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Diffstat (limited to 'vendor/golang.org/x/crypto/cryptobyte/builder.go')
| -rw-r--r-- | vendor/golang.org/x/crypto/cryptobyte/builder.go | 309 |
1 files changed, 0 insertions, 309 deletions
diff --git a/vendor/golang.org/x/crypto/cryptobyte/builder.go b/vendor/golang.org/x/crypto/cryptobyte/builder.go deleted file mode 100644 index 29b4c76..0000000 --- a/vendor/golang.org/x/crypto/cryptobyte/builder.go +++ /dev/null @@ -1,309 +0,0 @@ -// 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. -// Builders either allocate space as needed, or are ‘fixed’, which means that -// they write into a given buffer and produce an error if it's exhausted. -// -// The zero value is a usable Builder that allocates space as needed. -// -// Simple values are marshaled and appended to a Builder using methods on the -// Builder. Length-prefixed values are marshaled by providing a -// BuilderContinuation, which is a function that writes the inner contents of -// the value to a given Builder. See the documentation for BuilderContinuation -// for details. -type Builder struct { - err error - result []byte - fixedSize bool - child *Builder - offset int - pendingLenLen int - pendingIsASN1 bool - inContinuation *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. For 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. -// -// If the continuation panics with a value of type BuildError then the inner -// error will be returned as the error from Bytes. If the child panics -// otherwise then Bytes will repanic with the same value. -type BuilderContinuation func(child *Builder) - -// BuildError wraps an error. If a BuilderContinuation panics with this value, -// the panic will be recovered and the inner error will be returned from -// Builder.Bytes. -type BuildError struct { - Err error -} - -// 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) -} - -// AddUint32LengthPrefixed adds a big-endian, 32-bit length-prefixed byte sequence. -func (b *Builder) AddUint32LengthPrefixed(f BuilderContinuation) { - b.addLengthPrefixed(4, false, f) -} - -func (b *Builder) callContinuation(f BuilderContinuation, arg *Builder) { - if !*b.inContinuation { - *b.inContinuation = true - - defer func() { - *b.inContinuation = false - - r := recover() - if r == nil { - return - } - - if buildError, ok := r.(BuildError); ok { - b.err = buildError.Err - } else { - panic(r) - } - }() - } - - f(arg) -} - -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)...) - - if b.inContinuation == nil { - b.inContinuation = new(bool) - } - - b.child = &Builder{ - result: b.result, - fixedSize: b.fixedSize, - offset: offset, - pendingLenLen: lenLen, - pendingIsASN1: isASN1, - inContinuation: b.inContinuation, - } - - b.callContinuation(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 - } -} |