Function collapseGCode

FluidNC/src/GCode.cpp:157–220

Edit GCode line in-place, removing whitespace and comments and converting to uppercase

// Edit GCode line in-place, removing whitespace and comments and
// converting to uppercase
void collapseGCode(char* line) {
    // parenPtr, if non-NULL, is the address of the character after (
    const char* parenPtr = NULL;
    // outPtr is the address where newly-processed characters will be placed.
    // outPtr is always less than or equal to inPtr.
    char* outPtr = line;
    char  c;
    bool  hasComment = false;
    for (char* inPtr = line; (c = *inPtr) != '\0'; inPtr++) {
        if (isspace(c)) {
            continue;
        }
        switch (c) {
            case ')':
                if (parenPtr) {
                    // Terminate comment by replacing ) with NUL
                    *inPtr = '\0';
                    gcode_comment_msg(parenPtr);
                    parenPtr = NULL;
                }
                // Strip out ) that does not follow a (
                break;
            case '(':
                hasComment = true;
                // Start the comment at the character after (
                parenPtr = inPtr + 1;
                break;
            case ';':
                // NOTE: ';' comment to EOL is a LinuxCNC definition. Not NIST.
                *outPtr = '\0';
                return;
            case '\r':
                // In case one sneaks in
                break;
            default:
                if (!parenPtr) {
                    *outPtr++ = toupper(c);  // make upper case
                }
        }
    }
    // On loop exit, *inPtr is '\0'

    *outPtr = '\0';

    if (parenPtr) {
        // Handle unterminated ( comments
        gcode_comment_msg(parenPtr);
    }
    if (!hasComment && strcmp(line, "%") == 0) {
        // Per https://linuxcnc.org/docs/2.6/html/gcode/overview.html#_overview, % lines
        // can contain spaces, so this check happens after space removal.

        // Per https://linuxcnc.org/docs/html/gcode/overview.html#gcode:file-requirements
        // % only applies to "job" channels like files and macros, not to serial channels
        // where the sequence of lines is potentially never-ending.  A sender that handles
        // files on the host system could apply the % semantics.

        if (Job::active()) {