“private extern String PadHelper”的源代码在哪里

Question

当我在 .NET 源代码中寻找以下源代码时，我没有找到源代码PadHelper是里面的方法PadLeft和PadRight.我的搜索有问题吗？[System.Security.SecuritySafeCritical]  // auto-generated[ResourceExposure(ResourceScope.None)][MethodImplAttribute(MethodImplOptions.InternalCall)]private extern String PadHelper(int totalWidth, char paddingChar, bool isRightPadded);

Answer 1

这似乎不是一个有据可查的事情。我也不知道更多细节以及它是如何工作的，但是看看CodeProject上的这个线程。该方法似乎位于 comstring.cpp 中。

不幸的是，该线程中链接的帖子不再可用。这可能是一个有趣的。

编辑：在 github 上找到完整的源代码。

/*==================================PadHelper===================================

**Action:

**Returns:

**Arguments:

**Exceptions:

==============================================================================*/

FCIMPL4(Object*, COMString::PadHelper, StringObject* thisRefUNSAFE, INT32 totalWidth, CLR_CHAR paddingChar, CLR_BOOL isRightPadded)

{

    CONTRACTL {

        DISABLED(GC_TRIGGERS);

        THROWS;

        MODE_COOPERATIVE;

        SO_TOLERANT;        

    } CONTRACTL_END;

    STRINGREF refRetVal = NULL;

    STRINGREF thisRef = (STRINGREF) thisRefUNSAFE;

    HELPER_METHOD_FRAME_BEGIN_RET_ATTRIB_1(Frame::FRAME_ATTR_RETURNOBJ, thisRef);

    //-[autocvtpro]-------------------------------------------------------

    WCHAR *thisChars, *padChars;

    INT32 thisLength;

    if (thisRef==NULL) {

        COMPlusThrow(kNullReferenceException, L"NullReference_This");

    }

    RefInterpretGetStringValuesDangerousForGC(thisRef, &thisChars, &thisLength);

    //Don't let them pass in a negative totalWidth

    if (totalWidth<0) {

        COMPlusThrowArgumentOutOfRange(L"totalWidth", L"ArgumentOutOfRange_NeedNonNegNum");

    }

    //If the string is longer than the length which they requested, give them

    //back the old string.

    if (totalWidth<thisLength) {

        refRetVal = thisRef;

        goto lExit;

    }

    if (isRightPadded) {

        refRetVal = NewString(&(thisRef), 0, thisLength, totalWidth);

        padChars = refRetVal->GetBuffer();

        for (int i=thisLength; i<totalWidth; i++) {

            padChars[i] = paddingChar;

        }

        refRetVal->SetStringLength(totalWidth);

        _ASSERTE(padChars[totalWidth] == 0);

    } else {

        refRetVal = NewString(totalWidth);

        INT32 startingPos = totalWidth-thisLength;

        padChars = refRetVal->GetBuffer();

        // Reget thisChars, since if NewString triggers GC, thisChars may become trash.

        RefInterpretGetStringValuesDangerousForGC(thisRef, &thisChars, &thisLength);

            memcpyNoGCRefs(padChars+startingPos, thisChars, thisLength * sizeof(WCHAR));

        for (int i=0; i<startingPos; i++) {

            padChars[i] = paddingChar;

        }

    }

lExit: ;

    //-[autocvtepi]-------------------------------------------------------

    HELPER_METHOD_FRAME_END();

    return OBJECTREFToObject(refRetVal);

}

FCIMPLEND