lnav/src/base/string_util.cc

/**
 * Copyright (c) 2019, Timothy Stack
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * * Neither the name of Timothy Stack nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <algorithm>
#include <iterator>
#include <regex>
#include <sstream>

#include "string_util.hh"

#include "config.h"
#include "is_utf8.hh"
#include "lnav_log.hh"

void
scrub_to_utf8(char* buffer, size_t length)
{
    const char* msg;
    int faulty_bytes;

    while (true) {
        ssize_t utf8_end
            = is_utf8((unsigned char*) buffer, length, &msg, &faulty_bytes);

        if (msg == nullptr) {
            break;
        }
        for (int lpc = 0; lpc < faulty_bytes; lpc++) {
            buffer[utf8_end + lpc] = '?';
        }
    }
}

size_t
unquote(char* dst, const char* str, size_t len)
{
    if (str[0] == 'r' || str[0] == 'u') {
        str += 1;
        len -= 1;
    }
    char quote_char = str[0];
    size_t index = 0;

    require(str[0] == '\'' || str[0] == '"');

    for (size_t lpc = 1; lpc < (len - 1); lpc++, index++) {
        dst[index] = str[lpc];
        if (str[lpc] == quote_char) {
            lpc += 1;
        } else if (str[lpc] == '\\' && (lpc + 1) < len) {
            switch (str[lpc + 1]) {
                case 'n':
                    dst[index] = '\n';
                    break;
                case 'r':
                    dst[index] = '\r';
                    break;
                case 't':
                    dst[index] = '\t';
                    break;
                default:
                    dst[index] = str[lpc + 1];
                    break;
            }
            lpc += 1;
        }
    }
    dst[index] = '\0';

    return index;
}

size_t
unquote_w3c(char* dst, const char* str, size_t len)
{
    size_t index = 0;

    require(str[0] == '\'' || str[0] == '"');

    for (size_t lpc = 1; lpc < (len - 1); lpc++, index++) {
        dst[index] = str[lpc];
        if (str[lpc] == '"') {
            lpc += 1;
        }
    }
    dst[index] = '\0';

    return index;
}

void
truncate_to(std::string& str, size_t max_char_len)
{
    static const std::string ELLIPSIS = "\u22ef";

    if (str.length() < max_char_len) {
        return;
    }

    auto str_char_len_res = utf8_string_length(str);

    if (str_char_len_res.isErr()) {
        // XXX
        return;
    }

    auto str_char_len = str_char_len_res.unwrap();
    if (str_char_len <= max_char_len) {
        return;
    }

    if (max_char_len < 3) {
        str = ELLIPSIS;
        return;
    }

    auto chars_to_remove = (str_char_len - max_char_len) + 1;
    auto midpoint = str_char_len / 2;
    auto chars_to_keep_at_front = midpoint - (chars_to_remove / 2);
    auto bytes_to_keep_at_front
        = utf8_char_to_byte_index(str, chars_to_keep_at_front);
    auto remove_up_to_bytes = utf8_char_to_byte_index(
        str, chars_to_keep_at_front + chars_to_remove);
    auto bytes_to_remove = remove_up_to_bytes - bytes_to_keep_at_front;
    str.erase(bytes_to_keep_at_front, bytes_to_remove);
    str.insert(bytes_to_keep_at_front, ELLIPSIS);
}

bool
is_url(const std::string& fn)
{
    static const auto url_re = std::regex("^(file|https?|ftps?|scp|sftp):.*");

    return std::regex_match(fn, url_re);
}

size_t
abbreviate_str(char* str, size_t len, size_t max_len)
{
    size_t last_start = 1;

    if (len < max_len) {
        return len;
    }

    for (size_t index = 0; index < len; index++) {
        switch (str[index]) {
            case '.':
            case '-':
            case '/':
            case ':':
                memmove(&str[last_start], &str[index], len - index);
                len -= (index - last_start);
                index = last_start + 1;
                last_start = index + 1;

                if (len < max_len) {
                    return len;
                }
                break;
        }
    }

    return len;
}

void
split_ws(const std::string& str, std::vector<std::string>& toks_out)
{
    std::stringstream ss(str);
    std::string buf;

    while (ss >> buf) {
        toks_out.push_back(buf);
    }
}

std::string
repeat(const std::string& input, size_t num)
{
    std::ostringstream os;
    std::fill_n(std::ostream_iterator<std::string>(os), num, input);
    return os.str();
}

std::string
center_str(const std::string& subject, size_t width)
{
    std::string retval = subject;

    truncate_to(retval, width);

    auto retval_length = utf8_string_length(retval).unwrapOr(retval.length());
    auto total_fill = width - retval_length;
    auto before = total_fill / 2;
    auto after = total_fill - before;

    retval.insert(0, before, ' ');
    retval.append(after, ' ');

    return retval;
}

template<typename T>
size_t
strtonum(T& num_out, const char* string, size_t len)
{
    size_t retval = 0;
    T sign = 1;

    num_out = 0;

    for (; retval < len && isspace(string[retval]); retval++) {
        ;
    }
    for (; retval < len && string[retval] == '-'; retval++) {
        sign *= -1;
    }
    for (; retval < len && string[retval] == '+'; retval++) {
        ;
    }
    for (; retval < len && isdigit(string[retval]); retval++) {
        num_out *= 10;
        num_out += string[retval] - '0';
    }
    num_out *= sign;

    return retval;
}

bool
is_blank(const std::string& str)
{
    return std::all_of(
        str.begin(), str.end(), [](const auto ch) { return isspace(ch); });
}

template size_t strtonum<long long>(long long& num_out,
                                    const char* string,
                                    size_t len);

template size_t strtonum<long>(long& num_out, const char* string, size_t len);

template size_t strtonum<int>(int& num_out, const char* string, size_t len);