rust/src/libserialize/ebml.rs
2014-06-28 11:53:58 -07:00

1180 lines
39 KiB
Rust

// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![allow(missing_doc)]
use std::io;
use std::str;
// Simple Extensible Binary Markup Language (ebml) reader and writer on a
// cursor model. See the specification here:
// http://www.matroska.org/technical/specs/rfc/index.html
// Common data structures
#[deriving(Clone)]
pub struct Doc<'a> {
pub data: &'a [u8],
pub start: uint,
pub end: uint,
}
impl<'doc> Doc<'doc> {
pub fn new(data: &'doc [u8]) -> Doc<'doc> {
Doc { data: data, start: 0u, end: data.len() }
}
pub fn get<'a>(&'a self, tag: uint) -> Doc<'a> {
reader::get_doc(*self, tag)
}
pub fn as_str_slice<'a>(&'a self) -> &'a str {
str::from_utf8(self.data.slice(self.start, self.end)).unwrap()
}
pub fn as_str(&self) -> String {
self.as_str_slice().to_string()
}
}
pub struct TaggedDoc<'a> {
tag: uint,
pub doc: Doc<'a>,
}
#[deriving(Show)]
pub enum EbmlEncoderTag {
EsUint, // 0
EsU64, // 1
EsU32, // 2
EsU16, // 3
EsU8, // 4
EsInt, // 5
EsI64, // 6
EsI32, // 7
EsI16, // 8
EsI8, // 9
EsBool, // 10
EsChar, // 11
EsStr, // 12
EsF64, // 13
EsF32, // 14
EsFloat, // 15
EsEnum, // 16
EsEnumVid, // 17
EsEnumBody, // 18
EsVec, // 19
EsVecLen, // 20
EsVecElt, // 21
EsMap, // 22
EsMapLen, // 23
EsMapKey, // 24
EsMapVal, // 25
EsOpaque,
EsLabel, // Used only when debugging
}
#[deriving(Show)]
pub enum Error {
IntTooBig(uint),
Expected(String),
IoError(io::IoError)
}
// --------------------------------------
pub mod reader {
use std::char;
use std::mem::transmute;
use std::int;
use std::option::{None, Option, Some};
use std::io::extensions::u64_from_be_bytes;
use serialize;
use super::{ EsVec, EsMap, EsEnum, EsVecLen, EsVecElt, EsMapLen, EsMapKey,
EsEnumVid, EsU64, EsU32, EsU16, EsU8, EsInt, EsI64, EsI32, EsI16, EsI8,
EsBool, EsF64, EsF32, EsChar, EsStr, EsMapVal, EsEnumBody, EsUint,
EsOpaque, EsLabel, EbmlEncoderTag, Doc, TaggedDoc, Error, IntTooBig,
Expected };
pub type DecodeResult<T> = Result<T, Error>;
// ebml reading
macro_rules! try_or(
($e:expr, $r:expr) => (
match $e {
Ok(e) => e,
Err(e) => {
debug!("ignored error: {}", e);
return $r
}
}
)
)
pub struct Res {
pub val: uint,
pub next: uint
}
#[inline(never)]
fn vuint_at_slow(data: &[u8], start: uint) -> DecodeResult<Res> {
let a = data[start];
if a & 0x80u8 != 0u8 {
return Ok(Res {val: (a & 0x7fu8) as uint, next: start + 1u});
}
if a & 0x40u8 != 0u8 {
return Ok(Res {val: ((a & 0x3fu8) as uint) << 8u |
(data[start + 1u] as uint),
next: start + 2u});
}
if a & 0x20u8 != 0u8 {
return Ok(Res {val: ((a & 0x1fu8) as uint) << 16u |
(data[start + 1u] as uint) << 8u |
(data[start + 2u] as uint),
next: start + 3u});
}
if a & 0x10u8 != 0u8 {
return Ok(Res {val: ((a & 0x0fu8) as uint) << 24u |
(data[start + 1u] as uint) << 16u |
(data[start + 2u] as uint) << 8u |
(data[start + 3u] as uint),
next: start + 4u});
}
Err(IntTooBig(a as uint))
}
pub fn vuint_at(data: &[u8], start: uint) -> DecodeResult<Res> {
if data.len() - start < 4 {
return vuint_at_slow(data, start);
}
// Lookup table for parsing EBML Element IDs as per http://ebml.sourceforge.net/specs/
// The Element IDs are parsed by reading a big endian u32 positioned at data[start].
// Using the four most significant bits of the u32 we lookup in the table below how the
// element ID should be derived from it.
//
// The table stores tuples (shift, mask) where shift is the number the u32 should be right
// shifted with and mask is the value the right shifted value should be masked with.
// If for example the most significant bit is set this means it's a class A ID and the u32
// should be right shifted with 24 and masked with 0x7f. Therefore we store (24, 0x7f) at
// index 0x8 - 0xF (four bit numbers where the most significant bit is set).
//
// By storing the number of shifts and masks in a table instead of checking in order if
// the most significant bit is set, the second most significant bit is set etc. we can
// replace up to three "and+branch" with a single table lookup which gives us a measured
// speedup of around 2x on x86_64.
static SHIFT_MASK_TABLE: [(uint, u32), ..16] = [
(0, 0x0), (0, 0x0fffffff),
(8, 0x1fffff), (8, 0x1fffff),
(16, 0x3fff), (16, 0x3fff), (16, 0x3fff), (16, 0x3fff),
(24, 0x7f), (24, 0x7f), (24, 0x7f), (24, 0x7f),
(24, 0x7f), (24, 0x7f), (24, 0x7f), (24, 0x7f)
];
unsafe {
let ptr = data.as_ptr().offset(start as int) as *const u32;
let val = Int::from_be(*ptr);
let i = (val >> 28u) as uint;
let (shift, mask) = SHIFT_MASK_TABLE[i];
Ok(Res {
val: ((val >> shift) & mask) as uint,
next: start + (((32 - shift) >> 3) as uint)
})
}
}
pub fn doc_at<'a>(data: &'a [u8], start: uint) -> DecodeResult<TaggedDoc<'a>> {
let elt_tag = try!(vuint_at(data, start));
let elt_size = try!(vuint_at(data, elt_tag.next));
let end = elt_size.next + elt_size.val;
Ok(TaggedDoc {
tag: elt_tag.val,
doc: Doc { data: data, start: elt_size.next, end: end }
})
}
pub fn maybe_get_doc<'a>(d: Doc<'a>, tg: uint) -> Option<Doc<'a>> {
let mut pos = d.start;
while pos < d.end {
let elt_tag = try_or!(vuint_at(d.data, pos), None);
let elt_size = try_or!(vuint_at(d.data, elt_tag.next), None);
pos = elt_size.next + elt_size.val;
if elt_tag.val == tg {
return Some(Doc { data: d.data, start: elt_size.next,
end: pos });
}
}
None
}
pub fn get_doc<'a>(d: Doc<'a>, tg: uint) -> Doc<'a> {
match maybe_get_doc(d, tg) {
Some(d) => d,
None => {
error!("failed to find block with tag {}", tg);
fail!();
}
}
}
pub fn docs<'a>(d: Doc<'a>, it: |uint, Doc<'a>| -> bool) -> bool {
let mut pos = d.start;
while pos < d.end {
let elt_tag = try_or!(vuint_at(d.data, pos), false);
let elt_size = try_or!(vuint_at(d.data, elt_tag.next), false);
pos = elt_size.next + elt_size.val;
let doc = Doc { data: d.data, start: elt_size.next, end: pos };
if !it(elt_tag.val, doc) {
return false;
}
}
return true;
}
pub fn tagged_docs<'a>(d: Doc<'a>, tg: uint, it: |Doc<'a>| -> bool) -> bool {
let mut pos = d.start;
while pos < d.end {
let elt_tag = try_or!(vuint_at(d.data, pos), false);
let elt_size = try_or!(vuint_at(d.data, elt_tag.next), false);
pos = elt_size.next + elt_size.val;
if elt_tag.val == tg {
let doc = Doc { data: d.data, start: elt_size.next,
end: pos };
if !it(doc) {
return false;
}
}
}
return true;
}
pub fn with_doc_data<'a, T>(d: Doc<'a>, f: |x: &'a [u8]| -> T) -> T {
f(d.data.slice(d.start, d.end))
}
pub fn doc_as_u8(d: Doc) -> u8 {
assert_eq!(d.end, d.start + 1u);
d.data[d.start]
}
pub fn doc_as_u16(d: Doc) -> u16 {
assert_eq!(d.end, d.start + 2u);
u64_from_be_bytes(d.data, d.start, 2u) as u16
}
pub fn doc_as_u32(d: Doc) -> u32 {
assert_eq!(d.end, d.start + 4u);
u64_from_be_bytes(d.data, d.start, 4u) as u32
}
pub fn doc_as_u64(d: Doc) -> u64 {
assert_eq!(d.end, d.start + 8u);
u64_from_be_bytes(d.data, d.start, 8u)
}
pub fn doc_as_i8(d: Doc) -> i8 { doc_as_u8(d) as i8 }
pub fn doc_as_i16(d: Doc) -> i16 { doc_as_u16(d) as i16 }
pub fn doc_as_i32(d: Doc) -> i32 { doc_as_u32(d) as i32 }
pub fn doc_as_i64(d: Doc) -> i64 { doc_as_u64(d) as i64 }
pub struct Decoder<'a> {
parent: Doc<'a>,
pos: uint,
}
impl<'doc> Decoder<'doc> {
pub fn new(d: Doc<'doc>) -> Decoder<'doc> {
Decoder {
parent: d,
pos: d.start
}
}
fn _check_label(&mut self, lbl: &str) -> DecodeResult<()> {
if self.pos < self.parent.end {
let TaggedDoc { tag: r_tag, doc: r_doc } =
try!(doc_at(self.parent.data, self.pos));
if r_tag == (EsLabel as uint) {
self.pos = r_doc.end;
let str = r_doc.as_str_slice();
if lbl != str {
return Err(Expected(format!("Expected label {} but \
found {}", lbl, str)));
}
}
}
Ok(())
}
fn next_doc(&mut self, exp_tag: EbmlEncoderTag) -> DecodeResult<Doc<'doc>> {
debug!(". next_doc(exp_tag={})", exp_tag);
if self.pos >= self.parent.end {
return Err(Expected(format!("no more documents in \
current node!")));
}
let TaggedDoc { tag: r_tag, doc: r_doc } =
try!(doc_at(self.parent.data, self.pos));
debug!("self.parent={}-{} self.pos={} r_tag={} r_doc={}-{}",
self.parent.start,
self.parent.end,
self.pos,
r_tag,
r_doc.start,
r_doc.end);
if r_tag != (exp_tag as uint) {
return Err(Expected(format!("expected EBML doc with tag {} but \
found tag {}", exp_tag, r_tag)));
}
if r_doc.end > self.parent.end {
return Err(Expected(format!("invalid EBML, child extends to \
{:#x}, parent to {:#x}",
r_doc.end, self.parent.end)));
}
self.pos = r_doc.end;
Ok(r_doc)
}
fn push_doc<T>(&mut self, exp_tag: EbmlEncoderTag,
f: |&mut Decoder<'doc>| -> DecodeResult<T>) -> DecodeResult<T> {
let d = try!(self.next_doc(exp_tag));
let old_parent = self.parent;
let old_pos = self.pos;
self.parent = d;
self.pos = d.start;
let r = try!(f(self));
self.parent = old_parent;
self.pos = old_pos;
Ok(r)
}
fn _next_uint(&mut self, exp_tag: EbmlEncoderTag) -> DecodeResult<uint> {
let r = doc_as_u32(try!(self.next_doc(exp_tag)));
debug!("_next_uint exp_tag={} result={}", exp_tag, r);
Ok(r as uint)
}
pub fn read_opaque<R>(&mut self,
op: |&mut Decoder<'doc>, Doc| -> DecodeResult<R>) -> DecodeResult<R> {
let doc = try!(self.next_doc(EsOpaque));
let (old_parent, old_pos) = (self.parent, self.pos);
self.parent = doc;
self.pos = doc.start;
let result = try!(op(self, doc));
self.parent = old_parent;
self.pos = old_pos;
Ok(result)
}
}
impl<'doc> serialize::Decoder<Error> for Decoder<'doc> {
fn read_nil(&mut self) -> DecodeResult<()> { Ok(()) }
fn read_u64(&mut self) -> DecodeResult<u64> { Ok(doc_as_u64(try!(self.next_doc(EsU64)))) }
fn read_u32(&mut self) -> DecodeResult<u32> { Ok(doc_as_u32(try!(self.next_doc(EsU32)))) }
fn read_u16(&mut self) -> DecodeResult<u16> { Ok(doc_as_u16(try!(self.next_doc(EsU16)))) }
fn read_u8 (&mut self) -> DecodeResult<u8 > { Ok(doc_as_u8 (try!(self.next_doc(EsU8 )))) }
fn read_uint(&mut self) -> DecodeResult<uint> {
let v = doc_as_u64(try!(self.next_doc(EsUint)));
if v > (::std::uint::MAX as u64) {
Err(IntTooBig(v as uint))
} else {
Ok(v as uint)
}
}
fn read_i64(&mut self) -> DecodeResult<i64> {
Ok(doc_as_u64(try!(self.next_doc(EsI64))) as i64)
}
fn read_i32(&mut self) -> DecodeResult<i32> {
Ok(doc_as_u32(try!(self.next_doc(EsI32))) as i32)
}
fn read_i16(&mut self) -> DecodeResult<i16> {
Ok(doc_as_u16(try!(self.next_doc(EsI16))) as i16)
}
fn read_i8 (&mut self) -> DecodeResult<i8> {
Ok(doc_as_u8(try!(self.next_doc(EsI8 ))) as i8)
}
fn read_int(&mut self) -> DecodeResult<int> {
let v = doc_as_u64(try!(self.next_doc(EsInt))) as i64;
if v > (int::MAX as i64) || v < (int::MIN as i64) {
debug!("FIXME \\#6122: Removing this makes this function miscompile");
Err(IntTooBig(v as uint))
} else {
Ok(v as int)
}
}
fn read_bool(&mut self) -> DecodeResult<bool> {
Ok(doc_as_u8(try!(self.next_doc(EsBool))) != 0)
}
fn read_f64(&mut self) -> DecodeResult<f64> {
let bits = doc_as_u64(try!(self.next_doc(EsF64)));
Ok(unsafe { transmute(bits) })
}
fn read_f32(&mut self) -> DecodeResult<f32> {
let bits = doc_as_u32(try!(self.next_doc(EsF32)));
Ok(unsafe { transmute(bits) })
}
fn read_char(&mut self) -> DecodeResult<char> {
Ok(char::from_u32(doc_as_u32(try!(self.next_doc(EsChar)))).unwrap())
}
fn read_str(&mut self) -> DecodeResult<String> {
Ok(try!(self.next_doc(EsStr)).as_str())
}
// Compound types:
fn read_enum<T>(&mut self,
name: &str,
f: |&mut Decoder<'doc>| -> DecodeResult<T>) -> DecodeResult<T> {
debug!("read_enum({})", name);
try!(self._check_label(name));
let doc = try!(self.next_doc(EsEnum));
let (old_parent, old_pos) = (self.parent, self.pos);
self.parent = doc;
self.pos = self.parent.start;
let result = try!(f(self));
self.parent = old_parent;
self.pos = old_pos;
Ok(result)
}
fn read_enum_variant<T>(&mut self,
_: &[&str],
f: |&mut Decoder<'doc>, uint| -> DecodeResult<T>)
-> DecodeResult<T> {
debug!("read_enum_variant()");
let idx = try!(self._next_uint(EsEnumVid));
debug!(" idx={}", idx);
let doc = try!(self.next_doc(EsEnumBody));
let (old_parent, old_pos) = (self.parent, self.pos);
self.parent = doc;
self.pos = self.parent.start;
let result = try!(f(self, idx));
self.parent = old_parent;
self.pos = old_pos;
Ok(result)
}
fn read_enum_variant_arg<T>(&mut self,
idx: uint,
f: |&mut Decoder<'doc>| -> DecodeResult<T>) -> DecodeResult<T> {
debug!("read_enum_variant_arg(idx={})", idx);
f(self)
}
fn read_enum_struct_variant<T>(&mut self,
_: &[&str],
f: |&mut Decoder<'doc>, uint| -> DecodeResult<T>)
-> DecodeResult<T> {
debug!("read_enum_struct_variant()");
let idx = try!(self._next_uint(EsEnumVid));
debug!(" idx={}", idx);
let doc = try!(self.next_doc(EsEnumBody));
let (old_parent, old_pos) = (self.parent, self.pos);
self.parent = doc;
self.pos = self.parent.start;
let result = try!(f(self, idx));
self.parent = old_parent;
self.pos = old_pos;
Ok(result)
}
fn read_enum_struct_variant_field<T>(&mut self,
name: &str,
idx: uint,
f: |&mut Decoder<'doc>| -> DecodeResult<T>)
-> DecodeResult<T> {
debug!("read_enum_struct_variant_arg(name={}, idx={})", name, idx);
f(self)
}
fn read_struct<T>(&mut self,
name: &str,
_: uint,
f: |&mut Decoder<'doc>| -> DecodeResult<T>)
-> DecodeResult<T> {
debug!("read_struct(name={})", name);
f(self)
}
fn read_struct_field<T>(&mut self,
name: &str,
idx: uint,
f: |&mut Decoder<'doc>| -> DecodeResult<T>)
-> DecodeResult<T> {
debug!("read_struct_field(name={}, idx={})", name, idx);
try!(self._check_label(name));
f(self)
}
fn read_tuple<T>(&mut self,
f: |&mut Decoder<'doc>, uint| -> DecodeResult<T>) -> DecodeResult<T> {
debug!("read_tuple()");
self.read_seq(f)
}
fn read_tuple_arg<T>(&mut self, idx: uint, f: |&mut Decoder<'doc>| -> DecodeResult<T>)
-> DecodeResult<T> {
debug!("read_tuple_arg(idx={})", idx);
self.read_seq_elt(idx, f)
}
fn read_tuple_struct<T>(&mut self,
name: &str,
f: |&mut Decoder<'doc>, uint| -> DecodeResult<T>)
-> DecodeResult<T> {
debug!("read_tuple_struct(name={})", name);
self.read_tuple(f)
}
fn read_tuple_struct_arg<T>(&mut self,
idx: uint,
f: |&mut Decoder<'doc>| -> DecodeResult<T>)
-> DecodeResult<T> {
debug!("read_tuple_struct_arg(idx={})", idx);
self.read_tuple_arg(idx, f)
}
fn read_option<T>(&mut self,
f: |&mut Decoder<'doc>, bool| -> DecodeResult<T>) -> DecodeResult<T> {
debug!("read_option()");
self.read_enum("Option", |this| {
this.read_enum_variant(["None", "Some"], |this, idx| {
match idx {
0 => f(this, false),
1 => f(this, true),
_ => {
Err(Expected(format!("Expected None or Some")))
}
}
})
})
}
fn read_seq<T>(&mut self,
f: |&mut Decoder<'doc>, uint| -> DecodeResult<T>) -> DecodeResult<T> {
debug!("read_seq()");
self.push_doc(EsVec, |d| {
let len = try!(d._next_uint(EsVecLen));
debug!(" len={}", len);
f(d, len)
})
}
fn read_seq_elt<T>(&mut self, idx: uint, f: |&mut Decoder<'doc>| -> DecodeResult<T>)
-> DecodeResult<T> {
debug!("read_seq_elt(idx={})", idx);
self.push_doc(EsVecElt, f)
}
fn read_map<T>(&mut self,
f: |&mut Decoder<'doc>, uint| -> DecodeResult<T>) -> DecodeResult<T> {
debug!("read_map()");
self.push_doc(EsMap, |d| {
let len = try!(d._next_uint(EsMapLen));
debug!(" len={}", len);
f(d, len)
})
}
fn read_map_elt_key<T>(&mut self, idx: uint, f: |&mut Decoder<'doc>| -> DecodeResult<T>)
-> DecodeResult<T> {
debug!("read_map_elt_key(idx={})", idx);
self.push_doc(EsMapKey, f)
}
fn read_map_elt_val<T>(&mut self, idx: uint, f: |&mut Decoder<'doc>| -> DecodeResult<T>)
-> DecodeResult<T> {
debug!("read_map_elt_val(idx={})", idx);
self.push_doc(EsMapVal, f)
}
}
}
pub mod writer {
use std::clone::Clone;
use std::io::extensions::u64_to_be_bytes;
use std::io::{Writer, Seek};
use std::io;
use std::mem;
use super::{ EsVec, EsMap, EsEnum, EsVecLen, EsVecElt, EsMapLen, EsMapKey,
EsEnumVid, EsU64, EsU32, EsU16, EsU8, EsInt, EsI64, EsI32, EsI16, EsI8,
EsBool, EsF64, EsF32, EsChar, EsStr, EsMapVal, EsEnumBody, EsUint,
EsOpaque, EsLabel, EbmlEncoderTag };
use serialize;
pub type EncodeResult = io::IoResult<()>;
// ebml writing
pub struct Encoder<'a, W> {
pub writer: &'a mut W,
size_positions: Vec<uint>,
}
fn write_sized_vuint<W: Writer>(w: &mut W, n: uint, size: uint) -> EncodeResult {
match size {
1u => w.write(&[0x80u8 | (n as u8)]),
2u => w.write(&[0x40u8 | ((n >> 8_u) as u8), n as u8]),
3u => w.write(&[0x20u8 | ((n >> 16_u) as u8), (n >> 8_u) as u8,
n as u8]),
4u => w.write(&[0x10u8 | ((n >> 24_u) as u8), (n >> 16_u) as u8,
(n >> 8_u) as u8, n as u8]),
_ => Err(io::IoError {
kind: io::OtherIoError,
desc: "int too big",
detail: Some(format!("{}", n))
})
}
}
fn write_vuint<W: Writer>(w: &mut W, n: uint) -> EncodeResult {
if n < 0x7f_u { return write_sized_vuint(w, n, 1u); }
if n < 0x4000_u { return write_sized_vuint(w, n, 2u); }
if n < 0x200000_u { return write_sized_vuint(w, n, 3u); }
if n < 0x10000000_u { return write_sized_vuint(w, n, 4u); }
Err(io::IoError {
kind: io::OtherIoError,
desc: "int too big",
detail: Some(format!("{}", n))
})
}
// FIXME (#2741): Provide a function to write the standard ebml header.
impl<'a, W: Writer + Seek> Encoder<'a, W> {
pub fn new(w: &'a mut W) -> Encoder<'a, W> {
Encoder {
writer: w,
size_positions: vec!(),
}
}
/// FIXME(pcwalton): Workaround for badness in trans. DO NOT USE ME.
pub unsafe fn unsafe_clone(&self) -> Encoder<'a, W> {
Encoder {
writer: mem::transmute_copy(&self.writer),
size_positions: self.size_positions.clone(),
}
}
pub fn start_tag(&mut self, tag_id: uint) -> EncodeResult {
debug!("Start tag {}", tag_id);
// Write the enum ID:
try!(write_vuint(self.writer, tag_id));
// Write a placeholder four-byte size.
self.size_positions.push(try!(self.writer.tell()) as uint);
let zeroes: &[u8] = &[0u8, 0u8, 0u8, 0u8];
self.writer.write(zeroes)
}
pub fn end_tag(&mut self) -> EncodeResult {
let last_size_pos = self.size_positions.pop().unwrap();
let cur_pos = try!(self.writer.tell());
try!(self.writer.seek(last_size_pos as i64, io::SeekSet));
let size = cur_pos as uint - last_size_pos - 4;
try!(write_sized_vuint(self.writer, size, 4u));
let r = try!(self.writer.seek(cur_pos as i64, io::SeekSet));
debug!("End tag (size = {})", size);
Ok(r)
}
pub fn wr_tag(&mut self, tag_id: uint, blk: || -> EncodeResult) -> EncodeResult {
try!(self.start_tag(tag_id));
try!(blk());
self.end_tag()
}
pub fn wr_tagged_bytes(&mut self, tag_id: uint, b: &[u8]) -> EncodeResult {
try!(write_vuint(self.writer, tag_id));
try!(write_vuint(self.writer, b.len()));
self.writer.write(b)
}
pub fn wr_tagged_u64(&mut self, tag_id: uint, v: u64) -> EncodeResult {
u64_to_be_bytes(v, 8u, |v| {
self.wr_tagged_bytes(tag_id, v)
})
}
pub fn wr_tagged_u32(&mut self, tag_id: uint, v: u32) -> EncodeResult{
u64_to_be_bytes(v as u64, 4u, |v| {
self.wr_tagged_bytes(tag_id, v)
})
}
pub fn wr_tagged_u16(&mut self, tag_id: uint, v: u16) -> EncodeResult {
u64_to_be_bytes(v as u64, 2u, |v| {
self.wr_tagged_bytes(tag_id, v)
})
}
pub fn wr_tagged_u8(&mut self, tag_id: uint, v: u8) -> EncodeResult {
self.wr_tagged_bytes(tag_id, &[v])
}
pub fn wr_tagged_i64(&mut self, tag_id: uint, v: i64) -> EncodeResult {
u64_to_be_bytes(v as u64, 8u, |v| {
self.wr_tagged_bytes(tag_id, v)
})
}
pub fn wr_tagged_i32(&mut self, tag_id: uint, v: i32) -> EncodeResult {
u64_to_be_bytes(v as u64, 4u, |v| {
self.wr_tagged_bytes(tag_id, v)
})
}
pub fn wr_tagged_i16(&mut self, tag_id: uint, v: i16) -> EncodeResult {
u64_to_be_bytes(v as u64, 2u, |v| {
self.wr_tagged_bytes(tag_id, v)
})
}
pub fn wr_tagged_i8(&mut self, tag_id: uint, v: i8) -> EncodeResult {
self.wr_tagged_bytes(tag_id, &[v as u8])
}
pub fn wr_tagged_str(&mut self, tag_id: uint, v: &str) -> EncodeResult {
self.wr_tagged_bytes(tag_id, v.as_bytes())
}
pub fn wr_bytes(&mut self, b: &[u8]) -> EncodeResult {
debug!("Write {} bytes", b.len());
self.writer.write(b)
}
pub fn wr_str(&mut self, s: &str) -> EncodeResult {
debug!("Write str: {}", s);
self.writer.write(s.as_bytes())
}
}
// FIXME (#2743): optionally perform "relaxations" on end_tag to more
// efficiently encode sizes; this is a fixed point iteration
// Set to true to generate more debugging in EBML code.
// Totally lame approach.
static DEBUG: bool = true;
impl<'a, W: Writer + Seek> Encoder<'a, W> {
// used internally to emit things like the vector length and so on
fn _emit_tagged_uint(&mut self, t: EbmlEncoderTag, v: uint) -> EncodeResult {
assert!(v <= 0xFFFF_FFFF_u);
self.wr_tagged_u32(t as uint, v as u32)
}
fn _emit_label(&mut self, label: &str) -> EncodeResult {
// There are various strings that we have access to, such as
// the name of a record field, which do not actually appear in
// the encoded EBML (normally). This is just for
// efficiency. When debugging, though, we can emit such
// labels and then they will be checked by decoder to
// try and check failures more quickly.
if DEBUG { self.wr_tagged_str(EsLabel as uint, label) }
else { Ok(()) }
}
pub fn emit_opaque(&mut self, f: |&mut Encoder<W>| -> EncodeResult) -> EncodeResult {
try!(self.start_tag(EsOpaque as uint));
try!(f(self));
self.end_tag()
}
}
impl<'a, W: Writer + Seek> serialize::Encoder<io::IoError> for Encoder<'a, W> {
fn emit_nil(&mut self) -> EncodeResult {
Ok(())
}
fn emit_uint(&mut self, v: uint) -> EncodeResult {
self.wr_tagged_u64(EsUint as uint, v as u64)
}
fn emit_u64(&mut self, v: u64) -> EncodeResult {
self.wr_tagged_u64(EsU64 as uint, v)
}
fn emit_u32(&mut self, v: u32) -> EncodeResult {
self.wr_tagged_u32(EsU32 as uint, v)
}
fn emit_u16(&mut self, v: u16) -> EncodeResult {
self.wr_tagged_u16(EsU16 as uint, v)
}
fn emit_u8(&mut self, v: u8) -> EncodeResult {
self.wr_tagged_u8(EsU8 as uint, v)
}
fn emit_int(&mut self, v: int) -> EncodeResult {
self.wr_tagged_i64(EsInt as uint, v as i64)
}
fn emit_i64(&mut self, v: i64) -> EncodeResult {
self.wr_tagged_i64(EsI64 as uint, v)
}
fn emit_i32(&mut self, v: i32) -> EncodeResult {
self.wr_tagged_i32(EsI32 as uint, v)
}
fn emit_i16(&mut self, v: i16) -> EncodeResult {
self.wr_tagged_i16(EsI16 as uint, v)
}
fn emit_i8(&mut self, v: i8) -> EncodeResult {
self.wr_tagged_i8(EsI8 as uint, v)
}
fn emit_bool(&mut self, v: bool) -> EncodeResult {
self.wr_tagged_u8(EsBool as uint, v as u8)
}
fn emit_f64(&mut self, v: f64) -> EncodeResult {
let bits = unsafe { mem::transmute(v) };
self.wr_tagged_u64(EsF64 as uint, bits)
}
fn emit_f32(&mut self, v: f32) -> EncodeResult {
let bits = unsafe { mem::transmute(v) };
self.wr_tagged_u32(EsF32 as uint, bits)
}
fn emit_char(&mut self, v: char) -> EncodeResult {
self.wr_tagged_u32(EsChar as uint, v as u32)
}
fn emit_str(&mut self, v: &str) -> EncodeResult {
self.wr_tagged_str(EsStr as uint, v)
}
fn emit_enum(&mut self,
name: &str,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
try!(self._emit_label(name));
try!(self.start_tag(EsEnum as uint));
try!(f(self));
self.end_tag()
}
fn emit_enum_variant(&mut self,
_: &str,
v_id: uint,
_: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
try!(self._emit_tagged_uint(EsEnumVid, v_id));
try!(self.start_tag(EsEnumBody as uint));
try!(f(self));
self.end_tag()
}
fn emit_enum_variant_arg(&mut self,
_: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
f(self)
}
fn emit_enum_struct_variant(&mut self,
v_name: &str,
v_id: uint,
cnt: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
self.emit_enum_variant(v_name, v_id, cnt, f)
}
fn emit_enum_struct_variant_field(&mut self,
_: &str,
idx: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult)
-> EncodeResult {
self.emit_enum_variant_arg(idx, f)
}
fn emit_struct(&mut self,
_: &str,
_len: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
f(self)
}
fn emit_struct_field(&mut self,
name: &str,
_: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
try!(self._emit_label(name));
f(self)
}
fn emit_tuple(&mut self,
len: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
self.emit_seq(len, f)
}
fn emit_tuple_arg(&mut self,
idx: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
self.emit_seq_elt(idx, f)
}
fn emit_tuple_struct(&mut self,
_: &str,
len: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
self.emit_seq(len, f)
}
fn emit_tuple_struct_arg(&mut self,
idx: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
self.emit_seq_elt(idx, f)
}
fn emit_option(&mut self,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
self.emit_enum("Option", f)
}
fn emit_option_none(&mut self) -> EncodeResult {
self.emit_enum_variant("None", 0, 0, |_| Ok(()))
}
fn emit_option_some(&mut self,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
self.emit_enum_variant("Some", 1, 1, f)
}
fn emit_seq(&mut self,
len: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
try!(self.start_tag(EsVec as uint));
try!(self._emit_tagged_uint(EsVecLen, len));
try!(f(self));
self.end_tag()
}
fn emit_seq_elt(&mut self,
_idx: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
try!(self.start_tag(EsVecElt as uint));
try!(f(self));
self.end_tag()
}
fn emit_map(&mut self,
len: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
try!(self.start_tag(EsMap as uint));
try!(self._emit_tagged_uint(EsMapLen, len));
try!(f(self));
self.end_tag()
}
fn emit_map_elt_key(&mut self,
_idx: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
try!(self.start_tag(EsMapKey as uint));
try!(f(self));
self.end_tag()
}
fn emit_map_elt_val(&mut self,
_idx: uint,
f: |&mut Encoder<'a, W>| -> EncodeResult) -> EncodeResult {
try!(self.start_tag(EsMapVal as uint));
try!(f(self));
self.end_tag()
}
}
}
// ___________________________________________________________________________
// Testing
#[cfg(test)]
mod tests {
use super::Doc;
use ebml::reader;
use ebml::writer;
use {Encodable, Decodable};
use std::io::MemWriter;
use std::option::{None, Option, Some};
#[test]
fn test_vuint_at() {
let data = [
0x80,
0xff,
0x40, 0x00,
0x7f, 0xff,
0x20, 0x00, 0x00,
0x3f, 0xff, 0xff,
0x10, 0x00, 0x00, 0x00,
0x1f, 0xff, 0xff, 0xff
];
let mut res: reader::Res;
// Class A
res = reader::vuint_at(data, 0).unwrap();
assert_eq!(res.val, 0);
assert_eq!(res.next, 1);
res = reader::vuint_at(data, res.next).unwrap();
assert_eq!(res.val, (1 << 7) - 1);
assert_eq!(res.next, 2);
// Class B
res = reader::vuint_at(data, res.next).unwrap();
assert_eq!(res.val, 0);
assert_eq!(res.next, 4);
res = reader::vuint_at(data, res.next).unwrap();
assert_eq!(res.val, (1 << 14) - 1);
assert_eq!(res.next, 6);
// Class C
res = reader::vuint_at(data, res.next).unwrap();
assert_eq!(res.val, 0);
assert_eq!(res.next, 9);
res = reader::vuint_at(data, res.next).unwrap();
assert_eq!(res.val, (1 << 21) - 1);
assert_eq!(res.next, 12);
// Class D
res = reader::vuint_at(data, res.next).unwrap();
assert_eq!(res.val, 0);
assert_eq!(res.next, 16);
res = reader::vuint_at(data, res.next).unwrap();
assert_eq!(res.val, (1 << 28) - 1);
assert_eq!(res.next, 20);
}
#[test]
fn test_option_int() {
fn test_v(v: Option<int>) {
debug!("v == {}", v);
let mut wr = MemWriter::new();
{
let mut ebml_w = writer::Encoder::new(&mut wr);
let _ = v.encode(&mut ebml_w);
}
let ebml_doc = Doc::new(wr.get_ref());
let mut deser = reader::Decoder::new(ebml_doc);
let v1 = Decodable::decode(&mut deser).unwrap();
debug!("v1 == {}", v1);
assert_eq!(v, v1);
}
test_v(Some(22));
test_v(None);
test_v(Some(3));
}
}
#[cfg(test)]
mod bench {
#![allow(non_snake_case_functions)]
extern crate test;
use self::test::Bencher;
use ebml::reader;
#[bench]
pub fn vuint_at_A_aligned(b: &mut Bencher) {
let data = Vec::from_fn(4*100, |i| {
match i % 2 {
0 => 0x80u8,
_ => i as u8,
}
});
let mut sum = 0u;
b.iter(|| {
let mut i = 0;
while i < data.len() {
sum += reader::vuint_at(data.as_slice(), i).unwrap().val;
i += 4;
}
});
}
#[bench]
pub fn vuint_at_A_unaligned(b: &mut Bencher) {
let data = Vec::from_fn(4*100+1, |i| {
match i % 2 {
1 => 0x80u8,
_ => i as u8
}
});
let mut sum = 0u;
b.iter(|| {
let mut i = 1;
while i < data.len() {
sum += reader::vuint_at(data.as_slice(), i).unwrap().val;
i += 4;
}
});
}
#[bench]
pub fn vuint_at_D_aligned(b: &mut Bencher) {
let data = Vec::from_fn(4*100, |i| {
match i % 4 {
0 => 0x10u8,
3 => i as u8,
_ => 0u8
}
});
let mut sum = 0u;
b.iter(|| {
let mut i = 0;
while i < data.len() {
sum += reader::vuint_at(data.as_slice(), i).unwrap().val;
i += 4;
}
});
}
#[bench]
pub fn vuint_at_D_unaligned(b: &mut Bencher) {
let data = Vec::from_fn(4*100+1, |i| {
match i % 4 {
1 => 0x10u8,
0 => i as u8,
_ => 0u8
}
});
let mut sum = 0u;
b.iter(|| {
let mut i = 1;
while i < data.len() {
sum += reader::vuint_at(data.as_slice(), i).unwrap().val;
i += 4;
}
});
}
}