Function read_f64

nodedb-query/src/msgpack_scan/reader.rs:216–241

Read an f64 from the value at `offset`. Handles float32, float64, and all integer types (coerced to f64).

(buf: &[u8], offset: usize)

/// Read an f64 from the value at `offset`. Handles float32, float64,
/// and all integer types (coerced to f64).
pub fn read_f64(buf: &[u8], offset: usize) -> Option<f64> {
    let tag = get(buf, offset)?;
    match tag {
        // positive fixint
        0x00..=0x7f => Some(tag as f64),
        // negative fixint
        0xe0..=0xff => Some((tag as i8) as f64),
        FLOAT64 => {
            let bits = read_u64_be(buf, offset + 1)?;
            Some(f64::from_bits(bits))
        }
        FLOAT32 => {
            let bits = read_u32_be(buf, offset + 1)?;
            Some(f32::from_bits(bits) as f64)
        }
        UINT8 => Some(get(buf, offset + 1)? as f64),
        UINT16 => Some(read_u16_be(buf, offset + 1)? as f64),
        UINT32 => Some(read_u32_be(buf, offset + 1)? as f64),
        UINT64 => Some(read_u64_be(buf, offset + 1)? as f64),
        INT8 => Some(get(buf, offset + 1)? as i8 as f64),
        INT16 => Some(read_u16_be(buf, offset + 1)? as i16 as f64),
        INT32 => Some(read_u32_be(buf, offset + 1)? as i32 as f64),
        INT64 => Some(read_u64_be(buf, offset + 1)? as i64 as f64),
        _ => None,
    }
}

/// Read an i64 from the value at `offset`. Handles all integer types.
/// Floats return `None` — use `read_f64` for those.