@Immutable
    public static Memory substr_replace(Environment env, TraceInfo trace,
                                        Memory string, Memory replacementM, Memory startM) {
        return substr_replace(env, trace, string, replacementM, startM, LongMemory.valueOf(Integer.MAX_VALUE / 2));
    }
Parses the cslashes bitmap returning an actual bitmap.

@param charset the bitmap string

@return the actual bitmap
exts/jphp-zend-ext/src/main/java/org/develnext/jphp/zend/ext/standard/StringFunctions.java