$convmap = array (
int start_code1, int end_code1, int offset1, int mask1,
int start_code2, int end_code2, int offset2, int mask2,
........
int start_codeN, int end_codeN, int offsetN, int maskN );
// Specify Unicode value for start_codeN and end_codeN
// Add offsetN to value and take bit-wise 'AND' with maskN,
// then convert value to numeric string reference.