C++ wcstring::at方法代码示例

void path_make_canonical(wcstring &path)
{
    // Ignore trailing slashes, unless it's the first character
    size_t len = path.size();
    while (len > 1 && path.at(len - 1) == L'/')
        len--;

    // Turn runs of slashes into a single slash
    size_t trailing = 0;
    bool prev_was_slash = false;
    for (size_t leading = 0; leading < len; leading++)
    {
        wchar_t c = path.at(leading);
        bool is_slash = (c == '/');
        if (! prev_was_slash || ! is_slash)
        {
            // This is either the first slash in a run, or not a slash at all
            path.at(trailing++) = c;
        }
        prev_was_slash = is_slash;
    }
    assert(trailing <= len);
    if (trailing < len)
        path.resize(trailing);
}

// If the given path looks like it's relative to the working directory, then prepend that working
// directory. This operates on unescaped paths only (so a ~ means a literal ~).
wcstring path_apply_working_directory(const wcstring &path, const wcstring &working_directory) {
    if (path.empty() || working_directory.empty()) return path;

    // We're going to make sure that if we want to prepend the wd, that the string has no leading
    // "/".
    bool prepend_wd = path.at(0) != L'/' && path.at(0) != HOME_DIRECTORY;
    if (!prepend_wd) {
        // No need to prepend the wd, so just return the path we were given.
        return path;
    }

    // Remove up to one "./".
    wcstring path_component = path;
    if (string_prefixes_string(L"./", path_component)) {
        path_component.erase(0, 2);
    }

    // Removing leading /s.
    while (string_prefixes_string(L"/", path_component)) {
        path_component.erase(0, 1);
    }

    // Construct and return a new path.
    wcstring new_path = working_directory;
    append_path_component(new_path, path_component);
    return new_path;
}

void expand_tilde(wcstring &input)
{
    if (! input.empty() && input.at(0) == L'~')
    {
        input.at(0) = HOME_DIRECTORY;
        expand_home_directory(input);
    }
}

/* Given a command like "cat file", truncate it to a reasonable length */
static wcstring truncate_command(const wcstring &cmd)
{
    const size_t max_len = 32;
    if (cmd.size() <= max_len)
    {
        // No truncation necessary
        return cmd;
    }
    
    // Truncation required
    const bool ellipsis_is_unicode = (ellipsis_char == L'\x2026');
    const size_t ellipsis_length = ellipsis_is_unicode ? 1 : 3;
    size_t trunc_length = max_len - ellipsis_length;
    // Eat trailing whitespace
    while (trunc_length > 0 && iswspace(cmd.at(trunc_length - 1)))
    {
        trunc_length -= 1;
    }
    wcstring result = wcstring(cmd, 0, trunc_length);
    // Append ellipsis
    if (ellipsis_is_unicode)
    {
        result.push_back(ellipsis_char);
    }
    else
    {
        result.append(L"...");
    }
    return result;
}

bool path_is_valid(const wcstring &path, const wcstring &working_directory)
{
    bool path_is_valid;
    /* Some special paths are always valid */
    if (path.empty())
    {
        path_is_valid = false;
    }
    else if (path == L"." || path == L"./")
    {
        path_is_valid = true;
    }
    else if (path == L".." || path == L"../")
    {
        path_is_valid = (! working_directory.empty() && working_directory != L"/");
    }
    else if (path.at(0) != '/')
    {
        /* Prepend the working directory. Note that we know path is not empty here. */
        wcstring tmp = working_directory;
        tmp.append(path);
        path_is_valid = (0 == waccess(tmp, F_OK));
    }
    else
    {
        /* Simple check */
        path_is_valid = (0 == waccess(path, F_OK));
    }
    return path_is_valid;
}

/* Given a string and list of colors of the same size, return the string with ANSI escape sequences representing the colors. */
static std::string ansi_colorize(const wcstring &text, const std::vector<highlight_spec_t> &colors)
{
    assert(colors.size() == text.size());
    assert(output_receiver.empty());

    int (*saved)(char) = output_get_writer();
    output_set_writer(write_to_output_receiver);

    highlight_spec_t last_color = highlight_spec_normal;
    for (size_t i=0; i < text.size(); i++)
    {
        highlight_spec_t color = colors.at(i);
        if (color != last_color)
        {
            set_color(highlight_get_color(color, false), rgb_color_t::normal());
            last_color = color;
        }
        writech(text.at(i));
    }

    output_set_writer(saved);
    std::string result;
    result.swap(output_receiver);
    return result;
}

void append_path_component(wcstring &path, const wcstring &component)
{
    if (path.empty() || component.empty()) {
        path.append(component);
    } else {
        size_t path_len = path.size();
        bool path_slash = path.at(path_len-1) == L'/';
        bool comp_slash = component.at(0) == L'/';
        if (! path_slash && ! comp_slash) {
            // Need a slash
            path.push_back(L'/');
        } else if (path_slash && comp_slash) {
            // Too many slashes
            path.erase(path_len - 1, 1);
        }
        path.append(component);
    }
}

/// Test if the specified argument is clean, i.e. it does not contain any tokens which need to be
/// expanded or otherwise altered. Clean strings can be passed through expand_string and expand_one
/// without changing them. About two thirds of all strings are clean, so skipping expansion on them
/// actually does save a small amount of time, since it avoids multiple memory allocations during
/// the expansion process.
///
/// \param in the string to test
static bool expand_is_clean(const wcstring &in) {
    if (in.empty()) return true;

    // Test characters that have a special meaning in the first character position.
    if (wcschr(UNCLEAN_FIRST, in.at(0)) != NULL) return false;

    // Test characters that have a special meaning in any character position.
    return in.find_first_of(UNCLEAN) == wcstring::npos;
}

bool paths_are_equivalent(const wcstring &p1, const wcstring &p2) {
    if (p1 == p2) return true;

    size_t len1 = p1.size(), len2 = p2.size();

    // Ignore trailing slashes after the first character.
    while (len1 > 1 && p1.at(len1 - 1) == L'/') len1--;
    while (len2 > 1 && p2.at(len2 - 1) == L'/') len2--;

    // Start walking
    size_t idx1 = 0, idx2 = 0;
    while (idx1 < len1 && idx2 < len2) {
        wchar_t c1 = p1.at(idx1), c2 = p2.at(idx2);

        // If the characters are different, the strings are not equivalent.
        if (c1 != c2) break;

        idx1++;
        idx2++;

        // If the character was a slash, walk forwards until we hit the end of the string, or a
        // non-slash. Note the first condition is invariant within the loop.
        while (c1 == L'/' && idx1 < len1 && p1.at(idx1) == L'/') idx1++;
        while (c2 == L'/' && idx2 < len2 && p2.at(idx2) == L'/') idx2++;
    }

    // We matched if we consumed all of the characters in both strings.
    return idx1 == len1 && idx2 == len2;
}

bool rgb_color_t::try_parse_rgb(const wcstring &name) {
    bzero(&data, sizeof data);
    /* We support the following style of rgb formats (case insensitive):
        #FA3
        #F3A035
        FA3
        F3A035
    */
    
    size_t digit_idx = 0, len = name.size();
    
    /* Skip any leading # */
    if (len > 0 && name.at(0) == L'#')
        digit_idx++;
    
    bool success = false;
    size_t i;
    if (len - digit_idx == 3) {
        // type FA3
        for (i=0; i < 3; i++) {
            int val = parse_hex_digit(name.at(digit_idx++));
            if (val < 0) break;
            data.rgb[i] = val*16+val;
        }
        success = (i == 3);
    } else if (len - digit_idx == 6) {
        // type F3A035
        for (i=0; i < 3; i++) {
            int hi = parse_hex_digit(name.at(digit_idx++));
            int lo = parse_hex_digit(name.at(digit_idx++));
            if (lo < 0 || hi < 0) break;
            data.rgb[i] = hi*16+lo;
        }
        success = (i == 3);
    } 
    if (success) {
        this->type = type_rgb;
    }
    return success;
}

static std::string html_colorize(const wcstring &text,
                                 const std::vector<highlight_spec_t> &colors) {
    if (text.empty()) {
        return "";
    }

    assert(colors.size() == text.size());
    wcstring html = L"<pre><code>";
    highlight_spec_t last_color = highlight_spec_normal;
    for (size_t i = 0; i < text.size(); i++) {
        // Handle colors.
        highlight_spec_t color = colors.at(i);
        if (i > 0 && color != last_color) {
            html.append(L"</span>");
        }
        if (i == 0 || color != last_color) {
            append_format(html, L"<span class=\"%ls\">", html_class_name_for_color(color));
        }
        last_color = color;

        // Handle text.
        wchar_t wc = text.at(i);
        switch (wc) {
            case L'&': {
                html.append(L"&amp;");
                break;
            }
            case L'\'': {
                html.append(L"&apos;");
                break;
            }
            case L'"': {
                html.append(L"&quot;");
                break;
            }
            case L'<': {
                html.append(L"&lt;");
                break;
            }
            case L'>': {
                html.append(L"&gt;");
                break;
            }
            default: {
                html.push_back(wc);
                break;
            }
        }
    }
    html.append(L"</span></code></pre>");
    return wcs2string(html);
}

/**
   Remove any internal separators. Also optionally convert wildcard characters to
   regular equivalents. This is done to support EXPAND_SKIP_WILDCARDS.
*/
static void remove_internal_separator(wcstring &str, bool conv)
{
    /* Remove all instances of INTERNAL_SEPARATOR */
    str.erase(std::remove(str.begin(), str.end(), (wchar_t)INTERNAL_SEPARATOR), str.end());

    /* If conv is true, replace all instances of ANY_CHAR with '?', ANY_STRING with '*', ANY_STRING_RECURSIVE with '*' */
    if (conv)
    {
        for (size_t idx = 0; idx < str.size(); idx++)
        {
            switch (str.at(idx))
            {
                case ANY_CHAR:
                    str.at(idx) = L'?';
                    break;
                case ANY_STRING:
                case ANY_STRING_RECURSIVE:
                    str.at(idx) = L'*';
                    break;
            }
        }
    }
}

    // Given a start point as an absolute path, for any directory that has exactly one non-hidden
    // entity in it which is itself a directory, return that. The result is a relative path. For
    // example, if start_point is '/usr' we may return 'local/bin/'.
    //
    // The result does not have a leading slash, but does have a trailing slash if non-empty.
    wcstring descend_unique_hierarchy(const wcstring &start_point) {
        assert(!start_point.empty() && start_point.at(0) == L'/');

        wcstring unique_hierarchy;
        wcstring abs_unique_hierarchy = start_point;

        bool stop_descent = false;
        DIR *dir;
        while (!stop_descent && (dir = wopendir(abs_unique_hierarchy))) {
            // We keep track of the single unique_entry entry. If we get more than one, it's not
            // unique and we stop the descent.
            wcstring unique_entry;

            bool child_is_dir;
            wcstring child_entry;
            while (wreaddir_resolving(dir, abs_unique_hierarchy, child_entry, &child_is_dir)) {
                if (child_entry.empty() || child_entry.at(0) == L'.') {
                    continue;  // either hidden, or . and .. entries -- skip them
                } else if (child_is_dir && unique_entry.empty()) {
                    unique_entry = child_entry;  // first candidate
                } else {
                    // We either have two or more candidates, or the child is not a directory. We're
                    // done.
                    stop_descent = true;
                    break;
                }
            }

            // We stop if we got two or more entries; also stop if we got zero or were interrupted
            if (unique_entry.empty() || interrupted()) {
                stop_descent = true;
            }

            if (!stop_descent) {
                // We have an entry in the unique hierarchy!
                append_path_component(unique_hierarchy, unique_entry);
                unique_hierarchy.push_back(L'/');

                append_path_component(abs_unique_hierarchy, unique_entry);
                abs_unique_hierarchy.push_back(L'/');
            }
            closedir(dir);
        }
        return unique_hierarchy;
    }

/* If the given path looks like it's relative to the working directory, then prepend that working directory. This operates on unescaped paths only (so a ~ means a literal ~) */
wcstring path_apply_working_directory(const wcstring &path, const wcstring &working_directory)
{
    if (path.empty() || working_directory.empty())
        return path;
    
    /* We're going to make sure that if we want to prepend the wd, that the string has no leading / */
    bool prepend_wd;
    switch (path.at(0))
    {
        case L'/':
        case HOME_DIRECTORY:
            prepend_wd = false;
            break;
        default:
            prepend_wd = true;
            break;
    }
    
    if (! prepend_wd)
    {
        /* No need to prepend the wd, so just return the path we were given */
        return path;
    }
    else
    {
        /* Remove up to one ./ */
        wcstring path_component = path;
        if (string_prefixes_string(L"./", path_component))
        {
            path_component.erase(0, 2);
        }
        
        /* Removing leading /s */
        while (string_prefixes_string(L"/", path_component))
        {
            path_component.erase(0, 1);
        }
        
        /* Construct and return a new path */
        wcstring new_path = working_directory;
        append_path_component(new_path, path_component);
        return new_path;
    }
}

/// Given a command like "cat file", truncate it to a reasonable length.
static wcstring truncate_command(const wcstring &cmd) {
    const size_t max_len = 32;
    if (cmd.size() <= max_len) {
        // No truncation necessary.
        return cmd;
    }

    // Truncation required.
    const size_t ellipsis_length = wcslen(ellipsis_str); //no need for wcwidth
    size_t trunc_length = max_len - ellipsis_length;
    // Eat trailing whitespace.
    while (trunc_length > 0 && iswspace(cmd.at(trunc_length - 1))) {
        trunc_length -= 1;
    }
    wcstring result = wcstring(cmd, 0, trunc_length);
    // Append ellipsis.
    result.append(ellipsis_str);
    return result;
}