diff --git a/cpu/byteorder.go b/cpu/byteorder.go index da6b9e43..ed8da8de 100644 --- a/cpu/byteorder.go +++ b/cpu/byteorder.go @@ -5,26 +5,56 @@ package cpu import ( - "encoding/binary" "runtime" ) +// byteOrder is a subset of encoding/binary.ByteOrder. +type byteOrder interface { + Uint32([]byte) uint32 + Uint64([]byte) uint64 +} + +type littleEndian struct{} +type bigEndian struct{} + +func (littleEndian) Uint32(b []byte) uint32 { + _ = b[3] // bounds check hint to compiler; see golang.org/issue/14808 + return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24 +} + +func (littleEndian) Uint64(b []byte) uint64 { + _ = b[7] // bounds check hint to compiler; see golang.org/issue/14808 + return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | + uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56 +} + +func (bigEndian) Uint32(b []byte) uint32 { + _ = b[3] // bounds check hint to compiler; see golang.org/issue/14808 + return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24 +} + +func (bigEndian) Uint64(b []byte) uint64 { + _ = b[7] // bounds check hint to compiler; see golang.org/issue/14808 + return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 | + uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56 +} + // hostByteOrder returns binary.LittleEndian on little-endian machines and // binary.BigEndian on big-endian machines. -func hostByteOrder() binary.ByteOrder { +func hostByteOrder() byteOrder { switch runtime.GOARCH { case "386", "amd64", "amd64p32", "arm", "arm64", "mipsle", "mips64le", "mips64p32le", "ppc64le", "riscv", "riscv64": - return binary.LittleEndian + return littleEndian{} case "armbe", "arm64be", "mips", "mips64", "mips64p32", "ppc", "ppc64", "s390", "s390x", "sparc", "sparc64": - return binary.BigEndian + return bigEndian{} } panic("unknown architecture") }