TUN-528: Move cloudflared into a separate repo

vendor/zombiezen.com/go/capnproto2/address.go

@@ -0,0 +1,116 @@
+package capnp
+
+// An Address is an index inside a segment's data (in bytes).
+type Address uint32
+
+// addSize returns the address a+sz.
+func (a Address) addSize(sz Size) (b Address, ok bool) {
+	x := int64(a) + int64(sz)
+	if x > int64(maxSize) {
+		return 0, false
+	}
+	return Address(x), true
+}
+
+// element returns the address a+i*sz.
+func (a Address) element(i int32, sz Size) (b Address, ok bool) {
+	x := int64(i) * int64(sz)
+	if x > int64(maxSize) {
+		return 0, false
+	}
+	x += int64(a)
+	if x > int64(maxSize) {
+		return 0, false
+	}
+	return Address(x), true
+}
+
+// addOffset returns the address a+o.
+func (a Address) addOffset(o DataOffset) Address {
+	return a + Address(o)
+}
+
+// A Size is a size (in bytes).
+type Size uint32
+
+// wordSize is the number of bytes in a Cap'n Proto word.
+const wordSize Size = 8
+
+// maxSize is the maximum representable size.
+const maxSize Size = 1<<32 - 1
+
+// times returns the size sz*n.
+func (sz Size) times(n int32) (ns Size, ok bool) {
+	x := int64(sz) * int64(n)
+	if x > int64(maxSize) {
+		return 0, false
+	}
+	return Size(x), true
+}
+
+// padToWord adds padding to sz to make it divisible by wordSize.
+func (sz Size) padToWord() Size {
+	n := Size(wordSize - 1)
+	return (sz + n) &^ n
+}
+
+// DataOffset is an offset in bytes from the beginning of a struct's data section.
+type DataOffset uint32
+
+// ObjectSize records section sizes for a struct or list.
+type ObjectSize struct {
+	DataSize     Size
+	PointerCount uint16
+}
+
+// isZero reports whether sz is the zero size.
+func (sz ObjectSize) isZero() bool {
+	return sz.DataSize == 0 && sz.PointerCount == 0
+}
+
+// isOneByte reports whether the object size is one byte (for Text/Data element sizes).
+func (sz ObjectSize) isOneByte() bool {
+	return sz.DataSize == 1 && sz.PointerCount == 0
+}
+
+// isValid reports whether sz's fields are in range.
+func (sz ObjectSize) isValid() bool {
+	return sz.DataSize <= 0xffff*wordSize
+}
+
+// pointerSize returns the number of bytes the pointer section occupies.
+func (sz ObjectSize) pointerSize() Size {
+	// Guaranteed not to overflow
+	return wordSize * Size(sz.PointerCount)
+}
+
+// totalSize returns the number of bytes that the object occupies.
+func (sz ObjectSize) totalSize() Size {
+	return sz.DataSize + sz.pointerSize()
+}
+
+// dataWordCount returns the number of words in the data section.
+func (sz ObjectSize) dataWordCount() int32 {
+	if sz.DataSize%wordSize != 0 {
+		panic("data size not aligned by word")
+	}
+	return int32(sz.DataSize / wordSize)
+}
+
+// totalWordCount returns the number of words that the object occupies.
+func (sz ObjectSize) totalWordCount() int32 {
+	return sz.dataWordCount() + int32(sz.PointerCount)
+}
+
+// BitOffset is an offset in bits from the beginning of a struct's data section.
+type BitOffset uint32
+
+// offset returns the equivalent byte offset.
+func (bit BitOffset) offset() DataOffset {
+	return DataOffset(bit / 8)
+}
+
+// mask returns the bitmask for the bit.
+func (bit BitOffset) mask() byte {
+	return byte(1 << (bit % 8))
+}