mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-23 07:14:28 +00:00
remove seek from std::io::MemWriter, add SeekableMemWriter to librustc
Not all users of MemWriter need to seek, but having MemWriter seekable adds between 3-29% in overhead in certain circumstances. This fixes that performance gap by making a non-seekable MemWriter, and creating a new SeekableMemWriter for those circumstances when that functionality is actually needed. ``` test io::mem::test::bench_buf_reader ... bench: 682 ns/iter (+/- 85) test io::mem::test::bench_buf_writer ... bench: 580 ns/iter (+/- 57) test io::mem::test::bench_mem_reader ... bench: 793 ns/iter (+/- 99) test io::mem::test::bench_mem_writer_001_0000 ... bench: 48 ns/iter (+/- 27) test io::mem::test::bench_mem_writer_001_0010 ... bench: 65 ns/iter (+/- 27) = 153 MB/s test io::mem::test::bench_mem_writer_001_0100 ... bench: 132 ns/iter (+/- 12) = 757 MB/s test io::mem::test::bench_mem_writer_001_1000 ... bench: 802 ns/iter (+/- 151) = 1246 MB/s test io::mem::test::bench_mem_writer_100_0000 ... bench: 481 ns/iter (+/- 28) test io::mem::test::bench_mem_writer_100_0010 ... bench: 1957 ns/iter (+/- 126) = 510 MB/s test io::mem::test::bench_mem_writer_100_0100 ... bench: 8222 ns/iter (+/- 434) = 1216 MB/s test io::mem::test::bench_mem_writer_100_1000 ... bench: 82496 ns/iter (+/- 11191) = 1212 MB/s test io::mem::test::bench_seekable_mem_writer_001_0000 ... bench: 48 ns/iter (+/- 2) test io::mem::test::bench_seekable_mem_writer_001_0010 ... bench: 64 ns/iter (+/- 2) = 156 MB/s test io::mem::test::bench_seekable_mem_writer_001_0100 ... bench: 129 ns/iter (+/- 7) = 775 MB/s test io::mem::test::bench_seekable_mem_writer_001_1000 ... bench: 801 ns/iter (+/- 159) = 1248 MB/s test io::mem::test::bench_seekable_mem_writer_100_0000 ... bench: 711 ns/iter (+/- 51) test io::mem::test::bench_seekable_mem_writer_100_0010 ... bench: 2532 ns/iter (+/- 227) = 394 MB/s test io::mem::test::bench_seekable_mem_writer_100_0100 ... bench: 8962 ns/iter (+/- 947) = 1115 MB/s test io::mem::test::bench_seekable_mem_writer_100_1000 ... bench: 85086 ns/iter (+/- 11555) = 1175 MB/s ``` [breaking-change]
This commit is contained in:
Erick Tryzelaar
parent
ce2824dafe
commit
e27b88d5bd
@ -48,6 +48,9 @@ extern crate time;
|
||||
#[phase(plugin, link)] extern crate log;
|
||||
#[phase(plugin, link)] extern crate syntax;
|
||||
|
||||
#[cfg(test)]
|
||||
extern crate test;
|
||||
|
||||
mod diagnostics;
|
||||
|
||||
pub mod back {
|
||||
@ -129,6 +132,7 @@ pub mod util {
|
||||
|
||||
pub mod common;
|
||||
pub mod ppaux;
|
||||
pub mod io;
|
||||
pub mod nodemap;
|
||||
}
|
||||
|
||||
|
||||
@ -26,6 +26,7 @@ use middle::ty;
|
||||
use middle::typeck;
|
||||
use middle::stability;
|
||||
use middle;
|
||||
use util::io::SeekableMemWriter;
|
||||
use util::nodemap::{NodeMap, NodeSet};
|
||||
|
||||
use serialize::Encodable;
|
||||
@ -33,7 +34,6 @@ use std::cell::RefCell;
|
||||
use std::gc::Gc;
|
||||
use std::hash::Hash;
|
||||
use std::hash;
|
||||
use std::io::MemWriter;
|
||||
use std::mem;
|
||||
use std::collections::HashMap;
|
||||
use syntax::abi;
|
||||
@ -61,7 +61,7 @@ pub enum InlinedItemRef<'a> {
|
||||
IIForeignRef(&'a ast::ForeignItem)
|
||||
}
|
||||
|
||||
pub type Encoder<'a> = writer::Encoder<'a, MemWriter>;
|
||||
pub type Encoder<'a> = writer::Encoder<'a, SeekableMemWriter>;
|
||||
|
||||
pub type EncodeInlinedItem<'a> = |ecx: &EncodeContext,
|
||||
ebml_w: &mut Encoder,
|
||||
@ -1407,7 +1407,7 @@ fn encode_info_for_items(ecx: &EncodeContext,
|
||||
// Path and definition ID indexing
|
||||
|
||||
fn encode_index<T: Hash>(ebml_w: &mut Encoder, index: Vec<entry<T>>,
|
||||
write_fn: |&mut MemWriter, &T|) {
|
||||
write_fn: |&mut SeekableMemWriter, &T|) {
|
||||
let mut buckets: Vec<Vec<entry<T>>> = Vec::from_fn(256, |_| Vec::new());
|
||||
for elt in index.move_iter() {
|
||||
let h = hash::hash(&elt.val) as uint;
|
||||
@ -1424,7 +1424,7 @@ fn encode_index<T: Hash>(ebml_w: &mut Encoder, index: Vec<entry<T>>,
|
||||
ebml_w.start_tag(tag_index_buckets_bucket_elt);
|
||||
assert!(elt.pos < 0xffff_ffff);
|
||||
{
|
||||
let wr: &mut MemWriter = ebml_w.writer;
|
||||
let wr: &mut SeekableMemWriter = ebml_w.writer;
|
||||
wr.write_be_u32(elt.pos as u32);
|
||||
}
|
||||
write_fn(ebml_w.writer, &elt.val);
|
||||
@ -1436,15 +1436,15 @@ fn encode_index<T: Hash>(ebml_w: &mut Encoder, index: Vec<entry<T>>,
|
||||
ebml_w.start_tag(tag_index_table);
|
||||
for pos in bucket_locs.iter() {
|
||||
assert!(*pos < 0xffff_ffff);
|
||||
let wr: &mut MemWriter = ebml_w.writer;
|
||||
let wr: &mut SeekableMemWriter = ebml_w.writer;
|
||||
wr.write_be_u32(*pos as u32);
|
||||
}
|
||||
ebml_w.end_tag();
|
||||
ebml_w.end_tag();
|
||||
}
|
||||
|
||||
fn write_i64(writer: &mut MemWriter, &n: &i64) {
|
||||
let wr: &mut MemWriter = writer;
|
||||
fn write_i64(writer: &mut SeekableMemWriter, &n: &i64) {
|
||||
let wr: &mut SeekableMemWriter = writer;
|
||||
assert!(n < 0x7fff_ffff);
|
||||
wr.write_be_u32(n as u32);
|
||||
}
|
||||
@ -1545,14 +1545,14 @@ fn encode_lang_items(ecx: &EncodeContext, ebml_w: &mut Encoder) {
|
||||
|
||||
ebml_w.start_tag(tag_lang_items_item_id);
|
||||
{
|
||||
let wr: &mut MemWriter = ebml_w.writer;
|
||||
let wr: &mut SeekableMemWriter = ebml_w.writer;
|
||||
wr.write_be_u32(i as u32);
|
||||
}
|
||||
ebml_w.end_tag(); // tag_lang_items_item_id
|
||||
|
||||
ebml_w.start_tag(tag_lang_items_item_node_id);
|
||||
{
|
||||
let wr: &mut MemWriter = ebml_w.writer;
|
||||
let wr: &mut SeekableMemWriter = ebml_w.writer;
|
||||
wr.write_be_u32(id.node as u32);
|
||||
}
|
||||
ebml_w.end_tag(); // tag_lang_items_item_node_id
|
||||
@ -1824,12 +1824,12 @@ pub static metadata_encoding_version : &'static [u8] =
|
||||
0, 0, 0, 1 ];
|
||||
|
||||
pub fn encode_metadata(parms: EncodeParams, krate: &Crate) -> Vec<u8> {
|
||||
let mut wr = MemWriter::new();
|
||||
let mut wr = SeekableMemWriter::new();
|
||||
encode_metadata_inner(&mut wr, parms, krate);
|
||||
wr.unwrap().move_iter().collect()
|
||||
}
|
||||
|
||||
fn encode_metadata_inner(wr: &mut MemWriter, parms: EncodeParams, krate: &Crate) {
|
||||
fn encode_metadata_inner(wr: &mut SeekableMemWriter, parms: EncodeParams, krate: &Crate) {
|
||||
struct Stats {
|
||||
attr_bytes: u64,
|
||||
dep_bytes: u64,
|
||||
@ -1982,7 +1982,7 @@ fn encode_metadata_inner(wr: &mut MemWriter, parms: EncodeParams, krate: &Crate)
|
||||
|
||||
// Get the encoded string for a type
|
||||
pub fn encoded_ty(tcx: &ty::ctxt, t: ty::t) -> String {
|
||||
let mut wr = MemWriter::new();
|
||||
let mut wr = SeekableMemWriter::new();
|
||||
tyencode::enc_ty(&mut wr, &tyencode::ctxt {
|
||||
diag: tcx.sess.diagnostic(),
|
||||
ds: def_to_string,
|
||||
|
||||
@ -15,7 +15,6 @@
|
||||
|
||||
use std::cell::RefCell;
|
||||
use std::collections::HashMap;
|
||||
use std::io::MemWriter;
|
||||
|
||||
use middle::subst;
|
||||
use middle::subst::VecPerParamSpace;
|
||||
@ -28,6 +27,8 @@ use syntax::ast::*;
|
||||
use syntax::diagnostic::SpanHandler;
|
||||
use syntax::parse::token;
|
||||
|
||||
use util::io::SeekableMemWriter;
|
||||
|
||||
macro_rules! mywrite( ($($arg:tt)*) => ({ write!($($arg)*); }) )
|
||||
|
||||
pub struct ctxt<'a> {
|
||||
@ -48,7 +49,7 @@ pub struct ty_abbrev {
|
||||
|
||||
pub type abbrev_map = RefCell<HashMap<ty::t, ty_abbrev>>;
|
||||
|
||||
pub fn enc_ty(w: &mut MemWriter, cx: &ctxt, t: ty::t) {
|
||||
pub fn enc_ty(w: &mut SeekableMemWriter, cx: &ctxt, t: ty::t) {
|
||||
match cx.abbrevs.borrow_mut().find(&t) {
|
||||
Some(a) => { w.write(a.s.as_bytes()); return; }
|
||||
None => {}
|
||||
@ -72,19 +73,19 @@ pub fn enc_ty(w: &mut MemWriter, cx: &ctxt, t: ty::t) {
|
||||
}
|
||||
}
|
||||
|
||||
fn enc_mutability(w: &mut MemWriter, mt: ast::Mutability) {
|
||||
fn enc_mutability(w: &mut SeekableMemWriter, mt: ast::Mutability) {
|
||||
match mt {
|
||||
MutImmutable => (),
|
||||
MutMutable => mywrite!(w, "m"),
|
||||
}
|
||||
}
|
||||
|
||||
fn enc_mt(w: &mut MemWriter, cx: &ctxt, mt: ty::mt) {
|
||||
fn enc_mt(w: &mut SeekableMemWriter, cx: &ctxt, mt: ty::mt) {
|
||||
enc_mutability(w, mt.mutbl);
|
||||
enc_ty(w, cx, mt.ty);
|
||||
}
|
||||
|
||||
fn enc_opt<T>(w: &mut MemWriter, t: Option<T>, enc_f: |&mut MemWriter, T|) {
|
||||
fn enc_opt<T>(w: &mut SeekableMemWriter, t: Option<T>, enc_f: |&mut SeekableMemWriter, T|) {
|
||||
match t {
|
||||
None => mywrite!(w, "n"),
|
||||
Some(v) => {
|
||||
@ -94,10 +95,10 @@ fn enc_opt<T>(w: &mut MemWriter, t: Option<T>, enc_f: |&mut MemWriter, T|) {
|
||||
}
|
||||
}
|
||||
|
||||
fn enc_vec_per_param_space<T>(w: &mut MemWriter,
|
||||
fn enc_vec_per_param_space<T>(w: &mut SeekableMemWriter,
|
||||
cx: &ctxt,
|
||||
v: &VecPerParamSpace<T>,
|
||||
op: |&mut MemWriter, &ctxt, &T|) {
|
||||
op: |&mut SeekableMemWriter, &ctxt, &T|) {
|
||||
for &space in subst::ParamSpace::all().iter() {
|
||||
mywrite!(w, "[");
|
||||
for t in v.get_slice(space).iter() {
|
||||
@ -107,13 +108,13 @@ fn enc_vec_per_param_space<T>(w: &mut MemWriter,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn enc_substs(w: &mut MemWriter, cx: &ctxt, substs: &subst::Substs) {
|
||||
pub fn enc_substs(w: &mut SeekableMemWriter, cx: &ctxt, substs: &subst::Substs) {
|
||||
enc_region_substs(w, cx, &substs.regions);
|
||||
enc_vec_per_param_space(w, cx, &substs.types,
|
||||
|w, cx, &ty| enc_ty(w, cx, ty));
|
||||
}
|
||||
|
||||
fn enc_region_substs(w: &mut MemWriter, cx: &ctxt, substs: &subst::RegionSubsts) {
|
||||
fn enc_region_substs(w: &mut SeekableMemWriter, cx: &ctxt, substs: &subst::RegionSubsts) {
|
||||
match *substs {
|
||||
subst::ErasedRegions => {
|
||||
mywrite!(w, "e");
|
||||
@ -126,7 +127,7 @@ fn enc_region_substs(w: &mut MemWriter, cx: &ctxt, substs: &subst::RegionSubsts)
|
||||
}
|
||||
}
|
||||
|
||||
fn enc_region(w: &mut MemWriter, cx: &ctxt, r: ty::Region) {
|
||||
fn enc_region(w: &mut SeekableMemWriter, cx: &ctxt, r: ty::Region) {
|
||||
match r {
|
||||
ty::ReLateBound(id, br) => {
|
||||
mywrite!(w, "b[{}|", id);
|
||||
@ -161,7 +162,7 @@ fn enc_region(w: &mut MemWriter, cx: &ctxt, r: ty::Region) {
|
||||
}
|
||||
}
|
||||
|
||||
fn enc_bound_region(w: &mut MemWriter, cx: &ctxt, br: ty::BoundRegion) {
|
||||
fn enc_bound_region(w: &mut SeekableMemWriter, cx: &ctxt, br: ty::BoundRegion) {
|
||||
match br {
|
||||
ty::BrAnon(idx) => {
|
||||
mywrite!(w, "a{}|", idx);
|
||||
@ -177,12 +178,12 @@ fn enc_bound_region(w: &mut MemWriter, cx: &ctxt, br: ty::BoundRegion) {
|
||||
}
|
||||
}
|
||||
|
||||
pub fn enc_trait_ref(w: &mut MemWriter, cx: &ctxt, s: &ty::TraitRef) {
|
||||
pub fn enc_trait_ref(w: &mut SeekableMemWriter, cx: &ctxt, s: &ty::TraitRef) {
|
||||
mywrite!(w, "{}|", (cx.ds)(s.def_id));
|
||||
enc_substs(w, cx, &s.substs);
|
||||
}
|
||||
|
||||
pub fn enc_trait_store(w: &mut MemWriter, cx: &ctxt, s: ty::TraitStore) {
|
||||
pub fn enc_trait_store(w: &mut SeekableMemWriter, cx: &ctxt, s: ty::TraitStore) {
|
||||
match s {
|
||||
ty::UniqTraitStore => mywrite!(w, "~"),
|
||||
ty::RegionTraitStore(re, m) => {
|
||||
@ -193,7 +194,7 @@ pub fn enc_trait_store(w: &mut MemWriter, cx: &ctxt, s: ty::TraitStore) {
|
||||
}
|
||||
}
|
||||
|
||||
fn enc_sty(w: &mut MemWriter, cx: &ctxt, st: &ty::sty) {
|
||||
fn enc_sty(w: &mut SeekableMemWriter, cx: &ctxt, st: &ty::sty) {
|
||||
match *st {
|
||||
ty::ty_nil => mywrite!(w, "n"),
|
||||
ty::ty_bot => mywrite!(w, "z"),
|
||||
@ -293,33 +294,33 @@ fn enc_sty(w: &mut MemWriter, cx: &ctxt, st: &ty::sty) {
|
||||
}
|
||||
}
|
||||
|
||||
fn enc_fn_style(w: &mut MemWriter, p: FnStyle) {
|
||||
fn enc_fn_style(w: &mut SeekableMemWriter, p: FnStyle) {
|
||||
match p {
|
||||
NormalFn => mywrite!(w, "n"),
|
||||
UnsafeFn => mywrite!(w, "u"),
|
||||
}
|
||||
}
|
||||
|
||||
fn enc_abi(w: &mut MemWriter, abi: Abi) {
|
||||
fn enc_abi(w: &mut SeekableMemWriter, abi: Abi) {
|
||||
mywrite!(w, "[");
|
||||
mywrite!(w, "{}", abi.name());
|
||||
mywrite!(w, "]")
|
||||
}
|
||||
|
||||
fn enc_onceness(w: &mut MemWriter, o: Onceness) {
|
||||
fn enc_onceness(w: &mut SeekableMemWriter, o: Onceness) {
|
||||
match o {
|
||||
Once => mywrite!(w, "o"),
|
||||
Many => mywrite!(w, "m")
|
||||
}
|
||||
}
|
||||
|
||||
pub fn enc_bare_fn_ty(w: &mut MemWriter, cx: &ctxt, ft: &ty::BareFnTy) {
|
||||
pub fn enc_bare_fn_ty(w: &mut SeekableMemWriter, cx: &ctxt, ft: &ty::BareFnTy) {
|
||||
enc_fn_style(w, ft.fn_style);
|
||||
enc_abi(w, ft.abi);
|
||||
enc_fn_sig(w, cx, &ft.sig);
|
||||
}
|
||||
|
||||
pub fn enc_closure_ty(w: &mut MemWriter, cx: &ctxt, ft: &ty::ClosureTy) {
|
||||
pub fn enc_closure_ty(w: &mut SeekableMemWriter, cx: &ctxt, ft: &ty::ClosureTy) {
|
||||
enc_fn_style(w, ft.fn_style);
|
||||
enc_onceness(w, ft.onceness);
|
||||
enc_trait_store(w, cx, ft.store);
|
||||
@ -330,7 +331,7 @@ pub fn enc_closure_ty(w: &mut MemWriter, cx: &ctxt, ft: &ty::ClosureTy) {
|
||||
enc_abi(w, ft.abi);
|
||||
}
|
||||
|
||||
fn enc_fn_sig(w: &mut MemWriter, cx: &ctxt, fsig: &ty::FnSig) {
|
||||
fn enc_fn_sig(w: &mut SeekableMemWriter, cx: &ctxt, fsig: &ty::FnSig) {
|
||||
mywrite!(w, "[{}|", fsig.binder_id);
|
||||
for ty in fsig.inputs.iter() {
|
||||
enc_ty(w, cx, *ty);
|
||||
@ -344,7 +345,7 @@ fn enc_fn_sig(w: &mut MemWriter, cx: &ctxt, fsig: &ty::FnSig) {
|
||||
enc_ty(w, cx, fsig.output);
|
||||
}
|
||||
|
||||
fn enc_bounds(w: &mut MemWriter, cx: &ctxt, bs: &ty::ParamBounds) {
|
||||
fn enc_bounds(w: &mut SeekableMemWriter, cx: &ctxt, bs: &ty::ParamBounds) {
|
||||
for bound in bs.builtin_bounds.iter() {
|
||||
match bound {
|
||||
ty::BoundSend => mywrite!(w, "S"),
|
||||
@ -363,7 +364,7 @@ fn enc_bounds(w: &mut MemWriter, cx: &ctxt, bs: &ty::ParamBounds) {
|
||||
mywrite!(w, ".");
|
||||
}
|
||||
|
||||
pub fn enc_type_param_def(w: &mut MemWriter, cx: &ctxt, v: &ty::TypeParameterDef) {
|
||||
pub fn enc_type_param_def(w: &mut SeekableMemWriter, cx: &ctxt, v: &ty::TypeParameterDef) {
|
||||
mywrite!(w, "{}:{}|{}|{}|",
|
||||
token::get_ident(v.ident), (cx.ds)(v.def_id),
|
||||
v.space.to_uint(), v.index);
|
||||
|
||||
@ -28,6 +28,7 @@ use middle::subst;
|
||||
use middle::subst::VecPerParamSpace;
|
||||
use middle::typeck::{MethodCall, MethodCallee, MethodOrigin};
|
||||
use middle::{ty, typeck};
|
||||
use util::io::SeekableMemWriter;
|
||||
use util::ppaux::ty_to_string;
|
||||
|
||||
use syntax::{ast, ast_map, ast_util, codemap, fold};
|
||||
@ -39,7 +40,6 @@ use syntax;
|
||||
|
||||
use libc;
|
||||
use std::io::Seek;
|
||||
use std::io::MemWriter;
|
||||
use std::mem;
|
||||
use std::gc::GC;
|
||||
|
||||
@ -73,7 +73,7 @@ trait tr_intern {
|
||||
fn tr_intern(&self, xcx: &ExtendedDecodeContext) -> ast::DefId;
|
||||
}
|
||||
|
||||
pub type Encoder<'a> = writer::Encoder<'a, MemWriter>;
|
||||
pub type Encoder<'a> = writer::Encoder<'a, SeekableMemWriter>;
|
||||
|
||||
// ______________________________________________________________________
|
||||
// Top-level methods.
|
||||
@ -1573,10 +1573,8 @@ fn mk_ctxt() -> parse::ParseSess {
|
||||
|
||||
#[cfg(test)]
|
||||
fn roundtrip(in_item: Option<Gc<ast::Item>>) {
|
||||
use std::io::MemWriter;
|
||||
|
||||
let in_item = in_item.unwrap();
|
||||
let mut wr = MemWriter::new();
|
||||
let mut wr = SeekableMemWriter::new();
|
||||
{
|
||||
let mut ebml_w = writer::Encoder::new(&mut wr);
|
||||
encode_item_ast(&mut ebml_w, in_item);
|
||||
|
||||
232
src/librustc/util/io.rs
Normal file
232
src/librustc/util/io.rs
Normal file
@ -0,0 +1,232 @@
|
||||
// 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.
|
||||
|
||||
use std::io::{IoError, IoResult, SeekStyle};
|
||||
use std::io;
|
||||
use std::slice;
|
||||
|
||||
static BUF_CAPACITY: uint = 128;
|
||||
|
||||
fn combine(seek: SeekStyle, cur: uint, end: uint, offset: i64) -> IoResult<u64> {
|
||||
// compute offset as signed and clamp to prevent overflow
|
||||
let pos = match seek {
|
||||
io::SeekSet => 0,
|
||||
io::SeekEnd => end,
|
||||
io::SeekCur => cur,
|
||||
} as i64;
|
||||
|
||||
if offset + pos < 0 {
|
||||
Err(IoError {
|
||||
kind: io::InvalidInput,
|
||||
desc: "invalid seek to a negative offset",
|
||||
detail: None
|
||||
})
|
||||
} else {
|
||||
Ok((offset + pos) as u64)
|
||||
}
|
||||
}
|
||||
|
||||
/// Writes to an owned, growable byte vector that supports seeking.
|
||||
///
|
||||
/// # Example
|
||||
///
|
||||
/// ```rust
|
||||
/// # #![allow(unused_must_use)]
|
||||
/// use std::io::SeekableMemWriter;
|
||||
///
|
||||
/// let mut w = SeekableMemWriter::new();
|
||||
/// w.write([0, 1, 2]);
|
||||
///
|
||||
/// assert_eq!(w.unwrap(), vec!(0, 1, 2));
|
||||
/// ```
|
||||
pub struct SeekableMemWriter {
|
||||
buf: Vec<u8>,
|
||||
pos: uint,
|
||||
}
|
||||
|
||||
impl SeekableMemWriter {
|
||||
/// Create a new `SeekableMemWriter`.
|
||||
#[inline]
|
||||
pub fn new() -> SeekableMemWriter {
|
||||
SeekableMemWriter::with_capacity(BUF_CAPACITY)
|
||||
}
|
||||
/// Create a new `SeekableMemWriter`, allocating at least `n` bytes for
|
||||
/// the internal buffer.
|
||||
#[inline]
|
||||
pub fn with_capacity(n: uint) -> SeekableMemWriter {
|
||||
SeekableMemWriter { buf: Vec::with_capacity(n), pos: 0 }
|
||||
}
|
||||
|
||||
/// Acquires an immutable reference to the underlying buffer of this
|
||||
/// `SeekableMemWriter`.
|
||||
///
|
||||
/// No method is exposed for acquiring a mutable reference to the buffer
|
||||
/// because it could corrupt the state of this `MemWriter`.
|
||||
#[inline]
|
||||
pub fn get_ref<'a>(&'a self) -> &'a [u8] { self.buf.as_slice() }
|
||||
|
||||
/// Unwraps this `SeekableMemWriter`, returning the underlying buffer
|
||||
#[inline]
|
||||
pub fn unwrap(self) -> Vec<u8> { self.buf }
|
||||
}
|
||||
|
||||
impl Writer for SeekableMemWriter {
|
||||
#[inline]
|
||||
fn write(&mut self, buf: &[u8]) -> IoResult<()> {
|
||||
if self.pos == self.buf.len() {
|
||||
self.buf.push_all(buf)
|
||||
} else {
|
||||
// Make sure the internal buffer is as least as big as where we
|
||||
// currently are
|
||||
let difference = self.pos as i64 - self.buf.len() as i64;
|
||||
if difference > 0 {
|
||||
self.buf.grow(difference as uint, &0);
|
||||
}
|
||||
|
||||
// Figure out what bytes will be used to overwrite what's currently
|
||||
// there (left), and what will be appended on the end (right)
|
||||
let cap = self.buf.len() - self.pos;
|
||||
let (left, right) = if cap <= buf.len() {
|
||||
(buf.slice_to(cap), buf.slice_from(cap))
|
||||
} else {
|
||||
(buf, &[])
|
||||
};
|
||||
|
||||
// Do the necessary writes
|
||||
if left.len() > 0 {
|
||||
slice::bytes::copy_memory(self.buf.mut_slice_from(self.pos), left);
|
||||
}
|
||||
if right.len() > 0 {
|
||||
self.buf.push_all(right);
|
||||
}
|
||||
}
|
||||
|
||||
// Bump us forward
|
||||
self.pos += buf.len();
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
|
||||
impl Seek for SeekableMemWriter {
|
||||
#[inline]
|
||||
fn tell(&self) -> IoResult<u64> { Ok(self.pos as u64) }
|
||||
|
||||
#[inline]
|
||||
fn seek(&mut self, pos: i64, style: SeekStyle) -> IoResult<()> {
|
||||
let new = try!(combine(style, self.pos, self.buf.len(), pos));
|
||||
self.pos = new as uint;
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
|
||||
#[cfg(test)]
|
||||
mod tests {
|
||||
use super::SeekableMemWriter;
|
||||
use std::io;
|
||||
use test::Bencher;
|
||||
|
||||
#[test]
|
||||
fn test_seekable_mem_writer() {
|
||||
let mut writer = SeekableMemWriter::new();
|
||||
assert_eq!(writer.tell(), Ok(0));
|
||||
writer.write([0]).unwrap();
|
||||
assert_eq!(writer.tell(), Ok(1));
|
||||
writer.write([1, 2, 3]).unwrap();
|
||||
writer.write([4, 5, 6, 7]).unwrap();
|
||||
assert_eq!(writer.tell(), Ok(8));
|
||||
assert_eq!(writer.get_ref(), &[0, 1, 2, 3, 4, 5, 6, 7]);
|
||||
|
||||
writer.seek(0, io::SeekSet).unwrap();
|
||||
assert_eq!(writer.tell(), Ok(0));
|
||||
writer.write([3, 4]).unwrap();
|
||||
assert_eq!(writer.get_ref(), &[3, 4, 2, 3, 4, 5, 6, 7]);
|
||||
|
||||
writer.seek(1, io::SeekCur).unwrap();
|
||||
writer.write([0, 1]).unwrap();
|
||||
assert_eq!(writer.get_ref(), &[3, 4, 2, 0, 1, 5, 6, 7]);
|
||||
|
||||
writer.seek(-1, io::SeekEnd).unwrap();
|
||||
writer.write([1, 2]).unwrap();
|
||||
assert_eq!(writer.get_ref(), &[3, 4, 2, 0, 1, 5, 6, 1, 2]);
|
||||
|
||||
writer.seek(1, io::SeekEnd).unwrap();
|
||||
writer.write([1]).unwrap();
|
||||
assert_eq!(writer.get_ref(), &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1]);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn seek_past_end() {
|
||||
let mut r = SeekableMemWriter::new();
|
||||
r.seek(10, io::SeekSet).unwrap();
|
||||
assert!(r.write([3]).is_ok());
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn seek_before_0() {
|
||||
let mut r = SeekableMemWriter::new();
|
||||
assert!(r.seek(-1, io::SeekSet).is_err());
|
||||
}
|
||||
|
||||
fn do_bench_seekable_mem_writer(b: &mut Bencher, times: uint, len: uint) {
|
||||
let src: Vec<u8> = Vec::from_elem(len, 5);
|
||||
|
||||
b.bytes = (times * len) as u64;
|
||||
b.iter(|| {
|
||||
let mut wr = SeekableMemWriter::new();
|
||||
for _ in range(0, times) {
|
||||
wr.write(src.as_slice()).unwrap();
|
||||
}
|
||||
|
||||
let v = wr.unwrap();
|
||||
assert_eq!(v.len(), times * len);
|
||||
assert!(v.iter().all(|x| *x == 5));
|
||||
});
|
||||
}
|
||||
|
||||
#[bench]
|
||||
fn bench_seekable_mem_writer_001_0000(b: &mut Bencher) {
|
||||
do_bench_seekable_mem_writer(b, 1, 0)
|
||||
}
|
||||
|
||||
#[bench]
|
||||
fn bench_seekable_mem_writer_001_0010(b: &mut Bencher) {
|
||||
do_bench_seekable_mem_writer(b, 1, 10)
|
||||
}
|
||||
|
||||
#[bench]
|
||||
fn bench_seekable_mem_writer_001_0100(b: &mut Bencher) {
|
||||
do_bench_seekable_mem_writer(b, 1, 100)
|
||||
}
|
||||
|
||||
#[bench]
|
||||
fn bench_seekable_mem_writer_001_1000(b: &mut Bencher) {
|
||||
do_bench_seekable_mem_writer(b, 1, 1000)
|
||||
}
|
||||
|
||||
#[bench]
|
||||
fn bench_seekable_mem_writer_100_0000(b: &mut Bencher) {
|
||||
do_bench_seekable_mem_writer(b, 100, 0)
|
||||
}
|
||||
|
||||
#[bench]
|
||||
fn bench_seekable_mem_writer_100_0010(b: &mut Bencher) {
|
||||
do_bench_seekable_mem_writer(b, 100, 10)
|
||||
}
|
||||
|
||||
#[bench]
|
||||
fn bench_seekable_mem_writer_100_0100(b: &mut Bencher) {
|
||||
do_bench_seekable_mem_writer(b, 100, 100)
|
||||
}
|
||||
|
||||
#[bench]
|
||||
fn bench_seekable_mem_writer_100_1000(b: &mut Bencher) {
|
||||
do_bench_seekable_mem_writer(b, 100, 1000)
|
||||
}
|
||||
}
|
||||
@ -1023,8 +1023,124 @@ mod tests {
|
||||
use ebml::writer;
|
||||
use {Encodable, Decodable};
|
||||
|
||||
use std::io::MemWriter;
|
||||
use std::io::{IoError, IoResult, SeekStyle};
|
||||
use std::io;
|
||||
use std::option::{None, Option, Some};
|
||||
use std::slice;
|
||||
|
||||
static BUF_CAPACITY: uint = 128;
|
||||
|
||||
fn combine(seek: SeekStyle, cur: uint, end: uint, offset: i64) -> IoResult<u64> {
|
||||
// compute offset as signed and clamp to prevent overflow
|
||||
let pos = match seek {
|
||||
io::SeekSet => 0,
|
||||
io::SeekEnd => end,
|
||||
io::SeekCur => cur,
|
||||
} as i64;
|
||||
|
||||
if offset + pos < 0 {
|
||||
Err(IoError {
|
||||
kind: io::InvalidInput,
|
||||
desc: "invalid seek to a negative offset",
|
||||
detail: None
|
||||
})
|
||||
} else {
|
||||
Ok((offset + pos) as u64)
|
||||
}
|
||||
}
|
||||
|
||||
/// Writes to an owned, growable byte vector that supports seeking.
|
||||
///
|
||||
/// # Example
|
||||
///
|
||||
/// ```rust
|
||||
/// # #![allow(unused_must_use)]
|
||||
/// use std::io::SeekableMemWriter;
|
||||
///
|
||||
/// let mut w = SeekableMemWriter::new();
|
||||
/// w.write([0, 1, 2]);
|
||||
///
|
||||
/// assert_eq!(w.unwrap(), vec!(0, 1, 2));
|
||||
/// ```
|
||||
pub struct SeekableMemWriter {
|
||||
buf: Vec<u8>,
|
||||
pos: uint,
|
||||
}
|
||||
|
||||
impl SeekableMemWriter {
|
||||
/// Create a new `SeekableMemWriter`.
|
||||
#[inline]
|
||||
pub fn new() -> SeekableMemWriter {
|
||||
SeekableMemWriter::with_capacity(BUF_CAPACITY)
|
||||
}
|
||||
/// Create a new `SeekableMemWriter`, allocating at least `n` bytes for
|
||||
/// the internal buffer.
|
||||
#[inline]
|
||||
pub fn with_capacity(n: uint) -> SeekableMemWriter {
|
||||
SeekableMemWriter { buf: Vec::with_capacity(n), pos: 0 }
|
||||
}
|
||||
|
||||
/// Acquires an immutable reference to the underlying buffer of this
|
||||
/// `SeekableMemWriter`.
|
||||
///
|
||||
/// No method is exposed for acquiring a mutable reference to the buffer
|
||||
/// because it could corrupt the state of this `MemWriter`.
|
||||
#[inline]
|
||||
pub fn get_ref<'a>(&'a self) -> &'a [u8] { self.buf.as_slice() }
|
||||
|
||||
/// Unwraps this `SeekableMemWriter`, returning the underlying buffer
|
||||
#[inline]
|
||||
pub fn unwrap(self) -> Vec<u8> { self.buf }
|
||||
}
|
||||
|
||||
impl Writer for SeekableMemWriter {
|
||||
#[inline]
|
||||
fn write(&mut self, buf: &[u8]) -> IoResult<()> {
|
||||
if self.pos == self.buf.len() {
|
||||
self.buf.push_all(buf)
|
||||
} else {
|
||||
// Make sure the internal buffer is as least as big as where we
|
||||
// currently are
|
||||
let difference = self.pos as i64 - self.buf.len() as i64;
|
||||
if difference > 0 {
|
||||
self.buf.grow(difference as uint, &0);
|
||||
}
|
||||
|
||||
// Figure out what bytes will be used to overwrite what's currently
|
||||
// there (left), and what will be appended on the end (right)
|
||||
let cap = self.buf.len() - self.pos;
|
||||
let (left, right) = if cap <= buf.len() {
|
||||
(buf.slice_to(cap), buf.slice_from(cap))
|
||||
} else {
|
||||
(buf, &[])
|
||||
};
|
||||
|
||||
// Do the necessary writes
|
||||
if left.len() > 0 {
|
||||
slice::bytes::copy_memory(self.buf.mut_slice_from(self.pos), left);
|
||||
}
|
||||
if right.len() > 0 {
|
||||
self.buf.push_all(right);
|
||||
}
|
||||
}
|
||||
|
||||
// Bump us forward
|
||||
self.pos += buf.len();
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
|
||||
impl Seek for SeekableMemWriter {
|
||||
#[inline]
|
||||
fn tell(&self) -> IoResult<u64> { Ok(self.pos as u64) }
|
||||
|
||||
#[inline]
|
||||
fn seek(&mut self, pos: i64, style: SeekStyle) -> IoResult<()> {
|
||||
let new = try!(combine(style, self.pos, self.buf.len(), pos));
|
||||
self.pos = new as uint;
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_vuint_at() {
|
||||
@ -1078,7 +1194,7 @@ mod tests {
|
||||
fn test_option_int() {
|
||||
fn test_v(v: Option<int>) {
|
||||
debug!("v == {}", v);
|
||||
let mut wr = MemWriter::new();
|
||||
let mut wr = SeekableMemWriter::new();
|
||||
{
|
||||
let mut ebml_w = writer::Encoder::new(&mut wr);
|
||||
let _ = v.encode(&mut ebml_w);
|
||||
|
||||
@ -955,7 +955,7 @@ mod test {
|
||||
}
|
||||
) )
|
||||
|
||||
struct TempDir(Path);
|
||||
pub struct TempDir(Path);
|
||||
|
||||
impl TempDir {
|
||||
fn join(&self, path: &str) -> Path {
|
||||
|
||||
@ -22,6 +22,8 @@ use slice;
|
||||
use slice::{Vector, ImmutableVector, MutableVector};
|
||||
use vec::Vec;
|
||||
|
||||
static BUF_CAPACITY: uint = 128;
|
||||
|
||||
fn combine(seek: SeekStyle, cur: uint, end: uint, offset: i64) -> IoResult<u64> {
|
||||
// compute offset as signed and clamp to prevent overflow
|
||||
let pos = match seek {
|
||||
@ -56,27 +58,23 @@ fn combine(seek: SeekStyle, cur: uint, end: uint, offset: i64) -> IoResult<u64>
|
||||
/// ```
|
||||
pub struct MemWriter {
|
||||
buf: Vec<u8>,
|
||||
pos: uint,
|
||||
}
|
||||
|
||||
impl MemWriter {
|
||||
/// Create a new `MemWriter`.
|
||||
#[inline]
|
||||
pub fn new() -> MemWriter {
|
||||
MemWriter::with_capacity(128)
|
||||
MemWriter::with_capacity(BUF_CAPACITY)
|
||||
}
|
||||
/// Create a new `MemWriter`, allocating at least `n` bytes for
|
||||
/// the internal buffer.
|
||||
#[inline]
|
||||
pub fn with_capacity(n: uint) -> MemWriter {
|
||||
MemWriter { buf: Vec::with_capacity(n), pos: 0 }
|
||||
MemWriter { buf: Vec::with_capacity(n) }
|
||||
}
|
||||
|
||||
/// Acquires an immutable reference to the underlying buffer of this
|
||||
/// `MemWriter`.
|
||||
///
|
||||
/// No method is exposed for acquiring a mutable reference to the buffer
|
||||
/// because it could corrupt the state of this `MemWriter`.
|
||||
#[inline]
|
||||
pub fn get_ref<'a>(&'a self) -> &'a [u8] { self.buf.as_slice() }
|
||||
|
||||
@ -88,44 +86,7 @@ impl MemWriter {
|
||||
impl Writer for MemWriter {
|
||||
#[inline]
|
||||
fn write(&mut self, buf: &[u8]) -> IoResult<()> {
|
||||
// Make sure the internal buffer is as least as big as where we
|
||||
// currently are
|
||||
let difference = self.pos as i64 - self.buf.len() as i64;
|
||||
if difference > 0 {
|
||||
self.buf.grow(difference as uint, &0);
|
||||
}
|
||||
|
||||
// Figure out what bytes will be used to overwrite what's currently
|
||||
// there (left), and what will be appended on the end (right)
|
||||
let cap = self.buf.len() - self.pos;
|
||||
let (left, right) = if cap <= buf.len() {
|
||||
(buf.slice_to(cap), buf.slice_from(cap))
|
||||
} else {
|
||||
(buf, &[])
|
||||
};
|
||||
|
||||
// Do the necessary writes
|
||||
if left.len() > 0 {
|
||||
slice::bytes::copy_memory(self.buf.mut_slice_from(self.pos), left);
|
||||
}
|
||||
if right.len() > 0 {
|
||||
self.buf.push_all(right);
|
||||
}
|
||||
|
||||
// Bump us forward
|
||||
self.pos += buf.len();
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
|
||||
impl Seek for MemWriter {
|
||||
#[inline]
|
||||
fn tell(&self) -> IoResult<u64> { Ok(self.pos as u64) }
|
||||
|
||||
#[inline]
|
||||
fn seek(&mut self, pos: i64, style: SeekStyle) -> IoResult<()> {
|
||||
let new = try!(combine(style, self.pos, self.buf.len(), pos));
|
||||
self.pos = new as uint;
|
||||
self.buf.push_all(buf);
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
@ -381,30 +342,10 @@ mod test {
|
||||
#[test]
|
||||
fn test_mem_writer() {
|
||||
let mut writer = MemWriter::new();
|
||||
assert_eq!(writer.tell(), Ok(0));
|
||||
writer.write([0]).unwrap();
|
||||
assert_eq!(writer.tell(), Ok(1));
|
||||
writer.write([1, 2, 3]).unwrap();
|
||||
writer.write([4, 5, 6, 7]).unwrap();
|
||||
assert_eq!(writer.tell(), Ok(8));
|
||||
assert_eq!(writer.get_ref(), &[0, 1, 2, 3, 4, 5, 6, 7]);
|
||||
|
||||
writer.seek(0, SeekSet).unwrap();
|
||||
assert_eq!(writer.tell(), Ok(0));
|
||||
writer.write([3, 4]).unwrap();
|
||||
assert_eq!(writer.get_ref(), &[3, 4, 2, 3, 4, 5, 6, 7]);
|
||||
|
||||
writer.seek(1, SeekCur).unwrap();
|
||||
writer.write([0, 1]).unwrap();
|
||||
assert_eq!(writer.get_ref(), &[3, 4, 2, 0, 1, 5, 6, 7]);
|
||||
|
||||
writer.seek(-1, SeekEnd).unwrap();
|
||||
writer.write([1, 2]).unwrap();
|
||||
assert_eq!(writer.get_ref(), &[3, 4, 2, 0, 1, 5, 6, 1, 2]);
|
||||
|
||||
writer.seek(1, SeekEnd).unwrap();
|
||||
writer.write([1]).unwrap();
|
||||
assert_eq!(writer.get_ref(), &[3, 4, 2, 0, 1, 5, 6, 1, 2, 0, 1]);
|
||||
}
|
||||
|
||||
#[test]
|
||||
@ -570,10 +511,6 @@ mod test {
|
||||
r.seek(10, SeekSet).unwrap();
|
||||
assert!(r.read(&mut []).is_err());
|
||||
|
||||
let mut r = MemWriter::new();
|
||||
r.seek(10, SeekSet).unwrap();
|
||||
assert!(r.write([3]).is_ok());
|
||||
|
||||
let mut buf = [0];
|
||||
let mut r = BufWriter::new(buf);
|
||||
r.seek(10, SeekSet).unwrap();
|
||||
@ -589,9 +526,6 @@ mod test {
|
||||
let mut r = MemReader::new(vec!(10));
|
||||
assert!(r.seek(-1, SeekSet).is_err());
|
||||
|
||||
let mut r = MemWriter::new();
|
||||
assert!(r.seek(-1, SeekSet).is_err());
|
||||
|
||||
let mut buf = [0];
|
||||
let mut r = BufWriter::new(buf);
|
||||
assert!(r.seek(-1, SeekSet).is_err());
|
||||
@ -614,6 +548,7 @@ mod test {
|
||||
fn do_bench_mem_writer(b: &mut Bencher, times: uint, len: uint) {
|
||||
let src: Vec<u8> = Vec::from_elem(len, 5);
|
||||
|
||||
b.bytes = (times * len) as u64;
|
||||
b.iter(|| {
|
||||
let mut wr = MemWriter::new();
|
||||
for _ in range(0, times) {
|
||||
|
||||
@ -137,7 +137,7 @@ pub fn to_string(f: |&mut State| -> IoResult<()>) -> String {
|
||||
// downcasts.
|
||||
let (_, wr): (uint, Box<MemWriter>) = mem::transmute_copy(&s.s.out);
|
||||
let result =
|
||||
String::from_utf8(Vec::from_slice(wr.get_ref())).unwrap();
|
||||
String::from_utf8(Vec::from_slice(wr.get_ref().as_slice())).unwrap();
|
||||
mem::forget(wr);
|
||||
result.to_string()
|
||||
}
|
||||
|
||||
@ -790,16 +790,12 @@ mod test {
|
||||
|
||||
#[test]
|
||||
fn test_serialize_round_trip() {
|
||||
use serialize::ebml::Doc;
|
||||
use serialize::ebml::writer::Encoder;
|
||||
use serialize::ebml::reader::Decoder;
|
||||
use serialize::json;
|
||||
use serialize::{Encodable, Decodable};
|
||||
|
||||
let u = Uuid::new_v4();
|
||||
let mut wr = MemWriter::new();
|
||||
let _ = u.encode(&mut Encoder::new(&mut wr));
|
||||
let doc = Doc::new(wr.get_ref());
|
||||
let u2 = Decodable::decode(&mut Decoder::new(doc)).unwrap();
|
||||
let s = json::encode(&u);
|
||||
let u2 = json::decode(s.as_slice()).unwrap();
|
||||
assert_eq!(u, u2);
|
||||
}
|
||||
|
||||
|
||||
@ -16,9 +16,7 @@ extern crate serialize;
|
||||
use std::cell::{Cell, RefCell};
|
||||
use std::io::MemWriter;
|
||||
use serialize::{Encodable, Decodable};
|
||||
use serialize::ebml;
|
||||
use serialize::ebml::writer::Encoder;
|
||||
use serialize::ebml::reader::Decoder;
|
||||
use serialize::json;
|
||||
|
||||
#[deriving(Encodable, Decodable)]
|
||||
struct A {
|
||||
@ -36,20 +34,8 @@ fn main() {
|
||||
foo: Cell::new(true),
|
||||
bar: RefCell::new( A { baz: 2 } )
|
||||
};
|
||||
let mut w = MemWriter::new();
|
||||
{
|
||||
let mut e = Encoder::new(&mut w);
|
||||
match obj.encode(&mut e) {
|
||||
Ok(()) => (),
|
||||
Err(e) => fail!("Failed to encode: {}", e)
|
||||
};
|
||||
}
|
||||
let doc = ebml::Doc::new(w.get_ref());
|
||||
let mut dec = Decoder::new(doc);
|
||||
let obj2: B = match Decodable::decode(&mut dec) {
|
||||
Ok(v) => v,
|
||||
Err(e) => fail!("Failed to decode: {}", e)
|
||||
};
|
||||
let s = json::encode(&obj);
|
||||
let obj2: B = json::decode(s.as_slice()).unwrap();
|
||||
assert!(obj.foo.get() == obj2.foo.get());
|
||||
assert!(obj.bar.borrow().baz == obj2.bar.borrow().baz);
|
||||
}
|
||||
|
||||
@ -10,10 +10,127 @@
|
||||
|
||||
extern crate serialize;
|
||||
|
||||
use std::io;
|
||||
use std::io::{IoError, IoResult, SeekStyle};
|
||||
use std::slice;
|
||||
|
||||
use serialize::{Encodable, Encoder};
|
||||
use serialize::json;
|
||||
use serialize::ebml::writer;
|
||||
use std::io::MemWriter;
|
||||
|
||||
static BUF_CAPACITY: uint = 128;
|
||||
|
||||
fn combine(seek: SeekStyle, cur: uint, end: uint, offset: i64) -> IoResult<u64> {
|
||||
// compute offset as signed and clamp to prevent overflow
|
||||
let pos = match seek {
|
||||
io::SeekSet => 0,
|
||||
io::SeekEnd => end,
|
||||
io::SeekCur => cur,
|
||||
} as i64;
|
||||
|
||||
if offset + pos < 0 {
|
||||
Err(IoError {
|
||||
kind: io::InvalidInput,
|
||||
desc: "invalid seek to a negative offset",
|
||||
detail: None
|
||||
})
|
||||
} else {
|
||||
Ok((offset + pos) as u64)
|
||||
}
|
||||
}
|
||||
|
||||
/// Writes to an owned, growable byte vector that supports seeking.
|
||||
///
|
||||
/// # Example
|
||||
///
|
||||
/// ```rust
|
||||
/// # #![allow(unused_must_use)]
|
||||
/// use std::io::SeekableMemWriter;
|
||||
///
|
||||
/// let mut w = SeekableMemWriter::new();
|
||||
/// w.write([0, 1, 2]);
|
||||
///
|
||||
/// assert_eq!(w.unwrap(), vec!(0, 1, 2));
|
||||
/// ```
|
||||
pub struct SeekableMemWriter {
|
||||
buf: Vec<u8>,
|
||||
pos: uint,
|
||||
}
|
||||
|
||||
impl SeekableMemWriter {
|
||||
/// Create a new `SeekableMemWriter`.
|
||||
#[inline]
|
||||
pub fn new() -> SeekableMemWriter {
|
||||
SeekableMemWriter::with_capacity(BUF_CAPACITY)
|
||||
}
|
||||
/// Create a new `SeekableMemWriter`, allocating at least `n` bytes for
|
||||
/// the internal buffer.
|
||||
#[inline]
|
||||
pub fn with_capacity(n: uint) -> SeekableMemWriter {
|
||||
SeekableMemWriter { buf: Vec::with_capacity(n), pos: 0 }
|
||||
}
|
||||
|
||||
/// Acquires an immutable reference to the underlying buffer of this
|
||||
/// `SeekableMemWriter`.
|
||||
///
|
||||
/// No method is exposed for acquiring a mutable reference to the buffer
|
||||
/// because it could corrupt the state of this `MemWriter`.
|
||||
#[inline]
|
||||
pub fn get_ref<'a>(&'a self) -> &'a [u8] { self.buf.as_slice() }
|
||||
|
||||
/// Unwraps this `SeekableMemWriter`, returning the underlying buffer
|
||||
#[inline]
|
||||
pub fn unwrap(self) -> Vec<u8> { self.buf }
|
||||
}
|
||||
|
||||
impl Writer for SeekableMemWriter {
|
||||
#[inline]
|
||||
fn write(&mut self, buf: &[u8]) -> IoResult<()> {
|
||||
if self.pos == self.buf.len() {
|
||||
self.buf.push_all(buf)
|
||||
} else {
|
||||
// Make sure the internal buffer is as least as big as where we
|
||||
// currently are
|
||||
let difference = self.pos as i64 - self.buf.len() as i64;
|
||||
if difference > 0 {
|
||||
self.buf.grow(difference as uint, &0);
|
||||
}
|
||||
|
||||
// Figure out what bytes will be used to overwrite what's currently
|
||||
// there (left), and what will be appended on the end (right)
|
||||
let cap = self.buf.len() - self.pos;
|
||||
let (left, right) = if cap <= buf.len() {
|
||||
(buf.slice_to(cap), buf.slice_from(cap))
|
||||
} else {
|
||||
(buf, &[])
|
||||
};
|
||||
|
||||
// Do the necessary writes
|
||||
if left.len() > 0 {
|
||||
slice::bytes::copy_memory(self.buf.mut_slice_from(self.pos), left);
|
||||
}
|
||||
if right.len() > 0 {
|
||||
self.buf.push_all(right);
|
||||
}
|
||||
}
|
||||
|
||||
// Bump us forward
|
||||
self.pos += buf.len();
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
|
||||
impl Seek for SeekableMemWriter {
|
||||
#[inline]
|
||||
fn tell(&self) -> IoResult<u64> { Ok(self.pos as u64) }
|
||||
|
||||
#[inline]
|
||||
fn seek(&mut self, pos: i64, style: SeekStyle) -> IoResult<()> {
|
||||
let new = try!(combine(style, self.pos, self.buf.len(), pos));
|
||||
self.pos = new as uint;
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
|
||||
#[deriving(Encodable)]
|
||||
struct Foo {
|
||||
@ -34,21 +151,21 @@ enum WireProtocol {
|
||||
fn encode_json<'a,
|
||||
T: Encodable<json::Encoder<'a>,
|
||||
std::io::IoError>>(val: &T,
|
||||
wr: &'a mut MemWriter) {
|
||||
wr: &'a mut SeekableMemWriter) {
|
||||
let mut encoder = json::Encoder::new(wr);
|
||||
val.encode(&mut encoder);
|
||||
}
|
||||
fn encode_ebml<'a,
|
||||
T: Encodable<writer::Encoder<'a, MemWriter>,
|
||||
T: Encodable<writer::Encoder<'a, SeekableMemWriter>,
|
||||
std::io::IoError>>(val: &T,
|
||||
wr: &'a mut MemWriter) {
|
||||
wr: &'a mut SeekableMemWriter) {
|
||||
let mut encoder = writer::Encoder::new(wr);
|
||||
val.encode(&mut encoder);
|
||||
}
|
||||
|
||||
pub fn main() {
|
||||
let target = Foo{baz: false,};
|
||||
let mut wr = MemWriter::new();
|
||||
let mut wr = SeekableMemWriter::new();
|
||||
let proto = JSON;
|
||||
match proto {
|
||||
JSON => encode_json(&target, &mut wr),
|
||||
|
||||
Loading…
Reference in New Issue
Block a user