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Diffstat (limited to 'vendor/github.com/oklog/ulid/ulid.go')
| -rw-r--r-- | vendor/github.com/oklog/ulid/ulid.go | 614 |
1 files changed, 614 insertions, 0 deletions
diff --git a/vendor/github.com/oklog/ulid/ulid.go b/vendor/github.com/oklog/ulid/ulid.go new file mode 100644 index 000000000..c5d0d66fd --- /dev/null +++ b/vendor/github.com/oklog/ulid/ulid.go @@ -0,0 +1,614 @@ +// Copyright 2016 The Oklog Authors +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package ulid + +import ( + "bufio" + "bytes" + "database/sql/driver" + "encoding/binary" + "errors" + "io" + "math" + "math/bits" + "math/rand" + "time" +) + +/* +An ULID is a 16 byte Universally Unique Lexicographically Sortable Identifier + + The components are encoded as 16 octets. + Each component is encoded with the MSB first (network byte order). + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 32_bit_uint_time_high | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 16_bit_uint_time_low | 16_bit_uint_random | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 32_bit_uint_random | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 32_bit_uint_random | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +*/ +type ULID [16]byte + +var ( + // ErrDataSize is returned when parsing or unmarshaling ULIDs with the wrong + // data size. + ErrDataSize = errors.New("ulid: bad data size when unmarshaling") + + // ErrInvalidCharacters is returned when parsing or unmarshaling ULIDs with + // invalid Base32 encodings. + ErrInvalidCharacters = errors.New("ulid: bad data characters when unmarshaling") + + // ErrBufferSize is returned when marshalling ULIDs to a buffer of insufficient + // size. + ErrBufferSize = errors.New("ulid: bad buffer size when marshaling") + + // ErrBigTime is returned when constructing an ULID with a time that is larger + // than MaxTime. + ErrBigTime = errors.New("ulid: time too big") + + // ErrOverflow is returned when unmarshaling a ULID whose first character is + // larger than 7, thereby exceeding the valid bit depth of 128. + ErrOverflow = errors.New("ulid: overflow when unmarshaling") + + // ErrMonotonicOverflow is returned by a Monotonic entropy source when + // incrementing the previous ULID's entropy bytes would result in overflow. + ErrMonotonicOverflow = errors.New("ulid: monotonic entropy overflow") + + // ErrScanValue is returned when the value passed to scan cannot be unmarshaled + // into the ULID. + ErrScanValue = errors.New("ulid: source value must be a string or byte slice") +) + +// New returns an ULID with the given Unix milliseconds timestamp and an +// optional entropy source. Use the Timestamp function to convert +// a time.Time to Unix milliseconds. +// +// ErrBigTime is returned when passing a timestamp bigger than MaxTime. +// Reading from the entropy source may also return an error. +func New(ms uint64, entropy io.Reader) (id ULID, err error) { + if err = id.SetTime(ms); err != nil { + return id, err + } + + switch e := entropy.(type) { + case nil: + return id, err + case *monotonic: + err = e.MonotonicRead(ms, id[6:]) + default: + _, err = io.ReadFull(e, id[6:]) + } + + return id, err +} + +// MustNew is a convenience function equivalent to New that panics on failure +// instead of returning an error. +func MustNew(ms uint64, entropy io.Reader) ULID { + id, err := New(ms, entropy) + if err != nil { + panic(err) + } + return id +} + +// Parse parses an encoded ULID, returning an error in case of failure. +// +// ErrDataSize is returned if the len(ulid) is different from an encoded +// ULID's length. Invalid encodings produce undefined ULIDs. For a version that +// returns an error instead, see ParseStrict. +func Parse(ulid string) (id ULID, err error) { + return id, parse([]byte(ulid), false, &id) +} + +// ParseStrict parses an encoded ULID, returning an error in case of failure. +// +// It is like Parse, but additionally validates that the parsed ULID consists +// only of valid base32 characters. It is slightly slower than Parse. +// +// ErrDataSize is returned if the len(ulid) is different from an encoded +// ULID's length. Invalid encodings return ErrInvalidCharacters. +func ParseStrict(ulid string) (id ULID, err error) { + return id, parse([]byte(ulid), true, &id) +} + +func parse(v []byte, strict bool, id *ULID) error { + // Check if a base32 encoded ULID is the right length. + if len(v) != EncodedSize { + return ErrDataSize + } + + // Check if all the characters in a base32 encoded ULID are part of the + // expected base32 character set. + if strict && + (dec[v[0]] == 0xFF || + dec[v[1]] == 0xFF || + dec[v[2]] == 0xFF || + dec[v[3]] == 0xFF || + dec[v[4]] == 0xFF || + dec[v[5]] == 0xFF || + dec[v[6]] == 0xFF || + dec[v[7]] == 0xFF || + dec[v[8]] == 0xFF || + dec[v[9]] == 0xFF || + dec[v[10]] == 0xFF || + dec[v[11]] == 0xFF || + dec[v[12]] == 0xFF || + dec[v[13]] == 0xFF || + dec[v[14]] == 0xFF || + dec[v[15]] == 0xFF || + dec[v[16]] == 0xFF || + dec[v[17]] == 0xFF || + dec[v[18]] == 0xFF || + dec[v[19]] == 0xFF || + dec[v[20]] == 0xFF || + dec[v[21]] == 0xFF || + dec[v[22]] == 0xFF || + dec[v[23]] == 0xFF || + dec[v[24]] == 0xFF || + dec[v[25]] == 0xFF) { + return ErrInvalidCharacters + } + + // Check if the first character in a base32 encoded ULID will overflow. This + // happens because the base32 representation encodes 130 bits, while the + // ULID is only 128 bits. + // + // See https://github.com/oklog/ulid/issues/9 for details. + if v[0] > '7' { + return ErrOverflow + } + + // Use an optimized unrolled loop (from https://github.com/RobThree/NUlid) + // to decode a base32 ULID. + + // 6 bytes timestamp (48 bits) + (*id)[0] = ((dec[v[0]] << 5) | dec[v[1]]) + (*id)[1] = ((dec[v[2]] << 3) | (dec[v[3]] >> 2)) + (*id)[2] = ((dec[v[3]] << 6) | (dec[v[4]] << 1) | (dec[v[5]] >> 4)) + (*id)[3] = ((dec[v[5]] << 4) | (dec[v[6]] >> 1)) + (*id)[4] = ((dec[v[6]] << 7) | (dec[v[7]] << 2) | (dec[v[8]] >> 3)) + (*id)[5] = ((dec[v[8]] << 5) | dec[v[9]]) + + // 10 bytes of entropy (80 bits) + (*id)[6] = ((dec[v[10]] << 3) | (dec[v[11]] >> 2)) + (*id)[7] = ((dec[v[11]] << 6) | (dec[v[12]] << 1) | (dec[v[13]] >> 4)) + (*id)[8] = ((dec[v[13]] << 4) | (dec[v[14]] >> 1)) + (*id)[9] = ((dec[v[14]] << 7) | (dec[v[15]] << 2) | (dec[v[16]] >> 3)) + (*id)[10] = ((dec[v[16]] << 5) | dec[v[17]]) + (*id)[11] = ((dec[v[18]] << 3) | dec[v[19]]>>2) + (*id)[12] = ((dec[v[19]] << 6) | (dec[v[20]] << 1) | (dec[v[21]] >> 4)) + (*id)[13] = ((dec[v[21]] << 4) | (dec[v[22]] >> 1)) + (*id)[14] = ((dec[v[22]] << 7) | (dec[v[23]] << 2) | (dec[v[24]] >> 3)) + (*id)[15] = ((dec[v[24]] << 5) | dec[v[25]]) + + return nil +} + +// MustParse is a convenience function equivalent to Parse that panics on failure +// instead of returning an error. +func MustParse(ulid string) ULID { + id, err := Parse(ulid) + if err != nil { + panic(err) + } + return id +} + +// MustParseStrict is a convenience function equivalent to ParseStrict that +// panics on failure instead of returning an error. +func MustParseStrict(ulid string) ULID { + id, err := ParseStrict(ulid) + if err != nil { + panic(err) + } + return id +} + +// String returns a lexicographically sortable string encoded ULID +// (26 characters, non-standard base 32) e.g. 01AN4Z07BY79KA1307SR9X4MV3 +// Format: tttttttttteeeeeeeeeeeeeeee where t is time and e is entropy +func (id ULID) String() string { + ulid := make([]byte, EncodedSize) + _ = id.MarshalTextTo(ulid) + return string(ulid) +} + +// MarshalBinary implements the encoding.BinaryMarshaler interface by +// returning the ULID as a byte slice. +func (id ULID) MarshalBinary() ([]byte, error) { + ulid := make([]byte, len(id)) + return ulid, id.MarshalBinaryTo(ulid) +} + +// MarshalBinaryTo writes the binary encoding of the ULID to the given buffer. +// ErrBufferSize is returned when the len(dst) != 16. +func (id ULID) MarshalBinaryTo(dst []byte) error { + if len(dst) != len(id) { + return ErrBufferSize + } + + copy(dst, id[:]) + return nil +} + +// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface by +// copying the passed data and converting it to an ULID. ErrDataSize is +// returned if the data length is different from ULID length. +func (id *ULID) UnmarshalBinary(data []byte) error { + if len(data) != len(*id) { + return ErrDataSize + } + + copy((*id)[:], data) + return nil +} + +// Encoding is the base 32 encoding alphabet used in ULID strings. +const Encoding = "0123456789ABCDEFGHJKMNPQRSTVWXYZ" + +// MarshalText implements the encoding.TextMarshaler interface by +// returning the string encoded ULID. +func (id ULID) MarshalText() ([]byte, error) { + ulid := make([]byte, EncodedSize) + return ulid, id.MarshalTextTo(ulid) +} + +// MarshalTextTo writes the ULID as a string to the given buffer. +// ErrBufferSize is returned when the len(dst) != 26. +func (id ULID) MarshalTextTo(dst []byte) error { + // Optimized unrolled loop ahead. + // From https://github.com/RobThree/NUlid + + if len(dst) != EncodedSize { + return ErrBufferSize + } + + // 10 byte timestamp + dst[0] = Encoding[(id[0]&224)>>5] + dst[1] = Encoding[id[0]&31] + dst[2] = Encoding[(id[1]&248)>>3] + dst[3] = Encoding[((id[1]&7)<<2)|((id[2]&192)>>6)] + dst[4] = Encoding[(id[2]&62)>>1] + dst[5] = Encoding[((id[2]&1)<<4)|((id[3]&240)>>4)] + dst[6] = Encoding[((id[3]&15)<<1)|((id[4]&128)>>7)] + dst[7] = Encoding[(id[4]&124)>>2] + dst[8] = Encoding[((id[4]&3)<<3)|((id[5]&224)>>5)] + dst[9] = Encoding[id[5]&31] + + // 16 bytes of entropy + dst[10] = Encoding[(id[6]&248)>>3] + dst[11] = Encoding[((id[6]&7)<<2)|((id[7]&192)>>6)] + dst[12] = Encoding[(id[7]&62)>>1] + dst[13] = Encoding[((id[7]&1)<<4)|((id[8]&240)>>4)] + dst[14] = Encoding[((id[8]&15)<<1)|((id[9]&128)>>7)] + dst[15] = Encoding[(id[9]&124)>>2] + dst[16] = Encoding[((id[9]&3)<<3)|((id[10]&224)>>5)] + dst[17] = Encoding[id[10]&31] + dst[18] = Encoding[(id[11]&248)>>3] + dst[19] = Encoding[((id[11]&7)<<2)|((id[12]&192)>>6)] + dst[20] = Encoding[(id[12]&62)>>1] + dst[21] = Encoding[((id[12]&1)<<4)|((id[13]&240)>>4)] + dst[22] = Encoding[((id[13]&15)<<1)|((id[14]&128)>>7)] + dst[23] = Encoding[(id[14]&124)>>2] + dst[24] = Encoding[((id[14]&3)<<3)|((id[15]&224)>>5)] + dst[25] = Encoding[id[15]&31] + + return nil +} + +// Byte to index table for O(1) lookups when unmarshaling. +// We use 0xFF as sentinel value for invalid indexes. +var dec = [...]byte{ + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x01, + 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, + 0x0F, 0x10, 0x11, 0xFF, 0x12, 0x13, 0xFF, 0x14, 0x15, 0xFF, + 0x16, 0x17, 0x18, 0x19, 0x1A, 0xFF, 0x1B, 0x1C, 0x1D, 0x1E, + 0x1F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x0A, 0x0B, 0x0C, + 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0xFF, 0x12, 0x13, 0xFF, 0x14, + 0x15, 0xFF, 0x16, 0x17, 0x18, 0x19, 0x1A, 0xFF, 0x1B, 0x1C, + 0x1D, 0x1E, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, +} + +// EncodedSize is the length of a text encoded ULID. +const EncodedSize = 26 + +// UnmarshalText implements the encoding.TextUnmarshaler interface by +// parsing the data as string encoded ULID. +// +// ErrDataSize is returned if the len(v) is different from an encoded +// ULID's length. Invalid encodings produce undefined ULIDs. +func (id *ULID) UnmarshalText(v []byte) error { + return parse(v, false, id) +} + +// Time returns the Unix time in milliseconds encoded in the ULID. +// Use the top level Time function to convert the returned value to +// a time.Time. +func (id ULID) Time() uint64 { + return uint64(id[5]) | uint64(id[4])<<8 | + uint64(id[3])<<16 | uint64(id[2])<<24 | + uint64(id[1])<<32 | uint64(id[0])<<40 +} + +// maxTime is the maximum Unix time in milliseconds that can be +// represented in an ULID. +var maxTime = ULID{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}.Time() + +// MaxTime returns the maximum Unix time in milliseconds that +// can be encoded in an ULID. +func MaxTime() uint64 { return maxTime } + +// Now is a convenience function that returns the current +// UTC time in Unix milliseconds. Equivalent to: +// Timestamp(time.Now().UTC()) +func Now() uint64 { return Timestamp(time.Now().UTC()) } + +// Timestamp converts a time.Time to Unix milliseconds. +// +// Because of the way ULID stores time, times from the year +// 10889 produces undefined results. +func Timestamp(t time.Time) uint64 { + return uint64(t.Unix())*1000 + + uint64(t.Nanosecond()/int(time.Millisecond)) +} + +// Time converts Unix milliseconds in the format +// returned by the Timestamp function to a time.Time. +func Time(ms uint64) time.Time { + s := int64(ms / 1e3) + ns := int64((ms % 1e3) * 1e6) + return time.Unix(s, ns) +} + +// SetTime sets the time component of the ULID to the given Unix time +// in milliseconds. +func (id *ULID) SetTime(ms uint64) error { + if ms > maxTime { + return ErrBigTime + } + + (*id)[0] = byte(ms >> 40) + (*id)[1] = byte(ms >> 32) + (*id)[2] = byte(ms >> 24) + (*id)[3] = byte(ms >> 16) + (*id)[4] = byte(ms >> 8) + (*id)[5] = byte(ms) + + return nil +} + +// Entropy returns the entropy from the ULID. +func (id ULID) Entropy() []byte { + e := make([]byte, 10) + copy(e, id[6:]) + return e +} + +// SetEntropy sets the ULID entropy to the passed byte slice. +// ErrDataSize is returned if len(e) != 10. +func (id *ULID) SetEntropy(e []byte) error { + if len(e) != 10 { + return ErrDataSize + } + + copy((*id)[6:], e) + return nil +} + +// Compare returns an integer comparing id and other lexicographically. +// The result will be 0 if id==other, -1 if id < other, and +1 if id > other. +func (id ULID) Compare(other ULID) int { + return bytes.Compare(id[:], other[:]) +} + +// Scan implements the sql.Scanner interface. It supports scanning +// a string or byte slice. +func (id *ULID) Scan(src interface{}) error { + switch x := src.(type) { + case nil: + return nil + case string: + return id.UnmarshalText([]byte(x)) + case []byte: + return id.UnmarshalBinary(x) + } + + return ErrScanValue +} + +// Value implements the sql/driver.Valuer interface. This returns the value +// represented as a byte slice. If instead a string is desirable, a wrapper +// type can be created that calls String(). +// +// // stringValuer wraps a ULID as a string-based driver.Valuer. +// type stringValuer ULID +// +// func (id stringValuer) Value() (driver.Value, error) { +// return ULID(id).String(), nil +// } +// +// // Example usage. +// db.Exec("...", stringValuer(id)) +func (id ULID) Value() (driver.Value, error) { + return id.MarshalBinary() +} + +// Monotonic returns an entropy source that is guaranteed to yield +// strictly increasing entropy bytes for the same ULID timestamp. +// On conflicts, the previous ULID entropy is incremented with a +// random number between 1 and `inc` (inclusive). +// +// The provided entropy source must actually yield random bytes or else +// monotonic reads are not guaranteed to terminate, since there isn't +// enough randomness to compute an increment number. +// +// When `inc == 0`, it'll be set to a secure default of `math.MaxUint32`. +// The lower the value of `inc`, the easier the next ULID within the +// same millisecond is to guess. If your code depends on ULIDs having +// secure entropy bytes, then don't go under this default unless you know +// what you're doing. +// +// The returned io.Reader isn't safe for concurrent use. +func Monotonic(entropy io.Reader, inc uint64) io.Reader { + m := monotonic{ + Reader: bufio.NewReader(entropy), + inc: inc, + } + + if m.inc == 0 { + m.inc = math.MaxUint32 + } + + if rng, ok := entropy.(*rand.Rand); ok { + m.rng = rng + } + + return &m +} + +type monotonic struct { + io.Reader + ms uint64 + inc uint64 + entropy uint80 + rand [8]byte + rng *rand.Rand +} + +func (m *monotonic) MonotonicRead(ms uint64, entropy []byte) (err error) { + if !m.entropy.IsZero() && m.ms == ms { + err = m.increment() + m.entropy.AppendTo(entropy) + } else if _, err = io.ReadFull(m.Reader, entropy); err == nil { + m.ms = ms + m.entropy.SetBytes(entropy) + } + return err +} + +// increment the previous entropy number with a random number +// of up to m.inc (inclusive). +func (m *monotonic) increment() error { + if inc, err := m.random(); err != nil { + return err + } else if m.entropy.Add(inc) { + return ErrMonotonicOverflow + } + return nil +} + +// random returns a uniform random value in [1, m.inc), reading entropy +// from m.Reader. When m.inc == 0 || m.inc == 1, it returns 1. +// Adapted from: https://golang.org/pkg/crypto/rand/#Int +func (m *monotonic) random() (inc uint64, err error) { + if m.inc <= 1 { + return 1, nil + } + + // Fast path for using a underlying rand.Rand directly. + if m.rng != nil { + // Range: [1, m.inc) + return 1 + uint64(m.rng.Int63n(int64(m.inc))), nil + } + + // bitLen is the maximum bit length needed to encode a value < m.inc. + bitLen := bits.Len64(m.inc) + + // byteLen is the maximum byte length needed to encode a value < m.inc. + byteLen := uint(bitLen+7) / 8 + + // msbitLen is the number of bits in the most significant byte of m.inc-1. + msbitLen := uint(bitLen % 8) + if msbitLen == 0 { + msbitLen = 8 + } + + for inc == 0 || inc >= m.inc { + if _, err = io.ReadFull(m.Reader, m.rand[:byteLen]); err != nil { + return 0, err + } + + // Clear bits in the first byte to increase the probability + // that the candidate is < m.inc. + m.rand[0] &= uint8(int(1<<msbitLen) - 1) + + // Convert the read bytes into an uint64 with byteLen + // Optimized unrolled loop. + switch byteLen { + case 1: + inc = uint64(m.rand[0]) + case 2: + inc = uint64(binary.LittleEndian.Uint16(m.rand[:2])) + case 3, 4: + inc = uint64(binary.LittleEndian.Uint32(m.rand[:4])) + case 5, 6, 7, 8: + inc = uint64(binary.LittleEndian.Uint64(m.rand[:8])) + } + } + + // Range: [1, m.inc) + return 1 + inc, nil +} + +type uint80 struct { + Hi uint16 + Lo uint64 +} + +func (u *uint80) SetBytes(bs []byte) { + u.Hi = binary.BigEndian.Uint16(bs[:2]) + u.Lo = binary.BigEndian.Uint64(bs[2:]) +} + +func (u *uint80) AppendTo(bs []byte) { + binary.BigEndian.PutUint16(bs[:2], u.Hi) + binary.BigEndian.PutUint64(bs[2:], u.Lo) +} + +func (u *uint80) Add(n uint64) (overflow bool) { + lo, hi := u.Lo, u.Hi + if u.Lo += n; u.Lo < lo { + u.Hi++ + } + return u.Hi < hi +} + +func (u uint80) IsZero() bool { + return u.Hi == 0 && u.Lo == 0 +} |