rust/src/libstd/ebml.rs
2013-03-04 12:27:01 -05:00

705 lines
22 KiB
Rust

// Copyright 2012-2013 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.
use core::prelude::*;
// 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
struct EbmlTag {
id: uint,
size: uint,
}
struct EbmlState {
ebml_tag: EbmlTag,
tag_pos: uint,
data_pos: uint,
}
pub struct Doc {
data: @~[u8],
start: uint,
end: uint,
}
pub struct TaggedDoc {
tag: uint,
doc: Doc,
}
pub enum EbmlEncoderTag {
EsUint, EsU64, EsU32, EsU16, EsU8,
EsInt, EsI64, EsI32, EsI16, EsI8,
EsBool,
EsStr,
EsF64, EsF32, EsFloat,
EsEnum, EsEnumVid, EsEnumBody,
EsVec, EsVecLen, EsVecElt,
EsOpaque,
EsLabel // Used only when debugging
}
// --------------------------------------
pub mod reader {
use ebml::{Doc, EbmlEncoderTag, EsBool, EsEnum, EsEnumBody, EsEnumVid};
use ebml::{EsF32, EsF64, EsFloat, EsI16, EsI32, EsI64, EsI8, EsInt};
use ebml::{EsLabel, EsOpaque, EsStr, EsU16, EsU32, EsU64, EsU8, EsUint};
use ebml::{EsVec, EsVecElt, EsVecLen, TaggedDoc};
use serialize;
use core::int;
use core::io;
use core::ops;
use core::prelude::*;
use core::str;
use core::vec;
// ebml reading
impl ops::Index<uint,Doc> for Doc {
pure fn index(&self, tag: uint) -> Doc {
unsafe {
get_doc(*self, tag)
}
}
}
struct Res {
val: uint,
next: uint
}
fn vuint_at(data: &[u8], start: uint) -> Res {
let a = data[start];
if a & 0x80u8 != 0u8 {
return Res {val: (a & 0x7fu8) as uint, next: start + 1u};
}
if a & 0x40u8 != 0u8 {
return Res {val: ((a & 0x3fu8) as uint) << 8u |
(data[start + 1u] as uint),
next: start + 2u};
} else if a & 0x20u8 != 0u8 {
return Res {val: ((a & 0x1fu8) as uint) << 16u |
(data[start + 1u] as uint) << 8u |
(data[start + 2u] as uint),
next: start + 3u};
} else if a & 0x10u8 != 0u8 {
return 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};
} else { error!("vint too big"); fail!(); }
}
pub fn Doc(data: @~[u8]) -> Doc {
Doc { data: data, start: 0u, end: vec::len::<u8>(*data) }
}
pub fn doc_at(data: @~[u8], start: uint) -> TaggedDoc {
let elt_tag = vuint_at(*data, start);
let elt_size = vuint_at(*data, elt_tag.next);
let end = elt_size.next + elt_size.val;
TaggedDoc {
tag: elt_tag.val,
doc: Doc { data: data, start: elt_size.next, end: end }
}
}
pub fn maybe_get_doc(d: Doc, tg: uint) -> Option<Doc> {
let mut pos = d.start;
while pos < d.end {
let elt_tag = vuint_at(*d.data, pos);
let elt_size = vuint_at(*d.data, elt_tag.next);
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(d: Doc, tg: uint) -> Doc {
match maybe_get_doc(d, tg) {
Some(d) => d,
None => {
error!("failed to find block with tag %u", tg);
fail!();
}
}
}
pub fn docs(d: Doc, it: fn(uint, Doc) -> bool) {
let mut pos = d.start;
while pos < d.end {
let elt_tag = vuint_at(*d.data, pos);
let elt_size = vuint_at(*d.data, elt_tag.next);
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) {
break;
}
}
}
pub fn tagged_docs(d: Doc, tg: uint, it: fn(Doc) -> bool) {
let mut pos = d.start;
while pos < d.end {
let elt_tag = vuint_at(*d.data, pos);
let elt_size = vuint_at(*d.data, elt_tag.next);
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) {
break;
}
}
}
}
pub fn doc_data(d: Doc) -> ~[u8] {
vec::slice::<u8>(*d.data, d.start, d.end).to_vec()
}
pub fn with_doc_data<T>(d: Doc, f: fn(x: &[u8]) -> T) -> T {
f(vec::slice(*d.data, d.start, d.end))
}
pub fn doc_as_str(d: Doc) -> ~str { str::from_bytes(doc_data(d)) }
pub fn doc_as_u8(d: Doc) -> u8 {
assert d.end == d.start + 1u;
(*d.data)[d.start]
}
pub fn doc_as_u16(d: Doc) -> u16 {
assert d.end == d.start + 2u;
io::u64_from_be_bytes(*d.data, d.start, 2u) as u16
}
pub fn doc_as_u32(d: Doc) -> u32 {
assert d.end == d.start + 4u;
io::u64_from_be_bytes(*d.data, d.start, 4u) as u32
}
pub fn doc_as_u64(d: Doc) -> u64 {
assert d.end == d.start + 8u;
io::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 {
priv mut parent: Doc,
priv mut pos: uint,
}
pub fn Decoder(d: Doc) -> Decoder {
Decoder { parent: d, pos: d.start }
}
priv impl Decoder {
fn _check_label(lbl: &str) {
if self.pos < self.parent.end {
let TaggedDoc { tag: r_tag, doc: r_doc } =
doc_at(self.parent.data, self.pos);
if r_tag == (EsLabel as uint) {
self.pos = r_doc.end;
let str = doc_as_str(r_doc);
if lbl != str {
fail!(fmt!("Expected label %s but found %s", lbl,
str));
}
}
}
}
fn next_doc(exp_tag: EbmlEncoderTag) -> Doc {
debug!(". next_doc(exp_tag=%?)", exp_tag);
if self.pos >= self.parent.end {
fail!(~"no more documents in current node!");
}
let TaggedDoc { tag: r_tag, doc: r_doc } =
doc_at(self.parent.data, self.pos);
debug!("self.parent=%?-%? self.pos=%? r_tag=%? r_doc=%?-%?",
copy self.parent.start, copy self.parent.end,
copy self.pos, r_tag, r_doc.start, r_doc.end);
if r_tag != (exp_tag as uint) {
fail!(fmt!("expected EBML doc with tag %? but found tag %?",
exp_tag, r_tag));
}
if r_doc.end > self.parent.end {
fail!(fmt!("invalid EBML, child extends to 0x%x, \
parent to 0x%x", r_doc.end, self.parent.end));
}
self.pos = r_doc.end;
r_doc
}
fn push_doc<T>(d: Doc, f: fn() -> T) -> T {
let old_parent = self.parent;
let old_pos = self.pos;
self.parent = d;
self.pos = d.start;
let r = f();
self.parent = old_parent;
self.pos = old_pos;
r
}
fn _next_uint(exp_tag: EbmlEncoderTag) -> uint {
let r = doc_as_u32(self.next_doc(exp_tag));
debug!("_next_uint exp_tag=%? result=%?", exp_tag, r);
r as uint
}
}
pub impl Decoder {
fn read_opaque<R>(&self, op: fn(Doc) -> R) -> R {
do self.push_doc(self.next_doc(EsOpaque)) {
op(copy self.parent)
}
}
}
impl serialize::Decoder for Decoder {
fn read_nil(&self) -> () { () }
fn read_u64(&self) -> u64 { doc_as_u64(self.next_doc(EsU64)) }
fn read_u32(&self) -> u32 { doc_as_u32(self.next_doc(EsU32)) }
fn read_u16(&self) -> u16 { doc_as_u16(self.next_doc(EsU16)) }
fn read_u8 (&self) -> u8 { doc_as_u8 (self.next_doc(EsU8 )) }
fn read_uint(&self) -> uint {
let v = doc_as_u64(self.next_doc(EsUint));
if v > (::core::uint::max_value as u64) {
fail!(fmt!("uint %? too large for this architecture", v));
}
v as uint
}
fn read_i64(&self) -> i64 { doc_as_u64(self.next_doc(EsI64)) as i64 }
fn read_i32(&self) -> i32 { doc_as_u32(self.next_doc(EsI32)) as i32 }
fn read_i16(&self) -> i16 { doc_as_u16(self.next_doc(EsI16)) as i16 }
fn read_i8 (&self) -> i8 { doc_as_u8 (self.next_doc(EsI8 )) as i8 }
fn read_int(&self) -> int {
let v = doc_as_u64(self.next_doc(EsInt)) as i64;
if v > (int::max_value as i64) || v < (int::min_value as i64) {
fail!(fmt!("int %? out of range for this architecture", v));
}
v as int
}
fn read_bool(&self) -> bool { doc_as_u8(self.next_doc(EsBool))
as bool }
fn read_f64(&self) -> f64 { fail!(~"read_f64()"); }
fn read_f32(&self) -> f32 { fail!(~"read_f32()"); }
fn read_float(&self) -> float { fail!(~"read_float()"); }
fn read_char(&self) -> char { fail!(~"read_char()"); }
fn read_owned_str(&self) -> ~str { doc_as_str(self.next_doc(EsStr)) }
fn read_managed_str(&self) -> @str { fail!(~"read_managed_str()"); }
// Compound types:
fn read_owned<T>(&self, f: fn() -> T) -> T {
debug!("read_owned()");
f()
}
fn read_managed<T>(&self, f: fn() -> T) -> T {
debug!("read_managed()");
f()
}
fn read_enum<T>(&self, name: &str, f: fn() -> T) -> T {
debug!("read_enum(%s)", name);
self._check_label(name);
self.push_doc(self.next_doc(EsEnum), f)
}
fn read_enum_variant<T>(&self, f: fn(uint) -> T) -> T {
debug!("read_enum_variant()");
let idx = self._next_uint(EsEnumVid);
debug!(" idx=%u", idx);
do self.push_doc(self.next_doc(EsEnumBody)) {
f(idx)
}
}
fn read_enum_variant_arg<T>(&self, idx: uint, f: fn() -> T) -> T {
debug!("read_enum_variant_arg(idx=%u)", idx);
f()
}
fn read_owned_vec<T>(&self, f: fn(uint) -> T) -> T {
debug!("read_owned_vec()");
do self.push_doc(self.next_doc(EsVec)) {
let len = self._next_uint(EsVecLen);
debug!(" len=%u", len);
f(len)
}
}
fn read_managed_vec<T>(&self, f: fn(uint) -> T) -> T {
debug!("read_managed_vec()");
do self.push_doc(self.next_doc(EsVec)) {
let len = self._next_uint(EsVecLen);
debug!(" len=%u", len);
f(len)
}
}
fn read_vec_elt<T>(&self, idx: uint, f: fn() -> T) -> T {
debug!("read_vec_elt(idx=%u)", idx);
self.push_doc(self.next_doc(EsVecElt), f)
}
fn read_rec<T>(&self, f: fn() -> T) -> T {
debug!("read_rec()");
f()
}
fn read_struct<T>(&self, name: &str, _len: uint, f: fn() -> T) -> T {
debug!("read_struct(name=%s)", name);
f()
}
fn read_field<T>(&self, name: &str, idx: uint, f: fn() -> T) -> T {
debug!("read_field(name=%s, idx=%u)", name, idx);
self._check_label(name);
f()
}
fn read_tup<T>(&self, len: uint, f: fn() -> T) -> T {
debug!("read_tup(len=%u)", len);
f()
}
fn read_tup_elt<T>(&self, idx: uint, f: fn() -> T) -> T {
debug!("read_tup_elt(idx=%u)", idx);
f()
}
}
}
pub mod writer {
use ebml::{Doc, EbmlEncoderTag, EsBool, EsEnum, EsEnumBody, EsEnumVid};
use ebml::{EsF32, EsF64, EsFloat, EsI16, EsI32, EsI64, EsI8, EsInt};
use ebml::{EsLabel, EsOpaque, EsStr, EsU16, EsU32, EsU64, EsU8, EsUint};
use ebml::{EsVec, EsVecElt, EsVecLen, TaggedDoc};
use core::io;
use core::str;
use core::vec;
// ebml writing
pub struct Encoder {
writer: io::Writer,
priv mut size_positions: ~[uint],
}
fn write_sized_vuint(w: io::Writer, n: uint, size: uint) {
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]),
_ => fail!(fmt!("vint to write too big: %?", n))
};
}
fn write_vuint(w: io::Writer, n: uint) {
if n < 0x7f_u { write_sized_vuint(w, n, 1u); return; }
if n < 0x4000_u { write_sized_vuint(w, n, 2u); return; }
if n < 0x200000_u { write_sized_vuint(w, n, 3u); return; }
if n < 0x10000000_u { write_sized_vuint(w, n, 4u); return; }
fail!(fmt!("vint to write too big: %?", n));
}
pub fn Encoder(w: io::Writer) -> Encoder {
let size_positions: ~[uint] = ~[];
Encoder { writer: w, mut size_positions: size_positions }
}
// FIXME (#2741): Provide a function to write the standard ebml header.
pub impl Encoder {
fn start_tag(tag_id: uint) {
debug!("Start tag %u", tag_id);
// Write the enum ID:
write_vuint(self.writer, tag_id);
// Write a placeholder four-byte size.
self.size_positions.push(self.writer.tell());
let zeroes: &[u8] = &[0u8, 0u8, 0u8, 0u8];
self.writer.write(zeroes);
}
fn end_tag() {
let last_size_pos = self.size_positions.pop();
let cur_pos = self.writer.tell();
self.writer.seek(last_size_pos as int, io::SeekSet);
let size = (cur_pos - last_size_pos - 4u);
write_sized_vuint(self.writer, size, 4u);
self.writer.seek(cur_pos as int, io::SeekSet);
debug!("End tag (size = %u)", size);
}
fn wr_tag(tag_id: uint, blk: fn()) {
self.start_tag(tag_id);
blk();
self.end_tag();
}
fn wr_tagged_bytes(tag_id: uint, b: &[u8]) {
write_vuint(self.writer, tag_id);
write_vuint(self.writer, vec::len(b));
self.writer.write(b);
}
fn wr_tagged_u64(tag_id: uint, v: u64) {
do io::u64_to_be_bytes(v, 8u) |v| {
self.wr_tagged_bytes(tag_id, v);
}
}
fn wr_tagged_u32(tag_id: uint, v: u32) {
do io::u64_to_be_bytes(v as u64, 4u) |v| {
self.wr_tagged_bytes(tag_id, v);
}
}
fn wr_tagged_u16(tag_id: uint, v: u16) {
do io::u64_to_be_bytes(v as u64, 2u) |v| {
self.wr_tagged_bytes(tag_id, v);
}
}
fn wr_tagged_u8(tag_id: uint, v: u8) {
self.wr_tagged_bytes(tag_id, &[v]);
}
fn wr_tagged_i64(tag_id: uint, v: i64) {
do io::u64_to_be_bytes(v as u64, 8u) |v| {
self.wr_tagged_bytes(tag_id, v);
}
}
fn wr_tagged_i32(tag_id: uint, v: i32) {
do io::u64_to_be_bytes(v as u64, 4u) |v| {
self.wr_tagged_bytes(tag_id, v);
}
}
fn wr_tagged_i16(tag_id: uint, v: i16) {
do io::u64_to_be_bytes(v as u64, 2u) |v| {
self.wr_tagged_bytes(tag_id, v);
}
}
fn wr_tagged_i8(tag_id: uint, v: i8) {
self.wr_tagged_bytes(tag_id, &[v as u8]);
}
fn wr_tagged_str(tag_id: uint, v: &str) {
str::byte_slice(v, |b| self.wr_tagged_bytes(tag_id, b));
}
fn wr_bytes(b: &[u8]) {
debug!("Write %u bytes", vec::len(b));
self.writer.write(b);
}
fn wr_str(s: &str) {
debug!("Write str: %?", s);
self.writer.write(str::to_bytes(s));
}
}
// 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.
const debug: bool = false;
priv impl Encoder {
// used internally to emit things like the vector length and so on
fn _emit_tagged_uint(t: EbmlEncoderTag, v: uint) {
assert v <= 0xFFFF_FFFF_u;
self.wr_tagged_u32(t as uint, v as u32);
}
fn _emit_label(label: &str) {
// 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) }
}
}
pub impl Encoder {
fn emit_opaque(&self, f: fn()) {
do self.wr_tag(EsOpaque as uint) {
f()
}
}
}
impl ::serialize::Encoder for Encoder {
fn emit_nil(&self) {}
fn emit_uint(&self, v: uint) {
self.wr_tagged_u64(EsUint as uint, v as u64);
}
fn emit_u64(&self, v: u64) { self.wr_tagged_u64(EsU64 as uint, v); }
fn emit_u32(&self, v: u32) { self.wr_tagged_u32(EsU32 as uint, v); }
fn emit_u16(&self, v: u16) { self.wr_tagged_u16(EsU16 as uint, v); }
fn emit_u8(&self, v: u8) { self.wr_tagged_u8 (EsU8 as uint, v); }
fn emit_int(&self, v: int) {
self.wr_tagged_i64(EsInt as uint, v as i64);
}
fn emit_i64(&self, v: i64) { self.wr_tagged_i64(EsI64 as uint, v); }
fn emit_i32(&self, v: i32) { self.wr_tagged_i32(EsI32 as uint, v); }
fn emit_i16(&self, v: i16) { self.wr_tagged_i16(EsI16 as uint, v); }
fn emit_i8(&self, v: i8) { self.wr_tagged_i8 (EsI8 as uint, v); }
fn emit_bool(&self, v: bool) {
self.wr_tagged_u8(EsBool as uint, v as u8)
}
// FIXME (#2742): implement these
fn emit_f64(&self, _v: f64) {
fail!(~"Unimplemented: serializing an f64");
}
fn emit_f32(&self, _v: f32) {
fail!(~"Unimplemented: serializing an f32");
}
fn emit_float(&self, _v: float) {
fail!(~"Unimplemented: serializing a float");
}
fn emit_char(&self, _v: char) {
fail!(~"Unimplemented: serializing a char");
}
fn emit_borrowed_str(&self, v: &str) {
self.wr_tagged_str(EsStr as uint, v)
}
fn emit_owned_str(&self, v: &str) {
self.emit_borrowed_str(v)
}
fn emit_managed_str(&self, v: &str) {
self.emit_borrowed_str(v)
}
fn emit_borrowed(&self, f: fn()) { f() }
fn emit_owned(&self, f: fn()) { f() }
fn emit_managed(&self, f: fn()) { f() }
fn emit_enum(&self, name: &str, f: fn()) {
self._emit_label(name);
self.wr_tag(EsEnum as uint, f)
}
fn emit_enum_variant(&self, _v_name: &str, v_id: uint, _cnt: uint,
f: fn()) {
self._emit_tagged_uint(EsEnumVid, v_id);
self.wr_tag(EsEnumBody as uint, f)
}
fn emit_enum_variant_arg(&self, _idx: uint, f: fn()) { f() }
fn emit_borrowed_vec(&self, len: uint, f: fn()) {
do self.wr_tag(EsVec as uint) {
self._emit_tagged_uint(EsVecLen, len);
f()
}
}
fn emit_owned_vec(&self, len: uint, f: fn()) {
self.emit_borrowed_vec(len, f)
}
fn emit_managed_vec(&self, len: uint, f: fn()) {
self.emit_borrowed_vec(len, f)
}
fn emit_vec_elt(&self, _idx: uint, f: fn()) {
self.wr_tag(EsVecElt as uint, f)
}
fn emit_rec(&self, f: fn()) { f() }
fn emit_struct(&self, _name: &str, _len: uint, f: fn()) { f() }
fn emit_field(&self, name: &str, _idx: uint, f: fn()) {
self._emit_label(name);
f()
}
fn emit_tup(&self, _len: uint, f: fn()) { f() }
fn emit_tup_elt(&self, _idx: uint, f: fn()) { f() }
}
}
// ___________________________________________________________________________
// Testing
#[cfg(test)]
mod tests {
use ebml::reader;
use ebml::writer;
use serialize::Encodable;
use serialize;
use core::io;
use core::option::{None, Option, Some};
#[test]
fn test_option_int() {
fn test_v(v: Option<int>) {
debug!("v == %?", v);
let bytes = do io::with_bytes_writer |wr| {
let ebml_w = writer::Encoder(wr);
v.encode(&ebml_w)
};
let ebml_doc = reader::Doc(@bytes);
let deser = reader::Decoder(ebml_doc);
let v1 = serialize::Decodable::decode(&deser);
debug!("v1 == %?", v1);
assert v == v1;
}
test_v(Some(22));
test_v(None);
test_v(Some(3));
}
}