in h3_baseCells.c [877:889]
int _baseCellToCCWrot60(int baseCell, int face) {
if (face < 0 || face > NUM_ICOSA_FACES) return INVALID_ROTATIONS;
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
for (int k = 0; k < 3; k++) {
if (faceIjkBaseCells[face][i][j][k].baseCell == baseCell) {
return faceIjkBaseCells[face][i][j][k].ccwRot60;
}
}
}
}
return INVALID_ROTATIONS;
}