ssl: factorize and improved hex conversion code

Add inline qualifier to avoid exporting a function for one unique use

Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/24968)

1 files changed, 27 insertions, 0 deletions

diff --git a/include/internal/to_hex.h b/include/internal/to_hex.h
new file mode 100644
index 0000000..e37e9f0
--- /dev/null
+++ b/include/internal/to_hex.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2024 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#ifndef OSSL_INTERNAL_TO_HEX_H
+# define OSSL_INTERNAL_TO_HEX_H
+# pragma once
+
+static ossl_inline size_t to_hex(char *buf, uint8_t n, const char hexdig[17])
+{
+    *buf++ = hexdig[(n >> 4) & 0xf];
+    *buf = hexdig[n & 0xf];
+    return 2;
+}
+
+static ossl_inline size_t ossl_to_lowerhex(char *buf, uint8_t n)
+{
+    static const char hexdig[] = "0123456789abcdef";
+
+    return to_hex(buf, n, hexdig);
+}
+#endif