diesel/pg/types/floats/
mod.rs

1use crate::deserialize::{self, Defaultable, FromSql, FromSqlRow};
2use crate::expression::AsExpression;
3use crate::pg::{Pg, PgValue};
4use crate::serialize::{self, IsNull, Output, ToSql};
5use crate::sql_types;
6use byteorder::{NetworkEndian, ReadBytesExt, WriteBytesExt};
7use std::error::Error;
8
9#[cfg(feature = "quickcheck")]
10mod quickcheck_impls;
11
12#[derive(Debug, Default, Clone, PartialEq, Eq, AsExpression, FromSqlRow)]
13#[diesel(sql_type = sql_types::Numeric)]
14/// Represents a NUMERIC value, closely mirroring the PG wire protocol
15/// representation
16pub enum PgNumeric {
17    /// A positive number
18    Positive {
19        /// How many digits come before the decimal point?
20        weight: i16,
21        /// How many significant digits are there?
22        scale: u16,
23        /// The digits in this number, stored in base 10000
24        digits: Vec<i16>,
25    },
26    /// A negative number
27    Negative {
28        /// How many digits come before the decimal point?
29        weight: i16,
30        /// How many significant digits are there?
31        scale: u16,
32        /// The digits in this number, stored in base 10000
33        digits: Vec<i16>,
34    },
35    /// Not a number
36    #[default]
37    NaN,
38}
39
40#[derive(Debug, Clone, Copy)]
41#[allow(dead_code)] // that's used by debug in the error impl
42struct InvalidNumericSign(u16);
43
44impl ::std::fmt::Display for InvalidNumericSign {
45    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> ::std::fmt::Result {
46        f.write_str("sign for numeric field was not one of 0, 0x4000, 0xC000")
47    }
48}
49
50impl Error for InvalidNumericSign {}
51
52#[cfg(feature = "postgres_backend")]
53impl FromSql<sql_types::Numeric, Pg> for PgNumeric {
54    fn from_sql(bytes: PgValue<'_>) -> deserialize::Result<Self> {
55        let mut bytes = bytes.as_bytes();
56        let digit_count = bytes.read_u16::<NetworkEndian>()?;
57        let mut digits = Vec::with_capacity(digit_count as usize);
58        let weight = bytes.read_i16::<NetworkEndian>()?;
59        let sign = bytes.read_u16::<NetworkEndian>()?;
60        let scale = bytes.read_u16::<NetworkEndian>()?;
61        for _ in 0..digit_count {
62            digits.push(bytes.read_i16::<NetworkEndian>()?);
63        }
64
65        match sign {
66            0 => Ok(PgNumeric::Positive {
67                weight,
68                scale,
69                digits,
70            }),
71            0x4000 => Ok(PgNumeric::Negative {
72                weight,
73                scale,
74                digits,
75            }),
76            0xC000 => Ok(PgNumeric::NaN),
77            invalid => Err(Box::new(InvalidNumericSign(invalid))),
78        }
79    }
80}
81
82#[cfg(feature = "postgres_backend")]
83impl ToSql<sql_types::Numeric, Pg> for PgNumeric {
84    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
85        let sign = match *self {
86            PgNumeric::Positive { .. } => 0,
87            PgNumeric::Negative { .. } => 0x4000,
88            PgNumeric::NaN => 0xC000,
89        };
90        let empty_vec = Vec::new();
91        let digits = match *self {
92            PgNumeric::Positive { ref digits, .. } | PgNumeric::Negative { ref digits, .. } => {
93                digits
94            }
95            PgNumeric::NaN => &empty_vec,
96        };
97        let weight = match *self {
98            PgNumeric::Positive { weight, .. } | PgNumeric::Negative { weight, .. } => weight,
99            PgNumeric::NaN => 0,
100        };
101        let scale = match *self {
102            PgNumeric::Positive { scale, .. } | PgNumeric::Negative { scale, .. } => scale,
103            PgNumeric::NaN => 0,
104        };
105        out.write_u16::<NetworkEndian>(digits.len().try_into()?)?;
106        out.write_i16::<NetworkEndian>(weight)?;
107        out.write_u16::<NetworkEndian>(sign)?;
108        out.write_u16::<NetworkEndian>(scale)?;
109        for digit in digits.iter() {
110            out.write_i16::<NetworkEndian>(*digit)?;
111        }
112
113        Ok(IsNull::No)
114    }
115}
116
117#[cfg(feature = "postgres_backend")]
118impl Defaultable for PgNumeric {
119    fn default_value() -> Self {
120        Self::default()
121    }
122}
123
124#[cfg(feature = "postgres_backend")]
125impl FromSql<sql_types::Float, Pg> for f32 {
126    fn from_sql(value: PgValue<'_>) -> deserialize::Result<Self> {
127        let mut bytes = value.as_bytes();
128
129        if bytes.len() < 4 {
130            return deserialize::Result::Err(
131                "Received less than 4 bytes while decoding an f32. \
132                 Was a numeric accidentally marked as float?"
133                    .into(),
134            );
135        }
136
137        if bytes.len() > 4 {
138            return deserialize::Result::Err(
139                "Received more than 4 bytes while decoding an f32. \
140                 Was a double accidentally marked as float?"
141                    .into(),
142            );
143        }
144
145        bytes
146            .read_f32::<NetworkEndian>()
147            .map_err(|e| Box::new(e) as Box<dyn Error + Send + Sync>)
148    }
149}
150
151#[cfg(feature = "postgres_backend")]
152impl FromSql<sql_types::Double, Pg> for f64 {
153    fn from_sql(value: PgValue<'_>) -> deserialize::Result<Self> {
154        let mut bytes = value.as_bytes();
155
156        if bytes.len() < 8 {
157            return deserialize::Result::Err(
158                "Received less than 8 bytes while decoding an f64. \
159                    Was a float accidentally marked as double?"
160                    .into(),
161            );
162        }
163
164        if bytes.len() > 8 {
165            return deserialize::Result::Err(
166                "Received more than 8 bytes while decoding an f64. \
167                    Was a numeric accidentally marked as double?"
168                    .into(),
169            );
170        }
171
172        bytes
173            .read_f64::<NetworkEndian>()
174            .map_err(|e| Box::new(e) as Box<dyn Error + Send + Sync>)
175    }
176}
177
178#[cfg(feature = "postgres_backend")]
179impl ToSql<sql_types::Float, Pg> for f32 {
180    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
181        out.write_f32::<NetworkEndian>(*self)
182            .map(|_| IsNull::No)
183            .map_err(|e| Box::new(e) as Box<dyn Error + Send + Sync>)
184    }
185}
186
187#[cfg(feature = "postgres_backend")]
188impl ToSql<sql_types::Double, Pg> for f64 {
189    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
190        out.write_f64::<NetworkEndian>(*self)
191            .map(|_| IsNull::No)
192            .map_err(|e| Box::new(e) as Box<dyn Error + Send + Sync>)
193    }
194}
diesel/pg/types/floats/mod.rs

diesel/pg/types/floats/
mod.rs
