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Reorganize mysql encoding functions

This commit is contained in:
Gregory Eremin 2018-11-08 20:46:10 +01:00
parent 747d978171
commit 3a59fc8e53
1 changed files with 24 additions and 6 deletions
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30
mysql/encoding.go → mysql/binary.go
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@ -43,7 +43,7 @@ func EncodeUint24(data []byte, v uint32) {
// DecodeUint24 decodes 3 bytes as uint32 value from a given slice of bytes. // DecodeUint24 decodes 3 bytes as uint32 value from a given slice of bytes.
func DecodeUint24(data []byte) uint32 { func DecodeUint24(data []byte) uint32 {
return uint32(decodeVarLen64(data, 3)) return uint32(DecodeVarLen64(data, 3))
} }
// int<4> // int<4>
@ -68,7 +68,7 @@ func EncodeUint48(data []byte, v uint64) {
// DecodeUint48 decodes 6 bytes as uint64 value from a given slice of bytes. // DecodeUint48 decodes 6 bytes as uint64 value from a given slice of bytes.
func DecodeUint48(data []byte) uint64 { func DecodeUint48(data []byte) uint64 {
return decodeVarLen64(data, 6) return DecodeVarLen64(data, 6)
} }
// int<8> // int<8>
@ -140,11 +140,11 @@ func DecodeUintLenEnc(data []byte) (v uint64, isNull bool, size int) {
case 0xFB: case 0xFB:
return 0xFB, true, 1 return 0xFB, true, 1
case 0xFC: case 0xFC:
return decodeVarLen64(data[1:], 2), false, 3 return DecodeVarLen64(data[1:], 2), false, 3
case 0xFD: case 0xFD:
return decodeVarLen64(data[1:], 3), false, 4 return DecodeVarLen64(data[1:], 3), false, 4
case 0xFE: case 0xFE:
return decodeVarLen64(data[1:], 8), false, 9 return DecodeVarLen64(data[1:], 8), false, 9
default: default:
return uint64(data[0]), false, 1 return uint64(data[0]), false, 1
} }
@ -160,7 +160,8 @@ func encodeVarLen64(data []byte, v uint64, s int) {
} }
} }
func decodeVarLen64(data []byte, s int) uint64 { // DecodeVarLen64 decodes a number of given size in bytes using Little Endian.
func DecodeVarLen64(data []byte, s int) uint64 {
v := uint64(data[0]) v := uint64(data[0])
for i := 1; i < s; i++ { for i := 1; i < s; i++ {
v |= uint64(data[i]) << uint(i*8) v |= uint64(data[i]) << uint(i*8)
@ -168,6 +169,15 @@ func decodeVarLen64(data []byte, s int) uint64 {
return v return v
} }
// DecodeVarLen64BigEndian decodes a number of given size in bytes using Big Endian.
func DecodeVarLen64BigEndian(data []byte) uint64 {
var num uint64
for i, b := range data {
num |= uint64(b) << (uint(len(data)-i-1) * 8)
}
return num
}
// Protocol::NulTerminatedString // Protocol::NulTerminatedString
// Strings that are terminated by a 0x00 byte. // Strings that are terminated by a 0x00 byte.
// Spec: https://dev.mysql.com/doc/internals/en/string.html // Spec: https://dev.mysql.com/doc/internals/en/string.html
@ -232,3 +242,11 @@ func DecodeStringEOF(data []byte) []byte {
copy(s, data) copy(s, data)
return s return s
} }
// DecodeBit decodes a bit into not less than 8 bytes.
func DecodeBit(data []byte, nbits int, length int) uint64 {
if nbits > 1 {
return DecodeVarLen64(data, length)
}
return uint64(data[0])
}