#[cfg(feature = "bigdecimal")]
mod bigdecimal {
extern crate bigdecimal;
extern crate num_bigint;
extern crate num_integer;
extern crate num_traits;
use self::bigdecimal::BigDecimal;
use self::num_bigint::{BigInt, BigUint, Sign};
use self::num_integer::Integer;
use self::num_traits::{Signed, ToPrimitive, Zero};
use std::io::prelude::*;
use deserialize::{self, FromSql};
use pg::data_types::PgNumeric;
use pg::Pg;
use serialize::{self, Output, ToSql};
use sql_types::Numeric;
#[cfg(feature = "unstable")]
use std::convert::{TryFrom, TryInto};
#[cfg(feature = "unstable")]
use std::error::Error;
struct ToBase10000(Option<BigUint>);
impl Iterator for ToBase10000 {
type Item = i16;
fn next(&mut self) -> Option<Self::Item> {
self.0.take().map(|v| {
let (div, rem) = v.div_rem(&BigUint::from(10_000u16));
if !div.is_zero() {
self.0 = Some(div);
}
rem.to_i16().expect("10000 always fits in an i16")
})
}
}
fn pg_decimal_to_bigdecimal(numeric: &PgNumeric) -> deserialize::Result<BigDecimal> {
let (sign, weight, scale, digits) = match *numeric {
PgNumeric::Positive {
weight,
scale,
ref digits,
} => (Sign::Plus, weight, scale, digits),
PgNumeric::Negative {
weight,
scale,
ref digits,
} => (Sign::Minus, weight, scale, digits),
PgNumeric::NaN => return Err(Box::from("NaN is not (yet) supported in BigDecimal")),
};
let mut result = BigUint::default();
let count = digits.len() as i64;
for digit in digits {
result *= BigUint::from(10_000u64);
result += BigUint::from(*digit as u64);
}
let correction_exp = 4 * (i64::from(weight) - count + 1);
let result = BigDecimal::new(BigInt::from_biguint(sign, result), -correction_exp)
.with_scale(i64::from(scale));
Ok(result)
}
#[cfg(feature = "unstable")]
impl<'a> TryFrom<&'a PgNumeric> for BigDecimal {
type Error = Box<dyn Error + Send + Sync>;
fn try_from(numeric: &'a PgNumeric) -> deserialize::Result<Self> {
pg_decimal_to_bigdecimal(numeric)
}
}
#[cfg(feature = "unstable")]
impl TryFrom<PgNumeric> for BigDecimal {
type Error = Box<dyn Error + Send + Sync>;
fn try_from(numeric: PgNumeric) -> deserialize::Result<Self> {
(&numeric).try_into()
}
}
impl<'a> From<&'a BigDecimal> for PgNumeric {
#[allow(clippy::assign_op_pattern)]
fn from(decimal: &'a BigDecimal) -> Self {
let (mut integer, scale) = decimal.as_bigint_and_exponent();
let scale = scale as u16;
integer = integer.abs();
for _ in 0..(4 - scale % 4) {
integer = integer * 10;
}
let integer = integer.to_biguint().expect("integer is always positive");
let mut digits = ToBase10000(Some(integer)).collect::<Vec<_>>();
digits.reverse();
let digits_after_decimal = scale as u16 / 4 + 1;
let weight = digits.len() as i16 - digits_after_decimal as i16 - 1;
let unnecessary_zeroes = if weight >= 0 {
let index_of_decimal = (weight + 1) as usize;
digits
.get(index_of_decimal..)
.expect("enough digits exist")
.iter()
.rev()
.take_while(|i| i.is_zero())
.count()
} else {
0
};
let relevant_digits = digits.len() - unnecessary_zeroes;
digits.truncate(relevant_digits);
match decimal.sign() {
Sign::Plus => PgNumeric::Positive {
digits,
scale,
weight,
},
Sign::Minus => PgNumeric::Negative {
digits,
scale,
weight,
},
Sign::NoSign => PgNumeric::Positive {
digits: vec![0],
scale: 0,
weight: 0,
},
}
}
}
impl From<BigDecimal> for PgNumeric {
fn from(bigdecimal: BigDecimal) -> Self {
(&bigdecimal).into()
}
}
impl ToSql<Numeric, Pg> for BigDecimal {
fn to_sql<W: Write>(&self, out: &mut Output<W, Pg>) -> serialize::Result {
let numeric = PgNumeric::from(self);
ToSql::<Numeric, Pg>::to_sql(&numeric, out)
}
}
impl FromSql<Numeric, Pg> for BigDecimal {
fn from_sql(numeric: Option<&[u8]>) -> deserialize::Result<Self> {
let numeric = PgNumeric::from_sql(numeric)?;
pg_decimal_to_bigdecimal(&numeric)
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::str::FromStr;
#[test]
fn bigdecimal_to_pgnumeric_converts_digits_to_base_10000() {
let decimal = BigDecimal::from_str("1").unwrap();
let expected = PgNumeric::Positive {
weight: 0,
scale: 0,
digits: vec![1],
};
assert_eq!(expected, decimal.into());
let decimal = BigDecimal::from_str("10").unwrap();
let expected = PgNumeric::Positive {
weight: 0,
scale: 0,
digits: vec![10],
};
assert_eq!(expected, decimal.into());
let decimal = BigDecimal::from_str("10000").unwrap();
let expected = PgNumeric::Positive {
weight: 1,
scale: 0,
digits: vec![1, 0],
};
assert_eq!(expected, decimal.into());
let decimal = BigDecimal::from_str("10001").unwrap();
let expected = PgNumeric::Positive {
weight: 1,
scale: 0,
digits: vec![1, 1],
};
assert_eq!(expected, decimal.into());
let decimal = BigDecimal::from_str("100000000").unwrap();
let expected = PgNumeric::Positive {
weight: 2,
scale: 0,
digits: vec![1, 0, 0],
};
assert_eq!(expected, decimal.into());
}
#[test]
fn bigdecimal_to_pg_numeric_properly_adjusts_scale() {
let decimal = BigDecimal::from_str("1").unwrap();
let expected = PgNumeric::Positive {
weight: 0,
scale: 0,
digits: vec![1],
};
assert_eq!(expected, decimal.into());
let decimal = BigDecimal::from_str("1.0").unwrap();
let expected = PgNumeric::Positive {
weight: 0,
scale: 1,
digits: vec![1],
};
assert_eq!(expected, decimal.into());
let decimal = BigDecimal::from_str("1.1").unwrap();
let expected = PgNumeric::Positive {
weight: 0,
scale: 1,
digits: vec![1, 1000],
};
assert_eq!(expected, decimal.into());
let decimal = BigDecimal::from_str("1.10").unwrap();
let expected = PgNumeric::Positive {
weight: 0,
scale: 2,
digits: vec![1, 1000],
};
assert_eq!(expected, decimal.into());
let decimal = BigDecimal::from_str("100000000.0001").unwrap();
let expected = PgNumeric::Positive {
weight: 2,
scale: 4,
digits: vec![1, 0, 0, 1],
};
assert_eq!(expected, decimal.into());
let decimal = BigDecimal::from_str("0.1").unwrap();
let expected = PgNumeric::Positive {
weight: -1,
scale: 1,
digits: vec![1000],
};
assert_eq!(expected, decimal.into());
}
#[test]
fn bigdecimal_to_pg_numeric_retains_sign() {
let decimal = BigDecimal::from_str("123.456").unwrap();
let expected = PgNumeric::Positive {
weight: 0,
scale: 3,
digits: vec![123, 4560],
};
assert_eq!(expected, decimal.into());
let decimal = BigDecimal::from_str("-123.456").unwrap();
let expected = PgNumeric::Negative {
weight: 0,
scale: 3,
digits: vec![123, 4560],
};
assert_eq!(expected, decimal.into());
}
#[test]
#[cfg(feature = "unstable")]
fn pg_numeric_to_bigdecimal_works() {
let expected = BigDecimal::from_str("123.456").unwrap();
let pg_numeric = PgNumeric::Positive {
weight: 0,
scale: 3,
digits: vec![123, 4560],
};
let res: BigDecimal = pg_numeric.try_into().unwrap();
assert_eq!(res, expected);
let expected = BigDecimal::from_str("-56.78").unwrap();
let pg_numeric = PgNumeric::Negative {
weight: 0,
scale: 2,
digits: vec![56, 7800],
};
let res: BigDecimal = pg_numeric.try_into().unwrap();
assert_eq!(res, expected);
}
}
}