splitlines.hpp

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//    OpenVPN -- An application to securely tunnel IP networks
//               over a single port, with support for SSL/TLS-based
//               session authentication and key exchange,
//               packet encryption, packet authentication, and
//               packet compression.
//
//    Copyright (C) 2012- OpenVPN Inc.
//
//    SPDX-License-Identifier: MPL-2.0 OR AGPL-3.0-only WITH openvpn3-openssl-exception
//
 
// General purpose class to split a multi-line string into lines.
 
#ifndef OPENVPN_COMMON_SPLITLINES_H
#define OPENVPN_COMMON_SPLITLINES_H
 
#include <utility>
 
#include <openvpn/common/string.hpp>
 
namespace openvpn {
template <typename STRING>
class SplitLinesType
{
  public:
    OPENVPN_EXCEPTION(overflow_error);
    OPENVPN_EXCEPTION(moved_error);
 
    SplitLinesType(const STRING &str, const size_t max_line_len_arg = 0)
        : data((const char *)str.c_str()),
          size(str.length()),
          max_line_len(max_line_len_arg)
    {
    }
 
    bool operator()(const bool trim = true)
    {
        line.clear();
        overflow = false;
        line_valid = true;
        const size_t overflow_index = index + max_line_len;
        while (index < size)
        {
            if (max_line_len && index >= overflow_index)
            {
                overflow = true;
                return true;
            }
            const char c = data[index++];
            line += c;
            if (c == '\n' || index >= size)
            {
                if (trim)
                    string::trim_crlf(line);
                return true;
            }
        }
        line_valid = false;
        return false;
    }
 
    bool line_overflow() const
    {
        return overflow;
    }
 
    std::string &line_ref()
    {
        validate();
        return line;
    }
 
    const std::string &line_ref() const
    {
        validate();
        return line;
    }
 
    std::string line_move()
    {
        validate();
        line_valid = false;
        return std::move(line);
    }
 
    enum Status
    {
        S_OKAY, 
        S_EOF,  
        S_ERROR 
    };
 
    Status next(std::string &ln, const bool trim = true)
    {
        const bool s = (*this)(trim);
        if (!s)
            return S_EOF;
        if (overflow)
            return S_ERROR;
        ln = std::move(line);
        line_valid = false;
        return S_OKAY;
    }
 
  private:
    void validate()
    {
        if (!line_valid)
            throw moved_error();
        if (overflow)
            throw overflow_error(line);
    }
 
    const char *data;
    size_t size;
    const size_t max_line_len;
    size_t index = 0;
    std::string line;
    bool line_valid = false;
    bool overflow = false;
};
 
typedef SplitLinesType<std::string> SplitLines;
} // namespace openvpn
 
#endif