From ddbe2f089e698cc928e2f0539a3ff0c13ae9ebec Mon Sep 17 00:00:00 2001
From: mrbesen <y.g.2@gmx.de>
Date: Mon, 5 Oct 2020 13:35:42 +0200
Subject: [PATCH] base64, 16

---
 inc/util.h          |  4 ++++
 src/util.cpp        | 53 +++++++++++++++++++++++++++++++++++++++++++++
 tests/main.cpp      |  3 ++-
 tests/utilstest.cpp | 21 ++++++++++++++++++
 4 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/inc/util.h b/inc/util.h
index 117deea..875f6d0 100644
--- a/inc/util.h
+++ b/inc/util.h
@@ -26,6 +26,10 @@ unsigned int split(const std::string& str, const std::string& token, std::string
 
 void trim(std::string& str, char c = ' ');
 
+std::string bytesToBase16(char* buffer, unsigned int len);
+std::string bytesToBase64(char* buffer, unsigned int len);
+
+
 class StringSpliterator : public std::iterator<std::output_iterator_tag, std::string> {
 public:
 	StringSpliterator(const std::string& d, const std::string& token);
diff --git a/src/util.cpp b/src/util.cpp
index fa3b49f..1060fd9 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -129,6 +129,59 @@ void mrbesen::Util::trim(std::string& str, char c) {
 	str = str.substr(first, last-first);
 }
 
+std::string mrbesen::Util::bytesToBase16(char* buffer, unsigned int len) {
+	static const char hexmap[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
+	std::string s(len << 1, ' ');
+	for (unsigned int i = 0; i < len; ++i) {
+		s[ i<<1 ]     = hexmap[(buffer[i] & 0xF0) >> 4];
+		s[(i<<1) + 1] = hexmap[buffer[i] & 0x0F];
+	}
+	return s;
+}
+
+std::string mrbesen::Util::bytesToBase64(char* buffer, unsigned int len) {
+	//from: https://renenyffenegger.ch/notes/development/Base64/Encoding-and-decoding-base-64-with-cpp/index#cpp-base64-cpp
+
+	if(len == 0) return "";
+
+	const uint8_t overlen = len % 3;
+	const uint8_t len_padding = overlen ? (3 - overlen) : 0; //anzahl benötigter padding chars
+	size_t len_encoded = (len+2) / 3 * 4;
+
+	static const unsigned char trailing_char = '=';
+	static const char* base64_chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
+
+	std::string ret;
+	ret.reserve(len_encoded);
+
+	char nextb = 0;
+	for(unsigned int pos = 0; pos < len; pos ++) {
+		const char c = buffer[pos];
+		uint8_t tripos = pos % 3; //position im trible
+		uint8_t maskShift = (1+tripos) << 1; //2, 4, 6
+		uint8_t mask = 0xff << maskShift;
+		ret.push_back(base64_chars[((c & mask) >> maskShift) | nextb]);
+
+		if(tripos == 2) {
+			ret.push_back(base64_chars[c & ~mask]);
+			nextb = 0;
+		} else {
+			uint8_t invmaskShift = 6 - maskShift;
+			nextb = (c & ~mask) << invmaskShift;
+		}
+	}
+
+	if(nextb)
+		ret.push_back(base64_chars[(int) nextb]);
+
+	for(uint8_t i = 0; i < len_padding; ++i) {
+		ret.push_back(trailing_char);
+	}
+
+	return ret;
+}
+
+
 mrbesen::Util::StringSpliterator::StringSpliterator(const std::string& d, const std::string& token) : data(d), token(token) {
 	//trim
 	while(mrbesen::Util::removeStart(data, token));
diff --git a/tests/main.cpp b/tests/main.cpp
index 757a3c4..29fb975 100644
--- a/tests/main.cpp
+++ b/tests/main.cpp
@@ -14,12 +14,13 @@ int testUtil_start_endWith();
 int testUtil_removeStart_End();
 int testUtil_insertStart_End();
 int testUtil_trim();
+int testUtil_base();
 
 int testStringSpliterator();
 int testUtilSplit();
 
 test_t tests[] = {testFiles_parent, testFiles_file, testFiles_extention, testFiles_scan,
-	testUtil_Count, testUtil_equalsIgnoreCase, testUtil_toLower, testUtil_start_endWith, testUtil_removeStart_End, testUtil_insertStart_End, testUtil_trim,
+	testUtil_Count, testUtil_equalsIgnoreCase, testUtil_toLower, testUtil_start_endWith, testUtil_removeStart_End, testUtil_insertStart_End, testUtil_trim, testUtil_base,
 	testStringSpliterator, testUtilSplit,
 	NULL};
 
diff --git a/tests/utilstest.cpp b/tests/utilstest.cpp
index 181d1c8..75cc5cb 100644
--- a/tests/utilstest.cpp
+++ b/tests/utilstest.cpp
@@ -167,5 +167,26 @@ int testUtil_trim() {
 	trim(a);
 	ASSERT(a == "", a);
 
+	return TESTGOOD;
+}
+
+int testUtil_base() {
+	char buf[] {0, (char) 0xAB, (char) 0x12, (char) 0xCD, (char) 0x34};
+
+	std::string ret = bytesToBase16(buf, 5);
+	ASSERT(ret == "00ab12cd34", ret);
+
+	ret = bytesToBase64(buf, 5);
+	ASSERT(ret == "AKsSzTQ=", ret);
+
+	ret = bytesToBase64(buf, 4);
+	ASSERT(ret == "AKsSzQ==", ret);
+
+	ret = bytesToBase64(buf, 3);
+	ASSERT(ret == "AKsS", ret);
+
+	ret = bytesToBase64(buf, 0);
+	ASSERT(ret == "", ret);
+
 	return TESTGOOD;
 }
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