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author | Christopher Speller <crspeller@gmail.com> | 2017-03-13 12:54:22 -0400 |
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committer | GitHub <noreply@github.com> | 2017-03-13 12:54:22 -0400 |
commit | c281ee3b61e8ab53ff118866d72618ae8cce582b (patch) | |
tree | 776e7bdf6c8bfbb9a1dee5976496ab065959991f /vendor/golang.org/x/crypto/cryptobyte/builder.go | |
parent | 3ada7a41a7fb13abef19dd63dc56b720900dbaa9 (diff) | |
download | chat-c281ee3b61e8ab53ff118866d72618ae8cce582b.tar.gz chat-c281ee3b61e8ab53ff118866d72618ae8cce582b.tar.bz2 chat-c281ee3b61e8ab53ff118866d72618ae8cce582b.zip |
Updating server dependancies. Also adding github.com/jaytaylor/html2text and gopkg.in/gomail.v2 (#5748)
Diffstat (limited to 'vendor/golang.org/x/crypto/cryptobyte/builder.go')
-rw-r--r-- | vendor/golang.org/x/crypto/cryptobyte/builder.go | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/cryptobyte/builder.go b/vendor/golang.org/x/crypto/cryptobyte/builder.go new file mode 100644 index 000000000..9883fb3c3 --- /dev/null +++ b/vendor/golang.org/x/crypto/cryptobyte/builder.go @@ -0,0 +1,255 @@ +// Copyright 2017 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 cryptobyte + +import ( + "errors" + "fmt" +) + +// A Builder builds byte strings from fixed-length and length-prefixed values. +// The zero value is a usable Builder that allocates space as needed. +type Builder struct { + err error + result []byte + fixedSize bool + child *Builder + offset int + pendingLenLen int + pendingIsASN1 bool +} + +// NewBuilder creates a Builder that appends its output to the given buffer. +// Like append(), the slice will be reallocated if its capacity is exceeded. +// Use Bytes to get the final buffer. +func NewBuilder(buffer []byte) *Builder { + return &Builder{ + result: buffer, + } +} + +// NewFixedBuilder creates a Builder that appends its output into the given +// buffer. This builder does not reallocate the output buffer. Writes that +// would exceed the buffer's capacity are treated as an error. +func NewFixedBuilder(buffer []byte) *Builder { + return &Builder{ + result: buffer, + fixedSize: true, + } +} + +// Bytes returns the bytes written by the builder or an error if one has +// occurred during during building. +func (b *Builder) Bytes() ([]byte, error) { + if b.err != nil { + return nil, b.err + } + return b.result[b.offset:], nil +} + +// BytesOrPanic returns the bytes written by the builder or panics if an error +// has occurred during building. +func (b *Builder) BytesOrPanic() []byte { + if b.err != nil { + panic(b.err) + } + return b.result[b.offset:] +} + +// AddUint8 appends an 8-bit value to the byte string. +func (b *Builder) AddUint8(v uint8) { + b.add(byte(v)) +} + +// AddUint16 appends a big-endian, 16-bit value to the byte string. +func (b *Builder) AddUint16(v uint16) { + b.add(byte(v>>8), byte(v)) +} + +// AddUint24 appends a big-endian, 24-bit value to the byte string. The highest +// byte of the 32-bit input value is silently truncated. +func (b *Builder) AddUint24(v uint32) { + b.add(byte(v>>16), byte(v>>8), byte(v)) +} + +// AddUint32 appends a big-endian, 32-bit value to the byte string. +func (b *Builder) AddUint32(v uint32) { + b.add(byte(v>>24), byte(v>>16), byte(v>>8), byte(v)) +} + +// AddBytes appends a sequence of bytes to the byte string. +func (b *Builder) AddBytes(v []byte) { + b.add(v...) +} + +// BuilderContinuation is continuation-passing interface for building +// length-prefixed byte sequences. Builder methods for length-prefixed +// sequences (AddUint8LengthPrefixed etc.) will invoke the BuilderContinuation +// supplied to them. The child builder passed to the continuation can be used +// to build the content of the length-prefixed sequence. Example: +// +// parent := cryptobyte.NewBuilder() +// parent.AddUint8LengthPrefixed(func (child *Builder) { +// child.AddUint8(42) +// child.AddUint8LengthPrefixed(func (grandchild *Builder) { +// grandchild.AddUint8(5) +// }) +// }) +// +// It is an error to write more bytes to the child than allowed by the reserved +// length prefix. After the continuation returns, the child must be considered +// invalid, i.e. users must not store any copies or references of the child +// that outlive the continuation. +type BuilderContinuation func(child *Builder) + +// AddUint8LengthPrefixed adds a 8-bit length-prefixed byte sequence. +func (b *Builder) AddUint8LengthPrefixed(f BuilderContinuation) { + b.addLengthPrefixed(1, false, f) +} + +// AddUint16LengthPrefixed adds a big-endian, 16-bit length-prefixed byte sequence. +func (b *Builder) AddUint16LengthPrefixed(f BuilderContinuation) { + b.addLengthPrefixed(2, false, f) +} + +// AddUint24LengthPrefixed adds a big-endian, 24-bit length-prefixed byte sequence. +func (b *Builder) AddUint24LengthPrefixed(f BuilderContinuation) { + b.addLengthPrefixed(3, false, f) +} + +func (b *Builder) addLengthPrefixed(lenLen int, isASN1 bool, f BuilderContinuation) { + // Subsequent writes can be ignored if the builder has encountered an error. + if b.err != nil { + return + } + + offset := len(b.result) + b.add(make([]byte, lenLen)...) + + b.child = &Builder{ + result: b.result, + fixedSize: b.fixedSize, + offset: offset, + pendingLenLen: lenLen, + pendingIsASN1: isASN1, + } + + f(b.child) + b.flushChild() + if b.child != nil { + panic("cryptobyte: internal error") + } +} + +func (b *Builder) flushChild() { + if b.child == nil { + return + } + b.child.flushChild() + child := b.child + b.child = nil + + if child.err != nil { + b.err = child.err + return + } + + length := len(child.result) - child.pendingLenLen - child.offset + + if length < 0 { + panic("cryptobyte: internal error") // result unexpectedly shrunk + } + + if child.pendingIsASN1 { + // For ASN.1, we reserved a single byte for the length. If that turned out + // to be incorrect, we have to move the contents along in order to make + // space. + if child.pendingLenLen != 1 { + panic("cryptobyte: internal error") + } + var lenLen, lenByte uint8 + if int64(length) > 0xfffffffe { + b.err = errors.New("pending ASN.1 child too long") + return + } else if length > 0xffffff { + lenLen = 5 + lenByte = 0x80 | 4 + } else if length > 0xffff { + lenLen = 4 + lenByte = 0x80 | 3 + } else if length > 0xff { + lenLen = 3 + lenByte = 0x80 | 2 + } else if length > 0x7f { + lenLen = 2 + lenByte = 0x80 | 1 + } else { + lenLen = 1 + lenByte = uint8(length) + length = 0 + } + + // Insert the initial length byte, make space for successive length bytes, + // and adjust the offset. + child.result[child.offset] = lenByte + extraBytes := int(lenLen - 1) + if extraBytes != 0 { + child.add(make([]byte, extraBytes)...) + childStart := child.offset + child.pendingLenLen + copy(child.result[childStart+extraBytes:], child.result[childStart:]) + } + child.offset++ + child.pendingLenLen = extraBytes + } + + l := length + for i := child.pendingLenLen - 1; i >= 0; i-- { + child.result[child.offset+i] = uint8(l) + l >>= 8 + } + if l != 0 { + b.err = fmt.Errorf("cryptobyte: pending child length %d exceeds %d-byte length prefix", length, child.pendingLenLen) + return + } + + if !b.fixedSize { + b.result = child.result // In case child reallocated result. + } +} + +func (b *Builder) add(bytes ...byte) { + if b.err != nil { + return + } + if b.child != nil { + panic("attempted write while child is pending") + } + if len(b.result)+len(bytes) < len(bytes) { + b.err = errors.New("cryptobyte: length overflow") + } + if b.fixedSize && len(b.result)+len(bytes) > cap(b.result) { + b.err = errors.New("cryptobyte: Builder is exceeding its fixed-size buffer") + return + } + b.result = append(b.result, bytes...) +} + +// A MarshalingValue marshals itself into a Builder. +type MarshalingValue interface { + // Marshal is called by Builder.AddValue. It receives a pointer to a builder + // to marshal itself into. It may return an error that occurred during + // marshaling, such as unset or invalid values. + Marshal(b *Builder) error +} + +// AddValue calls Marshal on v, passing a pointer to the builder to append to. +// If Marshal returns an error, it is set on the Builder so that subsequent +// appends don't have an effect. +func (b *Builder) AddValue(v MarshalingValue) { + err := v.Marshal(b) + if err != nil { + b.err = err + } +} |