Make ot::encoding_converter use string views

src/cli.cc

@@ -86,14 +86,14 @@ ot::status ot::parse_options(int argc, char** argv, ot::options& opt, FILE* comm
 			opt.overwrite = true;
 			break;
 		case 'd':
-			rc = to_utf8(optarg, strlen(optarg), utf8);
+			rc = to_utf8(optarg, utf8);
 			if (rc != ot::st::ok)
 				return {st::bad_arguments, "Could not encode argument into UTF-8: " + rc.message};
 			opt.to_delete.emplace_back(std::move(utf8));
 			break;
 		case 'a':
 		case 's':
-			rc = to_utf8(optarg, strlen(optarg), utf8);
+			rc = to_utf8(optarg, utf8);
 			if (rc != ot::st::ok)
 				return {st::bad_arguments, "Could not encode argument into UTF-8: " + rc.message};
 			if ((equal = utf8.find('=')) == std::string::npos)
@@ -225,7 +225,7 @@ ot::status ot::read_comments(FILE* input, std::list<std::string>& comments)
 			return rc;
 		}
 		std::string utf8;
-		ot::status rc = to_utf8(line, nread, utf8);
+		ot::status rc = to_utf8(std::string_view(line, nread), utf8);
 		if (rc == ot::st::ok) {
 			comments.emplace_back(std::move(utf8));
 		} else {

src/opustags.h

@@ -161,9 +161,7 @@ class encoding_converter {
 	 * abort the processing. If some character could not be converted perfectly, keep converting
 	 * the string and finally return #st::information_lost.
 	 */
-	status operator()(const std::string& in, std::string& out)
-		{ return (*this)(in.data(), in.size(), out); }
-	status operator()(const char* in, size_t n, std::string& out);
+	status operator()(std::string_view in, std::string& out);
 private:
 	iconv_t cd; /**< conversion descriptor */
 };

src/system.cc

@@ -104,13 +104,13 @@ ot::encoding_converter::~encoding_converter()
 	iconv_close(cd);
 }
 
-ot::status ot::encoding_converter::operator()(const char* in, size_t n, std::string& out)
+ot::status ot::encoding_converter::operator()(std::string_view in, std::string& out)
 {
 	iconv(cd, nullptr, nullptr, nullptr, nullptr);
 	out.clear();
-	out.reserve(n);
-	char* in_cursor = const_cast<char*>(in);
-	size_t in_left = n;
+	out.reserve(in.size());
+	char* in_cursor = const_cast<char*>(in.data());
+	size_t in_left = in.size();
 	constexpr size_t chunk_size = 1024;
 	char chunk[chunk_size];
 	bool lost_information = false;
@@ -130,7 +130,7 @@ ot::status ot::encoding_converter::operator()(const char* in, size_t n, std::str
 			break;
 		} else if (rc == (size_t) -1 && errno != E2BIG) {
 			return {ot::st::badly_encoded,
-			        "Could not convert string '" + std::string(in, n) + "': " +
+			        "Could not convert string '" + std::string(in) + "': " +
 			        strerror(errno)};
 		} else if (rc != 0 && rc != (size_t) -1) {
 			lost_information = true;