1 /**

     2  * Relational pipes

     3  * Copyright © 2020 František Kučera (Frantovo.cz, GlobalCode.info)

     4  *

     5  * This program is free software: you can redistribute it and/or modify

     6  * it under the terms of the GNU General Public License as published by

     7  * the Free Software Foundation, version 3 of the License.

     8  *

     9  * This program is distributed in the hope that it will be useful,

    10  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

    12  * GNU General Public License for more details.

    13  *

    14  * You should have received a copy of the GNU General Public License

    15  * along with this program. If not, see <http://www.gnu.org/licenses/>.

    16  */

    17 #pragma once

    18 

    19 #include <sstream>

    20 

    21 #include "UnescapingProcessor.h"

    22 

    23 using namespace std;

    24 using namespace relpipe::writer;

    25 

    26 namespace relpipe {

    27 namespace in {

    28 namespace ini {

    29 namespace lib {

    30 

    31 class BackspaceUnescapingProcessor : public UnescapingProcessor {

    32 private:

    33 	const bool lastEscaphingPhase = true;

    34 public:

    35 

    36 	std::string unescape(const std::string& s, const TextType type) override {

    37 		std::stringstream result;

    38 		for (int i = 0, length = s.size(); i < length; i++) {

    39 			char ch = s[i];

    40 			if (i + 1 < length && ch == ESC) {

    41 				ch = s[i + 1];

    42 				if (ch == ESC) put(result, ESC, i); // unescape \\ to \.

    43 				else if (lastEscaphingPhase) throw std::logic_error(std::string("Unsupported escape sequence: ") + ch);

    44 				else result.put(ESC); // keep the escape sequence for later unescaping phase

    45 			} else if (ch == ESC) {

    46 				throw std::logic_error(std::string("Missing escape sequence")); // this should not happen

    47 			} else {

    48 				result.put(ch);

    49 			}

    50 		}

    51 		return result.str();

    52 	}

    53 

    54 	/**

    55 	 * @param lastEscaphingPhase whether this is final unescaping stage.

    56 	 * By default it is set to true, thus no unrecognized escape sequences may left after this stage.

    57 	 * Setting this to false is dangerous and may lead to errors and ambiguous behavior.

    58 	 * It should be used only as a last resort.

    59 	 * Because both "\\ \xxx" and "\ \xxx" will be converted to "\ \xxx" and the information will be lost.

    60 	 * So, it is usually better to keep the "\" escaped as "\\" and process both the escaped backspaces and unrecognized escape sequences later.

    61 	 */

    62 	BackspaceUnescapingProcessor(bool lastEscaphingPhase = true) : lastEscaphingPhase(lastEscaphingPhase) {

    63 	}

    64 

    65 };

    66 

    67 }

    68 }

    69 }

    70 }