hayro-syntax 0.4.0

//! Numbers.

use crate::object::macros::object;
use crate::object::{Object, ObjectLike};
use crate::reader::{Readable, Reader, ReaderContext, Skippable};
use log::debug;
use std::fmt::Debug;
use std::str::FromStr;

/// A number.
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct Number(pub(crate) InternalNumber);

impl Number {
    /// The number zero.
    pub const ZERO: Number = Number::from_i32(0);
    /// The number one.
    pub const ONE: Number = Number::from_i32(1);

    /// Returns the number as a f64.
    pub fn as_f64(&self) -> f64 {
        match self.0 {
            InternalNumber::Real(r) => r,
            InternalNumber::Integer(i) => i as f64,
        }
    }

    /// Returns the number as a f32.
    pub fn as_f32(&self) -> f32 {
        match self.0 {
            InternalNumber::Real(r) => r as f32,
            InternalNumber::Integer(i) => i as f32,
        }
    }

    /// Returns the number as an i64.
    pub fn as_i64(&self) -> i64 {
        match self.0 {
            InternalNumber::Real(r) => {
                let res = r as i64;

                if !(r.trunc() == r) {
                    debug!("float {r} was truncated to {res}");
                }

                res
            }
            InternalNumber::Integer(i) => i,
        }
    }

    /// Create a new `Number` from an f32 number.
    pub const fn from_f32(num: f32) -> Self {
        Self(InternalNumber::Real(num as f64))
    }

    /// Create a new `Number` from an i32 number.
    pub const fn from_i32(num: i32) -> Self {
        Self(InternalNumber::Integer(num as i64))
    }
}

impl Skippable for Number {
    fn skip(r: &mut Reader<'_>, _: bool) -> Option<()> {
        r.forward_if(|b| b == b'+' || b == b'-');

        // Some PDFs have weird trailing minuses, so try to accept those as well.
        match r.peek_byte()? {
            b'.' => {
                r.read_byte()?;
                r.forward_while_1(is_digit_or_minus)?;
            }

            b'0'..=b'9' | b'-' => {
                r.forward_while_1(is_digit_or_minus)?;
                if let Some(()) = r.forward_tag(b".") {
                    r.forward_while(is_digit_or_minus);
                }
            }
            _ => return None,
        }

        Some(())
    }
}

impl Readable<'_> for Number {
    fn read(r: &mut Reader<'_>, ctx: &ReaderContext) -> Option<Self> {
        // TODO: This function is probably the biggest bottleneck in content parsing, so
        // worth optimizing (i.e. reading the number directly from the bytes instead
        // of first parsing it to a number).

        let mut data = r.skip::<Number>(ctx.in_content_stream)?;
        // Some weird PDFs have trailing minus in the fraction of number, try to strip those.
        if let Some(idx) = data[1..].iter().position(|b| *b == b'-') {
            data = &data[..idx.saturating_sub(1)];
        }
        // We need to use f64 here, so that we can still parse a full `i32` without losing
        // precision.
        let num = f64::from_str(std::str::from_utf8(data).ok()?).ok()?;

        if num.fract() == 0.0 {
            Some(Number(InternalNumber::Integer(num as i64)))
        } else {
            Some(Number(InternalNumber::Real(num)))
        }
    }
}

object!(Number, Number);

#[derive(Clone, Copy, Debug, PartialEq)]
pub(crate) enum InternalNumber {
    Real(f64),
    Integer(i64),
}

macro_rules! int_num {
    ($i:ident) => {
        impl Skippable for $i {
            fn skip(r: &mut Reader<'_>, _: bool) -> Option<()> {
                r.forward_if(|b| b == b'+' || b == b'-');
                r.forward_while_1(is_digit)?;

                // We have a float instead of an integer.
                if r.peek_byte() == Some(b'.') {
                    return None;
                }

                Some(())
            }
        }

        impl<'a> Readable<'a> for $i {
            fn read(r: &mut Reader<'a>, ctx: &ReaderContext<'a>) -> Option<$i> {
                r.read::<Number>(ctx)
                    .map(|n| n.as_i64())
                    .and_then(|n| n.try_into().ok())
            }
        }

        impl TryFrom<Object<'_>> for $i {
            type Error = ();

            fn try_from(value: Object<'_>) -> std::result::Result<Self, Self::Error> {
                match value {
                    Object::Number(n) => n.as_i64().try_into().ok().ok_or(()),
                    _ => Err(()),
                }
            }
        }

        impl<'a> ObjectLike<'a> for $i {}
    };
}

int_num!(i32);
int_num!(i64);
int_num!(u32);
int_num!(u16);
int_num!(usize);
int_num!(u8);

impl Skippable for f32 {
    fn skip(r: &mut Reader<'_>, is_content_stream: bool) -> Option<()> {
        r.skip::<Number>(is_content_stream).map(|_| {})
    }
}

impl Readable<'_> for f32 {
    fn read(r: &mut Reader, _: &ReaderContext) -> Option<Self> {
        r.read_without_context::<Number>()
            .map(|n| n.as_f64() as f32)
    }
}

impl TryFrom<Object<'_>> for f32 {
    type Error = ();

    fn try_from(value: Object<'_>) -> Result<Self, Self::Error> {
        match value {
            Object::Number(n) => Ok(n.as_f64() as f32),
            _ => Err(()),
        }
    }
}

impl ObjectLike<'_> for f32 {}

impl Skippable for f64 {
    fn skip(r: &mut Reader<'_>, is_content_stream: bool) -> Option<()> {
        r.skip::<Number>(is_content_stream).map(|_| {})
    }
}

impl Readable<'_> for f64 {
    fn read(r: &mut Reader, _: &ReaderContext) -> Option<Self> {
        r.read_without_context::<Number>().map(|n| n.as_f64())
    }
}

impl TryFrom<Object<'_>> for f64 {
    type Error = ();

    fn try_from(value: Object<'_>) -> Result<Self, Self::Error> {
        match value {
            Object::Number(n) => Ok(n.as_f64()),
            _ => Err(()),
        }
    }
}

impl ObjectLike<'_> for f64 {}

pub(crate) fn is_digit(byte: u8) -> bool {
    byte.is_ascii_digit()
}

pub(crate) fn is_digit_or_minus(byte: u8) -> bool {
    is_digit(byte) || byte == b'-'
}

#[cfg(test)]
mod tests {
    use crate::object::Number;
    use crate::reader::Reader;

    #[test]
    fn int_1() {
        assert_eq!(
            Reader::new("0".as_bytes())
                .read_without_context::<i32>()
                .unwrap(),
            0
        );
    }

    #[test]
    fn int_3() {
        assert_eq!(
            Reader::new("+32".as_bytes())
                .read_without_context::<i32>()
                .unwrap(),
            32
        );
    }

    #[test]
    fn int_4() {
        assert_eq!(
            Reader::new("-32".as_bytes())
                .read_without_context::<i32>()
                .unwrap(),
            -32
        );
    }

    #[test]
    fn int_6() {
        assert_eq!(
            Reader::new("98349".as_bytes())
                .read_without_context::<i32>()
                .unwrap(),
            98349
        );
    }

    #[test]
    fn int_7() {
        assert_eq!(
            Reader::new("003245".as_bytes())
                .read_without_context::<i32>()
                .unwrap(),
            3245
        );
    }

    #[test]
    fn int_trailing() {
        assert_eq!(
            Reader::new("0abc".as_bytes())
                .read_without_context::<i32>()
                .unwrap(),
            0
        );
    }

    #[test]
    fn real_1() {
        assert_eq!(
            Reader::new("3".as_bytes())
                .read_without_context::<f32>()
                .unwrap(),
            3.0
        );
    }

    #[test]
    fn real_3() {
        assert_eq!(
            Reader::new("+32".as_bytes())
                .read_without_context::<f32>()
                .unwrap(),
            32.0
        );
    }

    #[test]
    fn real_4() {
        assert_eq!(
            Reader::new("-32".as_bytes())
                .read_without_context::<f32>()
                .unwrap(),
            -32.0
        );
    }

    #[test]
    fn real_5() {
        assert_eq!(
            Reader::new("-32.01".as_bytes())
                .read_without_context::<f32>()
                .unwrap(),
            -32.01
        );
    }

    #[test]
    fn real_6() {
        assert_eq!(
            Reader::new("-.345".as_bytes())
                .read_without_context::<f32>()
                .unwrap(),
            -0.345
        );
    }

    #[test]
    fn real_7() {
        assert_eq!(
            Reader::new("-.00143".as_bytes())
                .read_without_context::<f32>()
                .unwrap(),
            -0.00143
        );
    }

    #[test]
    fn real_8() {
        assert_eq!(
            Reader::new("-12.0013".as_bytes())
                .read_without_context::<f32>()
                .unwrap(),
            -12.0013
        );
    }

    #[test]
    fn real_9() {
        assert_eq!(
            Reader::new("98349.432534".as_bytes())
                .read_without_context::<f32>()
                .unwrap(),
            98_349.43
        );
    }

    #[test]
    fn real_10() {
        assert_eq!(
            Reader::new("-34534656.34".as_bytes())
                .read_without_context::<f32>()
                .unwrap(),
            -34534656.34
        );
    }

    #[test]
    fn real_trailing() {
        assert_eq!(
            Reader::new("0abc".as_bytes())
                .read_without_context::<f32>()
                .unwrap(),
            0.0
        );
    }

    #[test]
    fn real_failing() {
        assert!(
            Reader::new("+abc".as_bytes())
                .read_without_context::<f32>()
                .is_none()
        );
    }

    #[test]
    fn number_1() {
        assert_eq!(
            Reader::new("+32".as_bytes())
                .read_without_context::<Number>()
                .unwrap()
                .as_f64() as f32,
            32.0
        );
    }

    #[test]
    fn number_2() {
        assert_eq!(
            Reader::new("-32.01".as_bytes())
                .read_without_context::<Number>()
                .unwrap()
                .as_f64() as f32,
            -32.01
        );
    }

    #[test]
    fn number_3() {
        assert_eq!(
            Reader::new("-.345".as_bytes())
                .read_without_context::<Number>()
                .unwrap()
                .as_f64() as f32,
            -0.345
        );
    }

    #[test]
    fn large_number() {
        assert_eq!(
            Reader::new("38359922".as_bytes())
                .read_without_context::<Number>()
                .unwrap()
                .as_i64(),
            38359922
        );
    }

    #[test]
    fn large_number_2() {
        assert_eq!(
            Reader::new("4294966260".as_bytes())
                .read_without_context::<u32>()
                .unwrap(),
            4294966260
        );
    }
}