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use std::fs;
use std::io;
use std::io::prelude::*;
use std::cmp::max;
use std::path;
use std::string;
use std::iter;
use hash::hash;
use uint32::*;
pub use std::io::Result;
#[derive(Clone,Copy,Debug)]
struct HashPos {
hash: u32,
pos: u32,
}
fn err_toobig<T>() -> Result<T> {
Err(io::Error::new(io::ErrorKind::Other, "File too big"))
}
fn uint32_pack_hp(buf: &mut [u8], hp: &HashPos) {
uint32_pack2(buf, hp.hash, hp.pos);
}
pub struct CDBMake {
entries: Vec<Vec<HashPos>>,
pos: u32,
file: io::BufWriter<fs::File>,
}
impl CDBMake {
pub fn new(file: fs::File) -> Result<CDBMake> {
let mut w = io::BufWriter::new(file);
let buf = [0; 2048];
try!(w.seek(io::SeekFrom::Start(0)));
try!(w.write(&buf));
Ok(CDBMake{
entries: iter::repeat(vec![]).take(256).collect::<Vec<_>>(),
pos: 2048,
file: w,
})
}
fn pos_plus(&mut self, len: u32) -> Result<()> {
if self.pos + len < len {
err_toobig()
}
else {
self.pos += len;
Ok(())
}
}
fn add_end(&mut self, keylen: u32, datalen: u32, hash: u32) -> Result<()> {
self.entries[(hash & 0xff) as usize].push(HashPos{ hash: hash, pos: self.pos });
try!(self.pos_plus(8));
try!(self.pos_plus(keylen));
try!(self.pos_plus(datalen));
Ok(())
}
fn add_begin(&mut self, keylen: u32, datalen: u32) -> Result<()> {
let mut buf = [0; 8];
uint32_pack2(&mut buf[0..8], keylen, datalen);
try!(self.file.write(&buf));
Ok(())
}
pub fn add(&mut self, key: &[u8], data: &[u8]) -> Result<()> {
if key.len() >= 0xffffffff || data.len() >= 0xffffffff {
return Err(io::Error::new(io::ErrorKind::Other, "Key or data too big"));
}
try!(self.add_begin(key.len() as u32, data.len() as u32));
try!(self.file.write(key));
try!(self.file.write(data));
self.add_end(key.len() as u32, data.len() as u32, hash(&key[..]))
}
pub fn finish(&mut self) -> Result<()> {
let mut buf = [0; 8];
let maxsize = self.entries.iter().fold(1, |acc, e| max(acc, e.len() * 2));
let count = self.entries.iter().fold(0, |acc, e| acc + e.len());
if maxsize + count > (0xffffffff / 8) {
return err_toobig();
}
let mut table = vec![HashPos{ hash: 0, pos: 0 }; maxsize];
let mut header = [0 as u8; 2048];
for i in 0..256 {
let len = self.entries[i].len() * 2;
let j = i * 8;
uint32_pack2(&mut header[j..j+8], self.pos, len as u32);
for e in self.entries[i].iter() {
let mut wh = (e.hash as usize >> 8) % len;
while table[wh].pos != 0 {
wh += 1;
if wh == len {
wh = 0;
}
}
table[wh] = *e;
}
for hp in table.iter_mut().take(len) {
uint32_pack_hp(&mut buf, hp);
try!(self.file.write(&buf));
try!(self.pos_plus(8));
*hp = HashPos{ hash: 0, pos: 0 };
}
}
try!(self.file.flush());
try!(self.file.seek(io::SeekFrom::Start(0)));
try!(self.file.write(&header));
try!(self.file.flush());
Ok(())
}
}
pub struct CDBWriter {
dstname: String,
tmpname: String,
cdb: CDBMake,
}
impl CDBWriter {
pub fn create<P: AsRef<path::Path> + string::ToString>(filename: P) -> Result<CDBWriter> {
CDBWriter::with_suffix(filename, ".tmp")
}
pub fn with_suffix<P: AsRef<path::Path> + string::ToString>(filename: P, suffix: &str) -> Result<CDBWriter> {
let mut tmpname = filename.to_string();
tmpname.push_str(suffix);
CDBWriter::with_filenames(filename, &tmpname)
}
pub fn with_filenames<P: AsRef<path::Path> + string::ToString,
Q: AsRef<path::Path> + string::ToString>(filename: P, tmpname: Q) -> Result<CDBWriter> {
let file = try!(fs::File::create(&tmpname));
let cdb = try!(CDBMake::new(file));
Ok(CDBWriter {
dstname: filename.to_string(),
tmpname: tmpname.to_string(),
cdb: cdb,
})
}
pub fn add(&mut self, key: &[u8], data: &[u8]) -> Result<()> {
self.cdb.add(key, data)
}
pub fn set_permissions(&mut self, perm: fs::Permissions) -> Result<()> {
fs::set_permissions(&self.tmpname, perm)
}
pub fn finish(&mut self) -> Result<()> {
try!(self.cdb.finish());
try!(fs::rename(&self.tmpname, &self.dstname));
self.tmpname.clear();
Ok(())
}
}
impl Drop for CDBWriter {
#[allow(unused_must_use)]
fn drop(&mut self) {
if self.tmpname.len() > 0 {
fs::remove_file(&self.tmpname);
}
}
}