Refactor Crc64 type (#769)

Context: dotnet/android#5451
Split the code to static helper class, which can be used from
`Java.Interop.Tools.TypeNameMappings.JavaNativeTypeManager.GetPackageName`.
This way the linker can strip the whole
`System.Security.Cryptography.Primitives` assembly out in simple XA
apps.
The `Crc64` is still needed in XA, so we still keep it based
on `System.Security.Cryptography.HashAlgorithm`.

Author: radekdoulik

src/Java.Interop.Tools.JavaCallableWrappers/Java.Interop.Tools.JavaCallableWrappers/Crc64.Table.cs

@@ -1,8 +1,8 @@
 namespaceJava.Interop.Tools.JavaCallableWrappers
 {
-partialclassCrc64
+partialclassCrc64Helper
 {
-staticreadonlyulong[,]Table={
+staticreadonlyulong[,]table={
 {
 0x0000000000000000,0x7ad870c830358979,0xf5b0e190606b12f2,0x8f689158505e9b8b,
 0xc038e5739841b68f,0xbae095bba8743ff6,0x358804e3f82aa47d,0x4f50742bc81f2d04,

src/Java.Interop.Tools.JavaCallableWrappers/Java.Interop.Tools.JavaCallableWrappers/Crc64.cs

@@ -53,37 +53,9 @@ public override void Initialize ()
 length=0;
 }
 
-unsafeprotectedoverridevoidHashCore(byte[]array,intibStart,intcbSize)
+protectedoverrideunsafevoidHashCore(byte[]array,intibStart,intcbSize)
 {
-intlen=cbSize;
-intidx=ibStart;
-
- fixed (ulong*tptr=Table){
- fixed (byte*aptr=array){
-while(len>=8){
-crc^=*((ulong*)(aptr+idx));
-crc=
-tptr[7*256+(crc&0xff)]^
-tptr[6*256+((crc>>8)&0xff)]^
-tptr[5*256+((crc>>16)&0xff)]^
-tptr[4*256+((crc>>24)&0xff)]^
-tptr[3*256+((crc>>32)&0xff)]^
-tptr[2*256+((crc>>40)&0xff)]^
-tptr[1*256+((crc>>48)&0xff)]^
-tptr[0*256+(crc>>56)];
-idx+=8;
-len-=8;
-}
-
-while(len>0){
-crc=tptr[0*256+((crc^aptr[idx])&0xff)]^(crc>>8);
-idx++;
-len--;
-}
-}
-}
-
-length+=(ulong)cbSize;
+Crc64Helper.HashCore(array,ibStart,cbSize,refcrc,reflength);
 }
 
 protectedoverridebyte[]HashFinal()=>BitConverter.GetBytes(crc^length);

src/Java.Interop.Tools.JavaCallableWrappers/Java.Interop.Tools.JavaCallableWrappers/Crc64Helper.cs

@@ -0,0 +1,91 @@
+/*
+ * Originally ported from: https://github.com/gityf/crc/blob/8045f50ba6e4193d4ee5d2539025fef26e613c9f/crc/crc64.c
+ *
+ * Copyright (c) 2012, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * * Neither the name of Redis nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE. */
+
+usingSystem;
+usingSystem.Security.Cryptography;
+
+namespaceJava.Interop.Tools.JavaCallableWrappers
+{
+/// <summary>
+/// CRC64 variant: crc-64-jones 64-bit
+/// * Poly: 0xad93d23594c935a9
+///
+/// Changes beyond initial implementation:
+/// * Starting Value: ulong.MaxValue
+/// * XOR length in HashFinal()
+/// * Using spliced table for faster processing
+/// </summary>
+internalstaticpartialclassCrc64Helper
+{
+
+internalstaticbyte[]Compute(byte[]array)
+{
+ulongcrc=ulong.MaxValue;
+ulonglength=0;
+
+HashCore(array,0,array.Length,refcrc,reflength);
+
+returnBitConverter.GetBytes(crc^length);
+}
+
+internalstaticunsafevoidHashCore(byte[]array,intibStart,intcbSize,refulongcrc,refulonglength)
+{
+intlen=cbSize;
+intidx=ibStart;
+
+ fixed (ulong*tptr=table){
+ fixed (byte*aptr=array){
+while(len>=8){
+crc^=*((ulong*)(aptr+idx));
+crc=
+tptr[7*256+(crc&0xff)]^
+tptr[6*256+((crc>>8)&0xff)]^
+tptr[5*256+((crc>>16)&0xff)]^
+tptr[4*256+((crc>>24)&0xff)]^
+tptr[3*256+((crc>>32)&0xff)]^
+tptr[2*256+((crc>>40)&0xff)]^
+tptr[1*256+((crc>>48)&0xff)]^
+tptr[0*256+(crc>>56)];
+idx+=8;
+len-=8;
+}
+
+while(len>0){
+crc=tptr[0*256+((crc^aptr[idx])&0xff)]^(crc>>8);
+idx++;
+len--;
+}
+}
+}
+
+length+=(ulong)cbSize;
+}
+}
+}

src/Java.Interop.Tools.TypeNameMappings/Java.Interop.Tools.TypeNameMappings/JavaNativeTypeManager.cs

@@ -205,8 +205,7 @@ public static string GetPackageName (Type type)
 casePackageNamingPolicy.LowercaseWithAssemblyName:
 return"assembly_"+(assemblyName.Replace('.','_')+"."+type.Namespace).ToLowerInvariant();
 casePackageNamingPolicy.LowercaseCrc64:
-using(varcrc=newCrc64())
-returnCRC_PREFIX+ToHash(type.Namespace+":"+assemblyName,crc);
+returnCRC_PREFIX+ToCrc64(type.Namespace+":"+assemblyName);
 default:
 thrownewNotSupportedException($"PackageNamingPolicy.{PackageNamingPolicy} is no longer supported.");
 }
@@ -574,8 +573,7 @@ public static string GetPackageName (TypeDefinition type, TypeDefinitionCache? c
 casePackageNamingPolicy.LowercaseWithAssemblyName:
 return"assembly_"+(type.GetPartialAssemblyName(cache).Replace('.','_')+"."+type.Namespace).ToLowerInvariant();
 casePackageNamingPolicy.LowercaseCrc64:
-using(varcrc=newCrc64())
-returnCRC_PREFIX+ToHash(type.Namespace+":"+type.GetPartialAssemblyName(cache),crc);
+returnCRC_PREFIX+ToCrc64(type.Namespace+":"+type.GetPartialAssemblyName(cache));
 default:
 thrownewNotSupportedException($"PackageNamingPolicy.{PackageNamingPolicy} is no longer supported.");
 }
@@ -644,10 +642,10 @@ static IEnumerable<MethodDefinition> GetBaseConstructors (TypeDefinition type, T
 }
 #endif // HAVE_CECIL
 
-staticstringToHash(stringvalue,HashAlgorithmalgorithm)
+staticstringToCrc64(stringvalue)
 {
 vardata=Encoding.UTF8.GetBytes(value);
-varhash=algorithm.ComputeHash(data);
+varhash=Crc64Helper.Compute(data);
 varbuf=newStringBuilder(hash.Length*2);
 foreach(varbinhash)
 buf.AppendFormat("{0:x2}",b);