237 lines
5.5 KiB
Rust
237 lines
5.5 KiB
Rust
|
#![cfg(feature = "alloc")]
|
||
|
|
||
|
use nom::{
|
||
|
branch::alt,
|
||
|
bytes::complete::{tag, take},
|
||
|
character::complete::{anychar, char, multispace0, none_of},
|
||
|
combinator::{map, map_opt, map_res, value, verify},
|
||
|
error::ParseError,
|
||
|
multi::{fold_many0, separated_list0},
|
||
|
number::complete::double,
|
||
|
sequence::{delimited, preceded, separated_pair},
|
||
|
IResult, Parser,
|
||
|
};
|
||
|
|
||
|
use std::collections::HashMap;
|
||
|
|
||
|
#[derive(Debug, PartialEq, Clone)]
|
||
|
pub enum JsonValue {
|
||
|
Null,
|
||
|
Bool(bool),
|
||
|
Str(String),
|
||
|
Num(f64),
|
||
|
Array(Vec<JsonValue>),
|
||
|
Object(HashMap<String, JsonValue>),
|
||
|
}
|
||
|
|
||
|
fn boolean(input: &str) -> IResult<&str, bool> {
|
||
|
alt((value(false, tag("false")), value(true, tag("true"))))(input)
|
||
|
}
|
||
|
|
||
|
fn u16_hex(input: &str) -> IResult<&str, u16> {
|
||
|
map_res(take(4usize), |s| u16::from_str_radix(s, 16))(input)
|
||
|
}
|
||
|
|
||
|
fn unicode_escape(input: &str) -> IResult<&str, char> {
|
||
|
map_opt(
|
||
|
alt((
|
||
|
// Not a surrogate
|
||
|
map(verify(u16_hex, |cp| !(0xD800..0xE000).contains(cp)), |cp| {
|
||
|
cp as u32
|
||
|
}),
|
||
|
// See https://en.wikipedia.org/wiki/UTF-16#Code_points_from_U+010000_to_U+10FFFF for details
|
||
|
map(
|
||
|
verify(
|
||
|
separated_pair(u16_hex, tag("\\u"), u16_hex),
|
||
|
|(high, low)| (0xD800..0xDC00).contains(high) && (0xDC00..0xE000).contains(low),
|
||
|
),
|
||
|
|(high, low)| {
|
||
|
let high_ten = (high as u32) - 0xD800;
|
||
|
let low_ten = (low as u32) - 0xDC00;
|
||
|
(high_ten << 10) + low_ten + 0x10000
|
||
|
},
|
||
|
),
|
||
|
)),
|
||
|
// Could be probably replaced with .unwrap() or _unchecked due to the verify checks
|
||
|
std::char::from_u32,
|
||
|
)(input)
|
||
|
}
|
||
|
|
||
|
fn character(input: &str) -> IResult<&str, char> {
|
||
|
let (input, c) = none_of("\"")(input)?;
|
||
|
if c == '\\' {
|
||
|
alt((
|
||
|
map_res(anychar, |c| {
|
||
|
Ok(match c {
|
||
|
'"' | '\\' | '/' => c,
|
||
|
'b' => '\x08',
|
||
|
'f' => '\x0C',
|
||
|
'n' => '\n',
|
||
|
'r' => '\r',
|
||
|
't' => '\t',
|
||
|
_ => return Err(()),
|
||
|
})
|
||
|
}),
|
||
|
preceded(char('u'), unicode_escape),
|
||
|
))(input)
|
||
|
} else {
|
||
|
Ok((input, c))
|
||
|
}
|
||
|
}
|
||
|
|
||
|
fn string(input: &str) -> IResult<&str, String> {
|
||
|
delimited(
|
||
|
char('"'),
|
||
|
fold_many0(character, String::new, |mut string, c| {
|
||
|
string.push(c);
|
||
|
string
|
||
|
}),
|
||
|
char('"'),
|
||
|
)(input)
|
||
|
}
|
||
|
|
||
|
fn ws<'a, O, E: ParseError<&'a str>, F: Parser<&'a str, O, E>>(f: F) -> impl Parser<&'a str, O, E> {
|
||
|
delimited(multispace0, f, multispace0)
|
||
|
}
|
||
|
|
||
|
fn array(input: &str) -> IResult<&str, Vec<JsonValue>> {
|
||
|
delimited(
|
||
|
char('['),
|
||
|
ws(separated_list0(ws(char(',')), json_value)),
|
||
|
char(']'),
|
||
|
)(input)
|
||
|
}
|
||
|
|
||
|
fn object(input: &str) -> IResult<&str, HashMap<String, JsonValue>> {
|
||
|
map(
|
||
|
delimited(
|
||
|
char('{'),
|
||
|
ws(separated_list0(
|
||
|
ws(char(',')),
|
||
|
separated_pair(string, ws(char(':')), json_value),
|
||
|
)),
|
||
|
char('}'),
|
||
|
),
|
||
|
|key_values| key_values.into_iter().collect(),
|
||
|
)(input)
|
||
|
}
|
||
|
|
||
|
fn json_value(input: &str) -> IResult<&str, JsonValue> {
|
||
|
use JsonValue::*;
|
||
|
|
||
|
alt((
|
||
|
value(Null, tag("null")),
|
||
|
map(boolean, Bool),
|
||
|
map(string, Str),
|
||
|
map(double, Num),
|
||
|
map(array, Array),
|
||
|
map(object, Object),
|
||
|
))(input)
|
||
|
}
|
||
|
|
||
|
fn json(input: &str) -> IResult<&str, JsonValue> {
|
||
|
ws(json_value).parse(input)
|
||
|
}
|
||
|
|
||
|
#[test]
|
||
|
fn json_string() {
|
||
|
assert_eq!(string("\"\""), Ok(("", "".to_string())));
|
||
|
assert_eq!(string("\"abc\""), Ok(("", "abc".to_string())));
|
||
|
assert_eq!(
|
||
|
string("\"abc\\\"\\\\\\/\\b\\f\\n\\r\\t\\u0001\\u2014\u{2014}def\""),
|
||
|
Ok(("", "abc\"\\/\x08\x0C\n\r\t\x01——def".to_string())),
|
||
|
);
|
||
|
assert_eq!(string("\"\\uD83D\\uDE10\""), Ok(("", "😐".to_string())));
|
||
|
|
||
|
assert!(string("\"").is_err());
|
||
|
assert!(string("\"abc").is_err());
|
||
|
assert!(string("\"\\\"").is_err());
|
||
|
assert!(string("\"\\u123\"").is_err());
|
||
|
assert!(string("\"\\uD800\"").is_err());
|
||
|
assert!(string("\"\\uD800\\uD800\"").is_err());
|
||
|
assert!(string("\"\\uDC00\"").is_err());
|
||
|
}
|
||
|
|
||
|
#[test]
|
||
|
fn json_object() {
|
||
|
use JsonValue::*;
|
||
|
|
||
|
let input = r#"{"a":42,"b":"x"}"#;
|
||
|
|
||
|
let expected = Object(
|
||
|
vec![
|
||
|
("a".to_string(), Num(42.0)),
|
||
|
("b".to_string(), Str("x".to_string())),
|
||
|
]
|
||
|
.into_iter()
|
||
|
.collect(),
|
||
|
);
|
||
|
|
||
|
assert_eq!(json(input), Ok(("", expected)));
|
||
|
}
|
||
|
|
||
|
#[test]
|
||
|
fn json_array() {
|
||
|
use JsonValue::*;
|
||
|
|
||
|
let input = r#"[42,"x"]"#;
|
||
|
|
||
|
let expected = Array(vec![Num(42.0), Str("x".to_string())]);
|
||
|
|
||
|
assert_eq!(json(input), Ok(("", expected)));
|
||
|
}
|
||
|
|
||
|
#[test]
|
||
|
fn json_whitespace() {
|
||
|
use JsonValue::*;
|
||
|
|
||
|
let input = r#"
|
||
|
{
|
||
|
"null" : null,
|
||
|
"true" :true ,
|
||
|
"false": false ,
|
||
|
"number" : 123e4 ,
|
||
|
"string" : " abc 123 " ,
|
||
|
"array" : [ false , 1 , "two" ] ,
|
||
|
"object" : { "a" : 1.0 , "b" : "c" } ,
|
||
|
"empty_array" : [ ] ,
|
||
|
"empty_object" : { }
|
||
|
}
|
||
|
"#;
|
||
|
|
||
|
assert_eq!(
|
||
|
json(input),
|
||
|
Ok((
|
||
|
"",
|
||
|
Object(
|
||
|
vec![
|
||
|
("null".to_string(), Null),
|
||
|
("true".to_string(), Bool(true)),
|
||
|
("false".to_string(), Bool(false)),
|
||
|
("number".to_string(), Num(123e4)),
|
||
|
("string".to_string(), Str(" abc 123 ".to_string())),
|
||
|
(
|
||
|
"array".to_string(),
|
||
|
Array(vec![Bool(false), Num(1.0), Str("two".to_string())])
|
||
|
),
|
||
|
(
|
||
|
"object".to_string(),
|
||
|
Object(
|
||
|
vec![
|
||
|
("a".to_string(), Num(1.0)),
|
||
|
("b".to_string(), Str("c".to_string())),
|
||
|
]
|
||
|
.into_iter()
|
||
|
.collect()
|
||
|
)
|
||
|
),
|
||
|
("empty_array".to_string(), Array(vec![]),),
|
||
|
("empty_object".to_string(), Object(HashMap::new()),),
|
||
|
]
|
||
|
.into_iter()
|
||
|
.collect()
|
||
|
)
|
||
|
))
|
||
|
);
|
||
|
}
|