403 lines
12 KiB
Rust
403 lines
12 KiB
Rust
pub mod decode;
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use std::borrow::Cow;
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use crate::is_string_char;
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pub use decode::*;
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pub const STR_INLINE_MAX: usize = 18;
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pub type Pos = u32;
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#[derive(Clone, Copy, Debug)]
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pub struct ITerm(Pos);
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#[derive(Clone, Copy, Debug)]
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pub(crate) struct IRaw {
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start: Pos,
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end: Pos,
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}
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#[derive(Clone, Copy, Debug)]
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pub(crate) struct ISeq {
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seq_start: Pos,
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seq_end: Pos,
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}
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#[derive(Clone, Copy, Debug)]
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pub(crate) struct IDict {
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dict_start: Pos,
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dict_end: Pos,
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}
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#[derive(Debug)]
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pub(crate) enum TTerm {
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Str(IRaw),
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StrInline(u8, [u8; STR_INLINE_MAX]),
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RawSeq(IRaw, ISeq),
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RawList(IRaw, ISeq),
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RawDict(IRaw, IDict),
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Seq(ISeq),
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List(ISeq),
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Dict(IDict),
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}
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#[derive(Debug)]
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pub struct Buf<'a> {
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bytes: Cow<'a, [u8]>,
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seqs: Vec<ITerm>,
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dicts: Vec<(IRaw, ITerm)>,
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terms: Vec<TTerm>,
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}
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#[derive(Debug)]
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pub enum TermError {
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InvalidIndex(ITerm),
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WrongType(&'static str, &'static str),
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WrongLength(usize, usize),
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WrongKeys,
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NoRawRepresentation,
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}
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#[derive(Debug)]
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pub enum ValueError {
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InvalidIndex(ITerm),
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DuplicateKey,
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BadString,
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SeqInSeq,
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}
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impl<'a> Buf<'a> {
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pub fn new() -> Self {
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Self {
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bytes: Default::default(),
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seqs: Vec::with_capacity(16),
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dicts: Vec::with_capacity(16),
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terms: Vec::with_capacity(16),
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}
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}
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// ================ READING FUNCTIONS ==================
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pub fn raw(&self, term: ITerm) -> Result<&[u8], TermError> {
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match self.get_term(term)? {
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TTerm::StrInline(len, bytes) => Ok(&bytes[..*len as usize]),
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TTerm::Str(r) | TTerm::RawSeq(r, _) | TTerm::RawList(r, _) | TTerm::RawDict(r, _) => {
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Ok(self.get_bytes(*r))
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}
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_ => Err(TermError::NoRawRepresentation),
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}
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}
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pub fn str(&self, term: ITerm) -> Result<&str, TermError> {
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match self.get_term(term)? {
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TTerm::StrInline(len, bytes) => {
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let bytes = &bytes[..*len as usize];
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let s = unsafe { std::str::from_utf8_unchecked(bytes) };
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Ok(s)
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}
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TTerm::Str(r) => {
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let bytes = self.get_bytes(*r);
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let s = unsafe { std::str::from_utf8_unchecked(bytes) };
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Ok(s)
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}
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t => Err(TermError::WrongType("string", t.typename())),
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}
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}
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pub fn seq<'x>(&'x self, term: &'x ITerm) -> Result<&'x [ITerm], TermError> {
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match self.get_term(*term)? {
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TTerm::RawSeq(_, s) | TTerm::Seq(s) => {
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Ok(&self.seqs[s.seq_start as usize..s.seq_end as usize])
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}
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_ => Ok(std::slice::from_ref(term)),
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}
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}
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pub fn seq_of<const N: usize>(&self, term: ITerm) -> Result<[ITerm; N], TermError> {
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match self.get_term(term)? {
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TTerm::RawSeq(_, s) | TTerm::Seq(s) => {
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let seq_len = (s.seq_end - s.seq_start) as usize;
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if seq_len == N {
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let seq = &self.seqs[s.seq_start as usize..s.seq_end as usize];
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Ok(seq.try_into().unwrap())
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} else {
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Err(TermError::WrongLength(N, seq_len))
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}
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}
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t => Err(TermError::WrongType("seq", t.typename())),
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}
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}
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pub fn list(&self, term: ITerm) -> Result<&[ITerm], TermError> {
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match self.get_term(term)? {
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TTerm::RawList(_, s) | TTerm::List(s) => {
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Ok(&self.seqs[s.seq_start as usize..s.seq_end as usize])
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}
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t => Err(TermError::WrongType("list", t.typename())),
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}
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}
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pub fn list_of<const N: usize>(&self, term: ITerm) -> Result<[ITerm; N], TermError> {
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match self.get_term(term)? {
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TTerm::RawList(_, s) | TTerm::List(s) => {
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let list_len = (s.seq_end - s.seq_start) as usize;
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if list_len == N {
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let seq = &self.seqs[s.seq_start as usize..s.seq_end as usize];
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Ok(seq.try_into().unwrap())
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} else {
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Err(TermError::WrongLength(N, list_len))
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}
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}
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t => Err(TermError::WrongType("list", t.typename())),
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}
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}
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pub fn dict_get(&self, term: ITerm, key: &str) -> Result<Option<ITerm>, TermError> {
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match self.get_term(term)? {
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TTerm::RawDict(_, d) | TTerm::Dict(d) => {
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let dict = &self.dicts[d.dict_start as usize..d.dict_end as usize];
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let pos_opt = dict
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.binary_search_by(|(k, _)| self.get_bytes(*k).cmp(key.as_bytes()))
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.ok();
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Ok(pos_opt.map(|pos| dict[pos].1))
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}
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t => Err(TermError::WrongType("dict", t.typename())),
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}
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}
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pub fn dict_of<const N: usize>(
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&self,
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term: ITerm,
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keys: [&str; N],
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allow_other: bool,
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) -> Result<[ITerm; N], TermError> {
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match self.get_term(term)? {
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TTerm::RawDict(_, d) | TTerm::Dict(d) => {
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let dict = &self.dicts[d.dict_start as usize..d.dict_end as usize];
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if dict.len() < N || (dict.len() > N && !allow_other) {
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return Err(TermError::WrongKeys);
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}
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let mut ret = [ITerm(0); N];
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for i in 0..N {
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let pos = dict
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.binary_search_by(|(k, _)| self.get_bytes(*k).cmp(keys[i].as_bytes()))
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.map_err(|_| TermError::WrongKeys)?;
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ret[i] = dict[pos].1;
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}
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Ok(ret)
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}
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t => Err(TermError::WrongType("dict", t.typename())),
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}
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}
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pub fn dict_iter(
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&self,
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term: ITerm,
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) -> Result<impl Iterator<Item = (&str, ITerm)> + '_, TermError> {
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match self.get_term(term)? {
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TTerm::RawDict(_, d) | TTerm::Dict(d) => {
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let dict = &self.dicts[d.dict_start as usize..d.dict_end as usize];
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let iter = dict.iter().map(|(k, v)| {
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(
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unsafe { std::str::from_utf8_unchecked(self.get_bytes(*k)) },
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*v,
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)
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});
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Ok(iter)
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}
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t => Err(TermError::WrongType("dict", t.typename())),
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}
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}
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// ================= WRITING FUNCTIONS ================
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pub fn push_str(&mut self, s: &str) -> Result<ITerm, ValueError> {
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let b = s.as_bytes();
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if !b.iter().copied().all(is_string_char) {
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return Err(ValueError::BadString);
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}
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let term = if b.len() <= STR_INLINE_MAX {
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let mut bytes = [0u8; STR_INLINE_MAX];
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bytes[..b.len()].copy_from_slice(b);
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TTerm::StrInline(b.len() as u8, bytes)
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} else {
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TTerm::Str(self.push_bytes(b))
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};
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Ok(self.push_term(term))
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}
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pub fn push_seq(&mut self, iterator: impl Iterator<Item = ITerm>) -> Result<ITerm, ValueError> {
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let seq_start = self.seqs.len();
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for term in iterator {
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match self.terms.get(term.0 as usize) {
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None => {
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self.seqs.truncate(seq_start);
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return Err(ValueError::InvalidIndex(term));
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}
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Some(TTerm::RawSeq(_, _)) => {
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self.seqs.truncate(seq_start);
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return Err(ValueError::SeqInSeq);
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}
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_ => {
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self.seqs.push(term);
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}
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}
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}
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let seq = ISeq {
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seq_start: seq_start as Pos,
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seq_end: self.seqs.len() as Pos,
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};
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Ok(self.push_term(TTerm::Seq(seq)))
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}
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pub fn push_list(
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&mut self,
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iterator: impl Iterator<Item = ITerm>,
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) -> Result<ITerm, ValueError> {
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let list_start = self.seqs.len();
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for term in iterator {
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match self.terms.get(term.0 as usize) {
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None => {
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self.seqs.truncate(list_start);
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return Err(ValueError::InvalidIndex(term));
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}
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_ => {
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self.seqs.push(term);
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}
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}
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}
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let list = ISeq {
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seq_start: list_start as Pos,
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seq_end: self.seqs.len() as Pos,
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};
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Ok(self.push_term(TTerm::List(list)))
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}
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pub fn push_dict<'k>(
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&mut self,
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iterator: impl Iterator<Item = (&'k str, ITerm)>,
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) -> Result<ITerm, ValueError> {
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let bytes_start = self.bytes.len();
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let dict_start = self.dicts.len();
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for (key, term) in iterator {
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if !key.as_bytes().iter().copied().all(is_string_char) {
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return Err(ValueError::BadString);
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}
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let key = self.push_bytes(key.as_bytes());
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match self.terms.get(term.0 as usize) {
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None => {
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self.bytes.to_mut().truncate(bytes_start);
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self.dicts.truncate(dict_start);
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return Err(ValueError::InvalidIndex(term));
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}
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_ => {
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self.dicts.push((key, term));
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}
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}
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}
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self.dicts[dict_start..]
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.sort_by_key(|(k, _)| (&self.bytes[k.start as usize..k.end as usize], k.start));
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for ((k1, _), (k2, _)) in self.dicts[dict_start..]
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.iter()
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.zip(self.dicts[dict_start + 1..].iter())
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{
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if self.get_bytes(*k1) == self.get_bytes(*k2) {
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self.bytes.to_mut().truncate(bytes_start);
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self.dicts.truncate(dict_start);
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return Err(ValueError::DuplicateKey);
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}
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}
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let dict = IDict {
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dict_start: dict_start as Pos,
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dict_end: self.dicts.len() as Pos,
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};
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Ok(self.push_term(TTerm::Dict(dict)))
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}
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pub fn push_raw(&mut self, raw: &[u8]) -> Result<ITerm, ParseError> {
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let bytes_len = self.bytes.len();
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let seqs_len = self.seqs.len();
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let dicts_len = self.dicts.len();
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let terms_len = self.terms.len();
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let raw = self.push_bytes(raw);
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let result = self.decode(raw);
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if result.is_err() {
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// reset to initial state
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self.bytes.to_mut().truncate(bytes_len);
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self.seqs.truncate(seqs_len);
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self.dicts.truncate(dicts_len);
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self.terms.truncate(terms_len);
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}
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result
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}
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// ==== Internal ====
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#[inline]
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fn get_term(&self, term: ITerm) -> Result<&TTerm, TermError> {
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self.terms
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.get(term.0 as usize)
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.ok_or(TermError::InvalidIndex(term))
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}
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#[inline]
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fn push_term(&mut self, term: TTerm) -> ITerm {
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let ret = ITerm(self.terms.len() as Pos);
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self.terms.push(term);
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ret
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}
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#[inline]
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fn push_bytes(&mut self, raw: &[u8]) -> IRaw {
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let bytes_start = self.bytes.len();
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self.bytes.to_mut().extend(raw);
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IRaw {
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start: bytes_start as Pos,
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end: self.bytes.len() as Pos,
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}
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}
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}
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impl TTerm {
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fn typename(&self) -> &'static str {
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match self {
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TTerm::Str(_) | TTerm::StrInline(_, _) => "string",
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TTerm::RawSeq(_, _) | TTerm::Seq(_) => "seq",
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TTerm::RawList(_, _) | TTerm::List(_) => "list",
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TTerm::RawDict(_, _) | TTerm::Dict(_) => "dict",
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}
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}
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}
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#[cfg(test)]
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mod tests {
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pub use super::*;
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#[test]
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fn test_sizeof() {
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assert_eq!(std::mem::size_of::<TTerm>(), 20);
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}
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}
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