bufsz, Integral n) noexcept {
- const char *digits = "0123456789abcdef";
- memset(buf, '0', bufsz);
- unsigned i = bufsz;
- while (n) {
- assert(i > 0);
- buf[--i] = digits[n & 0xf];
- n >>= 4;
- }
+ convert_hex_safe<'0'>(buf, bufsz, n);
}

// Prints zero-padded hexadecimal representation of an integer to stderr.