return -1
}
-// IndexAny interprets s as a sequence of UTF-8 encoded Unicode code points.
+// IndexAny interprets s as a sequence of UTF-8-encoded Unicode code points.
// It returns the byte index of the first occurrence in s of any of the Unicode
// code points in chars. It returns -1 if chars is empty or if there is no code
// point in common.
// Map returns a copy of the byte array s with all its characters modified
// according to the mapping function. If mapping returns a negative value, the character is
// dropped from the string with no replacement. The characters in s and the
-// output are interpreted as UTF-8 encoded Unicode code points.
+// output are interpreted as UTF-8-encoded Unicode code points.
func Map(mapping func(rune int) int, s []byte) []byte {
// In the worst case, the array can grow when mapped, making
// things unpleasant. But it's so rare we barge in assuming it's
s)
}
-// TrimLeftFunc returns a subslice of s by slicing off all leading UTF-8 encoded
+// TrimLeftFunc returns a subslice of s by slicing off all leading UTF-8-encoded
// Unicode code points c that satisfy f(c).
func TrimLeftFunc(s []byte, f func(r int) bool) []byte {
- var start, wid int
- for start = 0; start < len(s); start += wid {
- wid = 1
+ i := indexFunc(s, f, false)
+ if i == -1 {
+ return nil
+ }
+ return s[i:]
+}
+
+// TrimRightFunc returns a subslice of s by slicing off all trailing UTF-8
+// encoded Unicode code points c that satisfy f(c).
+func TrimRightFunc(s []byte, f func(r int) bool) []byte {
+ i := lastIndexFunc(s, f, false)
+ if i >= 0 && s[i] >= utf8.RuneSelf {
+ _, wid := utf8.DecodeRune(s[i:])
+ i += wid
+ } else {
+ i++
+ }
+ return s[0:i]
+}
+
+// TrimFunc returns a subslice of s by slicing off all leading and trailing
+// UTF-8-encoded Unicode code points c that satisfy f(c).
+func TrimFunc(s []byte, f func(r int) bool) []byte {
+ return TrimRightFunc(TrimLeftFunc(s, f), f)
+}
+
+// IndexFunc interprets s as a sequence of UTF-8-encoded Unicode code points.
+// It returns the byte index in s of the first Unicode
+// code point satisfying f(c), or -1 if none do.
+func IndexFunc(s []byte, f func(r int) bool) int {
+ return indexFunc(s, f, true)
+}
+
+// LastIndexFunc interprets s as a sequence of UTF-8-encoded Unicode code points.
+// It returns the byte index in s of the last Unicode
+// code point satisfying f(c), or -1 if none do.
+func LastIndexFunc(s []byte, f func(r int) bool) int {
+ return lastIndexFunc(s, f, true)
+}
+
+// indexFunc is the same as IndexFunc except that if
+// truth==false, the sense of the predicate function is
+// inverted.
+func indexFunc(s []byte, f func(r int) bool, truth bool) int {
+ start := 0
+ for start < len(s) {
+ wid := 1
rune := int(s[start])
if rune >= utf8.RuneSelf {
rune, wid = utf8.DecodeRune(s[start:])
}
- if !f(rune) {
- break
+ if f(rune) == truth {
+ return start
}
+ start += wid
}
- return s[start:]
+ return -1
}
-// TrimRightFunc returns a subslice of s by slicing off all trailing UTF-8
-// encoded Unicode code points c that satisfy f(c).
-func TrimRightFunc(s []byte, f func(r int) bool) []byte {
- var end, wid int
- for end = len(s); end > 0; end -= wid {
- wid = 1
- rune := int(s[end-wid])
+// lastIndexFunc is the same as LastIndexFunc except that if
+// truth==false, the sense of the predicate function is
+// inverted.
+func lastIndexFunc(s []byte, f func(r int) bool, truth bool) int {
+ end := len(s)
+ for end > 0 {
+ start := end - 1
+ rune := int(s[start])
if rune >= utf8.RuneSelf {
// Back up & look for beginning of rune. Mustn't pass start.
- for wid = 2; end-wid >= 0 && !utf8.RuneStart(s[end-wid]); wid++ {
+ for start--; start >= 0; start-- {
+ if utf8.RuneStart(s[start]) {
+ break
+ }
+ }
+ if start < 0 {
+ return -1
}
- if end-wid < 0 { // invalid UTF-8 sequence; stop processing
- break
+ var wid int
+ rune, wid = utf8.DecodeRune(s[start:end])
+
+ // If we've decoded fewer bytes than we expected,
+ // we've got some invalid UTF-8, so make sure we return
+ // the last possible index in s.
+ if start+wid < end && f(utf8.RuneError) == truth {
+ return end - 1
}
- rune, wid = utf8.DecodeRune(s[end-wid : end])
}
- if !f(rune) {
- break
+ if f(rune) == truth {
+ return start
}
+ end = start
}
- return s[0:end]
-}
-
-// TrimFunc returns a subslice of s by slicing off all leading and trailing
-// UTF-8 encoded Unicode code points c that satisfy f(c).
-func TrimFunc(s []byte, f func(r int) bool) []byte {
- return TrimRightFunc(TrimLeftFunc(s, f), f)
+ return -1
}
func makeCutsetFunc(cutset string) func(rune int) bool {
}
// Trim returns a subslice of s by slicing off all leading and
-// trailing UTF-8 encoded Unicode code points contained in cutset.
+// trailing UTF-8-encoded Unicode code points contained in cutset.
func Trim(s []byte, cutset string) []byte {
return TrimFunc(s, makeCutsetFunc(cutset))
}
// TrimLeft returns a subslice of s by slicing off all leading
-// UTF-8 encoded Unicode code points contained in cutset.
+// UTF-8-encoded Unicode code points contained in cutset.
func TrimLeft(s []byte, cutset string) []byte {
return TrimLeftFunc(s, makeCutsetFunc(cutset))
}
// TrimRight returns a subslice of s by slicing off all trailing
-// UTF-8 encoded Unicode code points that are contained in cutset.
+// UTF-8-encoded Unicode code points that are contained in cutset.
func TrimRight(s []byte, cutset string) []byte {
return TrimRightFunc(s, makeCutsetFunc(cutset))
}
. "bytes"
"testing"
"unicode"
+ "utf8"
)
func eq(a, b []string) bool {
StringTest{" \t\r\n x\t\t\r\r\n\n ", "x"},
StringTest{" \u2000\t\r\n x\t\t\r\r\ny\n \u3000", "x\t\t\r\r\ny"},
StringTest{"1 \t\r\n2", "1 \t\r\n2"},
- StringTest{" x\x80", "x\x80"}, // invalid UTF-8 on end
- StringTest{" x\xc0", "x\xc0"}, // invalid UTF-8 on end
+ StringTest{" x\x80", "x\x80"},
+ StringTest{" x\xc0", "x\xc0"},
+ StringTest{"x \xc0\xc0 ", "x \xc0\xc0"},
+ StringTest{"x \xc0", "x \xc0"},
+ StringTest{"x \xc0 ", "x \xc0"},
+ StringTest{"x \xc0\xc0 ", "x \xc0\xc0"},
+ StringTest{"x ☺\xc0\xc0 ", "x ☺\xc0\xc0"},
+ StringTest{"x ☺ ", "x ☺"},
}
// Bytes returns a new slice containing the bytes in s.
TrimTest{TrimRight, "abba", "", "abba"},
TrimTest{TrimRight, "", "123", ""},
TrimTest{TrimRight, "", "", ""},
+ TrimTest{TrimRight, "☺\xc0", "☺", "☺\xc0"},
}
func TestTrim(t *testing.T) {
}
}
+type predicate struct {
+ f func(r int) bool
+ name string
+}
+
+var isSpace = predicate{unicode.IsSpace, "IsSpace"}
+var isDigit = predicate{unicode.IsDigit, "IsDigit"}
+var isUpper = predicate{unicode.IsUpper, "IsUpper"}
+var isValidRune = predicate{
+ func(r int) bool {
+ return r != utf8.RuneError
+ },
+ "IsValidRune",
+}
+
type TrimFuncTest struct {
- f func(r int) bool
- name, in, out string
+ f predicate
+ in, out string
+}
+
+func not(p predicate) predicate {
+ return predicate{
+ func(r int) bool {
+ return !p.f(r)
+ },
+ "not " + p.name,
+ }
}
var trimFuncTests = []TrimFuncTest{
- TrimFuncTest{unicode.IsSpace, "IsSpace", space + " hello " + space, "hello"},
- TrimFuncTest{unicode.IsDigit, "IsDigit", "\u0e50\u0e5212hello34\u0e50\u0e51", "hello"},
- TrimFuncTest{unicode.IsUpper, "IsUpper", "\u2C6F\u2C6F\u2C6F\u2C6FABCDhelloEF\u2C6F\u2C6FGH\u2C6F\u2C6F", "hello"},
+ TrimFuncTest{isSpace, space + " hello " + space, "hello"},
+ TrimFuncTest{isDigit, "\u0e50\u0e5212hello34\u0e50\u0e51", "hello"},
+ TrimFuncTest{isUpper, "\u2C6F\u2C6F\u2C6F\u2C6FABCDhelloEF\u2C6F\u2C6FGH\u2C6F\u2C6F", "hello"},
+ TrimFuncTest{not(isSpace), "hello" + space + "hello", space},
+ TrimFuncTest{not(isDigit), "hello\u0e50\u0e521234\u0e50\u0e51helo", "\u0e50\u0e521234\u0e50\u0e51"},
+ TrimFuncTest{isValidRune, "ab\xc0a\xc0cd", "\xc0a\xc0"},
+ TrimFuncTest{not(isValidRune), "\xc0a\xc0", "a"},
}
func TestTrimFunc(t *testing.T) {
for _, tc := range trimFuncTests {
- actual := string(TrimFunc([]byte(tc.in), tc.f))
+ actual := string(TrimFunc([]byte(tc.in), tc.f.f))
if actual != tc.out {
- t.Errorf("TrimFunc(%q, %q) = %q; want %q", tc.in, tc.name, actual, tc.out)
+ t.Errorf("TrimFunc(%q, %q) = %q; want %q", tc.in, tc.f.name, actual, tc.out)
+ }
+ }
+}
+
+type IndexFuncTest struct {
+ in string
+ f predicate
+ first, last int
+}
+
+var indexFuncTests = []IndexFuncTest{
+ IndexFuncTest{"", isValidRune, -1, -1},
+ IndexFuncTest{"abc", isDigit, -1, -1},
+ IndexFuncTest{"0123", isDigit, 0, 3},
+ IndexFuncTest{"a1b", isDigit, 1, 1},
+ IndexFuncTest{space, isSpace, 0, len(space) - 3}, // last rune in space is 3 bytes
+ IndexFuncTest{"\u0e50\u0e5212hello34\u0e50\u0e51", isDigit, 0, 18},
+ IndexFuncTest{"\u2C6F\u2C6F\u2C6F\u2C6FABCDhelloEF\u2C6F\u2C6FGH\u2C6F\u2C6F", isUpper, 0, 34},
+ IndexFuncTest{"12\u0e50\u0e52hello34\u0e50\u0e51", not(isDigit), 8, 12},
+
+ // tests of invalid UTF-8
+ IndexFuncTest{"\x801", isDigit, 1, 1},
+ IndexFuncTest{"\x80abc", isDigit, -1, -1},
+ IndexFuncTest{"\xc0a\xc0", isValidRune, 1, 1},
+ IndexFuncTest{"\xc0a\xc0", not(isValidRune), 0, 2},
+ IndexFuncTest{"\xc0☺\xc0", not(isValidRune), 0, 4},
+ IndexFuncTest{"\xc0☺\xc0\xc0", not(isValidRune), 0, 5},
+ IndexFuncTest{"ab\xc0a\xc0cd", not(isValidRune), 2, 4},
+ IndexFuncTest{"a\xe0\x80cd", not(isValidRune), 1, 2},
+}
+
+func TestIndexFunc(t *testing.T) {
+ for _, tc := range indexFuncTests {
+ first := IndexFunc([]byte(tc.in), tc.f.f)
+ if first != tc.first {
+ t.Errorf("IndexFunc(%q, %s) = %d; want %d", tc.in, tc.f.name, first, tc.first)
+ }
+ last := LastIndexFunc([]byte(tc.in), tc.f.f)
+ if last != tc.last {
+ t.Errorf("LastIndexFunc(%q, %s) = %d; want %d", tc.in, tc.f.name, last, tc.last)
}
}
}
// indexFunc is the same as IndexFunc except that if
// truth==false, the sense of the predicate function is
-// inverted. We could use IndexFunc directly, but this
-// way saves a closure allocation.
+// inverted.
func indexFunc(s string, f func(r int) bool, truth bool) int {
start := 0
for start < len(s) {
// lastIndexFunc is the same as LastIndexFunc except that if
// truth==false, the sense of the predicate function is
-// inverted. We could use IndexFunc directly, but this
-// way saves a closure allocation.
+// inverted.
func lastIndexFunc(s string, f func(r int) bool, truth bool) int {
end := len(s)
for end > 0 {
TrimTest{TrimRight, "☺\xc0", "☺", "☺\xc0"},
}
-// naiveTrimRight implements a version of TrimRight
-// by scanning forwards from the start of s.
-func naiveTrimRight(s string, cutset string) string {
- i := -1
- for j, r := range s {
- if IndexRune(cutset, r) == -1 {
- i = j
- }
- }
- if i >= 0 && s[i] >= utf8.RuneSelf {
- _, wid := utf8.DecodeRuneInString(s[i:])
- i += wid
- } else {
- i++
- }
- return s[0:i]
-}
-
-
func TestTrim(t *testing.T) {
for _, tc := range trimTests {
actual := tc.f(tc.in, tc.cutset)
if actual != tc.out {
t.Errorf("%s(%q, %q) = %q; want %q", name, tc.in, tc.cutset, actual, tc.out)
}
- // test equivalence of TrimRight to naive version
- if tc.f == TrimRight {
- naive := naiveTrimRight(tc.in, tc.cutset)
- if naive != actual {
- t.Errorf("TrimRight(%q, %q) = %q, want %q", tc.in, tc.cutset, actual, naive)
- }
- }
}
}
+type predicate struct {
+ f func(r int) bool
+ name string
+}
+
var isSpace = predicate{unicode.IsSpace, "IsSpace"}
var isDigit = predicate{unicode.IsDigit, "IsDigit"}
var isUpper = predicate{unicode.IsUpper, "IsUpper"}
"IsValidRune",
}
-type predicate struct {
- f func(r int) bool
- name string
-}
-
type TrimFuncTest struct {
f predicate
in, out string
IndexFuncTest{"\u2C6F\u2C6F\u2C6F\u2C6FABCDhelloEF\u2C6F\u2C6FGH\u2C6F\u2C6F", isUpper, 0, 34},
IndexFuncTest{"12\u0e50\u0e52hello34\u0e50\u0e51", not(isDigit), 8, 12},
- // broken unicode tests
+ // tests of invalid UTF-8
IndexFuncTest{"\x801", isDigit, 1, 1},
IndexFuncTest{"\x80abc", isDigit, -1, -1},
IndexFuncTest{"\xc0a\xc0", isValidRune, 1, 1},