libflate 0.1.11

use std::fmt;
use adler32::RollingAdler32;

pub struct Adler32(RollingAdler32);
impl Adler32 {
    pub fn new() -> Self {
        Adler32(RollingAdler32::new())
    }
    pub fn value(&self) -> u32 {
        self.0.hash()
    }
    pub fn update(&mut self, buf: &[u8]) {
        self.0.update_buffer(buf);
    }
}
impl fmt::Debug for Adler32 {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "Adler32(_)")
    }
}

#[derive(Debug, Clone)]
pub struct Crc32 {
    value: u32,
}
impl Crc32 {
    pub fn new() -> Self {
        Crc32 { value: 0 }
    }
    pub fn value(&self) -> u32 {
        self.value
    }
    pub fn update(&mut self, buf: &[u8]) {
        let c = buf.iter().fold(!self.value, |c, &b| {
            let i = (c ^ b as u32) as u8 as usize;
            (unsafe { *CRC32_TABLE.get_unchecked(i) }) ^ (c >> 8)
        });
        self.value = !c;
    }
}

/// See the second appendix of [RFC-1952](https://tools.ietf.org/html/rfc1952).
const CRC32_TABLE: [u32; 256] = [
    0x0,
    0x77073096,
    0xEE0E612C,
    0x990951BA,
    0x76DC419,
    0x706AF48F,
    0xE963A535,
    0x9E6495A3,
    0xEDB8832,
    0x79DCB8A4,
    0xE0D5E91E,
    0x97D2D988,
    0x9B64C2B,
    0x7EB17CBD,
    0xE7B82D07,
    0x90BF1D91,
    0x1DB71064,
    0x6AB020F2,
    0xF3B97148,
    0x84BE41DE,
    0x1ADAD47D,
    0x6DDDE4EB,
    0xF4D4B551,
    0x83D385C7,
    0x136C9856,
    0x646BA8C0,
    0xFD62F97A,
    0x8A65C9EC,
    0x14015C4F,
    0x63066CD9,
    0xFA0F3D63,
    0x8D080DF5,
    0x3B6E20C8,
    0x4C69105E,
    0xD56041E4,
    0xA2677172,
    0x3C03E4D1,
    0x4B04D447,
    0xD20D85FD,
    0xA50AB56B,
    0x35B5A8FA,
    0x42B2986C,
    0xDBBBC9D6,
    0xACBCF940,
    0x32D86CE3,
    0x45DF5C75,
    0xDCD60DCF,
    0xABD13D59,
    0x26D930AC,
    0x51DE003A,
    0xC8D75180,
    0xBFD06116,
    0x21B4F4B5,
    0x56B3C423,
    0xCFBA9599,
    0xB8BDA50F,
    0x2802B89E,
    0x5F058808,
    0xC60CD9B2,
    0xB10BE924,
    0x2F6F7C87,
    0x58684C11,
    0xC1611DAB,
    0xB6662D3D,
    0x76DC4190,
    0x1DB7106,
    0x98D220BC,
    0xEFD5102A,
    0x71B18589,
    0x6B6B51F,
    0x9FBFE4A5,
    0xE8B8D433,
    0x7807C9A2,
    0xF00F934,
    0x9609A88E,
    0xE10E9818,
    0x7F6A0DBB,
    0x86D3D2D,
    0x91646C97,
    0xE6635C01,
    0x6B6B51F4,
    0x1C6C6162,
    0x856530D8,
    0xF262004E,
    0x6C0695ED,
    0x1B01A57B,
    0x8208F4C1,
    0xF50FC457,
    0x65B0D9C6,
    0x12B7E950,
    0x8BBEB8EA,
    0xFCB9887C,
    0x62DD1DDF,
    0x15DA2D49,
    0x8CD37CF3,
    0xFBD44C65,
    0x4DB26158,
    0x3AB551CE,
    0xA3BC0074,
    0xD4BB30E2,
    0x4ADFA541,
    0x3DD895D7,
    0xA4D1C46D,
    0xD3D6F4FB,
    0x4369E96A,
    0x346ED9FC,
    0xAD678846,
    0xDA60B8D0,
    0x44042D73,
    0x33031DE5,
    0xAA0A4C5F,
    0xDD0D7CC9,
    0x5005713C,
    0x270241AA,
    0xBE0B1010,
    0xC90C2086,
    0x5768B525,
    0x206F85B3,
    0xB966D409,
    0xCE61E49F,
    0x5EDEF90E,
    0x29D9C998,
    0xB0D09822,
    0xC7D7A8B4,
    0x59B33D17,
    0x2EB40D81,
    0xB7BD5C3B,
    0xC0BA6CAD,
    0xEDB88320,
    0x9ABFB3B6,
    0x3B6E20C,
    0x74B1D29A,
    0xEAD54739,
    0x9DD277AF,
    0x4DB2615,
    0x73DC1683,
    0xE3630B12,
    0x94643B84,
    0xD6D6A3E,
    0x7A6A5AA8,
    0xE40ECF0B,
    0x9309FF9D,
    0xA00AE27,
    0x7D079EB1,
    0xF00F9344,
    0x8708A3D2,
    0x1E01F268,
    0x6906C2FE,
    0xF762575D,
    0x806567CB,
    0x196C3671,
    0x6E6B06E7,
    0xFED41B76,
    0x89D32BE0,
    0x10DA7A5A,
    0x67DD4ACC,
    0xF9B9DF6F,
    0x8EBEEFF9,
    0x17B7BE43,
    0x60B08ED5,
    0xD6D6A3E8,
    0xA1D1937E,
    0x38D8C2C4,
    0x4FDFF252,
    0xD1BB67F1,
    0xA6BC5767,
    0x3FB506DD,
    0x48B2364B,
    0xD80D2BDA,
    0xAF0A1B4C,
    0x36034AF6,
    0x41047A60,
    0xDF60EFC3,
    0xA867DF55,
    0x316E8EEF,
    0x4669BE79,
    0xCB61B38C,
    0xBC66831A,
    0x256FD2A0,
    0x5268E236,
    0xCC0C7795,
    0xBB0B4703,
    0x220216B9,
    0x5505262F,
    0xC5BA3BBE,
    0xB2BD0B28,
    0x2BB45A92,
    0x5CB36A04,
    0xC2D7FFA7,
    0xB5D0CF31,
    0x2CD99E8B,
    0x5BDEAE1D,
    0x9B64C2B0,
    0xEC63F226,
    0x756AA39C,
    0x26D930A,
    0x9C0906A9,
    0xEB0E363F,
    0x72076785,
    0x5005713,
    0x95BF4A82,
    0xE2B87A14,
    0x7BB12BAE,
    0xCB61B38,
    0x92D28E9B,
    0xE5D5BE0D,
    0x7CDCEFB7,
    0xBDBDF21,
    0x86D3D2D4,
    0xF1D4E242,
    0x68DDB3F8,
    0x1FDA836E,
    0x81BE16CD,
    0xF6B9265B,
    0x6FB077E1,
    0x18B74777,
    0x88085AE6,
    0xFF0F6A70,
    0x66063BCA,
    0x11010B5C,
    0x8F659EFF,
    0xF862AE69,
    0x616BFFD3,
    0x166CCF45,
    0xA00AE278,
    0xD70DD2EE,
    0x4E048354,
    0x3903B3C2,
    0xA7672661,
    0xD06016F7,
    0x4969474D,
    0x3E6E77DB,
    0xAED16A4A,
    0xD9D65ADC,
    0x40DF0B66,
    0x37D83BF0,
    0xA9BCAE53,
    0xDEBB9EC5,
    0x47B2CF7F,
    0x30B5FFE9,
    0xBDBDF21C,
    0xCABAC28A,
    0x53B39330,
    0x24B4A3A6,
    0xBAD03605,
    0xCDD70693,
    0x54DE5729,
    0x23D967BF,
    0xB3667A2E,
    0xC4614AB8,
    0x5D681B02,
    0x2A6F2B94,
    0xB40BBE37,
    0xC30C8EA1,
    0x5A05DF1B,
    0x2D02EF8D,
];

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn crc32_works() {
        let mut crc32 = Crc32::new();
        crc32.update(b"abcde");
        assert_eq!(crc32.value(), 0x8587D865);
    }

    #[test]
    fn adler32_works() {
        let mut adler32 = Adler32::new();
        adler32.update(b"abcde");
        assert_eq!(adler32.value(), 0x05C801F0);
    }
}