Add object layout, object parsing, instruction layout
* Object layout and parsing are done in the vm::obj module * Add MemCursor, a wrapper around the std::io::Cursor type for walking through VM memory * Add vm::tick module for containing the Vm::tick() method implementation, since it's pretty big * Instructions are now variable-sized, and are read lazily, one-at-a-time directly from memory. * Add VM runtime error structure * Probably some other stuff I forgot Signed-off-by: Alek Ratzloff <alekratz@gmail.com>
This commit is contained in:
42
src/vm/obj/error.rs
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42
src/vm/obj/error.rs
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@@ -0,0 +1,42 @@
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use snafu::Snafu;
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use std::{
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fmt::Debug,
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io,
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};
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#[derive(Debug, Snafu)]
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pub enum ParseError {
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#[snafu(display("IO error: {}", source))]
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Io { source: io::Error },
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#[snafu(display("wrong magic number"))]
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WrongMagic,
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#[snafu(display("unknown section kind: 0x{:02x}", kind))]
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UnknownSectionKind { kind: u8 },
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#[snafu(display("invalid UTF-8 string: {}", source))]
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InvalidUtf8String { source: std::string::FromUtf8Error },
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}
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macro_rules! into_parse_error {
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(
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$($type:ty : $variant:ident),* $(,)?
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) => {
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$(
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impl From<$type> for ParseError {
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fn from(other: $type) -> Self {
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ParseError::$variant { source: other }
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}
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}
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)*
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}
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}
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into_parse_error! {
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io::Error: Io,
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std::string::FromUtf8Error: InvalidUtf8String,
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}
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pub type Result<T> = std::result::Result<T, ParseError>;
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@@ -1,234 +1,3 @@
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use crate::vm::inst::Inst;
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use byteorder::{ReadBytesExt, LE};
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use snafu::{ensure, Snafu};
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use std::{
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convert::{TryFrom, TryInto},
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fmt::Debug,
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io::{self, Cursor, Read},
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};
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pub const MAGIC: u64 = 0xDEAD_BEA7_BA5E_BA11;
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#[derive(Debug)]
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pub struct Object {
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header: Header,
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sections: Vec<Box<dyn Section>>,
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}
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#[derive(Debug, Clone, Copy)]
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pub struct Header {
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version: u16,
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sections: u16,
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}
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macro_rules! section_kind {
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(
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pub enum $enum_name:ident {
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$($name:ident = $value:expr),* $(,)?
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}
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) => {
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#[derive(Debug, Clone, Copy)]
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#[repr(u8)]
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pub enum $enum_name {
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$($name = $value),*
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}
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impl TryFrom<u8> for SectionKind {
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type Error = ParseError;
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fn try_from(other: u8) -> std::result::Result<Self, Self::Error> {
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match other {
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$(
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$value => Ok($enum_name::$name),
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)*
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_ => Err(ParseError::UnknownSectionKind { kind: other }),
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}
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}
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}
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};
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}
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section_kind! {
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pub enum SectionKind {
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Data = 0x00,
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Code = 0x10,
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Meta = 0xFF,
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}
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}
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pub trait Section: Debug {
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fn header(&self) -> SectionHeader;
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}
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#[derive(Debug, Clone, Copy)]
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pub struct SectionHeader {
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kind: SectionKind,
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checksum: u32,
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len: u64,
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}
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#[derive(Debug, Clone)]
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pub struct DataSection {
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header: SectionHeader,
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load_location: u64,
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contents: Vec<u8>,
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}
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impl Section for DataSection {
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fn header(&self) -> SectionHeader {
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self.header
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}
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}
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#[derive(Debug, Clone)]
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pub struct CodeSection {
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header: SectionHeader,
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load_location: u64,
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contents: Vec<Inst>,
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}
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impl Section for CodeSection {
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fn header(&self) -> SectionHeader {
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self.header
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}
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}
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#[derive(Debug, Clone)]
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pub struct MetaSection {
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header: SectionHeader,
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entry_count: u64,
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entries: Vec<(String, Vec<u8>)>,
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}
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impl Section for MetaSection {
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fn header(&self) -> SectionHeader {
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self.header
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}
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}
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#[derive(Debug, Clone)]
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pub struct ObjectParser {
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bytes: Cursor<Vec<u8>>,
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}
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impl ObjectParser {
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pub fn parse(&mut self) -> Result<Object> {
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let header = self.parse_header()?;
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let sections = self.parse_sections(header)?;
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Ok(Object { header, sections })
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}
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fn parse_header(&mut self) -> Result<Header> {
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let magic = self.bytes.read_u64::<LE>()?;
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ensure!(magic == MAGIC, WrongMagic);
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let version = self.bytes.read_u16::<LE>()?;
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let sections = self.bytes.read_u16::<LE>()?;
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Ok(Header { version, sections })
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}
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fn parse_sections(&mut self, header: Header) -> Result<Vec<Box<dyn Section>>> {
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(0..header.sections)
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.map(|_| self.parse_section())
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.collect()
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}
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fn parse_section(&mut self) -> Result<Box<dyn Section>> {
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let header = self.parse_section_header()?;
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let section: Box<dyn Section> = match header.kind {
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SectionKind::Data => self.parse_data_section(header).map(Box::new)?,
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SectionKind::Code => self.parse_code_section(header).map(Box::new)?,
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SectionKind::Meta => self.parse_meta_section(header).map(Box::new)?,
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};
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Ok(section)
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}
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fn parse_section_header(&mut self) -> Result<SectionHeader> {
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let kind: SectionKind = self.bytes.read_u8()?.try_into()?;
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let checksum = self.bytes.read_u32::<LE>()?;
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let len = self.bytes.read_u64::<LE>()?;
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Ok(SectionHeader {
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kind,
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checksum,
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len,
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})
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}
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fn parse_data_section(&mut self, header: SectionHeader) -> Result<DataSection> {
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let load_location = self.bytes.read_u64::<LE>()?;
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let contents = self.take_bytes(header.len)?;
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Ok(DataSection {
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header,
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load_location,
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contents,
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})
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}
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fn parse_code_section(&mut self, _header: SectionHeader) -> Result<CodeSection> {
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let _load_location = self.bytes.read_u64::<LE>()?;
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todo!("instruction parsing")
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}
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fn parse_meta_section(&mut self, header: SectionHeader) -> Result<MetaSection> {
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let entry_count = self.bytes.read_u64::<LE>()?;
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let mut entries = Vec::with_capacity(entry_count as usize);
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for offset in 0 .. entry_count {
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let key_bytes = self.parse_sized_data()?;
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let key = String::from_utf8(key_bytes)?;
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let value = self.parse_sized_data()?;
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entries.push((key, value));
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}
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Ok(MetaSection {
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header,
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entry_count,
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entries,
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})
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}
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fn parse_sized_data(&mut self) -> Result<Vec<u8>> {
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let size = self.bytes.read_u64::<LE>()?;
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self.take_bytes(size)
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}
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fn take_bytes(&mut self, count: u64) -> Result<Vec<u8>> {
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let mut contents = vec!(0u8; count as usize);
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self.bytes.read_exact(&mut contents)?;
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Ok(contents)
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}
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}
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#[derive(Debug, Snafu)]
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pub enum ParseError {
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#[snafu(display("IO error: {}", source))]
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Io { source: io::Error },
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#[snafu(display("wrong magic number"))]
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WrongMagic,
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#[snafu(display("unknown section kind: 0x{:02x}", kind))]
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UnknownSectionKind { kind: u8 },
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#[snafu(display("invalid UTF-8 string: {}", source))]
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InvalidUtf8String { source: std::string::FromUtf8Error },
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}
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macro_rules! into_parse_error {
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(
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$($type:ty : $variant:ident),* $(,)?
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) => {
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$(
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impl From<$type> for ParseError {
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fn from(other: $type) -> Self {
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ParseError::$variant { source: other }
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}
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}
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)*
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}
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}
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into_parse_error! {
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io::Error: Io,
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std::string::FromUtf8Error: InvalidUtf8String,
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}
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pub type Result<T> = std::result::Result<T, ParseError>;
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pub mod obj;
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pub mod parser;
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pub mod error;
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107
src/vm/obj/obj.rs
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107
src/vm/obj/obj.rs
Normal file
@@ -0,0 +1,107 @@
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use crate::vm::obj::error::ParseError;
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use std::{
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convert::TryFrom,
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fmt::Debug,
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};
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pub const MAGIC: u64 = 0xDEAD_BEA7_BA5E_BA11;
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#[derive(Debug)]
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pub struct Object {
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pub header: Header,
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pub sections: Vec<Box<dyn Section>>,
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}
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#[derive(Debug, Clone, Copy)]
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pub struct Header {
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pub version: u16,
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pub sections: u16,
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}
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macro_rules! section_kind {
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(
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pub enum $enum_name:ident {
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$($name:ident = $value:expr),* $(,)?
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}
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) => {
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#[derive(Debug, Clone, Copy)]
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#[repr(u8)]
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pub enum $enum_name {
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$($name = $value),*
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}
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impl TryFrom<u8> for SectionKind {
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type Error = ParseError;
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fn try_from(other: u8) -> std::result::Result<Self, Self::Error> {
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match other {
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$(
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$value => Ok($enum_name::$name),
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)*
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_ => Err(ParseError::UnknownSectionKind { kind: other }),
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}
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}
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}
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};
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}
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section_kind! {
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pub enum SectionKind {
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Data = 0x00,
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Code = 0x10,
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Meta = 0xFF,
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}
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}
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pub trait Section: Debug {
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fn header(&self) -> SectionHeader;
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}
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#[derive(Debug, Clone, Copy)]
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pub struct SectionHeader {
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pub kind: SectionKind,
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pub checksum: u32,
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pub len: u64,
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}
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#[derive(Debug, Clone)]
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pub struct DataSection {
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pub header: SectionHeader,
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pub load_location: u64,
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pub contents: Vec<u8>,
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}
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impl Section for DataSection {
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fn header(&self) -> SectionHeader {
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self.header
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}
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}
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#[derive(Debug, Clone)]
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pub struct CodeSection {
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pub header: SectionHeader,
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pub load_location: u64,
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pub contents: Vec<u8>,
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}
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impl Section for CodeSection {
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fn header(&self) -> SectionHeader {
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self.header
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}
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}
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#[derive(Debug, Clone)]
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pub struct MetaSection {
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pub header: SectionHeader,
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pub entry_count: u64,
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pub entries: Vec<(String, Vec<u8>)>,
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}
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impl Section for MetaSection {
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fn header(&self) -> SectionHeader {
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self.header
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}
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}
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108
src/vm/obj/parser.rs
Normal file
108
src/vm/obj/parser.rs
Normal file
@@ -0,0 +1,108 @@
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use byteorder::{ReadBytesExt, LE};
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use crate::vm::obj::{
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obj::*,
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error::*,
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};
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use std::{
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convert::TryInto,
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fmt::Debug,
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io::{Cursor, Read},
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};
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#[derive(Debug, Clone)]
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pub struct ObjectParser {
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bytes: Cursor<Vec<u8>>,
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}
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impl ObjectParser {
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pub fn parse(&mut self) -> Result<Object> {
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let header = self.parse_header()?;
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let sections = self.parse_sections(header)?;
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Ok(Object { header, sections })
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}
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fn parse_header(&mut self) -> Result<Header> {
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let magic = self.bytes.read_u64::<LE>()?;
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if magic != magic {
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return Err(ParseError::WrongMagic);
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}
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let version = self.bytes.read_u16::<LE>()?;
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let sections = self.bytes.read_u16::<LE>()?;
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Ok(Header { version, sections })
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}
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fn parse_sections(&mut self, header: Header) -> Result<Vec<Box<dyn Section>>> {
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(0..header.sections)
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.map(|_| self.parse_section())
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.collect()
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}
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fn parse_section(&mut self) -> Result<Box<dyn Section>> {
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let header = self.parse_section_header()?;
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let section: Box<dyn Section> = match header.kind {
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SectionKind::Data => self.parse_data_section(header).map(Box::new)?,
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SectionKind::Code => self.parse_code_section(header).map(Box::new)?,
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SectionKind::Meta => self.parse_meta_section(header).map(Box::new)?,
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};
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Ok(section)
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}
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fn parse_section_header(&mut self) -> Result<SectionHeader> {
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let kind: SectionKind = self.bytes.read_u8()?.try_into()?;
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let checksum = self.bytes.read_u32::<LE>()?;
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let len = self.bytes.read_u64::<LE>()?;
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Ok(SectionHeader {
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kind,
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checksum,
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len,
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})
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}
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fn parse_data_section(&mut self, header: SectionHeader) -> Result<DataSection> {
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let load_location = self.bytes.read_u64::<LE>()?;
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let contents = self.take_bytes(header.len)?;
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Ok(DataSection {
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header,
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load_location,
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contents,
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})
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}
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|
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fn parse_code_section(&mut self, header: SectionHeader) -> Result<CodeSection> {
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let load_location = self.bytes.read_u64::<LE>()?;
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let contents = self.take_bytes(header.len)?;
|
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Ok(CodeSection {
|
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header,
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load_location,
|
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contents,
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})
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}
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|
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fn parse_meta_section(&mut self, header: SectionHeader) -> Result<MetaSection> {
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let entry_count = self.bytes.read_u64::<LE>()?;
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let mut entries = Vec::with_capacity(entry_count as usize);
|
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for _ in 0 .. entry_count {
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let key_bytes = self.parse_sized_data()?;
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let key = String::from_utf8(key_bytes)?;
|
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let value = self.parse_sized_data()?;
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entries.push((key, value));
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}
|
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Ok(MetaSection {
|
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header,
|
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entry_count,
|
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entries,
|
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})
|
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}
|
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|
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fn parse_sized_data(&mut self) -> Result<Vec<u8>> {
|
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let size = self.bytes.read_u64::<LE>()?;
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self.take_bytes(size)
|
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}
|
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|
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fn take_bytes(&mut self, count: u64) -> Result<Vec<u8>> {
|
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let mut contents = vec!(0u8; count as usize);
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self.bytes.read_exact(&mut contents)?;
|
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Ok(contents)
|
||||
}
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user