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Unified Diff: src/pkg/hash/adler32/adler32_test.go

Issue 6251044: code review 6251044: hash/adler32: optimize. (Closed)
Patch Set: diff -r e2e4e44b1804 https://go.googlecode.com/hg/ Created 11 years, 10 months ago
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Index: src/pkg/hash/adler32/adler32_test.go
===================================================================
--- a/src/pkg/hash/adler32/adler32_test.go
+++ b/src/pkg/hash/adler32/adler32_test.go
@@ -5,25 +5,23 @@
package adler32
import (
- "io"
+ "strings"
"testing"
)
-type _Adler32Test struct {
+var golden = []struct {
out uint32
in string
-}
-
-var golden = []_Adler32Test{
- {0x1, ""},
- {0x620062, "a"},
- {0x12600c4, "ab"},
- {0x24d0127, "abc"},
- {0x3d8018b, "abcd"},
- {0x5c801f0, "abcde"},
- {0x81e0256, "abcdef"},
- {0xadb02bd, "abcdefg"},
- {0xe000325, "abcdefgh"},
+}{
+ {0x00000001, ""},
+ {0x00620062, "a"},
+ {0x012600c4, "ab"},
+ {0x024d0127, "abc"},
+ {0x03d8018b, "abcd"},
+ {0x05c801f0, "abcde"},
+ {0x081e0256, "abcdef"},
+ {0x0adb02bd, "abcdefg"},
+ {0x0e000325, "abcdefgh"},
{0x118e038e, "abcdefghi"},
{0x158603f8, "abcdefghij"},
{0x3f090f02, "Discard medicine more than two years old."},
@@ -47,17 +45,44 @@
{0x91dd304f, "The fugacity of a constituent in a mixture of gases at a given temperature is proportional to its mole fraction. Lewis-Randall Rule"},
{0x2e5d1316, "How can you write a big system without C++? -Paul Glick"},
{0xd0201df6, "'Invariant assertions' is the most elegant programming technique! -Tom Szymanski"},
+ {0x211297c8, strings.Repeat("\xff", 5548) + "8"},
+ {0xbaa198c8, strings.Repeat("\xff", 5549) + "9"},
+ {0x553499be, strings.Repeat("\xff", 5550) + "0"},
+ {0xf0c19abe, strings.Repeat("\xff", 5551) + "1"},
+ {0x8d5c9bbe, strings.Repeat("\xff", 5552) + "2"},
+ {0x2af69cbe, strings.Repeat("\xff", 5553) + "3"},
+ {0xc9809dbe, strings.Repeat("\xff", 5554) + "4"},
+ {0x69189ebe, strings.Repeat("\xff", 5555) + "5"},
+ {0x86af0001, strings.Repeat("\x00", 1e5)},
+ {0x79660b4d, strings.Repeat("a", 1e5)},
+ {0x110588ee, strings.Repeat("ABCDEFGHIJKLMNOPQRSTUVWXYZ", 1e4)},
+}
+
+// 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 i := 0; i < len(golden); i++ {
- g := golden[i]
- c := New()
- io.WriteString(c, g.in)
- s := c.Sum32()
- if s != g.out {
- t.Errorf("adler32(%s) = 0x%x want 0x%x", g.in, s, g.out)
- t.FailNow()
+ 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
}
}
}
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