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Diffstat (limited to 'vendor/google.golang.org/protobuf/encoding/protowire/wire.go')
-rw-r--r-- | vendor/google.golang.org/protobuf/encoding/protowire/wire.go | 538 |
1 files changed, 538 insertions, 0 deletions
diff --git a/vendor/google.golang.org/protobuf/encoding/protowire/wire.go b/vendor/google.golang.org/protobuf/encoding/protowire/wire.go new file mode 100644 index 000000000..a427f8b70 --- /dev/null +++ b/vendor/google.golang.org/protobuf/encoding/protowire/wire.go @@ -0,0 +1,538 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package protowire parses and formats the raw wire encoding. +// See https://developers.google.com/protocol-buffers/docs/encoding. +// +// For marshaling and unmarshaling entire protobuf messages, +// use the "google.golang.org/protobuf/proto" package instead. +package protowire + +import ( + "io" + "math" + "math/bits" + + "google.golang.org/protobuf/internal/errors" +) + +// Number represents the field number. +type Number int32 + +const ( + MinValidNumber Number = 1 + FirstReservedNumber Number = 19000 + LastReservedNumber Number = 19999 + MaxValidNumber Number = 1<<29 - 1 +) + +// IsValid reports whether the field number is semantically valid. +// +// Note that while numbers within the reserved range are semantically invalid, +// they are syntactically valid in the wire format. +// Implementations may treat records with reserved field numbers as unknown. +func (n Number) IsValid() bool { + return MinValidNumber <= n && n < FirstReservedNumber || LastReservedNumber < n && n <= MaxValidNumber +} + +// Type represents the wire type. +type Type int8 + +const ( + VarintType Type = 0 + Fixed32Type Type = 5 + Fixed64Type Type = 1 + BytesType Type = 2 + StartGroupType Type = 3 + EndGroupType Type = 4 +) + +const ( + _ = -iota + errCodeTruncated + errCodeFieldNumber + errCodeOverflow + errCodeReserved + errCodeEndGroup +) + +var ( + errFieldNumber = errors.New("invalid field number") + errOverflow = errors.New("variable length integer overflow") + errReserved = errors.New("cannot parse reserved wire type") + errEndGroup = errors.New("mismatching end group marker") + errParse = errors.New("parse error") +) + +// ParseError converts an error code into an error value. +// This returns nil if n is a non-negative number. +func ParseError(n int) error { + if n >= 0 { + return nil + } + switch n { + case errCodeTruncated: + return io.ErrUnexpectedEOF + case errCodeFieldNumber: + return errFieldNumber + case errCodeOverflow: + return errOverflow + case errCodeReserved: + return errReserved + case errCodeEndGroup: + return errEndGroup + default: + return errParse + } +} + +// ConsumeField parses an entire field record (both tag and value) and returns +// the field number, the wire type, and the total length. +// This returns a negative length upon an error (see ParseError). +// +// The total length includes the tag header and the end group marker (if the +// field is a group). +func ConsumeField(b []byte) (Number, Type, int) { + num, typ, n := ConsumeTag(b) + if n < 0 { + return 0, 0, n // forward error code + } + m := ConsumeFieldValue(num, typ, b[n:]) + if m < 0 { + return 0, 0, m // forward error code + } + return num, typ, n + m +} + +// ConsumeFieldValue parses a field value and returns its length. +// This assumes that the field Number and wire Type have already been parsed. +// This returns a negative length upon an error (see ParseError). +// +// When parsing a group, the length includes the end group marker and +// the end group is verified to match the starting field number. +func ConsumeFieldValue(num Number, typ Type, b []byte) (n int) { + switch typ { + case VarintType: + _, n = ConsumeVarint(b) + return n + case Fixed32Type: + _, n = ConsumeFixed32(b) + return n + case Fixed64Type: + _, n = ConsumeFixed64(b) + return n + case BytesType: + _, n = ConsumeBytes(b) + return n + case StartGroupType: + n0 := len(b) + for { + num2, typ2, n := ConsumeTag(b) + if n < 0 { + return n // forward error code + } + b = b[n:] + if typ2 == EndGroupType { + if num != num2 { + return errCodeEndGroup + } + return n0 - len(b) + } + + n = ConsumeFieldValue(num2, typ2, b) + if n < 0 { + return n // forward error code + } + b = b[n:] + } + case EndGroupType: + return errCodeEndGroup + default: + return errCodeReserved + } +} + +// AppendTag encodes num and typ as a varint-encoded tag and appends it to b. +func AppendTag(b []byte, num Number, typ Type) []byte { + return AppendVarint(b, EncodeTag(num, typ)) +} + +// ConsumeTag parses b as a varint-encoded tag, reporting its length. +// This returns a negative length upon an error (see ParseError). +func ConsumeTag(b []byte) (Number, Type, int) { + v, n := ConsumeVarint(b) + if n < 0 { + return 0, 0, n // forward error code + } + num, typ := DecodeTag(v) + if num < MinValidNumber { + return 0, 0, errCodeFieldNumber + } + return num, typ, n +} + +func SizeTag(num Number) int { + return SizeVarint(EncodeTag(num, 0)) // wire type has no effect on size +} + +// AppendVarint appends v to b as a varint-encoded uint64. +func AppendVarint(b []byte, v uint64) []byte { + switch { + case v < 1<<7: + b = append(b, byte(v)) + case v < 1<<14: + b = append(b, + byte((v>>0)&0x7f|0x80), + byte(v>>7)) + case v < 1<<21: + b = append(b, + byte((v>>0)&0x7f|0x80), + byte((v>>7)&0x7f|0x80), + byte(v>>14)) + case v < 1<<28: + b = append(b, + byte((v>>0)&0x7f|0x80), + byte((v>>7)&0x7f|0x80), + byte((v>>14)&0x7f|0x80), + byte(v>>21)) + case v < 1<<35: + b = append(b, + byte((v>>0)&0x7f|0x80), + byte((v>>7)&0x7f|0x80), + byte((v>>14)&0x7f|0x80), + byte((v>>21)&0x7f|0x80), + byte(v>>28)) + case v < 1<<42: + b = append(b, + byte((v>>0)&0x7f|0x80), + byte((v>>7)&0x7f|0x80), + byte((v>>14)&0x7f|0x80), + byte((v>>21)&0x7f|0x80), + byte((v>>28)&0x7f|0x80), + byte(v>>35)) + case v < 1<<49: + b = append(b, + byte((v>>0)&0x7f|0x80), + byte((v>>7)&0x7f|0x80), + byte((v>>14)&0x7f|0x80), + byte((v>>21)&0x7f|0x80), + byte((v>>28)&0x7f|0x80), + byte((v>>35)&0x7f|0x80), + byte(v>>42)) + case v < 1<<56: + b = append(b, + byte((v>>0)&0x7f|0x80), + byte((v>>7)&0x7f|0x80), + byte((v>>14)&0x7f|0x80), + byte((v>>21)&0x7f|0x80), + byte((v>>28)&0x7f|0x80), + byte((v>>35)&0x7f|0x80), + byte((v>>42)&0x7f|0x80), + byte(v>>49)) + case v < 1<<63: + b = append(b, + byte((v>>0)&0x7f|0x80), + byte((v>>7)&0x7f|0x80), + byte((v>>14)&0x7f|0x80), + byte((v>>21)&0x7f|0x80), + byte((v>>28)&0x7f|0x80), + byte((v>>35)&0x7f|0x80), + byte((v>>42)&0x7f|0x80), + byte((v>>49)&0x7f|0x80), + byte(v>>56)) + default: + b = append(b, + byte((v>>0)&0x7f|0x80), + byte((v>>7)&0x7f|0x80), + byte((v>>14)&0x7f|0x80), + byte((v>>21)&0x7f|0x80), + byte((v>>28)&0x7f|0x80), + byte((v>>35)&0x7f|0x80), + byte((v>>42)&0x7f|0x80), + byte((v>>49)&0x7f|0x80), + byte((v>>56)&0x7f|0x80), + 1) + } + return b +} + +// ConsumeVarint parses b as a varint-encoded uint64, reporting its length. +// This returns a negative length upon an error (see ParseError). +func ConsumeVarint(b []byte) (v uint64, n int) { + var y uint64 + if len(b) <= 0 { + return 0, errCodeTruncated + } + v = uint64(b[0]) + if v < 0x80 { + return v, 1 + } + v -= 0x80 + + if len(b) <= 1 { + return 0, errCodeTruncated + } + y = uint64(b[1]) + v += y << 7 + if y < 0x80 { + return v, 2 + } + v -= 0x80 << 7 + + if len(b) <= 2 { + return 0, errCodeTruncated + } + y = uint64(b[2]) + v += y << 14 + if y < 0x80 { + return v, 3 + } + v -= 0x80 << 14 + + if len(b) <= 3 { + return 0, errCodeTruncated + } + y = uint64(b[3]) + v += y << 21 + if y < 0x80 { + return v, 4 + } + v -= 0x80 << 21 + + if len(b) <= 4 { + return 0, errCodeTruncated + } + y = uint64(b[4]) + v += y << 28 + if y < 0x80 { + return v, 5 + } + v -= 0x80 << 28 + + if len(b) <= 5 { + return 0, errCodeTruncated + } + y = uint64(b[5]) + v += y << 35 + if y < 0x80 { + return v, 6 + } + v -= 0x80 << 35 + + if len(b) <= 6 { + return 0, errCodeTruncated + } + y = uint64(b[6]) + v += y << 42 + if y < 0x80 { + return v, 7 + } + v -= 0x80 << 42 + + if len(b) <= 7 { + return 0, errCodeTruncated + } + y = uint64(b[7]) + v += y << 49 + if y < 0x80 { + return v, 8 + } + v -= 0x80 << 49 + + if len(b) <= 8 { + return 0, errCodeTruncated + } + y = uint64(b[8]) + v += y << 56 + if y < 0x80 { + return v, 9 + } + v -= 0x80 << 56 + + if len(b) <= 9 { + return 0, errCodeTruncated + } + y = uint64(b[9]) + v += y << 63 + if y < 2 { + return v, 10 + } + return 0, errCodeOverflow +} + +// SizeVarint returns the encoded size of a varint. +// The size is guaranteed to be within 1 and 10, inclusive. +func SizeVarint(v uint64) int { + // This computes 1 + (bits.Len64(v)-1)/7. + // 9/64 is a good enough approximation of 1/7 + return int(9*uint32(bits.Len64(v))+64) / 64 +} + +// AppendFixed32 appends v to b as a little-endian uint32. +func AppendFixed32(b []byte, v uint32) []byte { + return append(b, + byte(v>>0), + byte(v>>8), + byte(v>>16), + byte(v>>24)) +} + +// ConsumeFixed32 parses b as a little-endian uint32, reporting its length. +// This returns a negative length upon an error (see ParseError). +func ConsumeFixed32(b []byte) (v uint32, n int) { + if len(b) < 4 { + return 0, errCodeTruncated + } + v = uint32(b[0])<<0 | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24 + return v, 4 +} + +// SizeFixed32 returns the encoded size of a fixed32; which is always 4. +func SizeFixed32() int { + return 4 +} + +// AppendFixed64 appends v to b as a little-endian uint64. +func AppendFixed64(b []byte, v uint64) []byte { + return append(b, + byte(v>>0), + byte(v>>8), + byte(v>>16), + byte(v>>24), + byte(v>>32), + byte(v>>40), + byte(v>>48), + byte(v>>56)) +} + +// ConsumeFixed64 parses b as a little-endian uint64, reporting its length. +// This returns a negative length upon an error (see ParseError). +func ConsumeFixed64(b []byte) (v uint64, n int) { + if len(b) < 8 { + return 0, errCodeTruncated + } + v = uint64(b[0])<<0 | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56 + return v, 8 +} + +// SizeFixed64 returns the encoded size of a fixed64; which is always 8. +func SizeFixed64() int { + return 8 +} + +// AppendBytes appends v to b as a length-prefixed bytes value. +func AppendBytes(b []byte, v []byte) []byte { + return append(AppendVarint(b, uint64(len(v))), v...) +} + +// ConsumeBytes parses b as a length-prefixed bytes value, reporting its length. +// This returns a negative length upon an error (see ParseError). +func ConsumeBytes(b []byte) (v []byte, n int) { + m, n := ConsumeVarint(b) + if n < 0 { + return nil, n // forward error code + } + if m > uint64(len(b[n:])) { + return nil, errCodeTruncated + } + return b[n:][:m], n + int(m) +} + +// SizeBytes returns the encoded size of a length-prefixed bytes value, +// given only the length. +func SizeBytes(n int) int { + return SizeVarint(uint64(n)) + n +} + +// AppendString appends v to b as a length-prefixed bytes value. +func AppendString(b []byte, v string) []byte { + return append(AppendVarint(b, uint64(len(v))), v...) +} + +// ConsumeString parses b as a length-prefixed bytes value, reporting its length. +// This returns a negative length upon an error (see ParseError). +func ConsumeString(b []byte) (v string, n int) { + bb, n := ConsumeBytes(b) + return string(bb), n +} + +// AppendGroup appends v to b as group value, with a trailing end group marker. +// The value v must not contain the end marker. +func AppendGroup(b []byte, num Number, v []byte) []byte { + return AppendVarint(append(b, v...), EncodeTag(num, EndGroupType)) +} + +// ConsumeGroup parses b as a group value until the trailing end group marker, +// and verifies that the end marker matches the provided num. The value v +// does not contain the end marker, while the length does contain the end marker. +// This returns a negative length upon an error (see ParseError). +func ConsumeGroup(num Number, b []byte) (v []byte, n int) { + n = ConsumeFieldValue(num, StartGroupType, b) + if n < 0 { + return nil, n // forward error code + } + b = b[:n] + + // Truncate off end group marker, but need to handle denormalized varints. + // Assuming end marker is never 0 (which is always the case since + // EndGroupType is non-zero), we can truncate all trailing bytes where the + // lower 7 bits are all zero (implying that the varint is denormalized). + for len(b) > 0 && b[len(b)-1]&0x7f == 0 { + b = b[:len(b)-1] + } + b = b[:len(b)-SizeTag(num)] + return b, n +} + +// SizeGroup returns the encoded size of a group, given only the length. +func SizeGroup(num Number, n int) int { + return n + SizeTag(num) +} + +// DecodeTag decodes the field Number and wire Type from its unified form. +// The Number is -1 if the decoded field number overflows int32. +// Other than overflow, this does not check for field number validity. +func DecodeTag(x uint64) (Number, Type) { + // NOTE: MessageSet allows for larger field numbers than normal. + if x>>3 > uint64(math.MaxInt32) { + return -1, 0 + } + return Number(x >> 3), Type(x & 7) +} + +// EncodeTag encodes the field Number and wire Type into its unified form. +func EncodeTag(num Number, typ Type) uint64 { + return uint64(num)<<3 | uint64(typ&7) +} + +// DecodeZigZag decodes a zig-zag-encoded uint64 as an int64. +// Input: {…, 5, 3, 1, 0, 2, 4, 6, …} +// Output: {…, -3, -2, -1, 0, +1, +2, +3, …} +func DecodeZigZag(x uint64) int64 { + return int64(x>>1) ^ int64(x)<<63>>63 +} + +// EncodeZigZag encodes an int64 as a zig-zag-encoded uint64. +// Input: {…, -3, -2, -1, 0, +1, +2, +3, …} +// Output: {…, 5, 3, 1, 0, 2, 4, 6, …} +func EncodeZigZag(x int64) uint64 { + return uint64(x<<1) ^ uint64(x>>63) +} + +// DecodeBool decodes a uint64 as a bool. +// Input: { 0, 1, 2, …} +// Output: {false, true, true, …} +func DecodeBool(x uint64) bool { + return x != 0 +} + +// EncodeBool encodes a bool as a uint64. +// Input: {false, true} +// Output: { 0, 1} +func EncodeBool(x bool) uint64 { + if x { + return 1 + } + return 0 +} |