1 files changed, 252 insertions, 0 deletions
diff --git a/libgo/go/archive/tar/strconv.go b/libgo/go/archive/tar/strconv.go
new file mode 100644
index 00000000000..bb5b51c02de
--- /dev/null
+++ b/libgo/go/archive/tar/strconv.go
@@ -0,0 +1,252 @@
+// Copyright 2016 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 tar
+
+import (
+	"bytes"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func isASCII(s string) bool {
+	for _, c := range s {
+		if c >= 0x80 {
+			return false
+		}
+	}
+	return true
+}
+
+func toASCII(s string) string {
+	if isASCII(s) {
+		return s
+	}
+	var buf bytes.Buffer
+	for _, c := range s {
+		if c < 0x80 {
+			buf.WriteByte(byte(c))
+		}
+	}
+	return buf.String()
+}
+
+type parser struct {
+	err error // Last error seen
+}
+
+type formatter struct {
+	err error // Last error seen
+}
+
+// parseString parses bytes as a NUL-terminated C-style string.
+// If a NUL byte is not found then the whole slice is returned as a string.
+func (*parser) parseString(b []byte) string {
+	n := 0
+	for n < len(b) && b[n] != 0 {
+		n++
+	}
+	return string(b[0:n])
+}
+
+// Write s into b, terminating it with a NUL if there is room.
+func (f *formatter) formatString(b []byte, s string) {
+	if len(s) > len(b) {
+		f.err = ErrFieldTooLong
+		return
+	}
+	ascii := toASCII(s)
+	copy(b, ascii)
+	if len(ascii) < len(b) {
+		b[len(ascii)] = 0
+	}
+}
+
+// fitsInBase256 reports whether x can be encoded into n bytes using base-256
+// encoding. Unlike octal encoding, base-256 encoding does not require that the
+// string ends with a NUL character. Thus, all n bytes are available for output.
+//
+// If operating in binary mode, this assumes strict GNU binary mode; which means
+// that the first byte can only be either 0x80 or 0xff. Thus, the first byte is
+// equivalent to the sign bit in two's complement form.
+func fitsInBase256(n int, x int64) bool {
+	var binBits = uint(n-1) * 8
+	return n >= 9 || (x >= -1<<binBits && x < 1<<binBits)
+}
+
+// parseNumeric parses the input as being encoded in either base-256 or octal.
+// This function may return negative numbers.
+// If parsing fails or an integer overflow occurs, err will be set.
+func (p *parser) parseNumeric(b []byte) int64 {
+	// Check for base-256 (binary) format first.
+	// If the first bit is set, then all following bits constitute a two's
+	// complement encoded number in big-endian byte order.
+	if len(b) > 0 && b[0]&0x80 != 0 {
+		// Handling negative numbers relies on the following identity:
+		//	-a-1 == ^a
+		//
+		// If the number is negative, we use an inversion mask to invert the
+		// data bytes and treat the value as an unsigned number.
+		var inv byte // 0x00 if positive or zero, 0xff if negative
+		if b[0]&0x40 != 0 {
+			inv = 0xff
+		}
+
+		var x uint64
+		for i, c := range b {
+			c ^= inv // Inverts c only if inv is 0xff, otherwise does nothing
+			if i == 0 {
+				c &= 0x7f // Ignore signal bit in first byte
+			}
+			if (x >> 56) > 0 {
+				p.err = ErrHeader // Integer overflow
+				return 0
+			}
+			x = x<<8 | uint64(c)
+		}
+		if (x >> 63) > 0 {
+			p.err = ErrHeader // Integer overflow
+			return 0
+		}
+		if inv == 0xff {
+			return ^int64(x)
+		}
+		return int64(x)
+	}
+
+	// Normal case is base-8 (octal) format.
+	return p.parseOctal(b)
+}
+
+// Write x into b, as binary (GNUtar/star extension).
+func (f *formatter) formatNumeric(b []byte, x int64) {
+	if fitsInBase256(len(b), x) {
+		for i := len(b) - 1; i >= 0; i-- {
+			b[i] = byte(x)
+			x >>= 8
+		}
+		b[0] |= 0x80 // Highest bit indicates binary format
+		return
+	}
+
+	f.formatOctal(b, 0) // Last resort, just write zero
+	f.err = ErrFieldTooLong
+}
+
+func (p *parser) parseOctal(b []byte) int64 {
+	// Because unused fields are filled with NULs, we need
+	// to skip leading NULs. Fields may also be padded with
+	// spaces or NULs.
+	// So we remove leading and trailing NULs and spaces to
+	// be sure.
+	b = bytes.Trim(b, " \x00")
+
+	if len(b) == 0 {
+		return 0
+	}
+	x, perr := strconv.ParseUint(p.parseString(b), 8, 64)
+	if perr != nil {
+		p.err = ErrHeader
+	}
+	return int64(x)
+}
+
+func (f *formatter) formatOctal(b []byte, x int64) {
+	s := strconv.FormatInt(x, 8)
+	// Add leading zeros, but leave room for a NUL.
+	if n := len(b) - len(s) - 1; n > 0 {
+		s = strings.Repeat("0", n) + s
+	}
+	f.formatString(b, s)
+}
+
+// parsePAXTime takes a string of the form %d.%d as described in the PAX
+// specification. Note that this implementation allows for negative timestamps,
+// which is allowed for by the PAX specification, but not always portable.
+func parsePAXTime(s string) (time.Time, error) {
+	const maxNanoSecondDigits = 9
+
+	// Split string into seconds and sub-seconds parts.
+	ss, sn := s, ""
+	if pos := strings.IndexByte(s, '.'); pos >= 0 {
+		ss, sn = s[:pos], s[pos+1:]
+	}
+
+	// Parse the seconds.
+	secs, err := strconv.ParseInt(ss, 10, 64)
+	if err != nil {
+		return time.Time{}, ErrHeader
+	}
+	if len(sn) == 0 {
+		return time.Unix(secs, 0), nil // No sub-second values
+	}
+
+	// Parse the nanoseconds.
+	if strings.Trim(sn, "0123456789") != "" {
+		return time.Time{}, ErrHeader
+	}
+	if len(sn) < maxNanoSecondDigits {
+		sn += strings.Repeat("0", maxNanoSecondDigits-len(sn)) // Right pad
+	} else {
+		sn = sn[:maxNanoSecondDigits] // Right truncate
+	}
+	nsecs, _ := strconv.ParseInt(sn, 10, 64) // Must succeed
+	if len(ss) > 0 && ss[0] == '-' {
+		return time.Unix(secs, -1*int64(nsecs)), nil // Negative correction
+	}
+	return time.Unix(secs, int64(nsecs)), nil
+}
+
+// TODO(dsnet): Implement formatPAXTime.
+
+// parsePAXRecord parses the input PAX record string into a key-value pair.
+// If parsing is successful, it will slice off the currently read record and
+// return the remainder as r.
+//
+// A PAX record is of the following form:
+//	"%d %s=%s\n" % (size, key, value)
+func parsePAXRecord(s string) (k, v, r string, err error) {
+	// The size field ends at the first space.
+	sp := strings.IndexByte(s, ' ')
+	if sp == -1 {
+		return "", "", s, ErrHeader
+	}
+
+	// Parse the first token as a decimal integer.
+	n, perr := strconv.ParseInt(s[:sp], 10, 0) // Intentionally parse as native int
+	if perr != nil || n < 5 || int64(len(s)) < n {
+		return "", "", s, ErrHeader
+	}
+
+	// Extract everything between the space and the final newline.
+	rec, nl, rem := s[sp+1:n-1], s[n-1:n], s[n:]
+	if nl != "\n" {
+		return "", "", s, ErrHeader
+	}
+
+	// The first equals separates the key from the value.
+	eq := strings.IndexByte(rec, '=')
+	if eq == -1 {
+		return "", "", s, ErrHeader
+	}
+	return rec[:eq], rec[eq+1:], rem, nil
+}
+
+// formatPAXRecord formats a single PAX record, prefixing it with the
+// appropriate length.
+func formatPAXRecord(k, v string) string {
+	const padding = 3 // Extra padding for ' ', '=', and '\n'
+	size := len(k) + len(v) + padding
+	size += len(strconv.Itoa(size))
+	record := fmt.Sprintf("%d %s=%s\n", size, k, v)
+
+	// Final adjustment if adding size field increased the record size.
+	if len(record) != size {
+		size = len(record)
+		record = fmt.Sprintf("%d %s=%s\n", size, k, v)
+	}
+	return record
+}