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/*
* MinIO Go Library for Amazon S3 Compatible Cloud Storage
* Copyright 2015-2023 MinIO, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package minio
import (
"crypto/sha1"
"crypto/sha256"
"encoding/base64"
"hash"
"hash/crc32"
"io"
"math/bits"
)
// ChecksumType contains information about the checksum type.
type ChecksumType uint32
const (
// ChecksumSHA256 indicates a SHA256 checksum.
ChecksumSHA256 ChecksumType = 1 << iota
// ChecksumSHA1 indicates a SHA-1 checksum.
ChecksumSHA1
// ChecksumCRC32 indicates a CRC32 checksum with IEEE table.
ChecksumCRC32
// ChecksumCRC32C indicates a CRC32 checksum with Castagnoli table.
ChecksumCRC32C
// Keep after all valid checksums
checksumLast
// checksumMask is a mask for valid checksum types.
checksumMask = checksumLast - 1
// ChecksumNone indicates no checksum.
ChecksumNone ChecksumType = 0
amzChecksumAlgo = "x-amz-checksum-algorithm"
amzChecksumCRC32 = "x-amz-checksum-crc32"
amzChecksumCRC32C = "x-amz-checksum-crc32c"
amzChecksumSHA1 = "x-amz-checksum-sha1"
amzChecksumSHA256 = "x-amz-checksum-sha256"
)
// Is returns if c is all of t.
func (c ChecksumType) Is(t ChecksumType) bool {
return c&t == t
}
// Key returns the header key.
// returns empty string if invalid or none.
func (c ChecksumType) Key() string {
switch c & checksumMask {
case ChecksumCRC32:
return amzChecksumCRC32
case ChecksumCRC32C:
return amzChecksumCRC32C
case ChecksumSHA1:
return amzChecksumSHA1
case ChecksumSHA256:
return amzChecksumSHA256
}
return ""
}
// RawByteLen returns the size of the un-encoded checksum.
func (c ChecksumType) RawByteLen() int {
switch c & checksumMask {
case ChecksumCRC32, ChecksumCRC32C:
return 4
case ChecksumSHA1:
return sha1.Size
case ChecksumSHA256:
return sha256.Size
}
return 0
}
// Hasher returns a hasher corresponding to the checksum type.
// Returns nil if no checksum.
func (c ChecksumType) Hasher() hash.Hash {
switch c & checksumMask {
case ChecksumCRC32:
return crc32.NewIEEE()
case ChecksumCRC32C:
return crc32.New(crc32.MakeTable(crc32.Castagnoli))
case ChecksumSHA1:
return sha1.New()
case ChecksumSHA256:
return sha256.New()
}
return nil
}
// IsSet returns whether the type is valid and known.
func (c ChecksumType) IsSet() bool {
return bits.OnesCount32(uint32(c)) == 1
}
// String returns the type as a string.
// CRC32, CRC32C, SHA1, and SHA256 for valid values.
// Empty string for unset and "<invalid>" if not valid.
func (c ChecksumType) String() string {
switch c & checksumMask {
case ChecksumCRC32:
return "CRC32"
case ChecksumCRC32C:
return "CRC32C"
case ChecksumSHA1:
return "SHA1"
case ChecksumSHA256:
return "SHA256"
case ChecksumNone:
return ""
}
return "<invalid>"
}
// ChecksumReader reads all of r and returns a checksum of type c.
// Returns any error that may have occurred while reading.
func (c ChecksumType) ChecksumReader(r io.Reader) (Checksum, error) {
h := c.Hasher()
if h == nil {
return Checksum{}, nil
}
_, err := io.Copy(h, r)
if err != nil {
return Checksum{}, err
}
return NewChecksum(c, h.Sum(nil)), nil
}
// ChecksumBytes returns a checksum of the content b with type c.
func (c ChecksumType) ChecksumBytes(b []byte) Checksum {
h := c.Hasher()
if h == nil {
return Checksum{}
}
n, err := h.Write(b)
if err != nil || n != len(b) {
// Shouldn't happen with these checksummers.
return Checksum{}
}
return NewChecksum(c, h.Sum(nil))
}
// Checksum is a type and encoded value.
type Checksum struct {
Type ChecksumType
r []byte
}
// NewChecksum sets the checksum to the value of b,
// which is the raw hash output.
// If the length of c does not match t.RawByteLen,
// a checksum with ChecksumNone is returned.
func NewChecksum(t ChecksumType, b []byte) Checksum {
if t.IsSet() && len(b) == t.RawByteLen() {
return Checksum{Type: t, r: b}
}
return Checksum{}
}
// NewChecksumString sets the checksum to the value of s,
// which is the base 64 encoded raw hash output.
// If the length of c does not match t.RawByteLen, it is not added.
func NewChecksumString(t ChecksumType, s string) Checksum {
b, _ := base64.StdEncoding.DecodeString(s)
if t.IsSet() && len(b) == t.RawByteLen() {
return Checksum{Type: t, r: b}
}
return Checksum{}
}
// IsSet returns whether the checksum is valid and known.
func (c Checksum) IsSet() bool {
return c.Type.IsSet() && len(c.r) == c.Type.RawByteLen()
}
// Encoded returns the encoded value.
// Returns the empty string if not set or valid.
func (c Checksum) Encoded() string {
if !c.IsSet() {
return ""
}
return base64.StdEncoding.EncodeToString(c.r)
}
// Raw returns the raw checksum value if set.
func (c Checksum) Raw() []byte {
if !c.IsSet() {
return nil
}
return c.r
}
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