From 7084fb70257871d60a3ad70a2c98fec67a8f7d52 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gr=C3=A9gory=20Soutad=C3=A9?= <soutade@gmail.com>
Date: Sat, 27 Aug 2022 15:40:32 +0200
Subject: [PATCH] Add fromHex() static function to ByteArray

---
 include/bytearray.h |  9 ++++++++-
 src/bytearray.cpp   | 42 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/include/bytearray.h b/include/bytearray.h
index e2f8d29..8fb7680 100644
--- a/include/bytearray.h
+++ b/include/bytearray.h
@@ -104,6 +104,13 @@ namespace gourou
 	 */
 	std::string toBase64();
 
+	/**
+	 * @brief Convert hex string into bytes
+	 *
+	 * @param str     Hex string
+	 */
+	static ByteArray fromHex(const std::string& str);
+
 	/**
 	 * @brief Return a string with human readable hex encoded internal data
 	 */
@@ -130,7 +137,7 @@ namespace gourou
 	void append(const std::string& str);
 
 	/**
-	 * @brief Get internal data. Must bot be freed
+	 * @brief Get internal data. Must not be freed
 	 */
 	unsigned char* data() {return _data;}
 
diff --git a/src/bytearray.cpp b/src/bytearray.cpp
index fdaeed9..f7ec87f 100644
--- a/src/bytearray.cpp
+++ b/src/bytearray.cpp
@@ -17,6 +17,7 @@
   along with libgourou. If not, see <http://www.gnu.org/licenses/>.
 */
 #include <string.h>
+#include <stdexcept>
 
 #include <Base64.h>
 
@@ -155,6 +156,47 @@ namespace gourou
 	return macaron::Base64::Encode(std::string((char*)_data, _length));
     }
 
+    ByteArray ByteArray::fromHex(const std::string& str)
+    {
+	if (str.size() % 2)
+	    throw std::invalid_argument("Size of hex string not multiple of 2");
+
+	ByteArray res((unsigned int)(str.size()/2));
+	unsigned int i;
+
+	unsigned char* data = res.data();
+	unsigned char cur, tmp;
+	
+	for (i=0; i<str.size(); i+=2)
+	{
+	    cur = 0;
+
+	    tmp = str[i];
+	    if (tmp >= 'a' && tmp <= 'f')
+		cur = (tmp - 'a' + 10) << 4;
+	    else if (tmp >= 'A' && tmp <= 'F')
+		cur = (tmp - 'A' + 10) << 4;
+	    else if (tmp >= '0' && tmp <= '9')
+		cur = (tmp - '0') << 4;
+	    else
+		throw std::invalid_argument("Invalid character in hex string");
+
+	    tmp = str[i+1];
+	    if (tmp >= 'a' && tmp <= 'f')
+		cur += tmp - 'a' + 10;
+	    else if (tmp >= 'A' && tmp <= 'F')
+		cur += tmp - 'A' + 10;
+	    else if (tmp >= '0' && tmp <= '9')
+		cur += tmp - '0';
+	    else
+		throw std::invalid_argument("Invalid character in hex string");
+
+	    data[i/2] = cur;
+	}
+	
+	return res;
+    }
+    
     std::string ByteArray::toHex()
     {
 	char* tmp = new char[_length*2+1];