for (long i = j + 1; i <= j + blocks; i += batchSize) {
while (!excerpt.nextIndex()) {
// busy wait
}
for (int k = 0; k < batchSize; k++) {
char ch = (char) excerpt.readUnsignedByte();
long l = excerpt.readLong();
float d = excerpt.readFloat();
assert ch == 'M';
assert l == i;
assert d == (float) i;