forgejo/modules/avatar/hash.go
Gusted 362fd7aae1
[v1.22] [GITEA] Drop sha256-simd in favor of stdlib
- In Go 1.21 the crypto/sha256 [got a massive
improvement](https://go.dev/doc/go1.21#crypto/sha256) by utilizing the
SHA instructions for AMD64 CPUs, which sha256-simd already was doing.
The performance is now on par and I think it's preferable to use the
standard library rather than a package when possible.

```
cpu: AMD Ryzen 5 3600X 6-Core Processor
                │  simd.txt   │               go.txt                │
                │   sec/op    │    sec/op     vs base               │
Hash/8Bytes-12    63.25n ± 1%    73.38n ± 1%  +16.02% (p=0.002 n=6)
Hash/64Bytes-12   98.73n ± 1%   105.30n ± 1%   +6.65% (p=0.002 n=6)
Hash/1K-12        567.2n ± 1%    572.8n ± 1%   +0.99% (p=0.002 n=6)
Hash/8K-12        4.062µ ± 1%    4.062µ ± 1%        ~ (p=0.396 n=6)
Hash/1M-12        512.1µ ± 0%    510.6µ ± 1%        ~ (p=0.485 n=6)
Hash/5M-12        2.556m ± 1%    2.564m ± 0%        ~ (p=0.093 n=6)
Hash/10M-12       5.112m ± 0%    5.127m ± 0%        ~ (p=0.093 n=6)
geomean           13.82µ         14.27µ        +3.28%

                │   simd.txt   │               go.txt                │
                │     B/s      │     B/s       vs base               │
Hash/8Bytes-12    120.6Mi ± 1%   104.0Mi ± 1%  -13.81% (p=0.002 n=6)
Hash/64Bytes-12   618.2Mi ± 1%   579.8Mi ± 1%   -6.22% (p=0.002 n=6)
Hash/1K-12        1.682Gi ± 1%   1.665Gi ± 1%   -0.98% (p=0.002 n=6)
Hash/8K-12        1.878Gi ± 1%   1.878Gi ± 1%        ~ (p=0.310 n=6)
Hash/1M-12        1.907Gi ± 0%   1.913Gi ± 1%        ~ (p=0.485 n=6)
Hash/5M-12        1.911Gi ± 1%   1.904Gi ± 0%        ~ (p=0.093 n=6)
Hash/10M-12       1.910Gi ± 0%   1.905Gi ± 0%        ~ (p=0.093 n=6)
geomean           1.066Gi        1.032Gi        -3.18%
```

(cherry picked from commit abd94ff5b5)
(cherry picked from commit 15e81637ab)

Conflicts:
	go.mod
	https://codeberg.org/forgejo/forgejo/pulls/1581
(cherry picked from commit 325d92917f)

Conflicts:
	modules/context/context_cookie.go
	https://codeberg.org/forgejo/forgejo/pulls/1617
(cherry picked from commit 358819e895)
2023-10-23 15:28:16 +02:00

28 lines
978 B
Go

// Copyright 2023 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package avatar
import (
"crypto/sha256"
"encoding/hex"
"strconv"
)
// HashAvatar will generate a unique string, which ensures that when there's a
// different unique ID while the data is the same, it will generate a different
// output. It will generate the output according to:
// HEX(HASH(uniqueID || - || data))
// The hash being used is SHA256.
// The sole purpose of the unique ID is to generate a distinct hash Such that
// two unique IDs with the same data will have a different hash output.
// The "-" byte is important to ensure that data cannot be modified such that
// the first byte is a number, which could lead to a "collision" with the hash
// of another unique ID.
func HashAvatar(uniqueID int64, data []byte) string {
h := sha256.New()
h.Write([]byte(strconv.FormatInt(uniqueID, 10)))
h.Write([]byte{'-'})
h.Write(data)
return hex.EncodeToString(h.Sum(nil))
}