William Kurkian | ea86948 | 2019-04-09 15:16:11 -0400 | [diff] [blame] | 1 | package sarama |
| 2 | |
| 3 | import ( |
| 4 | "encoding/binary" |
| 5 | "fmt" |
| 6 | "hash/crc32" |
Abhilash S.L | 3b49463 | 2019-07-16 15:51:09 +0530 | [diff] [blame] | 7 | "sync" |
William Kurkian | ea86948 | 2019-04-09 15:16:11 -0400 | [diff] [blame] | 8 | ) |
| 9 | |
| 10 | type crcPolynomial int8 |
| 11 | |
| 12 | const ( |
| 13 | crcIEEE crcPolynomial = iota |
| 14 | crcCastagnoli |
| 15 | ) |
| 16 | |
Abhilash S.L | 3b49463 | 2019-07-16 15:51:09 +0530 | [diff] [blame] | 17 | var crc32FieldPool = sync.Pool{} |
| 18 | |
| 19 | func acquireCrc32Field(polynomial crcPolynomial) *crc32Field { |
| 20 | val := crc32FieldPool.Get() |
| 21 | if val != nil { |
| 22 | c := val.(*crc32Field) |
| 23 | c.polynomial = polynomial |
| 24 | return c |
| 25 | } |
| 26 | return newCRC32Field(polynomial) |
| 27 | } |
| 28 | |
| 29 | func releaseCrc32Field(c *crc32Field) { |
| 30 | crc32FieldPool.Put(c) |
| 31 | } |
| 32 | |
William Kurkian | ea86948 | 2019-04-09 15:16:11 -0400 | [diff] [blame] | 33 | var castagnoliTable = crc32.MakeTable(crc32.Castagnoli) |
| 34 | |
| 35 | // crc32Field implements the pushEncoder and pushDecoder interfaces for calculating CRC32s. |
| 36 | type crc32Field struct { |
| 37 | startOffset int |
| 38 | polynomial crcPolynomial |
| 39 | } |
| 40 | |
| 41 | func (c *crc32Field) saveOffset(in int) { |
| 42 | c.startOffset = in |
| 43 | } |
| 44 | |
| 45 | func (c *crc32Field) reserveLength() int { |
| 46 | return 4 |
| 47 | } |
| 48 | |
| 49 | func newCRC32Field(polynomial crcPolynomial) *crc32Field { |
| 50 | return &crc32Field{polynomial: polynomial} |
| 51 | } |
| 52 | |
| 53 | func (c *crc32Field) run(curOffset int, buf []byte) error { |
| 54 | crc, err := c.crc(curOffset, buf) |
| 55 | if err != nil { |
| 56 | return err |
| 57 | } |
| 58 | binary.BigEndian.PutUint32(buf[c.startOffset:], crc) |
| 59 | return nil |
| 60 | } |
| 61 | |
| 62 | func (c *crc32Field) check(curOffset int, buf []byte) error { |
| 63 | crc, err := c.crc(curOffset, buf) |
| 64 | if err != nil { |
| 65 | return err |
| 66 | } |
| 67 | |
| 68 | expected := binary.BigEndian.Uint32(buf[c.startOffset:]) |
| 69 | if crc != expected { |
| 70 | return PacketDecodingError{fmt.Sprintf("CRC didn't match expected %#x got %#x", expected, crc)} |
| 71 | } |
| 72 | |
| 73 | return nil |
| 74 | } |
| 75 | func (c *crc32Field) crc(curOffset int, buf []byte) (uint32, error) { |
| 76 | var tab *crc32.Table |
| 77 | switch c.polynomial { |
| 78 | case crcIEEE: |
| 79 | tab = crc32.IEEETable |
| 80 | case crcCastagnoli: |
| 81 | tab = castagnoliTable |
| 82 | default: |
| 83 | return 0, PacketDecodingError{"invalid CRC type"} |
| 84 | } |
| 85 | return crc32.Checksum(buf[c.startOffset+4:curOffset], tab), nil |
| 86 | } |