github.com/fisco-bcos/crypto@v0.0.0-20200202032121-bd8ab0b5d4f1/internal/bytealg/compare_generic.go (about)

     1  // Copyright 2018 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build !386,!amd64,!amd64p32,!s390x,!arm,!arm64,!ppc64,!ppc64le,!mips,!mipsle,!wasm
     6  
     7  package bytealg
     8  
     9  import _ "unsafe" // for go:linkname
    10  
    11  func Compare(a, b []byte) int {
    12  	l := len(a)
    13  	if len(b) < l {
    14  		l = len(b)
    15  	}
    16  	if l == 0 || &a[0] == &b[0] {
    17  		goto samebytes
    18  	}
    19  	for i := 0; i < l; i++ {
    20  		c1, c2 := a[i], b[i]
    21  		if c1 < c2 {
    22  			return -1
    23  		}
    24  		if c1 > c2 {
    25  			return +1
    26  		}
    27  	}
    28  samebytes:
    29  	if len(a) < len(b) {
    30  		return -1
    31  	}
    32  	if len(a) > len(b) {
    33  		return +1
    34  	}
    35  	return 0
    36  }
    37  
    38  //go:linkname runtime_cmpstring runtime.cmpstring
    39  func runtime_cmpstring(a, b string) int {
    40  	l := len(a)
    41  	if len(b) < l {
    42  		l = len(b)
    43  	}
    44  	for i := 0; i < l; i++ {
    45  		c1, c2 := a[i], b[i]
    46  		if c1 < c2 {
    47  			return -1
    48  		}
    49  		if c1 > c2 {
    50  			return +1
    51  		}
    52  	}
    53  	if len(a) < len(b) {
    54  		return -1
    55  	}
    56  	if len(a) > len(b) {
    57  		return +1
    58  	}
    59  	return 0
    60  }