From 73df946d56c74384511a194dd01dbe099584fd1a Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 15:14:23 +0200 Subject: Adding upstream version 1.16.10. Signed-off-by: Daniel Baumann --- src/hash/adler32/adler32.go | 134 +++++++++++++++++++++++++++++++++++++ src/hash/adler32/adler32_test.go | 140 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 274 insertions(+) create mode 100644 src/hash/adler32/adler32.go create mode 100644 src/hash/adler32/adler32_test.go (limited to 'src/hash/adler32') diff --git a/src/hash/adler32/adler32.go b/src/hash/adler32/adler32.go new file mode 100644 index 0000000..e8783e4 --- /dev/null +++ b/src/hash/adler32/adler32.go @@ -0,0 +1,134 @@ +// Copyright 2009 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 adler32 implements the Adler-32 checksum. +// +// It is defined in RFC 1950: +// Adler-32 is composed of two sums accumulated per byte: s1 is +// the sum of all bytes, s2 is the sum of all s1 values. Both sums +// are done modulo 65521. s1 is initialized to 1, s2 to zero. The +// Adler-32 checksum is stored as s2*65536 + s1 in most- +// significant-byte first (network) order. +package adler32 + +import ( + "errors" + "hash" +) + +const ( + // mod is the largest prime that is less than 65536. + mod = 65521 + // nmax is the largest n such that + // 255 * n * (n+1) / 2 + (n+1) * (mod-1) <= 2^32-1. + // It is mentioned in RFC 1950 (search for "5552"). + nmax = 5552 +) + +// The size of an Adler-32 checksum in bytes. +const Size = 4 + +// digest represents the partial evaluation of a checksum. +// The low 16 bits are s1, the high 16 bits are s2. +type digest uint32 + +func (d *digest) Reset() { *d = 1 } + +// New returns a new hash.Hash32 computing the Adler-32 checksum. Its +// Sum method will lay the value out in big-endian byte order. The +// returned Hash32 also implements encoding.BinaryMarshaler and +// encoding.BinaryUnmarshaler to marshal and unmarshal the internal +// state of the hash. +func New() hash.Hash32 { + d := new(digest) + d.Reset() + return d +} + +func (d *digest) Size() int { return Size } + +func (d *digest) BlockSize() int { return 4 } + +const ( + magic = "adl\x01" + marshaledSize = len(magic) + 4 +) + +func (d *digest) MarshalBinary() ([]byte, error) { + b := make([]byte, 0, marshaledSize) + b = append(b, magic...) + b = appendUint32(b, uint32(*d)) + return b, nil +} + +func (d *digest) UnmarshalBinary(b []byte) error { + if len(b) < len(magic) || string(b[:len(magic)]) != magic { + return errors.New("hash/adler32: invalid hash state identifier") + } + if len(b) != marshaledSize { + return errors.New("hash/adler32: invalid hash state size") + } + *d = digest(readUint32(b[len(magic):])) + return nil +} + +func appendUint32(b []byte, x uint32) []byte { + a := [4]byte{ + byte(x >> 24), + byte(x >> 16), + byte(x >> 8), + byte(x), + } + return append(b, a[:]...) +} + +func readUint32(b []byte) uint32 { + _ = b[3] + return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24 +} + +// Add p to the running checksum d. +func update(d digest, p []byte) digest { + s1, s2 := uint32(d&0xffff), uint32(d>>16) + for len(p) > 0 { + var q []byte + if len(p) > nmax { + p, q = p[:nmax], p[nmax:] + } + for len(p) >= 4 { + s1 += uint32(p[0]) + s2 += s1 + s1 += uint32(p[1]) + s2 += s1 + s1 += uint32(p[2]) + s2 += s1 + s1 += uint32(p[3]) + s2 += s1 + p = p[4:] + } + for _, x := range p { + s1 += uint32(x) + s2 += s1 + } + s1 %= mod + s2 %= mod + p = q + } + return digest(s2<<16 | s1) +} + +func (d *digest) Write(p []byte) (nn int, err error) { + *d = update(*d, p) + return len(p), nil +} + +func (d *digest) Sum32() uint32 { return uint32(*d) } + +func (d *digest) Sum(in []byte) []byte { + s := uint32(*d) + return append(in, byte(s>>24), byte(s>>16), byte(s>>8), byte(s)) +} + +// Checksum returns the Adler-32 checksum of data. +func Checksum(data []byte) uint32 { return uint32(update(1, data)) } diff --git a/src/hash/adler32/adler32_test.go b/src/hash/adler32/adler32_test.go new file mode 100644 index 0000000..6bac802 --- /dev/null +++ b/src/hash/adler32/adler32_test.go @@ -0,0 +1,140 @@ +// Copyright 2009 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 adler32 + +import ( + "encoding" + "io" + "strings" + "testing" +) + +var golden = []struct { + out uint32 + in string + halfState string // marshaled hash state after first half of in written, used by TestGoldenMarshal +}{ + {0x00000001, "", "adl\x01\x00\x00\x00\x01"}, + {0x00620062, "a", "adl\x01\x00\x00\x00\x01"}, + {0x012600c4, "ab", "adl\x01\x00b\x00b"}, + {0x024d0127, "abc", "adl\x01\x00b\x00b"}, + {0x03d8018b, "abcd", "adl\x01\x01&\x00\xc4"}, + {0x05c801f0, "abcde", "adl\x01\x01&\x00\xc4"}, + {0x081e0256, "abcdef", "adl\x01\x02M\x01'"}, + {0x0adb02bd, "abcdefg", "adl\x01\x02M\x01'"}, + {0x0e000325, "abcdefgh", "adl\x01\x03\xd8\x01\x8b"}, + {0x118e038e, "abcdefghi", "adl\x01\x03\xd8\x01\x8b"}, + {0x158603f8, "abcdefghij", "adl\x01\x05\xc8\x01\xf0"}, + {0x3f090f02, "Discard medicine more than two years old.", "adl\x01NU\a\x87"}, + {0x46d81477, "He who has a shady past knows that nice guys finish last.", "adl\x01\x89\x8e\t\xe9"}, + {0x40ee0ee1, "I wouldn't marry him with a ten foot pole.", "adl\x01R\t\ag"}, + {0x16661315, "Free! Free!/A trip/to Mars/for 900/empty jars/Burma Shave", "adl\x01\u007f\xbb\t\x10"}, + {0x5b2e1480, "The days of the digital watch are numbered. -Tom Stoppard", "adl\x01\x99:\n~"}, + {0x8c3c09ea, "Nepal premier won't resign.", "adl\x01\"\x05\x05\x05"}, + {0x45ac18fd, "For every action there is an equal and opposite government program.", "adl\x01\xcc\xfa\f\x00"}, + {0x53c61462, "His money is twice tainted: 'taint yours and 'taint mine.", "adl\x01\x93\xa9\n\b"}, + {0x7e511e63, "There is no reason for any individual to have a computer in their home. -Ken Olsen, 1977", "adl\x01e\xf5\x10\x14"}, + {0xe4801a6a, "It's a tiny change to the code and not completely disgusting. - Bob Manchek", "adl\x01\xee\x00\f\xb2"}, + {0x61b507df, "size: a.out: bad magic", "adl\x01\x1a\xfc\x04\x1d"}, + {0xb8631171, "The major problem is with sendmail. -Mark Horton", "adl\x01mi\b\xdc"}, + {0x8b5e1904, "Give me a rock, paper and scissors and I will move the world. CCFestoon", "adl\x01\xe3\n\f\x9f"}, + {0x7cc6102b, "If the enemy is within range, then so are you.", "adl\x01_\xe0\b\x1e"}, + {0x700318e7, "It's well we cannot hear the screams/That we create in others' dreams.", "adl\x01ۘ\f\x87"}, + {0x1e601747, "You remind me of a TV show, but that's all right: I watch it anyway.", "adl\x01\xcc}\v\x83"}, + {0xb55b0b09, "C is as portable as Stonehedge!!", "adl\x01,^\x05\xad"}, + {0x39111dd0, "Even if I could be Shakespeare, I think I should still choose to be Faraday. - A. Huxley", "adl\x01M\xd1\x0e\xc8"}, + {0x91dd304f, "The fugacity of a constituent in a mixture of gases at a given temperature is proportional to its mole fraction. Lewis-Randall Rule", "adl\x01#\xd8\x17\xd7"}, + {0x2e5d1316, "How can you write a big system without C++? -Paul Glick", "adl\x01\x8fU\n\x0f"}, + {0xd0201df6, "'Invariant assertions' is the most elegant programming technique! -Tom Szymanski", "adl\x01/\x98\x0e\xc4"}, + {0x211297c8, strings.Repeat("\xff", 5548) + "8", "adl\x01\x9a\xa6\xcb\xc1"}, + {0xbaa198c8, strings.Repeat("\xff", 5549) + "9", "adl\x01gu\xcc\xc0"}, + {0x553499be, strings.Repeat("\xff", 5550) + "0", "adl\x01gu\xcc\xc0"}, + {0xf0c19abe, strings.Repeat("\xff", 5551) + "1", "adl\x015CͿ"}, + {0x8d5c9bbe, strings.Repeat("\xff", 5552) + "2", "adl\x015CͿ"}, + {0x2af69cbe, strings.Repeat("\xff", 5553) + "3", "adl\x01\x04\x10ξ"}, + {0xc9809dbe, strings.Repeat("\xff", 5554) + "4", "adl\x01\x04\x10ξ"}, + {0x69189ebe, strings.Repeat("\xff", 5555) + "5", "adl\x01\xd3\xcdϽ"}, + {0x86af0001, strings.Repeat("\x00", 1e5), "adl\x01\xc3P\x00\x01"}, + {0x79660b4d, strings.Repeat("a", 1e5), "adl\x01\x81k\x05\xa7"}, + {0x110588ee, strings.Repeat("ABCDEFGHIJKLMNOPQRSTUVWXYZ", 1e4), "adl\x01e\xd2\xc4p"}, +} + +// checksum is a slow but simple implementation of the Adler-32 checksum. +// It is a straight port of the sample code in RFC 1950 section 9. +func checksum(p []byte) uint32 { + s1, s2 := uint32(1), uint32(0) + for _, x := range p { + s1 = (s1 + uint32(x)) % mod + s2 = (s2 + s1) % mod + } + return s2<<16 | s1 +} + +func TestGolden(t *testing.T) { + for _, g := range golden { + in := g.in + if len(in) > 220 { + in = in[:100] + "..." + in[len(in)-100:] + } + p := []byte(g.in) + if got := checksum(p); got != g.out { + t.Errorf("simple implementation: checksum(%q) = 0x%x want 0x%x", in, got, g.out) + continue + } + if got := Checksum(p); got != g.out { + t.Errorf("optimized implementation: Checksum(%q) = 0x%x want 0x%x", in, got, g.out) + continue + } + } +} + +func TestGoldenMarshal(t *testing.T) { + for _, g := range golden { + h := New() + h2 := New() + + io.WriteString(h, g.in[:len(g.in)/2]) + + state, err := h.(encoding.BinaryMarshaler).MarshalBinary() + if err != nil { + t.Errorf("could not marshal: %v", err) + continue + } + + if string(state) != g.halfState { + t.Errorf("checksum(%q) state = %q, want %q", g.in, state, g.halfState) + continue + } + + if err := h2.(encoding.BinaryUnmarshaler).UnmarshalBinary(state); err != nil { + t.Errorf("could not unmarshal: %v", err) + continue + } + + io.WriteString(h, g.in[len(g.in)/2:]) + io.WriteString(h2, g.in[len(g.in)/2:]) + + if h.Sum32() != h2.Sum32() { + t.Errorf("checksum(%q) = 0x%x != marshaled (0x%x)", g.in, h.Sum32(), h2.Sum32()) + } + } +} + +func BenchmarkAdler32KB(b *testing.B) { + b.SetBytes(1024) + data := make([]byte, 1024) + for i := range data { + data[i] = byte(i) + } + h := New() + in := make([]byte, 0, h.Size()) + + b.ResetTimer() + for i := 0; i < b.N; i++ { + h.Reset() + h.Write(data) + h.Sum(in) + } +} -- cgit v1.2.3