--- /dev/null
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// A package of simple functions to manipulate arrays of bytes.
+// Analagous to the facilities of the strings package.
+package bytes
+
+import "utf8"
+
+// Compare returns an integer comparing the two byte arrays lexicographically.
+// The result will be 0 if a==b, -1 if a < b, and +1 if a > b
+func Compare(a, b []byte) int {
+ for i := 0; i < len(a) && i < len(b); i++ {
+ switch {
+ case a[i] > b[i]:
+ return 1
+ case a[i] < b[i]:
+ return -1
+ }
+ }
+ switch {
+ case len(a) < len(b):
+ return -1
+ case len(a) > len(b):
+ return 1
+ }
+ return 0
+}
+
+// Equal returns a boolean reporting whether a == b.
+func Equal(a, b []byte) bool {
+ if len(a) != len(b) {
+ return false
+ }
+ for i := 0; i < len(a); i++ {
+ if a[i] != b[i] {
+ return false
+ }
+ }
+ return true
+}
+
+// Explode splits s into an array of UTF-8 sequences, one per Unicode character (still arrays of bytes).
+// Invalid UTF-8 sequences become correct encodings of U+FFF8.
+func Explode(s []byte) [][]byte {
+ a := make([][]byte, utf8.RuneCount(s));
+ var size, rune int;
+ i := 0;
+ for len(s) > 0 {
+ rune, size = utf8.DecodeRune(s);
+ a[i] = s[0:size];
+ s = s[size:len(s)];
+ i++;
+ }
+ return a
+}
+
+// Count counts the number of non-overlapping instances of sep in s.
+func Count(s, sep []byte) int {
+ if len(sep) == 0 {
+ return utf8.RuneCount(s)+1
+ }
+ c := sep[0];
+ n := 0;
+ for i := 0; i+len(sep) <= len(s); i++ {
+ if s[i] == c && (len(sep) == 1 || Equal(s[i:i+len(sep)], sep)) {
+ n++;
+ i += len(sep)-1
+ }
+ }
+ return n
+}
+
+// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
+func Index(s, sep []byte) int {
+ n := len(sep);
+ if n == 0 {
+ return 0
+ }
+ c := sep[0];
+ for i := 0; i+n <= len(s); i++ {
+ if s[i] == c && (n == 1 || Equal(s[i:i+n], sep)) {
+ return i
+ }
+ }
+ return -1
+}
+
+// Split returns the array representing the subarrays of s separated by sep. Adjacent
+// occurrences of sep produce empty subarrays. If sep is empty, it is the same as Explode.
+func Split(s, sep []byte) [][]byte {
+ if len(sep) == 0 {
+ return Explode(s)
+ }
+ c := sep[0];
+ start := 0;
+ n := Count(s, sep)+1;
+ a := make([][]byte, n);
+ na := 0;
+ for i := 0; i+len(sep) <= len(s); i++ {
+ if s[i] == c && (len(sep) == 1 || Equal(s[i:i+len(sep)], sep)) {
+ a[na] = s[start:i];
+ na++;
+ start = i+len(sep);
+ i += len(sep)-1
+ }
+ }
+ a[na] = s[start:len(s)];
+ return a
+}
+
+// Join concatenates the elements of a to create a single byte array. The separator
+// sep is placed between elements in the resulting array.
+func Join(a [][]byte, sep []byte) []byte {
+ if len(a) == 0 {
+ return []byte{}
+ }
+ if len(a) == 1 {
+ return a[0]
+ }
+ n := len(sep) * (len(a)-1);
+ for i := 0; i < len(a); i++ {
+ n += len(a[i])
+ }
+
+ b := make([]byte, n);
+ bp := 0;
+ for i := 0; i < len(a); i++ {
+ s := a[i];
+ for j := 0; j < len(s); j++ {
+ b[bp] = s[j];
+ bp++
+ }
+ if i + 1 < len(a) {
+ s = sep;
+ for j := 0; j < len(s); j++ {
+ b[bp] = s[j];
+ bp++
+ }
+ }
+ }
+ return b
+}
+
+// HasPrefix tests whether the byte array s begins with prefix.
+func HasPrefix(s, prefix []byte) bool {
+ return len(s) >= len(prefix) && Equal(s[0:len(prefix)], prefix)
+}
+
+// HasSuffix tests whether the byte array s ends with suffix.
+func HasSuffix(s, suffix []byte) bool {
+ return len(s) >= len(suffix) && Equal(s[len(s)-len(suffix):len(s)], suffix)
+}
--- /dev/null
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bytes
+
+import (
+ "bytes";
+ "io";
+ "testing";
+)
+
+func eq(a, b []string) bool {
+ if len(a) != len(b) {
+ return false;
+ }
+ for i := 0; i < len(a); i++ {
+ if a[i] != b[i] {
+ return false;
+ }
+ }
+ return true;
+}
+
+func arrayOfString(a [][]byte) []string {
+ result := make([]string, len(a));
+ for j := 0; j < len(a); j++ {
+ result[j] = string(a[j])
+ }
+ return result
+}
+
+// For ease of reading, the test cases use strings that are converted to byte
+// arrays before invoking the functions.
+
+var abcd = "abcd"
+var faces = "☺☻☹"
+var commas = "1,2,3,4"
+var dots = "1....2....3....4"
+
+type CompareTest struct {
+ a string;
+ b string;
+ cmp int;
+}
+var comparetests = []CompareTest {
+ CompareTest{ "", "", 0 },
+ CompareTest{ "a", "", 1 },
+ CompareTest{ "", "a", -1 },
+ CompareTest{ "abc", "abc", 0 },
+ CompareTest{ "ab", "abc", -1 },
+ CompareTest{ "abc", "ab", 1 },
+ CompareTest{ "x", "ab", 1 },
+ CompareTest{ "ab", "x", -1 },
+ CompareTest{ "x", "a", 1 },
+ CompareTest{ "b", "x", -1 },
+}
+
+func TestCompare(t *testing.T) {
+ for i := 0; i < len(comparetests); i++ {
+ tt := comparetests[i];
+ a := io.StringBytes(tt.a);
+ b := io.StringBytes(tt.b);
+ cmp := Compare(a, b);
+ eql := Equal(a, b);
+ if cmp != tt.cmp {
+ t.Errorf(`Compare(%q, %q) = %v`, tt.a, tt.b, cmp);
+ }
+ if eql != (tt.cmp==0) {
+ t.Errorf(`Equal(%q, %q) = %v`, tt.a, tt.b, eql);
+ }
+ }
+}
+
+
+type ExplodeTest struct {
+ s string;
+ a []string;
+}
+var explodetests = []ExplodeTest {
+ ExplodeTest{ abcd, []string{"a", "b", "c", "d"} },
+ ExplodeTest{ faces, []string{"☺", "☻", "☹" } },
+}
+func TestExplode(t *testing.T) {
+ for i := 0; i < len(explodetests); i++ {
+ tt := explodetests[i];
+ a := Explode(io.StringBytes(tt.s));
+ result := arrayOfString(a);
+ if !eq(result, tt.a) {
+ t.Errorf(`Explode("%s") = %v; want %v`, tt.s, result, tt.a);
+ continue;
+ }
+ s := Join(a, []byte{});
+ if string(s) != tt.s {
+ t.Errorf(`Join(Explode("%s"), "") = "%s"`, tt.s, s);
+ }
+ }
+}
+
+
+type SplitTest struct {
+ s string;
+ sep string;
+ a []string;
+}
+var splittests = []SplitTest {
+ SplitTest{ abcd, "a", []string{"", "bcd"} },
+ SplitTest{ abcd, "z", []string{"abcd"} },
+ SplitTest{ abcd, "", []string{"a", "b", "c", "d"} },
+ SplitTest{ commas, ",", []string{"1", "2", "3", "4"} },
+ SplitTest{ dots, "...", []string{"1", ".2", ".3", ".4"} },
+ SplitTest{ faces, "☹", []string{"☺☻", ""} },
+ SplitTest{ faces, "~", []string{faces} },
+ SplitTest{ faces, "", []string{"☺", "☻", "☹"} },
+}
+func TestSplit(t *testing.T) {
+ for i := 0; i < len(splittests); i++ {
+ tt := splittests[i];
+ a := Split(io.StringBytes(tt.s), io.StringBytes(tt.sep));
+ result := arrayOfString(a);
+ if !eq(result, tt.a) {
+ t.Errorf(`Split("%s", "%s") = %v; want %v`, tt.s, tt.sep, result, tt.a);
+ continue;
+ }
+ s := Join(a, io.StringBytes(tt.sep));
+ if string(s) != tt.s {
+ t.Errorf(`Join(Split("%s", "%s"), "%s") = "%s"`, tt.s, tt.sep, tt.sep, s);
+ }
+ }
+}