/*
 * Copyright 2015 Cloudius Systems
 */

#pragma once

#include <cstdint>
#include <smmintrin.h>

class crc32 {
    uint32_t _r = 0;
public:
    // All process() functions assume input is in
    // host byte order (i.e. equivalent to storing
    // the value in a buffer and crcing the buffer).
    void process(int8_t in) {
        _r = _mm_crc32_u8(_r, in);
    }
    void process(uint8_t in) {
        _r = _mm_crc32_u8(_r, in);
    }
    void process(int16_t in) {
        _r = _mm_crc32_u16(_r, in);
    }
    void process(uint16_t in) {
        _r = _mm_crc32_u16(_r, in);
    }
    void process(int32_t in) {
        _r = _mm_crc32_u32(_r, in);
    }
    void process(uint32_t in) {
        _r = _mm_crc32_u32(_r, in);
    }
    void process(int64_t in) {
        _r = _mm_crc32_u64(_r, in);
    }
    void process(uint64_t in) {
        _r = _mm_crc32_u64(_r, in);
    }
    void process(const uint8_t* in, size_t size) {
        if ((reinterpret_cast<uintptr_t>(in) & 1) && size >= 1) {
            process(*in);
            ++in;
            --size;
        }
        if ((reinterpret_cast<uintptr_t>(in) & 3) && size >= 2) {
            process(*reinterpret_cast<const uint16_t*>(in));
            in += 2;
            size -= 2;
        }
        if ((reinterpret_cast<uintptr_t>(in) & 7) && size >= 4) {
            process(*reinterpret_cast<const uint32_t*>(in));
            in += 4;
            size -= 4;
        }
        // FIXME: do in three parallel loops
        while (size >= 8) {
            process(*reinterpret_cast<const uint64_t*>(in));
            in += 8;
            size -= 8;
        }
        if (size >= 4) {
            process(*reinterpret_cast<const uint32_t*>(in));
            in += 4;
            size -= 4;
        }
        if (size >= 2) {
            process(*reinterpret_cast<const uint16_t*>(in));
            in += 2;
            size -= 2;
        }
        if (size >= 1) {
            process(*in);
        }

    }
    uint32_t get() const {
        return _r;
    }
};