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Diffstat (limited to 'vendor/github.com/nu7hatch/gouuid/uuid.go')
| -rw-r--r-- | vendor/github.com/nu7hatch/gouuid/uuid.go | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/vendor/github.com/nu7hatch/gouuid/uuid.go b/vendor/github.com/nu7hatch/gouuid/uuid.go new file mode 100644 index 0000000..ac9623b --- /dev/null +++ b/vendor/github.com/nu7hatch/gouuid/uuid.go @@ -0,0 +1,173 @@ +// This package provides immutable UUID structs and the functions +// NewV3, NewV4, NewV5 and Parse() for generating versions 3, 4 +// and 5 UUIDs as specified in RFC 4122. +// +// Copyright (C) 2011 by Krzysztof Kowalik <chris@nu7hat.ch> +package uuid + +import ( + "crypto/md5" + "crypto/rand" + "crypto/sha1" + "encoding/hex" + "errors" + "fmt" + "hash" + "regexp" +) + +// The UUID reserved variants. +const ( + ReservedNCS byte = 0x80 + ReservedRFC4122 byte = 0x40 + ReservedMicrosoft byte = 0x20 + ReservedFuture byte = 0x00 +) + +// The following standard UUIDs are for use with NewV3() or NewV5(). +var ( + NamespaceDNS, _ = ParseHex("6ba7b810-9dad-11d1-80b4-00c04fd430c8") + NamespaceURL, _ = ParseHex("6ba7b811-9dad-11d1-80b4-00c04fd430c8") + NamespaceOID, _ = ParseHex("6ba7b812-9dad-11d1-80b4-00c04fd430c8") + NamespaceX500, _ = ParseHex("6ba7b814-9dad-11d1-80b4-00c04fd430c8") +) + +// Pattern used to parse hex string representation of the UUID. +// FIXME: do something to consider both brackets at one time, +// current one allows to parse string with only one opening +// or closing bracket. +const hexPattern = "^(urn\\:uuid\\:)?\\{?([a-z0-9]{8})-([a-z0-9]{4})-" + + "([1-5][a-z0-9]{3})-([a-z0-9]{4})-([a-z0-9]{12})\\}?$" + +var re = regexp.MustCompile(hexPattern) + +// A UUID representation compliant with specification in +// RFC 4122 document. +type UUID [16]byte + +// ParseHex creates a UUID object from given hex string +// representation. Function accepts UUID string in following +// formats: +// +// uuid.ParseHex("6ba7b814-9dad-11d1-80b4-00c04fd430c8") +// uuid.ParseHex("{6ba7b814-9dad-11d1-80b4-00c04fd430c8}") +// uuid.ParseHex("urn:uuid:6ba7b814-9dad-11d1-80b4-00c04fd430c8") +// +func ParseHex(s string) (u *UUID, err error) { + md := re.FindStringSubmatch(s) + if md == nil { + err = errors.New("Invalid UUID string") + return + } + hash := md[2] + md[3] + md[4] + md[5] + md[6] + b, err := hex.DecodeString(hash) + if err != nil { + return + } + u = new(UUID) + copy(u[:], b) + return +} + +// Parse creates a UUID object from given bytes slice. +func Parse(b []byte) (u *UUID, err error) { + if len(b) != 16 { + err = errors.New("Given slice is not valid UUID sequence") + return + } + u = new(UUID) + copy(u[:], b) + return +} + +// Generate a UUID based on the MD5 hash of a namespace identifier +// and a name. +func NewV3(ns *UUID, name []byte) (u *UUID, err error) { + if ns == nil { + err = errors.New("Invalid namespace UUID") + return + } + u = new(UUID) + // Set all bits to MD5 hash generated from namespace and name. + u.setBytesFromHash(md5.New(), ns[:], name) + u.setVariant(ReservedRFC4122) + u.setVersion(3) + return +} + +// Generate a random UUID. +func NewV4() (u *UUID, err error) { + u = new(UUID) + // Set all bits to randomly (or pseudo-randomly) chosen values. + _, err = rand.Read(u[:]) + if err != nil { + return + } + u.setVariant(ReservedRFC4122) + u.setVersion(4) + return +} + +// Generate a UUID based on the SHA-1 hash of a namespace identifier +// and a name. +func NewV5(ns *UUID, name []byte) (u *UUID, err error) { + u = new(UUID) + // Set all bits to truncated SHA1 hash generated from namespace + // and name. + u.setBytesFromHash(sha1.New(), ns[:], name) + u.setVariant(ReservedRFC4122) + u.setVersion(5) + return +} + +// Generate a MD5 hash of a namespace and a name, and copy it to the +// UUID slice. +func (u *UUID) setBytesFromHash(hash hash.Hash, ns, name []byte) { + hash.Write(ns[:]) + hash.Write(name) + copy(u[:], hash.Sum([]byte{})[:16]) +} + +// Set the two most significant bits (bits 6 and 7) of the +// clock_seq_hi_and_reserved to zero and one, respectively. +func (u *UUID) setVariant(v byte) { + switch v { + case ReservedNCS: + u[8] = (u[8] | ReservedNCS) & 0xBF + case ReservedRFC4122: + u[8] = (u[8] | ReservedRFC4122) & 0x7F + case ReservedMicrosoft: + u[8] = (u[8] | ReservedMicrosoft) & 0x3F + } +} + +// Variant returns the UUID Variant, which determines the internal +// layout of the UUID. This will be one of the constants: RESERVED_NCS, +// RFC_4122, RESERVED_MICROSOFT, RESERVED_FUTURE. +func (u *UUID) Variant() byte { + if u[8]&ReservedNCS == ReservedNCS { + return ReservedNCS + } else if u[8]&ReservedRFC4122 == ReservedRFC4122 { + return ReservedRFC4122 + } else if u[8]&ReservedMicrosoft == ReservedMicrosoft { + return ReservedMicrosoft + } + return ReservedFuture +} + +// Set the four most significant bits (bits 12 through 15) of the +// time_hi_and_version field to the 4-bit version number. +func (u *UUID) setVersion(v byte) { + u[6] = (u[6] & 0xF) | (v << 4) +} + +// Version returns a version number of the algorithm used to +// generate the UUID sequence. +func (u *UUID) Version() uint { + return uint(u[6] >> 4) +} + +// Returns unparsed version of the generated UUID sequence. +func (u *UUID) String() string { + return fmt.Sprintf("%x-%x-%x-%x-%x", u[0:4], u[4:6], u[6:8], u[8:10], u[10:]) +} |