Data commit

Task/MD5-Implementation/Go/md5-implementation.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+    "fmt"
+    "math"
+    "bytes"
+    "encoding/binary"
+)
+
+type testCase struct {
+    hashCode string
+    string
+}
+
+var testCases = []testCase{
+    {"d41d8cd98f00b204e9800998ecf8427e", ""},
+    {"0cc175b9c0f1b6a831c399e269772661", "a"},
+    {"900150983cd24fb0d6963f7d28e17f72", "abc"},
+    {"f96b697d7cb7938d525a2f31aaf161d0", "message digest"},
+    {"c3fcd3d76192e4007dfb496cca67e13b", "abcdefghijklmnopqrstuvwxyz"},
+    {"d174ab98d277d9f5a5611c2c9f419d9f",
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"},
+    {"57edf4a22be3c955ac49da2e2107b67a", "12345678901234567890" +
+        "123456789012345678901234567890123456789012345678901234567890"},
+}
+
+func main() {
+    for _, tc := range testCases {
+        fmt.Printf("%s\n%x\n\n", tc.hashCode, md5(tc.string))
+    }
+}
+
+var shift = [...]uint{7, 12, 17, 22, 5, 9, 14, 20, 4, 11, 16, 23, 6, 10, 15, 21}
+var table [64]uint32
+
+func init() {
+    for i := range table {
+        table[i] = uint32((1 << 32) * math.Abs(math.Sin(float64(i + 1))))
+    }
+}
+
+func md5(s string) (r [16]byte) {
+    padded := bytes.NewBuffer([]byte(s))
+    padded.WriteByte(0x80)
+    for padded.Len() % 64 != 56 {
+        padded.WriteByte(0)
+    }
+    messageLenBits := uint64(len(s)) * 8
+    binary.Write(padded, binary.LittleEndian, messageLenBits)
+
+    var a, b, c, d uint32 = 0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476
+    var buffer [16]uint32
+    for binary.Read(padded, binary.LittleEndian, buffer[:]) == nil { // read every 64 bytes
+        a1, b1, c1, d1 := a, b, c, d
+        for j := 0; j < 64; j++ {
+            var f uint32
+            bufferIndex := j
+            round := j >> 4
+            switch round {
+            case 0:
+                f = (b1 & c1) | (^b1 & d1)
+            case 1:
+                f = (b1 & d1) | (c1 & ^d1)
+                bufferIndex = (bufferIndex*5 + 1) & 0x0F
+            case 2:
+                f = b1 ^ c1 ^ d1
+                bufferIndex = (bufferIndex*3 + 5) & 0x0F
+            case 3:
+                f = c1 ^ (b1 | ^d1)
+                bufferIndex = (bufferIndex * 7) & 0x0F
+            }
+            sa := shift[(round<<2)|(j&3)]
+            a1 += f + buffer[bufferIndex] + table[j]
+            a1, d1, c1, b1 = d1, c1, b1, a1<<sa|a1>>(32-sa)+b1
+        }
+        a, b, c, d = a+a1, b+b1, c+c1, d+d1
+    }
+
+    binary.Write(bytes.NewBuffer(r[:0]), binary.LittleEndian, []uint32{a, b, c, d})
+    return
+}