From 404aeae4545d2426c089a5f8d5e82dae56f5212b Mon Sep 17 00:00:00 2001
From: Rutger Broekhoff
Date: Fri, 29 Dec 2023 21:31:53 +0100
Subject: Make Nix builds work

---
 vendor/github.com/rs/xid/id.go | 391 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 391 insertions(+)
 create mode 100644 vendor/github.com/rs/xid/id.go

(limited to 'vendor/github.com/rs/xid/id.go')

diff --git a/vendor/github.com/rs/xid/id.go b/vendor/github.com/rs/xid/id.go
new file mode 100644
index 0000000..fcd7a04
--- /dev/null
+++ b/vendor/github.com/rs/xid/id.go
@@ -0,0 +1,391 @@
+// Package xid is a globally unique id generator suited for web scale
+//
+// Xid is using Mongo Object ID algorithm to generate globally unique ids:
+// https://docs.mongodb.org/manual/reference/object-id/
+//
+//   - 4-byte value representing the seconds since the Unix epoch,
+//   - 3-byte machine identifier,
+//   - 2-byte process id, and
+//   - 3-byte counter, starting with a random value.
+//
+// The binary representation of the id is compatible with Mongo 12 bytes Object IDs.
+// The string representation is using base32 hex (w/o padding) for better space efficiency
+// when stored in that form (20 bytes). The hex variant of base32 is used to retain the
+// sortable property of the id.
+//
+// Xid doesn't use base64 because case sensitivity and the 2 non alphanum chars may be an
+// issue when transported as a string between various systems. Base36 wasn't retained either
+// because 1/ it's not standard 2/ the resulting size is not predictable (not bit aligned)
+// and 3/ it would not remain sortable. To validate a base32 `xid`, expect a 20 chars long,
+// all lowercase sequence of `a` to `v` letters and `0` to `9` numbers (`[0-9a-v]{20}`).
+//
+// UUID is 16 bytes (128 bits), snowflake is 8 bytes (64 bits), xid stands in between
+// with 12 bytes with a more compact string representation ready for the web and no
+// required configuration or central generation server.
+//
+// Features:
+//
+//   - Size: 12 bytes (96 bits), smaller than UUID, larger than snowflake
+//   - Base32 hex encoded by default (16 bytes storage when transported as printable string)
+//   - Non configured, you don't need set a unique machine and/or data center id
+//   - K-ordered
+//   - Embedded time with 1 second precision
+//   - Unicity guaranteed for 16,777,216 (24 bits) unique ids per second and per host/process
+//
+// Best used with xlog's RequestIDHandler (https://godoc.org/github.com/rs/xlog#RequestIDHandler).
+//
+// References:
+//
+//   - http://www.slideshare.net/davegardnerisme/unique-id-generation-in-distributed-systems
+//   - https://en.wikipedia.org/wiki/Universally_unique_identifier
+//   - https://blog.twitter.com/2010/announcing-snowflake
+package xid
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"crypto/rand"
+	"database/sql/driver"
+	"encoding/binary"
+	"fmt"
+	"hash/crc32"
+	"io/ioutil"
+	"os"
+	"sort"
+	"sync/atomic"
+	"time"
+	"unsafe"
+)
+
+// Code inspired from mgo/bson ObjectId
+
+// ID represents a unique request id
+type ID [rawLen]byte
+
+const (
+	encodedLen = 20 // string encoded len
+	rawLen     = 12 // binary raw len
+
+	// encoding stores a custom version of the base32 encoding with lower case
+	// letters.
+	encoding = "0123456789abcdefghijklmnopqrstuv"
+)
+
+var (
+	// objectIDCounter is atomically incremented when generating a new ObjectId. It's
+	// used as the counter part of an id. This id is initialized with a random value.
+	objectIDCounter = randInt()
+
+	// machineID is generated once and used in subsequent calls to the New* functions.
+	machineID = readMachineID()
+
+	// pid stores the current process id
+	pid = os.Getpid()
+
+	nilID ID
+
+	// dec is the decoding map for base32 encoding
+	dec [256]byte
+)
+
+func init() {
+	for i := 0; i < len(dec); i++ {
+		dec[i] = 0xFF
+	}
+	for i := 0; i < len(encoding); i++ {
+		dec[encoding[i]] = byte(i)
+	}
+
+	// If /proc/self/cpuset exists and is not /, we can assume that we are in a
+	// form of container and use the content of cpuset xor-ed with the PID in
+	// order get a reasonable machine global unique PID.
+	b, err := ioutil.ReadFile("/proc/self/cpuset")
+	if err == nil && len(b) > 1 {
+		pid ^= int(crc32.ChecksumIEEE(b))
+	}
+}
+
+// readMachineID generates a machine ID, derived from a platform-specific machine ID
+// value, or else the machine's hostname, or else a randomly-generated number.
+// It panics if all of these methods fail.
+func readMachineID() []byte {
+	id := make([]byte, 3)
+	hid, err := readPlatformMachineID()
+	if err != nil || len(hid) == 0 {
+		hid, err = os.Hostname()
+	}
+	if err == nil && len(hid) != 0 {
+		hw := sha256.New()
+		hw.Write([]byte(hid))
+		copy(id, hw.Sum(nil))
+	} else {
+		// Fallback to rand number if machine id can't be gathered
+		if _, randErr := rand.Reader.Read(id); randErr != nil {
+			panic(fmt.Errorf("xid: cannot get hostname nor generate a random number: %v; %v", err, randErr))
+		}
+	}
+	return id
+}
+
+// randInt generates a random uint32
+func randInt() uint32 {
+	b := make([]byte, 3)
+	if _, err := rand.Reader.Read(b); err != nil {
+		panic(fmt.Errorf("xid: cannot generate random number: %v;", err))
+	}
+	return uint32(b[0])<<16 | uint32(b[1])<<8 | uint32(b[2])
+}
+
+// New generates a globally unique ID
+func New() ID {
+	return NewWithTime(time.Now())
+}
+
+// NewWithTime generates a globally unique ID with the passed in time
+func NewWithTime(t time.Time) ID {
+	var id ID
+	// Timestamp, 4 bytes, big endian
+	binary.BigEndian.PutUint32(id[:], uint32(t.Unix()))
+	// Machine ID, 3 bytes
+	id[4] = machineID[0]
+	id[5] = machineID[1]
+	id[6] = machineID[2]
+	// Pid, 2 bytes, specs don't specify endianness, but we use big endian.
+	id[7] = byte(pid >> 8)
+	id[8] = byte(pid)
+	// Increment, 3 bytes, big endian
+	i := atomic.AddUint32(&objectIDCounter, 1)
+	id[9] = byte(i >> 16)
+	id[10] = byte(i >> 8)
+	id[11] = byte(i)
+	return id
+}
+
+// FromString reads an ID from its string representation
+func FromString(id string) (ID, error) {
+	i := &ID{}
+	err := i.UnmarshalText([]byte(id))
+	return *i, err
+}
+
+// String returns a base32 hex lowercased with no padding representation of the id (char set is 0-9, a-v).
+func (id ID) String() string {
+	text := make([]byte, encodedLen)
+	encode(text, id[:])
+	return *(*string)(unsafe.Pointer(&text))
+}
+
+// Encode encodes the id using base32 encoding, writing 20 bytes to dst and return it.
+func (id ID) Encode(dst []byte) []byte {
+	encode(dst, id[:])
+	return dst
+}
+
+// MarshalText implements encoding/text TextMarshaler interface
+func (id ID) MarshalText() ([]byte, error) {
+	text := make([]byte, encodedLen)
+	encode(text, id[:])
+	return text, nil
+}
+
+// MarshalJSON implements encoding/json Marshaler interface
+func (id ID) MarshalJSON() ([]byte, error) {
+	if id.IsNil() {
+		return []byte("null"), nil
+	}
+	text := make([]byte, encodedLen+2)
+	encode(text[1:encodedLen+1], id[:])
+	text[0], text[encodedLen+1] = '"', '"'
+	return text, nil
+}
+
+// encode by unrolling the stdlib base32 algorithm + removing all safe checks
+func encode(dst, id []byte) {
+	_ = dst[19]
+	_ = id[11]
+
+	dst[19] = encoding[(id[11]<<4)&0x1F]
+	dst[18] = encoding[(id[11]>>1)&0x1F]
+	dst[17] = encoding[(id[11]>>6)&0x1F|(id[10]<<2)&0x1F]
+	dst[16] = encoding[id[10]>>3]
+	dst[15] = encoding[id[9]&0x1F]
+	dst[14] = encoding[(id[9]>>5)|(id[8]<<3)&0x1F]
+	dst[13] = encoding[(id[8]>>2)&0x1F]
+	dst[12] = encoding[id[8]>>7|(id[7]<<1)&0x1F]
+	dst[11] = encoding[(id[7]>>4)&0x1F|(id[6]<<4)&0x1F]
+	dst[10] = encoding[(id[6]>>1)&0x1F]
+	dst[9] = encoding[(id[6]>>6)&0x1F|(id[5]<<2)&0x1F]
+	dst[8] = encoding[id[5]>>3]
+	dst[7] = encoding[id[4]&0x1F]
+	dst[6] = encoding[id[4]>>5|(id[3]<<3)&0x1F]
+	dst[5] = encoding[(id[3]>>2)&0x1F]
+	dst[4] = encoding[id[3]>>7|(id[2]<<1)&0x1F]
+	dst[3] = encoding[(id[2]>>4)&0x1F|(id[1]<<4)&0x1F]
+	dst[2] = encoding[(id[1]>>1)&0x1F]
+	dst[1] = encoding[(id[1]>>6)&0x1F|(id[0]<<2)&0x1F]
+	dst[0] = encoding[id[0]>>3]
+}
+
+// UnmarshalText implements encoding/text TextUnmarshaler interface
+func (id *ID) UnmarshalText(text []byte) error {
+	if len(text) != encodedLen {
+		return ErrInvalidID
+	}
+	for _, c := range text {
+		if dec[c] == 0xFF {
+			return ErrInvalidID
+		}
+	}
+	if !decode(id, text) {
+		*id = nilID
+		return ErrInvalidID
+	}
+	return nil
+}
+
+// UnmarshalJSON implements encoding/json Unmarshaler interface
+func (id *ID) UnmarshalJSON(b []byte) error {
+	s := string(b)
+	if s == "null" {
+		*id = nilID
+		return nil
+	}
+	// Check the slice length to prevent panic on passing it to UnmarshalText()
+	if len(b) < 2 {
+		return ErrInvalidID
+	}
+	return id.UnmarshalText(b[1 : len(b)-1])
+}
+
+// decode by unrolling the stdlib base32 algorithm + customized safe check.
+func decode(id *ID, src []byte) bool {
+	_ = src[19]
+	_ = id[11]
+
+	id[11] = dec[src[17]]<<6 | dec[src[18]]<<1 | dec[src[19]]>>4
+	// check the last byte
+	if encoding[(id[11]<<4)&0x1F] != src[19] {
+		return false
+	}
+	id[10] = dec[src[16]]<<3 | dec[src[17]]>>2
+	id[9] = dec[src[14]]<<5 | dec[src[15]]
+	id[8] = dec[src[12]]<<7 | dec[src[13]]<<2 | dec[src[14]]>>3
+	id[7] = dec[src[11]]<<4 | dec[src[12]]>>1
+	id[6] = dec[src[9]]<<6 | dec[src[10]]<<1 | dec[src[11]]>>4
+	id[5] = dec[src[8]]<<3 | dec[src[9]]>>2
+	id[4] = dec[src[6]]<<5 | dec[src[7]]
+	id[3] = dec[src[4]]<<7 | dec[src[5]]<<2 | dec[src[6]]>>3
+	id[2] = dec[src[3]]<<4 | dec[src[4]]>>1
+	id[1] = dec[src[1]]<<6 | dec[src[2]]<<1 | dec[src[3]]>>4
+	id[0] = dec[src[0]]<<3 | dec[src[1]]>>2
+	return true
+}
+
+// Time returns the timestamp part of the id.
+// It's a runtime error to call this method with an invalid id.
+func (id ID) Time() time.Time {
+	// First 4 bytes of ObjectId is 32-bit big-endian seconds from epoch.
+	secs := int64(binary.BigEndian.Uint32(id[0:4]))
+	return time.Unix(secs, 0)
+}
+
+// Machine returns the 3-byte machine id part of the id.
+// It's a runtime error to call this method with an invalid id.
+func (id ID) Machine() []byte {
+	return id[4:7]
+}
+
+// Pid returns the process id part of the id.
+// It's a runtime error to call this method with an invalid id.
+func (id ID) Pid() uint16 {
+	return binary.BigEndian.Uint16(id[7:9])
+}
+
+// Counter returns the incrementing value part of the id.
+// It's a runtime error to call this method with an invalid id.
+func (id ID) Counter() int32 {
+	b := id[9:12]
+	// Counter is stored as big-endian 3-byte value
+	return int32(uint32(b[0])<<16 | uint32(b[1])<<8 | uint32(b[2]))
+}
+
+// Value implements the driver.Valuer interface.
+func (id ID) Value() (driver.Value, error) {
+	if id.IsNil() {
+		return nil, nil
+	}
+	b, err := id.MarshalText()
+	return string(b), err
+}
+
+// Scan implements the sql.Scanner interface.
+func (id *ID) Scan(value interface{}) (err error) {
+	switch val := value.(type) {
+	case string:
+		return id.UnmarshalText([]byte(val))
+	case []byte:
+		return id.UnmarshalText(val)
+	case nil:
+		*id = nilID
+		return nil
+	default:
+		return fmt.Errorf("xid: scanning unsupported type: %T", value)
+	}
+}
+
+// IsNil Returns true if this is a "nil" ID
+func (id ID) IsNil() bool {
+	return id == nilID
+}
+
+// Alias of IsNil
+func (id ID) IsZero() bool {
+	return id.IsNil()
+}
+
+// NilID returns a zero value for `xid.ID`.
+func NilID() ID {
+	return nilID
+}
+
+// Bytes returns the byte array representation of `ID`
+func (id ID) Bytes() []byte {
+	return id[:]
+}
+
+// FromBytes convert the byte array representation of `ID` back to `ID`
+func FromBytes(b []byte) (ID, error) {
+	var id ID
+	if len(b) != rawLen {
+		return id, ErrInvalidID
+	}
+	copy(id[:], b)
+	return id, nil
+}
+
+// Compare returns an integer comparing two IDs. It behaves just like `bytes.Compare`.
+// The result will be 0 if two IDs are identical, -1 if current id is less than the other one,
+// and 1 if current id is greater than the other.
+func (id ID) Compare(other ID) int {
+	return bytes.Compare(id[:], other[:])
+}
+
+type sorter []ID
+
+func (s sorter) Len() int {
+	return len(s)
+}
+
+func (s sorter) Less(i, j int) bool {
+	return s[i].Compare(s[j]) < 0
+}
+
+func (s sorter) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+// Sort sorts an array of IDs inplace.
+// It works by wrapping `[]ID` and use `sort.Sort`.
+func Sort(ids []ID) {
+	sort.Sort(sorter(ids))
+}
-- 
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