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Diffstat (limited to 'src/utils.rs')
| -rw-r--r-- | src/utils.rs | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/src/utils.rs b/src/utils.rs new file mode 100644 index 0000000..7371d1c --- /dev/null +++ b/src/utils.rs @@ -0,0 +1,132 @@ +use crate::{DeserializeResult, DeserializeErr, Deserialized}; + +#[inline] +pub fn read_one_byte(data: &[u8]) -> DeserializeResult<u8> { + match data.split_first() { + Some((byte, rest)) => Deserialized::ok(*byte, rest), + None => Err(DeserializeErr::Eof) + } +} + +#[inline] +pub const fn take(amount: usize) -> impl for<'b> Fn(&'b [u8]) -> DeserializeResult<'b, &'b [u8]> { + move |data| { + if data.len() < amount { + Err(DeserializeErr::Eof) + } else { + Ok(data.split_at(amount).into()) + } + } +} + +#[inline] +pub fn read_long(data: &[u8]) -> DeserializeResult<u64> { + Ok(take(8)(data)?.map(move |bytes| { + (bytes[0] as u64) << 56 | + (bytes[1] as u64) << 48 | + (bytes[2] as u64) << 40 | + (bytes[3] as u64) << 32 | + (bytes[4] as u64) << 24 | + (bytes[5] as u64) << 16 | + (bytes[6] as u64) << 8 | + (bytes[7] as u64) + })) +} + +#[inline] +pub fn write_long(v: u64) -> [u8; 8] { + [ + (v >> 56) as u8, + (v >> 48) as u8, + (v >> 40) as u8, + (v >> 32) as u8, + (v >> 24) as u8, + (v >> 16) as u8, + (v >> 8) as u8, + v as u8, + ] +} + +#[inline] +pub fn read_int(data: &[u8]) -> DeserializeResult<u32> { + Ok(take(4)(data)?.map(move |bytes| { + (bytes[0] as u32) << 24 | + (bytes[1] as u32) << 16 | + (bytes[2] as u32) << 8 | + (bytes[3] as u32) + })) +} + +#[inline] +pub fn write_int(v: u32) -> [u8; 4] { + [(v >> 24) as u8, (v >> 16) as u8, (v >> 8) as u8, v as u8] +} + +#[inline] +pub fn read_short(data: &[u8]) -> DeserializeResult<u16> { + Ok(take(2)(data)?.map(move |bytes| { + (bytes[0] as u16) << 8 | (bytes[1] as u16) + })) +} + +#[inline] +pub fn write_short(v: u16) -> [u8; 2] { + [(v >> 8) as u8, v as u8] +} + +#[inline] +pub fn hex(data: &[u8]) -> String { + let mut str = String::with_capacity(data.len() * 2); + for byte_ref in data { + let byte = *byte_ref; + str.push(hex_char_for(byte >> 4)); + str.push(hex_char_for(byte & 0xF)); + } + str +} + +const ZERO_ASCII_CODE: u8 = 48; +const LOWER_A_ASCII_CODE: u8 = 97; + +#[inline] +fn hex_char_for(half: u8) -> char { + if half > 0xF { + panic!("not defined for > 0xF (operates on half a byte)"); + } + + if half < 10 { + (half + ZERO_ASCII_CODE) as char + } else { + (half + (LOWER_A_ASCII_CODE - 10)) as char + } +} + +#[inline] +pub fn parse_hex_char(data: u8) -> Option<u8> { + const UPPER_A_ASCII_CODE: u8 = 65; + const LOWER_F_ASCII_CODE: u8 = 102; + const UPPER_F_ASCII_CODE: u8 = 70; + const NINE_ASCII_CODE: u8 = 57; + + if data >= LOWER_A_ASCII_CODE { + if data > LOWER_F_ASCII_CODE { + None + } else { + Some(10 + (data - LOWER_A_ASCII_CODE)) + } + } else if data >= UPPER_A_ASCII_CODE { + if data > UPPER_F_ASCII_CODE { + None + } else { + Some(10 + (data - UPPER_A_ASCII_CODE)) + } + } else if data >= ZERO_ASCII_CODE { + if data > NINE_ASCII_CODE { + None + } else { + Some(data - ZERO_ASCII_CODE) + } + } else { + None + } +}
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