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use std::io::{self, Write};
use byteorder::{WriteBytesExt, LittleEndian};
use error::Result;
use raw::{
VERSION, EMPTY_ADDRESS, NONE_ADDRESS,
CompiledAddr, FstType, Output, Transition,
};
use raw::counting_writer::CountingWriter;
use raw::error::Error;
use raw::registry::{Registry, RegistryEntry};
use stream::{IntoStreamer, Streamer};
pub struct Builder<W> {
wtr: CountingWriter<W>,
unfinished: UnfinishedNodes,
registry: Registry,
last: Option<Vec<u8>>,
last_addr: CompiledAddr,
len: usize,
}
#[derive(Debug)]
struct UnfinishedNodes {
stack: Vec<BuilderNodeUnfinished>,
}
#[derive(Debug)]
struct BuilderNodeUnfinished {
node: BuilderNode,
last: Option<LastTransition>,
}
#[derive(Debug, Hash, Eq, PartialEq)]
pub struct BuilderNode {
pub is_final: bool,
pub final_output: Output,
pub trans: Vec<Transition>,
}
#[derive(Debug)]
struct LastTransition {
inp: u8,
out: Output,
}
impl Builder<Vec<u8>> {
pub fn memory() -> Self {
Builder::new(Vec::with_capacity(10 * (1 << 10))).unwrap()
}
}
impl<W: io::Write> Builder<W> {
pub fn new(wtr: W) -> Result<Builder<W>> {
Builder::new_type(wtr, 0)
}
pub fn new_type(wtr: W, ty: FstType) -> Result<Builder<W>> {
let mut wtr = CountingWriter::new(wtr);
wtr.write_u64::<LittleEndian>(VERSION)?;
wtr.write_u64::<LittleEndian>(ty)?;
Ok(Builder {
wtr: wtr,
unfinished: UnfinishedNodes::new(),
registry: Registry::new(10_000, 2),
last: None,
last_addr: NONE_ADDRESS,
len: 0,
})
}
pub fn add<B>(&mut self, bs: B) -> Result<()>
where B: AsRef<[u8]> {
self.check_last_key(bs.as_ref(), false)?;
self.insert_output(bs, None)
}
pub fn insert<B>(&mut self, bs: B, val: u64) -> Result<()>
where B: AsRef<[u8]> {
self.check_last_key(bs.as_ref(), true)?;
self.insert_output(bs, Some(Output::new(val)))
}
pub fn extend_iter<T, I>(&mut self, iter: I) -> Result<()>
where T: AsRef<[u8]>, I: IntoIterator<Item=(T, Output)> {
for (key, out) in iter {
self.insert(key, out.value())?;
}
Ok(())
}
pub fn extend_stream<'f, I, S>(&mut self, stream: I) -> Result<()>
where I: for<'a> IntoStreamer<'a, Into=S, Item=(&'a [u8], Output)>,
S: 'f + for<'a> Streamer<'a, Item=(&'a [u8], Output)> {
let mut stream = stream.into_stream();
while let Some((key, out)) = stream.next() {
self.insert(key, out.value())?;
}
Ok(())
}
pub fn finish(self) -> Result<()> {
self.into_inner()?;
Ok(())
}
pub fn into_inner(mut self) -> Result<W> {
self.compile_from(0)?;
let root_node = self.unfinished.pop_root();
let root_addr = self.compile(&root_node)?;
self.wtr.write_u64::<LittleEndian>(self.len as u64)?;
self.wtr.write_u64::<LittleEndian>(root_addr as u64)?;
self.wtr.flush()?;
Ok(self.wtr.into_inner())
}
fn insert_output<B>(&mut self, bs: B, out: Option<Output>) -> Result<()>
where B: AsRef<[u8]> {
let bs = bs.as_ref();
if bs.is_empty() {
self.len = 1;
self.unfinished.set_root_output(out.unwrap_or(Output::zero()));
return Ok(());
}
let (prefix_len, out) = if let Some(out) = out {
self.unfinished.find_common_prefix_and_set_output(bs, out)
} else {
(self.unfinished.find_common_prefix(bs), Output::zero())
};
if prefix_len == bs.len() {
assert!(out.is_zero());
return Ok(());
}
self.len += 1;
self.compile_from(prefix_len)?;
self.unfinished.add_suffix(&bs[prefix_len..], out);
Ok(())
}
fn compile_from(&mut self, istate: usize) -> Result<()> {
let mut addr = NONE_ADDRESS;
while istate + 1 < self.unfinished.len() {
let node =
if addr == NONE_ADDRESS {
self.unfinished.pop_empty()
} else {
self.unfinished.pop_freeze(addr)
};
addr = self.compile(&node)?;
assert!(addr != NONE_ADDRESS);
}
self.unfinished.top_last_freeze(addr);
Ok(())
}
fn compile(&mut self, node: &BuilderNode) -> Result<CompiledAddr> {
if node.is_final
&& node.trans.is_empty()
&& node.final_output.is_zero() {
return Ok(EMPTY_ADDRESS);
}
let entry = self.registry.entry(&node);
if let RegistryEntry::Found(ref addr) = entry {
return Ok(*addr);
}
let start_addr = self.wtr.count() as CompiledAddr;
node.compile_to(&mut self.wtr, self.last_addr, start_addr)?;
self.last_addr = self.wtr.count() as CompiledAddr - 1;
if let RegistryEntry::NotFound(cell) = entry {
cell.insert(self.last_addr);
}
Ok(self.last_addr)
}
fn check_last_key(&mut self, bs: &[u8], check_dupe: bool) -> Result<()> {
if let Some(ref mut last) = self.last {
if check_dupe && bs == &**last {
return Err(Error::DuplicateKey { got: bs.to_vec() }.into());
}
if bs < &**last {
return Err(Error::OutOfOrder {
previous: last.to_vec(),
got: bs.to_vec(),
}.into());
}
last.clear();
for &b in bs {
last.push(b);
}
} else {
self.last = Some(bs.to_vec());
}
Ok(())
}
pub fn get_ref(&self) -> &W {
self.wtr.get_ref()
}
pub fn bytes_written(&self) -> u64 {
self.wtr.count()
}
}
impl UnfinishedNodes {
fn new() -> UnfinishedNodes {
let mut unfinished = UnfinishedNodes { stack: Vec::with_capacity(64) };
unfinished.push_empty(false);
unfinished
}
fn len(&self) -> usize {
self.stack.len()
}
fn push_empty(&mut self, is_final: bool) {
self.stack.push(BuilderNodeUnfinished {
node: BuilderNode { is_final: is_final, ..BuilderNode::default() },
last: None,
});
}
fn pop_root(&mut self) -> BuilderNode {
assert!(self.stack.len() == 1);
assert!(self.stack[0].last.is_none());
self.stack.pop().unwrap().node
}
fn pop_freeze(&mut self, addr: CompiledAddr) -> BuilderNode {
let mut unfinished = self.stack.pop().unwrap();
unfinished.last_compiled(addr);
unfinished.node
}
fn pop_empty(&mut self) -> BuilderNode {
let unfinished = self.stack.pop().unwrap();
assert!(unfinished.last.is_none());
unfinished.node
}
fn set_root_output(&mut self, out: Output) {
self.stack[0].node.is_final = true;
self.stack[0].node.final_output = out;
}
fn top_last_freeze(&mut self, addr: CompiledAddr) {
let last = self.stack.len().checked_sub(1).unwrap();
self.stack[last].last_compiled(addr);
}
fn add_suffix(&mut self, bs: &[u8], out: Output) {
if bs.is_empty() {
return;
}
let last = self.stack.len().checked_sub(1).unwrap();
assert!(self.stack[last].last.is_none());
self.stack[last].last = Some(LastTransition { inp: bs[0], out: out });
for &b in &bs[1..] {
self.stack.push(BuilderNodeUnfinished {
node: BuilderNode::default(),
last: Some(LastTransition { inp: b, out: Output::zero() }),
});
}
self.push_empty(true);
}
fn find_common_prefix(&mut self, bs: &[u8]) -> usize {
bs
.iter()
.zip(&self.stack)
.take_while(|&(&b, ref node)| {
node.last.as_ref().map(|t| t.inp == b).unwrap_or(false)
})
.count()
}
fn find_common_prefix_and_set_output(
&mut self,
bs: &[u8],
mut out: Output,
) -> (usize, Output) {
let mut i = 0;
while i < bs.len() {
let add_prefix = match self.stack[i].last.as_mut() {
Some(ref mut t) if t.inp == bs[i] => {
i += 1;
let common_pre = t.out.prefix(out);
let add_prefix = t.out.sub(common_pre);
out = out.sub(common_pre);
t.out = common_pre;
add_prefix
}
_ => break,
};
if !add_prefix.is_zero() {
self.stack[i].add_output_prefix(add_prefix);
}
}
(i, out)
}
}
impl BuilderNodeUnfinished {
fn last_compiled(&mut self, addr: CompiledAddr) {
if let Some(trans) = self.last.take() {
self.node.trans.push(Transition {
inp: trans.inp,
out: trans.out,
addr: addr,
});
}
}
fn add_output_prefix(&mut self, prefix: Output) {
if self.node.is_final {
self.node.final_output = prefix.cat(self.node.final_output);
}
for t in &mut self.node.trans {
t.out = prefix.cat(t.out);
}
if let Some(ref mut t) = self.last {
t.out = prefix.cat(t.out);
}
}
}
impl Clone for BuilderNode {
fn clone(&self) -> Self {
BuilderNode {
is_final: self.is_final,
final_output: self.final_output,
trans: self.trans.clone(),
}
}
fn clone_from(&mut self, source: &Self) {
self.is_final = source.is_final;
self.final_output = source.final_output;
self.trans.clear();
self.trans.extend(source.trans.iter());
}
}
impl Default for BuilderNode {
fn default() -> Self {
BuilderNode {
is_final: false,
final_output: Output::zero(),
trans: vec![],
}
}
}