Added AddZeroBits() method.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@33309 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/apps/debugger/util/BitBuffer.cpp

@@ -138,3 +138,38 @@ BitBuffer::AddBits(const void* _data, uint64 bitSize, uint32 bitOffset)
 
 	return true;
 }
+
+
+bool
+BitBuffer::AddZeroBits(uint64 bitSize)
+{
+	if (bitSize == 0)
+		return true;
+
+	// handle special case first: no more bits than missing
+	size_t oldSize = fBytes.Size();
+	if (fMissingBits > 0 && bitSize <= fMissingBits) {
+		fMissingBits -= bitSize;
+		return true;
+	}
+
+	// resize the buffer
+	if (!fBytes.AddUninitialized((bitSize - fMissingBits + 7) / 8))
+		return false;
+
+	// fill in missing bits
+	if (fMissingBits > 0) {
+		bitSize -= fMissingBits;
+		fMissingBits = 0;
+	}
+
+	// zero the remaining bytes, including a potentially partial last byte
+	uint8* buffer = fBytes.Elements() + oldSize;
+	memset(buffer, 0, (bitSize + 7) / 8);
+	bitSize %= 8;
+
+	if (bitSize > 0)
+		fMissingBits = 8 - bitSize;
+
+	return true;
+}

src/apps/debugger/util/BitBuffer.h

@@ -20,6 +20,7 @@ public:
 			bool				AddBytes(const void* data, size_t size);
 			bool				AddBits(const void* data, uint64 bitSize,
 									uint32 bitOffset = 0);
+			bool				AddZeroBits(uint64 bitSize);
 
 			uint8*				Bytes() const	{ return fBytes.Elements(); }
 			size_t				Size() const	{ return fBytes.Size(); }