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use std::io;
use byteorder::{ LittleEndian, ReadBytesExt, WriteBytesExt };
use RoaringBitmap;
use super::store::Store;
use super::container::Container;
const SERIAL_COOKIE_NO_RUNCONTAINER: u32 = 12346;
const SERIAL_COOKIE: u16 = 12347;
impl RoaringBitmap {
pub fn serialized_size(&self) -> usize {
let container_sizes: usize = self.containers.iter().map(|container| {
match container.store {
Store::Array(ref values) => {
8 + values.len() * 2
}
Store::Bitmap(..) => {
8 + 8 * 1024
}
}
}).sum();
8 + container_sizes
}
pub fn serialize_into<W: io::Write>(&self, mut writer: W) -> io::Result<()> {
try!(writer.write_u32::<LittleEndian>(SERIAL_COOKIE_NO_RUNCONTAINER));
try!(writer.write_u32::<LittleEndian>(self.containers.len() as u32));
for container in &self.containers {
try!(writer.write_u16::<LittleEndian>(container.key));
try!(writer.write_u16::<LittleEndian>((container.len - 1) as u16));
}
let mut offset = 8 + 8 * self.containers.len() as u32;
for container in &self.containers {
try!(writer.write_u32::<LittleEndian>(offset));
match container.store {
Store::Array(ref values) => {
offset += values.len() as u32 * 2;
}
Store::Bitmap(..) => {
offset += 8 * 1024;
}
}
}
for container in &self.containers {
match container.store {
Store::Array(ref values) => {
for &value in values {
try!(writer.write_u16::<LittleEndian>(value));
}
}
Store::Bitmap(ref values) => {
for &value in values.iter() {
try!(writer.write_u64::<LittleEndian>(value));
}
}
}
}
Ok(())
}
pub fn deserialize_from<R: io::Read>(mut reader: R) -> io::Result<RoaringBitmap> {
let (size, has_offsets) = {
let cookie = try!(reader.read_u32::<LittleEndian>());
if cookie == SERIAL_COOKIE_NO_RUNCONTAINER {
(try!(reader.read_u32::<LittleEndian>()) as usize, true)
} else if (cookie as u16) == SERIAL_COOKIE {
return Err(io::Error::new(
io::ErrorKind::Other,
"run containers are unsupported"));
} else {
return Err(io::Error::new(
io::ErrorKind::Other,
"unknown cookie value"));
}
};
if size > u16::max_value() as usize {
return Err(io::Error::new(
io::ErrorKind::Other,
"size is greater than supported"));
}
let mut description_bytes = vec![0u8; size * 4];
try!(reader.read_exact(&mut description_bytes));
let description_bytes = &mut &description_bytes[..];
if has_offsets {
let mut offsets = vec![0u8; size * 4];
try!(reader.read_exact(&mut offsets));
drop(offsets);
}
let mut containers = Vec::with_capacity(size);
for _ in 0..size {
let key = try!(description_bytes.read_u16::<LittleEndian>());
let len = try!(description_bytes.read_u16::<LittleEndian>()) as u64 + 1;
let store = if len < 4096 {
let mut values = Vec::with_capacity(len as usize);
for _ in 0..len {
values.push(try!(reader.read_u16::<LittleEndian>()));
}
Store::Array(values)
} else {
let mut values = Box::new([0; 1024]);
for value in values.iter_mut() {
*value = try!(reader.read_u64::<LittleEndian>());
}
Store::Bitmap(values)
};
containers.push(Container { key: key, len: len, store: store });
}
Ok(RoaringBitmap { containers: containers })
}
}