README
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digest
This package consolidates all our digest algorithms used for data integrity into a single place. Adler32 is used and dependendent on the use case we rely on the standard library or a modified rolling hash version that can be stack allocated.
For highly concurrent callsites that require digests, they use the stack based adler32 library to avoid having to pool digest structs. The stack based adler32 library is a few percent slower than the standard library adler32 algorithm but heap allocation free.
For less concurrent callsites or callsites already under a mutex a cached digest struct can be kept and reused, these callsites use the standard library methods.
For callsites that do not need to incremental checksumming, meaning they only need to checksum a single byte slice, the static checksum method from the standard library is used.
Documentation
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Overview ¶
Package digest is a generated GoMock package.
Index ¶
- Constants
- func Checksum(buf []byte) uint32
- func NewDigest() stackadler32.Digest
- func SegmentChecksum(segment ts.Segment) uint32
- type Buffer
- type FdWithDigest
- type FdWithDigestContentsReader
- type FdWithDigestContentsWriter
- type FdWithDigestReader
- type FdWithDigestWriter
- type MockReaderWithDigest
- type MockReaderWithDigestMockRecorder
- func (mr *MockReaderWithDigestMockRecorder) Digest() *gomock.Call
- func (mr *MockReaderWithDigestMockRecorder) Read(arg0 interface{}) *gomock.Call
- func (mr *MockReaderWithDigestMockRecorder) Reset(arg0 interface{}) *gomock.Call
- func (mr *MockReaderWithDigestMockRecorder) Validate(arg0 interface{}) *gomock.Call
- type ReaderWithDigest
Constants ¶
const (
// DigestLenBytes is the length of generated digests in bytes.
DigestLenBytes = 4
)
Variables ¶
This section is empty.
Functions ¶
func NewDigest ¶
func NewDigest() stackadler32.Digest
NewDigest creates a new digest. The default 32-bit hashing algorithm is adler32.
func SegmentChecksum ¶
SegmentChecksum returns the 32-bit checksum for a segment avoiding any allocations.
Types ¶
type Buffer ¶
type Buffer []byte
Buffer is a byte slice that facilitates digest reading and writing.
func (Buffer) ReadDigest ¶
ReadDigest reads the digest from the buffer.
func (Buffer) ReadDigestFromFile ¶
ReadDigestFromFile reads the digest from the file.
func (Buffer) WriteDigest ¶
WriteDigest writes a digest to the buffer.
type FdWithDigest ¶
type FdWithDigest interface {
xclose.Closer
// Fd returns the file descriptor.
Fd() *os.File
// Digest returns the digest.
Digest() hash.Hash32
// Reset resets the file descriptor and the digest.
Reset(fd *os.File)
}
FdWithDigest is a container for a file descriptor and the digest for the file contents.
type FdWithDigestContentsReader ¶
type FdWithDigestContentsReader interface {
FdWithDigestReader
// ReadDigest reads a digest from the underlying file.
ReadDigest() (uint32, error)
}
FdWithDigestContentsReader provides additional functionality of reading a digest from the underlying file.
func NewFdWithDigestContentsReader ¶
func NewFdWithDigestContentsReader(bufferSize int) FdWithDigestContentsReader
NewFdWithDigestContentsReader creates a new FdWithDigestContentsReader.
type FdWithDigestContentsWriter ¶
type FdWithDigestContentsWriter interface {
FdWithDigestWriter
// WriteDigests writes a list of digests to the underlying file.
WriteDigests(digests ...uint32) error
}
FdWithDigestContentsWriter provides additional functionality of writing a digest to the underlying file.
func NewFdWithDigestContentsWriter ¶
func NewFdWithDigestContentsWriter(bufferSize int) FdWithDigestContentsWriter
NewFdWithDigestContentsWriter creates a new FdWithDigestContentsWriter.
type FdWithDigestReader ¶
type FdWithDigestReader interface {
FdWithDigest
io.Reader
// ReadAllAndValidate reads everything in the underlying file and validates
// it against the expected digest, returning an error if they don't match.
// Note: the buffer "b" must be an exact match for how long the contents being
// read is, the signature is structured this way to allow for buffer reuse.
ReadAllAndValidate(b []byte, expectedDigest uint32) (int, error)
// Validate compares the current digest against the expected digest and returns
// an error if they don't match.
Validate(expectedDigest uint32) error
}
FdWithDigestReader provides a buffered reader for reading from the underlying file.
func NewFdWithDigestReader ¶
func NewFdWithDigestReader(bufferSize int) FdWithDigestReader
NewFdWithDigestReader creates a new FdWithDigestReader.
type FdWithDigestWriter ¶
type FdWithDigestWriter interface {
FdWithDigest
io.Writer
Flush() error
}
FdWithDigestWriter provides a buffered writer for writing to the underlying file.
func NewFdWithDigestWriter ¶
func NewFdWithDigestWriter(bufferSize int) FdWithDigestWriter
NewFdWithDigestWriter creates a new FdWithDigestWriter.
type MockReaderWithDigest ¶
type MockReaderWithDigest struct {
// contains filtered or unexported fields
}
MockReaderWithDigest is a mock of ReaderWithDigest interface
func NewMockReaderWithDigest ¶
func NewMockReaderWithDigest(ctrl *gomock.Controller) *MockReaderWithDigest
NewMockReaderWithDigest creates a new mock instance
func (*MockReaderWithDigest) Digest ¶
func (m *MockReaderWithDigest) Digest() hash.Hash32
Digest mocks base method
func (*MockReaderWithDigest) EXPECT ¶
func (m *MockReaderWithDigest) EXPECT() *MockReaderWithDigestMockRecorder
EXPECT returns an object that allows the caller to indicate expected use
func (*MockReaderWithDigest) Read ¶
func (m *MockReaderWithDigest) Read(arg0 []byte) (int, error)
Read mocks base method
func (*MockReaderWithDigest) Reset ¶
func (m *MockReaderWithDigest) Reset(arg0 io.Reader)
Reset mocks base method
func (*MockReaderWithDigest) Validate ¶
func (m *MockReaderWithDigest) Validate(arg0 uint32) error
Validate mocks base method
type MockReaderWithDigestMockRecorder ¶
type MockReaderWithDigestMockRecorder struct {
// contains filtered or unexported fields
}
MockReaderWithDigestMockRecorder is the mock recorder for MockReaderWithDigest
func (*MockReaderWithDigestMockRecorder) Digest ¶
func (mr *MockReaderWithDigestMockRecorder) Digest() *gomock.Call
Digest indicates an expected call of Digest
func (*MockReaderWithDigestMockRecorder) Read ¶
func (mr *MockReaderWithDigestMockRecorder) Read(arg0 interface{}) *gomock.Call
Read indicates an expected call of Read
func (*MockReaderWithDigestMockRecorder) Reset ¶
func (mr *MockReaderWithDigestMockRecorder) Reset(arg0 interface{}) *gomock.Call
Reset indicates an expected call of Reset
func (*MockReaderWithDigestMockRecorder) Validate ¶
func (mr *MockReaderWithDigestMockRecorder) Validate(arg0 interface{}) *gomock.Call
Validate indicates an expected call of Validate
type ReaderWithDigest ¶
type ReaderWithDigest interface {
io.Reader
// Reset resets the reader for use with a new reader.
Reset(reader io.Reader)
// Digest returns the digest.
Digest() hash.Hash32
// Validate compares the current digest against the expected digest and returns
// an error if they don't match.
Validate(expectedDigest uint32) error
}
ReaderWithDigest is a reader that that calculates a digest as it is read.
func NewReaderWithDigest ¶
func NewReaderWithDigest(reader io.Reader) ReaderWithDigest
NewReaderWithDigest creates a new reader that calculates a digest as it reads an input.
Source Files