lib/encoding: remove uneeded re-slicing of byte slice before passing it to binary.BigEndian.Uint*

This commit is contained in:
Aliaksandr Valialkin 2024-01-23 22:50:11 +02:00
parent 1c58c00618
commit 8fb8b71295
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@ -12,9 +12,11 @@ func MarshalUint16(dst []byte, u uint16) []byte {
} }
// UnmarshalUint16 returns unmarshaled uint16 from src. // UnmarshalUint16 returns unmarshaled uint16 from src.
//
// the caller must ensure that len(src) >= 2
func UnmarshalUint16(src []byte) uint16 { func UnmarshalUint16(src []byte) uint16 {
// This is faster than the manual conversion. // This is faster than the manual conversion.
return binary.BigEndian.Uint16(src[:2]) return binary.BigEndian.Uint16(src)
} }
// MarshalUint32 appends marshaled v to dst and returns the result. // MarshalUint32 appends marshaled v to dst and returns the result.
@ -23,9 +25,11 @@ func MarshalUint32(dst []byte, u uint32) []byte {
} }
// UnmarshalUint32 returns unmarshaled uint32 from src. // UnmarshalUint32 returns unmarshaled uint32 from src.
//
// The caller must ensure than len(src) >= 4
func UnmarshalUint32(src []byte) uint32 { func UnmarshalUint32(src []byte) uint32 {
// This is faster than the manual conversion. // This is faster than the manual conversion.
return binary.BigEndian.Uint32(src[:4]) return binary.BigEndian.Uint32(src)
} }
// MarshalUint64 appends marshaled v to dst and returns the result. // MarshalUint64 appends marshaled v to dst and returns the result.
@ -34,9 +38,11 @@ func MarshalUint64(dst []byte, u uint64) []byte {
} }
// UnmarshalUint64 returns unmarshaled uint64 from src. // UnmarshalUint64 returns unmarshaled uint64 from src.
//
// The caller must ensure that len(src) >= 8
func UnmarshalUint64(src []byte) uint64 { func UnmarshalUint64(src []byte) uint64 {
// This is faster than the manual conversion. // This is faster than the manual conversion.
return binary.BigEndian.Uint64(src[:8]) return binary.BigEndian.Uint64(src)
} }
// MarshalInt16 appends marshaled v to dst and returns the result. // MarshalInt16 appends marshaled v to dst and returns the result.
@ -48,9 +54,11 @@ func MarshalInt16(dst []byte, v int16) []byte {
} }
// UnmarshalInt16 returns unmarshaled int16 from src. // UnmarshalInt16 returns unmarshaled int16 from src.
//
// The caller must ensure that len(src) >= 2
func UnmarshalInt16(src []byte) int16 { func UnmarshalInt16(src []byte) int16 {
// This is faster than the manual conversion. // This is faster than the manual conversion.
u := binary.BigEndian.Uint16(src[:2]) u := binary.BigEndian.Uint16(src)
v := int16(u>>1) ^ (int16(u<<15) >> 15) // zig-zag decoding without branching. v := int16(u>>1) ^ (int16(u<<15) >> 15) // zig-zag decoding without branching.
return v return v
} }
@ -64,9 +72,11 @@ func MarshalInt64(dst []byte, v int64) []byte {
} }
// UnmarshalInt64 returns unmarshaled int64 from src. // UnmarshalInt64 returns unmarshaled int64 from src.
//
// The caller must ensure that len(src) >= 8
func UnmarshalInt64(src []byte) int64 { func UnmarshalInt64(src []byte) int64 {
// This is faster than the manual conversion. // This is faster than the manual conversion.
u := binary.BigEndian.Uint64(src[:8]) u := binary.BigEndian.Uint64(src)
v := int64(u>>1) ^ (int64(u<<63) >> 63) // zig-zag decoding without branching. v := int64(u>>1) ^ (int64(u<<63) >> 63) // zig-zag decoding without branching.
return v return v
} }