third_party_rust_nom/benches/json.rs
2016-11-24 15:40:07 +01:00

123 lines
2.4 KiB
Rust

//#![feature(trace_macros)]
#![feature(test)]
extern crate test;
#[macro_use]
extern crate nom;
use nom::{digit, alphanumeric};
use test::Bencher;
use std::str::{self,FromStr};
use std::collections::HashMap;
#[derive(Debug,PartialEq)]
pub enum JsonValue {
Str(String),
Num(f32),
Array(Vec<JsonValue>),
Object(HashMap<String,JsonValue>)
}
// FIXME: since we already parsed a serie of digits and dots,
// we know it is correct UTF-8. no need to use from_utf8 to
// verify it is correct
// FIXME: use alt_complete (implement ws for alt_complete)
named!(unsigned_float <f32>, map_res!(
map_res!(
recognize!(
alt_complete!(
delimited!(digit, tag!("."), opt!(complete!(digit))) |
delimited!(opt!(digit), tag!("."), digit) |
digit
)
),
str::from_utf8
),
FromStr::from_str
));
named!(float<f32>, map!(
pair!(
opt!(alt!(tag!("+") | tag!("-"))),
unsigned_float
),
|(sign, value): (Option<&[u8]>, f32)| {
sign.and_then(|s| if s[0] == ('-' as u8) { Some(-1f32) } else { None }).unwrap_or(1f32) * value
}
));
//FIXME: verify how json strings are formatted
named!(string<&str>,
delimited!(
tag!("\""),
map_res!(escaped!(call!(alphanumeric), '\\', is_a!("\"n\\")), str::from_utf8),
tag!("\"")
)
);
named!(array < Vec<JsonValue> >,
ws!(
delimited!(
tag!("["),
separated_list!(tag!(","), value),
tag!("]")
)
)
);
named!(key_value<(&str,JsonValue)>,
ws!(
separated_pair!(
string,
tag!(":"),
value
)
)
);
named!(hash< HashMap<String,JsonValue> >,
ws!(
map!(
delimited!(
tag!("{"),
separated_list!(tag!(","), key_value),
tag!("}")
),
|tuple_vec| {
let mut h: HashMap<String, JsonValue> = HashMap::new();
for (k, v) in tuple_vec {
h.insert(String::from(k), v);
}
h
}
)
)
);
named!(value<JsonValue>,
ws!(
alt!(
hash => { |h| JsonValue::Object(h) } |
array => { |v| JsonValue::Array(v) } |
string => { |s| JsonValue::Str(String::from(s)) } |
float => { |num| JsonValue::Num(num) }
)
)
);
#[bench]
fn json_bench(b: &mut Bencher) {
let data = &b" { \"a\"\t: 42,
\"b\": [ \"x\", \"y\", 12 ] ,
\"c\": { \"hello\" : \"world\"
}
} ";
//println!("data:\n{:?}", value(&data[..]));
b.iter(||{
value(&data[..])
});
}