.NET Decompiler with support for PDB generation, ReadyToRun, Metadata (&more) - cross-platform!
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// Copyright (c) 2018 Siegfried Pammer
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
using System.Reflection.Metadata;
namespace ICSharpCode.Decompiler.Metadata
{
public static class SignatureBlobComparer
{
public static bool EqualsMethodSignature(BlobReader a, BlobReader b, MetadataReader contextForA, MetadataReader contextForB)
{
return EqualsMethodSignature(ref a, ref b, contextForA, contextForB);
}
static bool EqualsMethodSignature(ref BlobReader a, ref BlobReader b, MetadataReader contextForA, MetadataReader contextForB)
{
SignatureHeader header;
// compare signature headers
if (a.RemainingBytes == 0 || b.RemainingBytes == 0 || (header = a.ReadSignatureHeader()) != b.ReadSignatureHeader())
return false;
if (header.IsGeneric)
{
// read & compare generic parameter count
if (!IsSameCompressedInteger(ref a, ref b, out _))
return false;
}
// read & compare parameter count
if (!IsSameCompressedInteger(ref a, ref b, out int totalParameterCount))
return false;
if (!IsSameCompressedInteger(ref a, ref b, out int typeCode))
return false;
if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
return false;
int i = 0;
for (; i < totalParameterCount; i++)
{
if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
return false;
// varargs sentinel
if (typeCode == 65)
break;
if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
return false;
}
for (; i < totalParameterCount; i++)
{
if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
return false;
if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
return false;
}
return true;
}
public static bool EqualsTypeSignature(BlobReader a, BlobReader b, MetadataReader contextForA, MetadataReader contextForB)
{
return EqualsTypeSignature(ref a, ref b, contextForA, contextForB);
}
static bool EqualsTypeSignature(ref BlobReader a, ref BlobReader b, MetadataReader contextForA, MetadataReader contextForB)
{
if (!IsSameCompressedInteger(ref a, ref b, out int typeCode))
return false;
return TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode);
}
static bool IsSameCompressedInteger(ref BlobReader a, ref BlobReader b, out int value)
{
return a.TryReadCompressedInteger(out value) && b.TryReadCompressedInteger(out int otherValue) && value == otherValue;
}
static bool IsSameCompressedSignedInteger(ref BlobReader a, ref BlobReader b, out int value)
{
return a.TryReadCompressedSignedInteger(out value) && b.TryReadCompressedSignedInteger(out int otherValue) && value == otherValue;
}
static bool TypesAreEqual(ref BlobReader a, ref BlobReader b, MetadataReader contextForA, MetadataReader contextForB, int typeCode)
{
switch (typeCode)
{
case 0x1: // ELEMENT_TYPE_VOID
case 0x2: // ELEMENT_TYPE_BOOLEAN
case 0x3: // ELEMENT_TYPE_CHAR
case 0x4: // ELEMENT_TYPE_I1
case 0x5: // ELEMENT_TYPE_U1
case 0x6: // ELEMENT_TYPE_I2
case 0x7: // ELEMENT_TYPE_U2
case 0x8: // ELEMENT_TYPE_I4
case 0x9: // ELEMENT_TYPE_U4
case 0xA: // ELEMENT_TYPE_I8
case 0xB: // ELEMENT_TYPE_U8
case 0xC: // ELEMENT_TYPE_R4
case 0xD: // ELEMENT_TYPE_R8
case 0xE: // ELEMENT_TYPE_STRING
case 0x16: // ELEMENT_TYPE_TYPEDBYREF
case 0x18: // ELEMENT_TYPE_I
case 0x19: // ELEMENT_TYPE_U
case 0x1C: // ELEMENT_TYPE_OBJECT
return true;
case 0xF: // ELEMENT_TYPE_PTR
case 0x10: // ELEMENT_TYPE_BYREF
case 0x45: // ELEMENT_TYPE_PINNED
case 0x1D: // ELEMENT_TYPE_SZARRAY
if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
return false;
if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
return false;
return true;
case 0x1B: // ELEMENT_TYPE_FNPTR
if (!EqualsMethodSignature(ref a, ref b, contextForA, contextForB))
return false;
return true;
case 0x14: // ELEMENT_TYPE_ARRAY
// element type
if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
return false;
if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
return false;
// rank
if (!IsSameCompressedInteger(ref a, ref b, out _))
return false;
// sizes
if (!IsSameCompressedInteger(ref a, ref b, out int numOfSizes))
return false;
for (int i = 0; i < numOfSizes; i++)
{
if (!IsSameCompressedInteger(ref a, ref b, out _))
return false;
}
// lower bounds
if (!IsSameCompressedInteger(ref a, ref b, out int numOfLowerBounds))
return false;
for (int i = 0; i < numOfLowerBounds; i++)
{
if (!IsSameCompressedSignedInteger(ref a, ref b, out _))
return false;
}
return true;
case 0x1F: // ELEMENT_TYPE_CMOD_REQD
case 0x20: // ELEMENT_TYPE_CMOD_OPT
// modifier
if (!TypeHandleEquals(ref a, ref b, contextForA, contextForB))
return false;
// unmodified type
if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
return false;
if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
return false;
return true;
case 0x15: // ELEMENT_TYPE_GENERICINST
// generic type
if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
return false;
if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
return false;
if (!IsSameCompressedInteger(ref a, ref b, out int numOfArguments))
return false;
for (int i = 0; i < numOfArguments; i++)
{
if (!IsSameCompressedInteger(ref a, ref b, out typeCode))
return false;
if (!TypesAreEqual(ref a, ref b, contextForA, contextForB, typeCode))
return false;
}
return true;
case 0x13: // ELEMENT_TYPE_VAR
case 0x1E: // ELEMENT_TYPE_MVAR
// index
if (!IsSameCompressedInteger(ref a, ref b, out _))
return false;
return true;
case 0x11: // ELEMENT_TYPE_VALUETYPE
case 0x12: // ELEMENT_TYPE_CLASS
if (!TypeHandleEquals(ref a, ref b, contextForA, contextForB))
return false;
return true;
default:
return false;
}
}
static bool TypeHandleEquals(ref BlobReader a, ref BlobReader b, MetadataReader contextForA, MetadataReader contextForB)
{
var typeA = a.ReadTypeHandle();
var typeB = b.ReadTypeHandle();
if (typeA.IsNil || typeB.IsNil)
return false;
return typeA.GetFullTypeName(contextForA) == typeB.GetFullTypeName(contextForB);
}
}
}