Function truncateText

tools/shell/linenoise.cpp:2004–2061

}

static void truncateText(char*& buf, size_t& len, size_t pos, size_t cols, size_t plen,
    bool highlight, size_t& render_pos, char* highlightBuf) {
    if (Utf8Proc::isValid(buf, len)) {
        // UTF8 in prompt, handle rendering.
        size_t remainingRenderWidth = cols - plen - 1;
        size_t startPos = 0;
        size_t charPos = 0;
        size_t prevPos = 0;
        size_t totalRenderWidth = 0;
        while (charPos < len) {
            uint32_t charRenderWidth = Utf8Proc::renderWidth(buf, charPos);
            prevPos = charPos;
            charPos = utf8proc_next_grapheme(buf, len, charPos);
            totalRenderWidth += charPos - prevPos;
            if (totalRenderWidth >= remainingRenderWidth) {
                if (prevPos >= pos) {
                    // We passed the cursor: break, we no longer need to render.
                    charPos = prevPos;
                    break;
                } else {
                    // We did not pass the cursor yet, meaning we still need to render.
                    // Remove characters from the start until it fits again.
                    while (totalRenderWidth >= remainingRenderWidth) {
                        uint32_t startCharWidth = Utf8Proc::renderWidth(buf, startPos);
                        uint32_t newStart = utf8proc_next_grapheme(buf, len, startPos);
                        totalRenderWidth -= newStart - startPos;
                        startPos = newStart;
                        render_pos -= startCharWidth;
                    }
                }
            }
            if (prevPos < pos) {
                render_pos += charRenderWidth;
            }
        }
        std::string highlight_buffer;
        if (highlight) {
            bool is_shell_command = buf[0] == ':';
            auto tokens = highlightingTokenize(buf, len, is_shell_command);
            highlight_buffer = linenoiseHighlightText(buf, len, startPos, charPos, tokens);
        } else {
            highlight_buffer = std::string(buf + startPos, charPos - startPos);
        }
        std::strcpy(highlightBuf, highlight_buffer.c_str());
        len = highlight_buffer.size();
    } else {
        // Invalid UTF8: fallback.
        while ((plen + pos) >= cols) {
            buf++;
            len--;
            pos--;
        }
        while (plen + len > cols) {
            len--;
        }
        render_pos = pos;
    }
}