mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
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4a3172f150
This allows Go complier to generate more optimal code without bound checks
298 lines
7.9 KiB
Go
298 lines
7.9 KiB
Go
package encoding
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import (
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"encoding/binary"
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"fmt"
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"sync"
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)
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// MarshalUint16 appends marshaled v to dst and returns the result.
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func MarshalUint16(dst []byte, u uint16) []byte {
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return append(dst, byte(u>>8), byte(u))
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}
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// UnmarshalUint16 returns unmarshaled uint32 from src.
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func UnmarshalUint16(src []byte) uint16 {
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// This is faster than the manual conversion.
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return binary.BigEndian.Uint16(src[:2])
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}
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// MarshalUint32 appends marshaled v to dst and returns the result.
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func MarshalUint32(dst []byte, u uint32) []byte {
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return append(dst, byte(u>>24), byte(u>>16), byte(u>>8), byte(u))
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}
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// UnmarshalUint32 returns unmarshaled uint32 from src.
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func UnmarshalUint32(src []byte) uint32 {
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// This is faster than the manual conversion.
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return binary.BigEndian.Uint32(src[:4])
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}
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// MarshalUint64 appends marshaled v to dst and returns the result.
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func MarshalUint64(dst []byte, u uint64) []byte {
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return append(dst, byte(u>>56), byte(u>>48), byte(u>>40), byte(u>>32), byte(u>>24), byte(u>>16), byte(u>>8), byte(u))
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}
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// UnmarshalUint64 returns unmarshaled uint64 from src.
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func UnmarshalUint64(src []byte) uint64 {
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// This is faster than the manual conversion.
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return binary.BigEndian.Uint64(src[:8])
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}
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// MarshalInt16 appends marshaled v to dst and returns the result.
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func MarshalInt16(dst []byte, v int16) []byte {
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// Such encoding for negative v must improve compression.
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v = (v << 1) ^ (v >> 15) // zig-zag encoding without branching.
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u := uint16(v)
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return append(dst, byte(u>>8), byte(u))
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}
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// UnmarshalInt16 returns unmarshaled int16 from src.
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func UnmarshalInt16(src []byte) int16 {
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// This is faster than the manual conversion.
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u := binary.BigEndian.Uint16(src[:2])
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v := int16(u>>1) ^ (int16(u<<15) >> 15) // zig-zag decoding without branching.
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return v
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}
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// MarshalInt64 appends marshaled v to dst and returns the result.
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func MarshalInt64(dst []byte, v int64) []byte {
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// Such encoding for negative v must improve compression.
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v = (v << 1) ^ (v >> 63) // zig-zag encoding without branching.
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u := uint64(v)
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return append(dst, byte(u>>56), byte(u>>48), byte(u>>40), byte(u>>32), byte(u>>24), byte(u>>16), byte(u>>8), byte(u))
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}
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// UnmarshalInt64 returns unmarshaled int64 from src.
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func UnmarshalInt64(src []byte) int64 {
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// This is faster than the manual conversion.
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u := binary.BigEndian.Uint64(src[:8])
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v := int64(u>>1) ^ (int64(u<<63) >> 63) // zig-zag decoding without branching.
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return v
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}
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// MarshalVarInt64 appends marshalsed v to dst and returns the result.
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func MarshalVarInt64(dst []byte, v int64) []byte {
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var tmp [1]int64
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tmp[0] = v
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return MarshalVarInt64s(dst, tmp[:])
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}
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// MarshalVarInt64s appends marshaled vs to dst and returns the result.
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func MarshalVarInt64s(dst []byte, vs []int64) []byte {
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for _, v := range vs {
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if v < 0x40 && v > -0x40 {
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// Fast path
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c := int8(v)
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v := (c << 1) ^ (c >> 7) // zig-zag encoding without branching.
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dst = append(dst, byte(v))
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continue
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}
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v = (v << 1) ^ (v >> 63) // zig-zag encoding without branching.
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u := uint64(v)
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for u > 0x7f {
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dst = append(dst, 0x80|byte(u))
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u >>= 7
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}
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dst = append(dst, byte(u))
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}
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return dst
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}
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// UnmarshalVarInt64 returns unmarshaled int64 from src and returns
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// the remaining tail from src.
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func UnmarshalVarInt64(src []byte) ([]byte, int64, error) {
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var tmp [1]int64
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tail, err := UnmarshalVarInt64s(tmp[:], src)
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return tail, tmp[0], err
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}
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// UnmarshalVarInt64s unmarshals len(dst) int64 values from src to dst
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// and returns the remaining tail from src.
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func UnmarshalVarInt64s(dst []int64, src []byte) ([]byte, error) {
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idx := uint(0)
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for i := range dst {
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if idx >= uint(len(src)) {
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return nil, fmt.Errorf("cannot unmarshal varint from empty data")
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}
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c := src[idx]
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idx++
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if c < 0x80 {
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// Fast path
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v := int8(c>>1) ^ (int8(c<<7) >> 7) // zig-zag decoding without branching.
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dst[i] = int64(v)
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continue
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}
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// Slow path
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u := uint64(c & 0x7f)
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startIdx := idx - 1
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shift := uint8(0)
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for c >= 0x80 {
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if idx >= uint(len(src)) {
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return nil, fmt.Errorf("unexpected end of encoded varint at byte %d; src=%x", idx-startIdx, src[startIdx:])
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}
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if idx-startIdx > 9 {
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return src[idx:], fmt.Errorf("too long encoded varint; the maximum allowed length is 10 bytes; got %d bytes; src=%x",
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(idx-startIdx)+1, src[startIdx:])
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}
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c = src[idx]
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idx++
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shift += 7
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u |= uint64(c&0x7f) << shift
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}
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v := int64(u>>1) ^ (int64(u<<63) >> 63) // zig-zag decoding without branching.
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dst[i] = v
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}
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return src[idx:], nil
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}
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// MarshalVarUint64 appends marshaled u to dst and returns the result.
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func MarshalVarUint64(dst []byte, u uint64) []byte {
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var tmp [1]uint64
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tmp[0] = u
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return MarshalVarUint64s(dst, tmp[:])
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}
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// MarshalVarUint64s appends marshaled us to dst and returns the result.
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func MarshalVarUint64s(dst []byte, us []uint64) []byte {
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for _, u := range us {
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if u < 0x80 {
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// Fast path
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dst = append(dst, byte(u))
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continue
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}
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for u > 0x7f {
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dst = append(dst, 0x80|byte(u))
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u >>= 7
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}
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dst = append(dst, byte(u))
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}
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return dst
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}
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// UnmarshalVarUint64 returns unmarshaled uint64 from src and returns
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// the remaining tail from src.
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func UnmarshalVarUint64(src []byte) ([]byte, uint64, error) {
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var tmp [1]uint64
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tail, err := UnmarshalVarUint64s(tmp[:], src)
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return tail, tmp[0], err
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}
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// UnmarshalVarUint64s unmarshals len(dst) uint64 values from src to dst
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// and returns the remaining tail from src.
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func UnmarshalVarUint64s(dst []uint64, src []byte) ([]byte, error) {
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idx := uint(0)
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for i := range dst {
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if idx >= uint(len(src)) {
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return nil, fmt.Errorf("cannot unmarshal varuint from empty data")
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}
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c := src[idx]
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idx++
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if c < 0x80 {
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// Fast path
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dst[i] = uint64(c)
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continue
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}
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// Slow path
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u := uint64(c & 0x7f)
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startIdx := idx - 1
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shift := uint8(0)
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for c >= 0x80 {
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if idx >= uint(len(src)) {
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return nil, fmt.Errorf("unexpected end of encoded varint at byte %d; src=%x", idx-startIdx, src[startIdx:])
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}
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if idx-startIdx > 9 {
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return src[idx:], fmt.Errorf("too long encoded varint; the maximum allowed length is 10 bytes; got %d bytes; src=%x",
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(idx-startIdx)+1, src[startIdx:])
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}
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c = src[idx]
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idx++
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shift += 7
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u |= uint64(c&0x7f) << shift
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}
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dst[i] = u
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}
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return src[idx:], nil
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}
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// MarshalBytes appends marshaled b to dst and returns the result.
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func MarshalBytes(dst, b []byte) []byte {
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dst = MarshalVarUint64(dst, uint64(len(b)))
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dst = append(dst, b...)
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return dst
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}
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// UnmarshalBytes returns unmarshaled bytes from src.
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func UnmarshalBytes(src []byte) ([]byte, []byte, error) {
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tail, n, err := UnmarshalVarUint64(src)
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if err != nil {
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return nil, nil, fmt.Errorf("cannot unmarshal string size: %w", err)
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}
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src = tail
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if uint64(len(src)) < n {
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return nil, nil, fmt.Errorf("src is too short for reading string with size %d; len(src)=%d", n, len(src))
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}
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return src[n:], src[:n], nil
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}
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// GetInt64s returns an int64 slice with the given size.
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// The slice contents isn't initialized - it may contain garbage.
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func GetInt64s(size int) *Int64s {
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v := int64sPool.Get()
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if v == nil {
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return &Int64s{
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A: make([]int64, size),
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}
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}
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is := v.(*Int64s)
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if n := size - cap(is.A); n > 0 {
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is.A = append(is.A[:cap(is.A)], make([]int64, n)...)
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}
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is.A = is.A[:size]
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return is
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}
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// PutInt64s returns is to the pool.
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func PutInt64s(is *Int64s) {
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int64sPool.Put(is)
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}
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// Int64s holds an int64 slice
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type Int64s struct {
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A []int64
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}
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var int64sPool sync.Pool
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// GetUint64s returns an uint64 slice with the given size.
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// The slice contents isn't initialized - it may contain garbage.
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func GetUint64s(size int) *Uint64s {
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v := uint64sPool.Get()
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if v == nil {
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return &Uint64s{
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A: make([]uint64, size),
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}
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}
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is := v.(*Uint64s)
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if n := size - cap(is.A); n > 0 {
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is.A = append(is.A[:cap(is.A)], make([]uint64, n)...)
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}
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is.A = is.A[:size]
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return is
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}
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// PutUint64s returns is to the pool.
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func PutUint64s(is *Uint64s) {
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uint64sPool.Put(is)
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}
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// Uint64s holds an uint64 slice
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type Uint64s struct {
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A []uint64
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}
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var uint64sPool sync.Pool
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