1 files changed, 625 insertions, 0 deletions
diff --git a/libgo/go/bytes/bytes.go b/libgo/go/bytes/bytes.go
new file mode 100644
index 00000000000..1939fd56784
--- /dev/null
+++ b/libgo/go/bytes/bytes.go
@@ -0,0 +1,625 @@
+// 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.
+
+// The bytes package implements functions for the manipulation of byte slices.
+// Analogous to the facilities of the strings package.
+package bytes
+
+import (
+	"unicode"
+	"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 {
+	m := len(a)
+	if m > len(b) {
+		m = len(b)
+	}
+	for i, ac := range a[0:m] {
+		bc := b[i]
+		switch {
+		case ac > bc:
+			return 1
+		case ac < bc:
+			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, c := range a {
+		if c != b[i] {
+			return false
+		}
+	}
+	return true
+}
+
+// explode splits s into an array of UTF-8 sequences, one per Unicode character (still arrays of bytes),
+// up to a maximum of n byte arrays. Invalid UTF-8 sequences are chopped into individual bytes.
+func explode(s []byte, n int) [][]byte {
+	if n <= 0 {
+		n = len(s)
+	}
+	a := make([][]byte, n)
+	var size int
+	na := 0
+	for len(s) > 0 {
+		if na+1 >= n {
+			a[na] = s
+			na++
+			break
+		}
+		_, size = utf8.DecodeRune(s)
+		a[na] = s[0:size]
+		s = s[size:]
+		na++
+	}
+	return a[0:na]
+}
+
+// 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
+}
+
+func indexBytePortable(s []byte, c byte) int {
+	for i, b := range s {
+		if b == c {
+			return i
+		}
+	}
+	return -1
+}
+
+// LastIndex returns the index of the last instance of sep in s, or -1 if sep is not present in s.
+func LastIndex(s, sep []byte) int {
+	n := len(sep)
+	if n == 0 {
+		return len(s)
+	}
+	c := sep[0]
+	for i := len(s) - n; i >= 0; i-- {
+		if s[i] == c && (n == 1 || Equal(s[i:i+n], sep)) {
+			return i
+		}
+	}
+	return -1
+}
+
+// IndexRune interprets s as a sequence of UTF-8-encoded Unicode code points.
+// It returns the byte index of the first occurrence in s of the given rune.
+// It returns -1 if rune is not present in s.
+func IndexRune(s []byte, rune int) int {
+	for i := 0; i < len(s); {
+		r, size := utf8.DecodeRune(s[i:])
+		if r == rune {
+			return i
+		}
+		i += size
+	}
+	return -1
+}
+
+// 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.
+func IndexAny(s []byte, chars string) int {
+	if len(chars) > 0 {
+		var rune, width int
+		for i := 0; i < len(s); i += width {
+			rune = int(s[i])
+			if rune < utf8.RuneSelf {
+				width = 1
+			} else {
+				rune, width = utf8.DecodeRune(s[i:])
+			}
+			for _, r := range chars {
+				if rune == r {
+					return i
+				}
+			}
+		}
+	}
+	return -1
+}
+
+// Generic split: splits after each instance of sep,
+// including sepSave bytes of sep in the subarrays.
+func genSplit(s, sep []byte, sepSave, n int) [][]byte {
+	if n == 0 {
+		return nil
+	}
+	if len(sep) == 0 {
+		return explode(s, n)
+	}
+	if n < 0 {
+		n = Count(s, sep) + 1
+	}
+	c := sep[0]
+	start := 0
+	a := make([][]byte, n)
+	na := 0
+	for i := 0; i+len(sep) <= len(s) && na+1 < n; i++ {
+		if s[i] == c && (len(sep) == 1 || Equal(s[i:i+len(sep)], sep)) {
+			a[na] = s[start : i+sepSave]
+			na++
+			start = i + len(sep)
+			i += len(sep) - 1
+		}
+	}
+	a[na] = s[start:]
+	return a[0 : na+1]
+}
+
+// Split slices s into subslices separated by sep and returns a slice of
+// the subslices between those separators.
+// If sep is empty, Split splits after each UTF-8 sequence.
+// The count determines the number of subslices to return:
+//   n > 0: at most n subslices; the last subslice will be the unsplit remainder.
+//   n == 0: the result is nil (zero subslices)
+//   n < 0: all subslices
+func Split(s, sep []byte, n int) [][]byte { return genSplit(s, sep, 0, n) }
+
+// SplitAfter slices s into subslices after each instance of sep and
+// returns a slice of those subslices.
+// If sep is empty, Split splits after each UTF-8 sequence.
+// The count determines the number of subslices to return:
+//   n > 0: at most n subslices; the last subslice will be the unsplit remainder.
+//   n == 0: the result is nil (zero subslices)
+//   n < 0: all subslices
+func SplitAfter(s, sep []byte, n int) [][]byte {
+	return genSplit(s, sep, len(sep), n)
+}
+
+// Fields splits the array s around each instance of one or more consecutive white space
+// characters, returning a slice of subarrays of s or an empty list if s contains only white space.
+func Fields(s []byte) [][]byte {
+	return FieldsFunc(s, unicode.IsSpace)
+}
+
+// FieldsFunc interprets s as a sequence of UTF-8-encoded Unicode code points.
+// It splits the array s at each run of code points c satisfying f(c) and
+// returns a slice of subarrays of s.  If no code points in s satisfy f(c), an
+// empty slice is returned.
+func FieldsFunc(s []byte, f func(int) bool) [][]byte {
+	n := 0
+	inField := false
+	for i := 0; i < len(s); {
+		rune, size := utf8.DecodeRune(s[i:])
+		wasInField := inField
+		inField = !f(rune)
+		if inField && !wasInField {
+			n++
+		}
+		i += size
+	}
+
+	a := make([][]byte, n)
+	na := 0
+	fieldStart := -1
+	for i := 0; i <= len(s) && na < n; {
+		rune, size := utf8.DecodeRune(s[i:])
+		if fieldStart < 0 && size > 0 && !f(rune) {
+			fieldStart = i
+			i += size
+			continue
+		}
+		if fieldStart >= 0 && (size == 0 || f(rune)) {
+			a[na] = s[fieldStart:i]
+			na++
+			fieldStart = -1
+		}
+		if size == 0 {
+			break
+		}
+		i += size
+	}
+	return a[0:na]
+}
+
+// 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):], suffix)
+}
+
+// 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.
+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
+	// fine.  It could also shrink but that falls out naturally.
+	maxbytes := len(s) // length of b
+	nbytes := 0        // number of bytes encoded in b
+	b := make([]byte, maxbytes)
+	for i := 0; i < len(s); {
+		wid := 1
+		rune := int(s[i])
+		if rune >= utf8.RuneSelf {
+			rune, wid = utf8.DecodeRune(s[i:])
+		}
+		rune = mapping(rune)
+		if rune >= 0 {
+			if nbytes+utf8.RuneLen(rune) > maxbytes {
+				// Grow the buffer.
+				maxbytes = maxbytes*2 + utf8.UTFMax
+				nb := make([]byte, maxbytes)
+				copy(nb, b[0:nbytes])
+				b = nb
+			}
+			nbytes += utf8.EncodeRune(rune, b[nbytes:maxbytes])
+		}
+		i += wid
+	}
+	return b[0:nbytes]
+}
+
+// Repeat returns a new byte slice consisting of count copies of b.
+func Repeat(b []byte, count int) []byte {
+	nb := make([]byte, len(b)*count)
+	bp := 0
+	for i := 0; i < count; i++ {
+		for j := 0; j < len(b); j++ {
+			nb[bp] = b[j]
+			bp++
+		}
+	}
+	return nb
+}
+
+// ToUpper returns a copy of the byte array s with all Unicode letters mapped to their upper case.
+func ToUpper(s []byte) []byte { return Map(unicode.ToUpper, s) }
+
+// ToUpper returns a copy of the byte array s with all Unicode letters mapped to their lower case.
+func ToLower(s []byte) []byte { return Map(unicode.ToLower, s) }
+
+// ToTitle returns a copy of the byte array s with all Unicode letters mapped to their title case.
+func ToTitle(s []byte) []byte { return Map(unicode.ToTitle, s) }
+
+// ToUpperSpecial returns a copy of the byte array s with all Unicode letters mapped to their
+// upper case, giving priority to the special casing rules.
+func ToUpperSpecial(_case unicode.SpecialCase, s []byte) []byte {
+	return Map(func(r int) int { return _case.ToUpper(r) }, s)
+}
+
+// ToLowerSpecial returns a copy of the byte array s with all Unicode letters mapped to their
+// lower case, giving priority to the special casing rules.
+func ToLowerSpecial(_case unicode.SpecialCase, s []byte) []byte {
+	return Map(func(r int) int { return _case.ToLower(r) }, s)
+}
+
+// ToTitleSpecial returns a copy of the byte array s with all Unicode letters mapped to their
+// title case, giving priority to the special casing rules.
+func ToTitleSpecial(_case unicode.SpecialCase, s []byte) []byte {
+	return Map(func(r int) int { return _case.ToTitle(r) }, s)
+}
+
+
+// isSeparator reports whether the rune could mark a word boundary.
+// TODO: update when package unicode captures more of the properties.
+func isSeparator(rune int) bool {
+	// ASCII alphanumerics and underscore are not separators
+	if rune <= 0x7F {
+		switch {
+		case '0' <= rune && rune <= '9':
+			return false
+		case 'a' <= rune && rune <= 'z':
+			return false
+		case 'A' <= rune && rune <= 'Z':
+			return false
+		case rune == '_':
+			return false
+		}
+		return true
+	}
+	// Letters and digits are not separators
+	if unicode.IsLetter(rune) || unicode.IsDigit(rune) {
+		return false
+	}
+	// Otherwise, all we can do for now is treat spaces as separators.
+	return unicode.IsSpace(rune)
+}
+
+// BUG(r): The rule Title uses for word boundaries does not handle Unicode punctuation properly.
+
+// Title returns a copy of s with all Unicode letters that begin words
+// mapped to their title case.
+func Title(s []byte) []byte {
+	// Use a closure here to remember state.
+	// Hackish but effective. Depends on Map scanning in order and calling
+	// the closure once per rune.
+	prev := ' '
+	return Map(
+		func(r int) int {
+			if isSeparator(prev) {
+				prev = r
+				return unicode.ToTitle(r)
+			}
+			prev = r
+			return r
+		},
+		s)
+}
+
+// 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 {
+	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) == truth {
+			return start
+		}
+		start += wid
+	}
+	return -1
+}
+
+// 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 {
+	for i := len(s); i > 0; {
+		rune, size := utf8.DecodeLastRune(s[0:i])
+		i -= size
+		if f(rune) == truth {
+			return i
+		}
+	}
+	return -1
+}
+
+func makeCutsetFunc(cutset string) func(rune int) bool {
+	return func(rune int) bool {
+		for _, c := range cutset {
+			if c == rune {
+				return true
+			}
+		}
+		return false
+	}
+}
+
+// Trim returns a subslice of s by slicing off all leading and
+// 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.
+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.
+func TrimRight(s []byte, cutset string) []byte {
+	return TrimRightFunc(s, makeCutsetFunc(cutset))
+}
+
+// TrimSpace returns a subslice of s by slicing off all leading and
+// trailing white space, as as defined by Unicode.
+func TrimSpace(s []byte) []byte {
+	return TrimFunc(s, unicode.IsSpace)
+}
+
+// How big to make a byte array when growing.
+// Heuristic: Scale by 50% to give n log n time.
+func resize(n int) int {
+	if n < 16 {
+		n = 16
+	}
+	return n + n/2
+}
+
+// Add appends the contents of t to the end of s and returns the result.
+// If s has enough capacity, it is extended in place; otherwise a
+// new array is allocated and returned.
+func Add(s, t []byte) []byte { // TODO
+	lens := len(s)
+	lent := len(t)
+	if lens+lent <= cap(s) {
+		s = s[0 : lens+lent]
+	} else {
+		news := make([]byte, lens+lent, resize(lens+lent))
+		copy(news, s)
+		s = news
+	}
+	copy(s[lens:lens+lent], t)
+	return s
+}
+
+// AddByte appends byte t to the end of s and returns the result.
+// If s has enough capacity, it is extended in place; otherwise a
+// new array is allocated and returned.
+func AddByte(s []byte, t byte) []byte { // TODO
+	lens := len(s)
+	if lens+1 <= cap(s) {
+		s = s[0 : lens+1]
+	} else {
+		news := make([]byte, lens+1, resize(lens+1))
+		copy(news, s)
+		s = news
+	}
+	s[lens] = t
+	return s
+}
+
+// Runes returns a slice of runes (Unicode code points) equivalent to s.
+func Runes(s []byte) []int {
+	t := make([]int, utf8.RuneCount(s))
+	i := 0
+	for len(s) > 0 {
+		r, l := utf8.DecodeRune(s)
+		t[i] = r
+		i++
+		s = s[l:]
+	}
+	return t
+}
+
+// Replace returns a copy of the slice s with the first n
+// non-overlapping instances of old replaced by new.
+// If n < 0, there is no limit on the number of replacements.
+func Replace(s, old, new []byte, n int) []byte {
+	if n == 0 {
+		return s // avoid allocation
+	}
+	// Compute number of replacements.
+	if m := Count(s, old); m == 0 {
+		return s // avoid allocation
+	} else if n <= 0 || m < n {
+		n = m
+	}
+
+	// Apply replacements to buffer.
+	t := make([]byte, len(s)+n*(len(new)-len(old)))
+	w := 0
+	start := 0
+	for i := 0; i < n; i++ {
+		j := start
+		if len(old) == 0 {
+			if i > 0 {
+				_, wid := utf8.DecodeRune(s[start:])
+				j += wid
+			}
+		} else {
+			j += Index(s[start:], old)
+		}
+		w += copy(t[w:], s[start:j])
+		w += copy(t[w:], new)
+		start = j + len(old)
+	}
+	w += copy(t[w:], s[start:])
+	return t[0:w]
+}