macHash() — netty Function Reference

Architecture documentation for the macHash() function in SipHash.java from the netty codebase.

Function java Buffer Allocators calls 1

Entity Profile

Buffer→ Allocators→ macHash() — netty Function Reference

Dependency Diagram

graph TD
  901f01bc_21b3_69fb_38c8_2e3a75334e00["macHash()"]
  32c45fc1_8885_8768_58c7_65f5ff579eb7["SipHash"]
  901f01bc_21b3_69fb_38c8_2e3a75334e00 -->|defined in| 32c45fc1_8885_8768_58c7_65f5ff579eb7
  62ea4b31_3219_5aab_2cc2_04bbec862c0a["sipround()"]
  901f01bc_21b3_69fb_38c8_2e3a75334e00 -->|calls| 62ea4b31_3219_5aab_2cc2_04bbec862c0a
  style 901f01bc_21b3_69fb_38c8_2e3a75334e00 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

codec-classes-quic/src/main/java/io/netty/handler/codec/quic/SipHash.java lines 69–129

    long macHash(ByteBuffer input) {
        v0 = initialStateV0;
        v1 = initialStateV1;
        v2 = initialStateV2;
        v3 = initialStateV3;
        int remaining = input.remaining();
        int position = input.position();
        int len = remaining - (remaining % Long.BYTES);
        boolean needsReverse = input.order() == ByteOrder.BIG_ENDIAN;
        for (int offset = position; offset < len; offset +=  Long.BYTES) {
            long m = input.getLong(offset);
            if (needsReverse) {
                // We use little-endian as in the paper.
                m = Long.reverseBytes(m);
            }
            v3 ^= m;
            for (int i = 0; i < compressionRounds; i++) {
                sipround();
            }
            v0 ^= m;
        }

        // Get last bits.
        final int left = remaining & (Long.BYTES - 1);
        long b = (long) remaining << 56;
        assert left < Long.BYTES;
        switch (left) {
            case 7:
                b |= (long) input.get(position + len + 6) << 48;
            case 6:
                b |= (long) input.get(position + len + 5) << 40;
            case 5:
                b |= (long) input.get(position + len + 4) << 32;
            case 4:
                b |= (long) input.get(position + len + 3) << 24;
            case 3:
                b |= (long) input.get(position + len + 2) << 16;
            case 2:
                b |= (long) input.get(position + len + 1) << 8;
            case 1:
                b |= input.get(position + len);
                break;
            case 0:
                break;
            default:
                throw new IllegalStateException("Unexpected value: " + left);
        }

        v3 ^= b;
        for (int i = 0; i < compressionRounds; i++) {
            sipround();
        }

        v0 ^= b;
        v2 ^= 0xFF;
        for (int i = 0; i < finalizationRounds; i++) {
            sipround();
        }

        return v0 ^ v1 ^ v2 ^ v3;
    }