81 lines
1.4 KiB
Go
81 lines
1.4 KiB
Go
package kafka
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import (
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"bytes"
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"encoding/binary"
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"hash/crc32"
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"sync"
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)
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func crc32OfMessage(magicByte int8, attributes int8, timestamp int64, key []byte, value []byte) uint32 {
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b := acquireCrc32Buffer()
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b.writeInt8(magicByte)
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b.writeInt8(attributes)
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if magicByte != 0 {
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b.writeInt64(timestamp)
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}
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b.writeBytes(key)
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b.writeBytes(value)
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sum := b.sum
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releaseCrc32Buffer(b)
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return sum
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}
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type crc32Buffer struct {
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sum uint32
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buf bytes.Buffer
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}
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func (c *crc32Buffer) writeInt8(i int8) {
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c.buf.Truncate(0)
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c.buf.WriteByte(byte(i))
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c.update()
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}
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func (c *crc32Buffer) writeInt32(i int32) {
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a := [4]byte{}
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binary.BigEndian.PutUint32(a[:], uint32(i))
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c.buf.Truncate(0)
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c.buf.Write(a[:])
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c.update()
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}
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func (c *crc32Buffer) writeInt64(i int64) {
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a := [8]byte{}
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binary.BigEndian.PutUint64(a[:], uint64(i))
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c.buf.Truncate(0)
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c.buf.Write(a[:])
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c.update()
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}
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func (c *crc32Buffer) writeBytes(b []byte) {
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if b == nil {
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c.writeInt32(-1)
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} else {
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c.writeInt32(int32(len(b)))
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}
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c.sum = crc32Update(c.sum, b)
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}
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func (c *crc32Buffer) update() {
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c.sum = crc32Update(c.sum, c.buf.Bytes())
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}
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func crc32Update(sum uint32, b []byte) uint32 {
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return crc32.Update(sum, crc32.IEEETable, b)
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}
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var crc32BufferPool = sync.Pool{
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New: func() interface{} { return &crc32Buffer{} },
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}
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func acquireCrc32Buffer() *crc32Buffer {
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c := crc32BufferPool.Get().(*crc32Buffer)
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c.sum = 0
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return c
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}
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func releaseCrc32Buffer(b *crc32Buffer) {
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crc32BufferPool.Put(b)
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}
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