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use std::borrow::Cow;
use itoa;
use ryu;
use ser::{Fragment, Map, Seq, Serialize};
pub fn to_string<T: ?Sized + Serialize>(value: &T) -> String {
to_string_impl(&value)
}
struct Serializer<'a> {
stack: Vec<Layer<'a>>,
}
enum Layer<'a> {
Seq(Box<Seq + 'a>),
Map(Box<Map + 'a>),
}
impl<'a> Drop for Serializer<'a> {
fn drop(&mut self) {
while !self.stack.is_empty() {
self.stack.pop();
}
}
}
fn to_string_impl(value: &Serialize) -> String {
let mut out = String::new();
let mut serializer = Serializer { stack: Vec::new() };
let mut fragment = value.begin();
loop {
match fragment {
Fragment::Null => out.push_str("null"),
Fragment::Bool(b) => out.push_str(if b { "true" } else { "false" }),
Fragment::Str(s) => escape_str(&s, &mut out),
Fragment::U64(n) => out.push_str(itoa::Buffer::new().format(n)),
Fragment::I64(n) => out.push_str(itoa::Buffer::new().format(n)),
Fragment::F64(n) => out.push_str(ryu::Buffer::new().format(n)),
Fragment::Seq(mut seq) => {
out.push('[');
match careful!(seq.next() as Option<&Serialize>) {
Some(first) => {
serializer.stack.push(Layer::Seq(seq));
fragment = first.begin();
continue;
}
None => out.push(']'),
}
}
Fragment::Map(mut map) => {
out.push('{');
match careful!(map.next() as Option<(Cow<str>, &Serialize)>) {
Some((key, first)) => {
escape_str(&key, &mut out);
out.push(':');
serializer.stack.push(Layer::Map(map));
fragment = first.begin();
continue;
}
None => out.push('}'),
}
}
}
loop {
match serializer.stack.last_mut() {
Some(Layer::Seq(seq)) => {
match careful!(seq.next() as Option<&Serialize>) {
Some(next) => {
out.push(',');
fragment = next.begin();
break;
}
None => out.push(']'),
}
}
Some(Layer::Map(map)) => {
match careful!(map.next() as Option<(Cow<str>, &Serialize)>) {
Some((key, next)) => {
out.push(',');
escape_str(&key, &mut out);
out.push(':');
fragment = next.begin();
break;
}
None => out.push('}'),
}
}
None => return out,
}
serializer.stack.pop();
}
}
}
fn escape_str(value: &str, out: &mut String) {
out.push('"');
let bytes = value.as_bytes();
let mut start = 0;
for (i, &byte) in bytes.iter().enumerate() {
let escape = ESCAPE[byte as usize];
if escape == 0 {
continue;
}
if start < i {
out.push_str(&value[start..i]);
}
match escape {
self::BB => out.push_str("\\b"),
self::TT => out.push_str("\\t"),
self::NN => out.push_str("\\n"),
self::FF => out.push_str("\\f"),
self::RR => out.push_str("\\r"),
self::QU => out.push_str("\\\""),
self::BS => out.push_str("\\\\"),
self::U => {
static HEX_DIGITS: [u8; 16] = *b"0123456789abcdef";
out.push_str("\\u00");
out.push(HEX_DIGITS[(byte >> 4) as usize] as char);
out.push(HEX_DIGITS[(byte & 0xF) as usize] as char);
}
_ => unreachable!(),
}
start = i + 1;
}
if start != bytes.len() {
out.push_str(&value[start..]);
}
out.push('"');
}
const BB: u8 = b'b';
const TT: u8 = b't';
const NN: u8 = b'n';
const FF: u8 = b'f';
const RR: u8 = b'r';
const QU: u8 = b'"';
const BS: u8 = b'\\';
const U: u8 = b'u';
#[cfg_attr(rustfmt, rustfmt_skip)]
static ESCAPE: [u8; 256] = [
U, U, U, U, U, U, U, U, BB, TT, NN, U, FF, RR, U, U,
U, U, U, U, U, U, U, U, U, U, U, U, U, U, U, U,
0, 0, QU, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, BS, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
];