Little improved base64 implementation.

Global variable type changed from dynamic constructed std::string to constant char array.
Truncating conversion eliminated (no MSVC warning).
Unit tests added.

libdevcore/Base64.cpp

@@ -27,11 +27,9 @@
 /// Originally by René Nyffenegger, modified by some other guy and then devified by Gav Wood.
 
 #include "Base64.h"
-#include <iostream>
-using namespace std;
 using namespace dev;
 
-static const std::string base64_chars =
+static const char base64_chars[] =
 		"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 		"abcdefghijklmnopqrstuvwxyz"
 		"0123456789+/";
@@ -40,6 +38,11 @@ static inline bool is_base64(byte c) {
 	return (isalnum(c) || (c == '+') || (c == '/'));
 }
 
+static inline byte find_base64_char_index(byte c) {
+	auto it = std::find(base64_chars, base64_chars + sizeof(base64_chars), c);
+	return static_cast<byte>(it - base64_chars);
+}
+
 std::string dev::toBase64(bytesConstRef _in) {
 	std::string ret;
 	int i = 0;
@@ -85,7 +88,7 @@ std::string dev::toBase64(bytesConstRef _in) {
 }
 
 bytes dev::fromBase64(std::string const& encoded_string) {
-	int in_len = encoded_string.size();
+	auto in_len = encoded_string.size();
 	int i = 0;
 	int j = 0;
 	int in_ = 0;
@@ -94,9 +97,9 @@ bytes dev::fromBase64(std::string const& encoded_string) {
 
 	while (in_len-- && ( encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {
 		char_array_4[i++] = encoded_string[in_]; in_++;
-		if (i ==4) {
-			for (i = 0; i <4; i++)
-				char_array_4[i] = base64_chars.find(char_array_4[i]);
+		if (i == 4) {
+			for (i = 0; i < 4; i++)
+				char_array_4[i] = find_base64_char_index(char_array_4[i]);
 
 			char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
 			char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
@@ -109,11 +112,11 @@ bytes dev::fromBase64(std::string const& encoded_string) {
 	}
 
 	if (i) {
-		for (j = i; j <4; j++)
+		for (j = i; j < 4; j++)
 			char_array_4[j] = 0;
 
-		for (j = 0; j <4; j++)
-			char_array_4[j] = base64_chars.find(char_array_4[j]);
+		for (j = 0; j < 4; j++)
+		char_array_4[j] = find_base64_char_index(char_array_4[j]);
 
 		char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
 		char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);

libdevcore/Base64.h

@@ -28,7 +28,6 @@
 /// DEVified by Gav Wood.
 #pragma once
 
-#include <vector>
 #include <string>
 #include "Common.h"
 #include "FixedHash.h"

test/libdevcrypto/hexPrefix.cpp

@@ -27,6 +27,7 @@
 #include "../JsonSpiritHeaders.h"
 #include <libdevcore/Log.h>
 #include <libdevcore/CommonIO.h>
+#include <libdevcore/Base64.h>
 #include <libdevcrypto/TrieCommon.h>
 #include "../TestHelper.h"
 
@@ -60,4 +61,30 @@ BOOST_AUTO_TEST_CASE(hexPrefix_test)
 	}
 }
 
+BOOST_AUTO_TEST_CASE(base64)
+{
+	static char const* const s_tests[][2] = {
+		{"", ""},
+		{"f", "Zg=="},
+		{"fo", "Zm8="},
+		{"foo", "Zm9v"},
+		{"foob", "Zm9vYg=="},
+		{"fooba", "Zm9vYmE="},
+		{"foobar", "Zm9vYmFy"}
+	};
+	static const auto c_numTests = sizeof(s_tests) / sizeof(s_tests[0]);
+
+	for (size_t i = 0; i < c_numTests; ++i)
+	{
+		auto expectedDecoded = std::string{s_tests[i][0]};
+		auto expectedEncoded = std::string{s_tests[i][1]};
+
+		auto encoded = toBase64(expectedDecoded);
+		BOOST_CHECK_EQUAL(expectedEncoded, encoded);
+		auto decodedBytes = fromBase64(expectedEncoded);
+		auto decoded = bytesConstRef{decodedBytes.data(), decodedBytes.size()}.toString();
+		BOOST_CHECK_EQUAL(decoded, expectedDecoded);
+	}
+}
+
 BOOST_AUTO_TEST_SUITE_END()