// Hash is the common interface implemented by all hash functions. // // Hash implementations in the standard library (e.g. hash/crc32 and // crypto/sha256) implement the encoding.BinaryMarshaler and // encoding.BinaryUnmarshaler interfaces. Marshaling a hash implementation // allows its internal state to be saved and used for additional processing // later, without having to re-write the data previously written to the hash. // The hash state may contain portions of the input in its original form, // which users are expected to handle for any possible security implications. // // Compatibility: Any future changes to hash or crypto packages will endeavor // to maintain compatibility with state encoded using previous versions. // That is, any released versions of the packages should be able to // decode data written with any previously released version, // subject to issues such as security fixes. // See the Go compatibility document for background: https://golang.org/doc/go1compat type Hash interface { // Write (via the embedded io.Writer interface) adds more data to the running hash. // It never returns an error. io.Writer // Sum appends the current hash to b and returns the resulting slice. // It does not change the underlying hash state. Sum(b []byte) []byte // Reset resets the Hash to its initial state. Reset() // Size returns the number of bytes Sum will return. Size() int // BlockSize returns the hash's underlying block size. // The Write method must be able to accept any amount // of data, but it may operate more efficiently if all writes // are a multiple of the block size. BlockSize() int }


// Hash32 is the common interface implemented by all 32-bit hash functions. type Hash32 interface { Hash Sum32() uint32 }


// Hash64 is the common interface implemented by all 64-bit hash functions. type Hash64 interface { Hash Sum64() uint64 }