From 541c0cdde4b99bace190cdf380bc7bca16085809 Mon Sep 17 00:00:00 2001 From: Kovid Goyal Date: Mon, 4 Sep 2023 21:32:25 +0530 Subject: [PATCH] Do not build decode table for base85 until it is actually needed Also make the tests actual tests --- tools/utils/base85/base85.go | 43 +++++++++----- tools/utils/base85/base85_test.go | 98 +++++++++++++++---------------- 2 files changed, 75 insertions(+), 66 deletions(-) diff --git a/tools/utils/base85/base85.go b/tools/utils/base85/base85.go index 552a28d06..3e24e8582 100644 --- a/tools/utils/base85/base85.go +++ b/tools/utils/base85/base85.go @@ -10,10 +10,11 @@ import ( "errors" "io" "strconv" + "sync" ) // 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~ -var b2c_table = [85]byte{ +var encode = [85]byte{ // 0 1 2 3 4 5 6 7 8 9 A B C D E F 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, //0 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, //1 @@ -23,22 +24,35 @@ var b2c_table = [85]byte{ 0x60, 0x7B, 0x7C, 0x7D, 0x7E, } -var encode [85]byte -var decode [256]byte - -func init() { - copy(encode[:], b2c_table[:]) - for i := 0; i < len(decode); i++ { - decode[i] = 0xFF +var decoder_array = sync.OnceValue(func() [256]byte { + var decode = [256]byte{ + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, } for i := 0; i < len(encode); i++ { decode[encode[i]] = byte(i) } -} + return decode + +}) // encodeChunk encodes 4 byte-chunk to 5 byte -// if chunk size is less then 4, then it is padded before convertion. -// return written bytes or error +// if chunk size is less then 4, then it is padded before encoding. +// return written bytes func encodeChunk(dst, src []byte) int { if len(src) == 0 { return 0 @@ -78,7 +92,7 @@ var decode_base = [5]uint32{85 * 85 * 85 * 85, 85 * 85 * 85, 85 * 85, 85, 1} // decodeChunk decodes 5 byte-chunk to 4 byte // if chunk size is less then 5, then it is padded before convertion. // return written bytes and error input index -func decodeChunk(dst, src []byte) (int, int) { +func decodeChunk(decode *[256]byte, dst, src []byte) (int, int) { if len(src) == 0 { return 0, 0 } @@ -150,16 +164,17 @@ func DecodeString(src string) ([]byte, error) { func Decode(dst, src []byte) (int, error) { f := 0 t := 0 + decode := decoder_array() for len(src) > 0 { if len(src) < 5 { - w, err := decodeChunk(dst, src) + w, err := decodeChunk(&decode, dst, src) if err > 0 { return t, CorruptInputError(f + err) } return t + w, nil } - _, err := decodeChunk(dst[:4], src[:5]) + _, err := decodeChunk(&decode, dst[:4], src[:5]) if err > 0 { return t, CorruptInputError(f + err) } else { diff --git a/tools/utils/base85/base85_test.go b/tools/utils/base85/base85_test.go index 9dd66e326..395dc185e 100644 --- a/tools/utils/base85/base85_test.go +++ b/tools/utils/base85/base85_test.go @@ -1,60 +1,54 @@ package base85 import ( - "testing" "fmt" + "testing" + + "github.com/google/go-cmp/cmp" ) -func TestChunked (t *testing.T) { - a := []byte("M") - fmt.Printf("a %#v\n", a) - b := make([]byte, EncodedLen(len(a))) - encodeChunk(b, a) - fmt.Printf("b %#v\n", b) - c := make([]byte, DecodedLen(len(b))) - decodeChunk(c, b) - fmt.Printf("c %#v\n", c) +var _ = fmt.Print - a = []byte("Ma") - fmt.Printf("a %#v\n", a) - b = make([]byte, EncodedLen(len(a))) - encodeChunk(b, a) - fmt.Printf("b %#v\n", b) - c = make([]byte, DecodedLen(len(b))) - decodeChunk(c, b) - fmt.Printf("c %#v\n", c) - - a = []byte("Man") - fmt.Printf("a %#v\n", a) - b = make([]byte, EncodedLen(len(a))) - encodeChunk(b, a) - fmt.Printf("b %#v\n", b) - c = make([]byte, DecodedLen(len(b))) - decodeChunk(c, b) - fmt.Printf("c %#v\n", c) - - a = []byte("Man ") - fmt.Printf("a %#v\n", a) - b = make([]byte, EncodedLen(len(a))) - encodeChunk(b, a) - fmt.Printf("b %#v\n", b) - c = make([]byte, DecodedLen(len(b))) - decodeChunk(c, b) - fmt.Printf("c %#v\n", c) - - a = []byte("Manual") - fmt.Printf("a %#v\n", a) - b = make([]byte, EncodedLen(len(a))) - n := Encode(b, a) - fmt.Printf("b %#v %d\n", b, n) - c = make([]byte, DecodedLen(len(b))) - n, _ = Decode(c, b) - fmt.Printf("c %#v %d\n", c, n) - - a = []byte("Manual") - fmt.Printf("a %s\n", a) - sb := EncodeToString(a) + "\"" - fmt.Printf("b %#v\n", sb) - sc, err := DecodeString(sb) - fmt.Printf("c %s %s\n", sc, err) +type pair struct { + src, encoded string +} + +func TestBase85(t *testing.T) { + dst, dst2 := [8]byte{}, [8]byte{} + decode := decoder_array() + var el int + for _, x := range []string{"M", "Ma", "Man", "Man "} { + a := []byte(x) + if el = encodeChunk(dst[:], a); el != EncodedLen(len(a)) { + t.Fatalf("Encoded len for %#v wrong: %d != %d", x, el, EncodedLen(len(a))) + } + encoded := dst[:el] + dl, bad_idx := decodeChunk(&decode, dst2[:], encoded) + if bad_idx != 0 { + t.Fatalf("Decode for %#v returned bad data at: %d (%#v)", x, bad_idx, encoded) + } + if dl != DecodedLen(len(encoded)) { + t.Fatalf("Decoded len for %#v wrong: %d != %d", x, dl, DecodedLen(len(a))) + } + decoded := string(dst2[:dl]) + if diff := cmp.Diff(x, decoded); diff != "" { + t.Fatalf("Roundtrip failed for %#v: %s", x, diff) + } + } + for _, p := range []pair{ + {"M", "O#"}, + {"Manual", "O<`_zVQc"}, + } { + q := EncodeToString([]byte(p.src)) + if diff := cmp.Diff(p.encoded, q); diff != "" { + t.Fatalf("Incorrect encoding of: %#v\n%s", p.src, diff) + } + sc, err := DecodeString(q) + if err != nil { + t.Fatalf("Failed to decode %#v with error: %s", p.src, err) + } + if diff := cmp.Diff(p.src, string(sc)); diff != "" { + t.Fatalf("Failed to roundtrip %#v\n%s", p.src, diff) + } + } }