diesel/pg/types/floats/
mod.rs

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1use crate::deserialize::{self, 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, 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    NaN,
37}
38
39#[derive(Debug, Clone, Copy)]
40#[allow(dead_code)] // that's used by debug in the error impl
41struct InvalidNumericSign(u16);
42
43impl ::std::fmt::Display for InvalidNumericSign {
44    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> ::std::fmt::Result {
45        f.write_str("sign for numeric field was not one of 0, 0x4000, 0xC000")
46    }
47}
48
49impl Error for InvalidNumericSign {}
50
51#[cfg(feature = "postgres_backend")]
52impl FromSql<sql_types::Numeric, Pg> for PgNumeric {
53    fn from_sql(bytes: PgValue<'_>) -> deserialize::Result<Self> {
54        let mut bytes = bytes.as_bytes();
55        let digit_count = bytes.read_u16::<NetworkEndian>()?;
56        let mut digits = Vec::with_capacity(digit_count as usize);
57        let weight = bytes.read_i16::<NetworkEndian>()?;
58        let sign = bytes.read_u16::<NetworkEndian>()?;
59        let scale = bytes.read_u16::<NetworkEndian>()?;
60        for _ in 0..digit_count {
61            digits.push(bytes.read_i16::<NetworkEndian>()?);
62        }
63
64        match sign {
65            0 => Ok(PgNumeric::Positive {
66                weight,
67                scale,
68                digits,
69            }),
70            0x4000 => Ok(PgNumeric::Negative {
71                weight,
72                scale,
73                digits,
74            }),
75            0xC000 => Ok(PgNumeric::NaN),
76            invalid => Err(Box::new(InvalidNumericSign(invalid))),
77        }
78    }
79}
80
81#[cfg(feature = "postgres_backend")]
82impl ToSql<sql_types::Numeric, Pg> for PgNumeric {
83    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
84        let sign = match *self {
85            PgNumeric::Positive { .. } => 0,
86            PgNumeric::Negative { .. } => 0x4000,
87            PgNumeric::NaN => 0xC000,
88        };
89        let empty_vec = Vec::new();
90        let digits = match *self {
91            PgNumeric::Positive { ref digits, .. } | PgNumeric::Negative { ref digits, .. } => {
92                digits
93            }
94            PgNumeric::NaN => &empty_vec,
95        };
96        let weight = match *self {
97            PgNumeric::Positive { weight, .. } | PgNumeric::Negative { weight, .. } => weight,
98            PgNumeric::NaN => 0,
99        };
100        let scale = match *self {
101            PgNumeric::Positive { scale, .. } | PgNumeric::Negative { scale, .. } => scale,
102            PgNumeric::NaN => 0,
103        };
104        out.write_u16::<NetworkEndian>(digits.len().try_into()?)?;
105        out.write_i16::<NetworkEndian>(weight)?;
106        out.write_u16::<NetworkEndian>(sign)?;
107        out.write_u16::<NetworkEndian>(scale)?;
108        for digit in digits.iter() {
109            out.write_i16::<NetworkEndian>(*digit)?;
110        }
111
112        Ok(IsNull::No)
113    }
114}
115
116#[cfg(feature = "postgres_backend")]
117impl FromSql<sql_types::Float, Pg> for f32 {
118    fn from_sql(value: PgValue<'_>) -> deserialize::Result<Self> {
119        let mut bytes = value.as_bytes();
120
121        if bytes.len() < 4 {
122            return deserialize::Result::Err(
123                "Received less than 4 bytes while decoding an f32. \
124                 Was a numeric accidentally marked as float?"
125                    .into(),
126            );
127        }
128
129        if bytes.len() > 4 {
130            return deserialize::Result::Err(
131                "Received more than 4 bytes while decoding an f32. \
132                 Was a double accidentally marked as float?"
133                    .into(),
134            );
135        }
136
137        bytes
138            .read_f32::<NetworkEndian>()
139            .map_err(|e| Box::new(e) as Box<dyn Error + Send + Sync>)
140    }
141}
142
143#[cfg(feature = "postgres_backend")]
144impl FromSql<sql_types::Double, Pg> for f64 {
145    fn from_sql(value: PgValue<'_>) -> deserialize::Result<Self> {
146        let mut bytes = value.as_bytes();
147
148        if bytes.len() < 8 {
149            return deserialize::Result::Err(
150                "Received less than 8 bytes while decoding an f64. \
151                    Was a float accidentally marked as double?"
152                    .into(),
153            );
154        }
155
156        if bytes.len() > 8 {
157            return deserialize::Result::Err(
158                "Received more than 8 bytes while decoding an f64. \
159                    Was a numeric accidentally marked as double?"
160                    .into(),
161            );
162        }
163
164        bytes
165            .read_f64::<NetworkEndian>()
166            .map_err(|e| Box::new(e) as Box<dyn Error + Send + Sync>)
167    }
168}
169
170#[cfg(feature = "postgres_backend")]
171impl ToSql<sql_types::Float, Pg> for f32 {
172    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
173        out.write_f32::<NetworkEndian>(*self)
174            .map(|_| IsNull::No)
175            .map_err(|e| Box::new(e) as Box<dyn Error + Send + Sync>)
176    }
177}
178
179#[cfg(feature = "postgres_backend")]
180impl ToSql<sql_types::Double, Pg> for f64 {
181    fn to_sql<'b>(&'b self, out: &mut Output<'b, '_, Pg>) -> serialize::Result {
182        out.write_f64::<NetworkEndian>(*self)
183            .map(|_| IsNull::No)
184            .map_err(|e| Box::new(e) as Box<dyn Error + Send + Sync>)
185    }
186}
diesel/pg/types/floats/mod.rs

diesel/pg/types/floats/
mod.rs
