From 9f90f31291c64088f5baedcda4e03759a448ce53 Mon Sep 17 00:00:00 2001
From: Toon Stegen <tstegen@nalys-group.com>
Date: Wed, 1 Aug 2018 18:09:41 +0200
Subject: [PATCH] sys/fmt: add function for converting hex byte
---
sys/fmt/fmt.c | 7 ++++++-
sys/include/fmt.h | 11 +++++++++++
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/sys/fmt/fmt.c b/sys/fmt/fmt.c
index 5ea21e8b8e..0c7fa2c7f5 100644
--- a/sys/fmt/fmt.c
+++ b/sys/fmt/fmt.c
@@ -132,6 +132,11 @@ static uint8_t _hex_nib(uint8_t nib)
return _byte_mod25((nib & 0x1f) + 9);
}
+uint8_t fmt_hex_byte(const char *hex)
+{
+ return (_hex_nib(hex[0]) << 4) | _hex_nib(hex[1]);
+}
+
size_t fmt_hex_bytes(uint8_t *out, const char *hex)
{
size_t len = fmt_strlen(hex);
@@ -143,7 +148,7 @@ size_t fmt_hex_bytes(uint8_t *out, const char *hex)
size_t final_len = len >> 1;
for (size_t i = 0, j = 0; j < final_len; i += 2, j++) {
- out[j] = (_hex_nib(hex[i]) << 4) | _hex_nib(hex[i+1]);
+ out[j] = fmt_hex_byte(hex + i);
}
return final_len;
diff --git a/sys/include/fmt.h b/sys/include/fmt.h
index 229f939611..7176494d30 100644
--- a/sys/include/fmt.h
+++ b/sys/include/fmt.h
@@ -91,6 +91,17 @@ size_t fmt_bytes_hex(char *out, const uint8_t *ptr, size_t n);
*/
size_t fmt_bytes_hex_reverse(char *out, const uint8_t *ptr, size_t n);
+/**
+ * @brief Converts a sequence of two hex characters to a byte
+ *
+ * The hex characters sequence must contain valid hexadecimal characters
+ * otherwise the result is undefined.
+ *
+ * @param[in] hex Pointer to input buffer
+ * @returns byte based on hex string
+ */
+uint8_t fmt_hex_byte(const char *hex);
+
/**
* @brief Converts a sequence of hex bytes to an array of bytes
*
--
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