Adds unmodified source files from golang.org.

third_party/golang/src/fmt/fmt.go

Index: third_party/golang/src/fmt/fmt.go
diff --git a/third_party/golang/src/fmt/fmt.go b/third_party/golang/src/fmt/fmt.go
new file mode 100644
index 0000000000000000000000000000000000000000..517b18f7d4378e3c60bc3f9c123d10273d42a2ac
--- /dev/null
+++ b/third_party/golang/src/fmt/fmt.go
@@ -0,0 +1,535 @@
+// 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 fmt
+
+import (
+	"math"
+	"strconv"
+	"unicode/utf8"
+)
+
+const (
+	// %b of an int64, plus a sign.
+	// Hex can add 0x and we handle it specially.
+	nByte = 65
+
+	ldigits = "0123456789abcdef"
+	udigits = "0123456789ABCDEF"
+)
+
+const (
+	signed   = true
+	unsigned = false
+)
+
+var padZeroBytes = make([]byte, nByte)
+var padSpaceBytes = make([]byte, nByte)
+
+func init() {
+	for i := 0; i < nByte; i++ {
+		padZeroBytes[i] = '0'
+		padSpaceBytes[i] = ' '
+	}
+}
+
+// flags placed in a separate struct for easy clearing.
+type fmtFlags struct {
+	widPresent  bool
+	precPresent bool
+	minus       bool
+	plus        bool
+	sharp       bool
+	space       bool
+	unicode     bool
+	uniQuote    bool // Use 'x'= prefix for %U if printable.
+	zero        bool
+
+	// For the formats %+v %#v, we set the plusV/sharpV flags
+	// and clear the plus/sharp flags since %+v and %#v are in effect
+	// different, flagless formats set at the top level.
+	plusV  bool
+	sharpV bool
+}
+
+// A fmt is the raw formatter used by Printf etc.
+// It prints into a buffer that must be set up separately.
+type fmt struct {
+	intbuf [nByte]byte
+	buf    *buffer
+	// width, precision
+	wid  int
+	prec int
+	fmtFlags
+}
+
+func (f *fmt) clearflags() {
+	f.fmtFlags = fmtFlags{}
+}
+
+func (f *fmt) init(buf *buffer) {
+	f.buf = buf
+	f.clearflags()
+}
+
+// computePadding computes left and right padding widths (only one will be non-zero).
+func (f *fmt) computePadding(width int) (padding []byte, leftWidth, rightWidth int) {
+	left := !f.minus
+	w := f.wid
+	if w < 0 {
+		left = false
+		w = -w
+	}
+	w -= width
+	if w > 0 {
+		if left && f.zero {
+			return padZeroBytes, w, 0
+		}
+		if left {
+			return padSpaceBytes, w, 0
+		} else {
+			// can't be zero padding on the right
+			return padSpaceBytes, 0, w
+		}
+	}
+	return
+}
+
+// writePadding generates n bytes of padding.
+func (f *fmt) writePadding(n int, padding []byte) {
+	for n > 0 {
+		m := n
+		if m > nByte {
+			m = nByte
+		}
+		f.buf.Write(padding[0:m])
+		n -= m
+	}
+}
+
+// pad appends b to f.buf, padded on left (w > 0) or right (w < 0 or f.minus).
+func (f *fmt) pad(b []byte) {
+	if !f.widPresent || f.wid == 0 {
+		f.buf.Write(b)
+		return
+	}
+	padding, left, right := f.computePadding(utf8.RuneCount(b))
+	if left > 0 {
+		f.writePadding(left, padding)
+	}
+	f.buf.Write(b)
+	if right > 0 {
+		f.writePadding(right, padding)
+	}
+}
+
+// padString appends s to buf, padded on left (w > 0) or right (w < 0 or f.minus).
+func (f *fmt) padString(s string) {
+	if !f.widPresent || f.wid == 0 {
+		f.buf.WriteString(s)
+		return
+	}
+	padding, left, right := f.computePadding(utf8.RuneCountInString(s))
+	if left > 0 {
+		f.writePadding(left, padding)
+	}
+	f.buf.WriteString(s)
+	if right > 0 {
+		f.writePadding(right, padding)
+	}
+}
+
+var (
+	trueBytes  = []byte("true")
+	falseBytes = []byte("false")
+)
+
+// fmt_boolean formats a boolean.
+func (f *fmt) fmt_boolean(v bool) {
+	if v {
+		f.pad(trueBytes)
+	} else {
+		f.pad(falseBytes)
+	}
+}
+
+// integer; interprets prec but not wid.  Once formatted, result is sent to pad()
+// and then flags are cleared.
+func (f *fmt) integer(a int64, base uint64, signedness bool, digits string) {
+	// precision of 0 and value of 0 means "print nothing"
+	if f.precPresent && f.prec == 0 && a == 0 {
+		return
+	}
+
+	negative := signedness == signed && a < 0
+	if negative {
+		a = -a
+	}
+
+	var buf []byte = f.intbuf[0:]
+	if f.widPresent || f.precPresent || f.plus || f.space {
+		width := f.wid + f.prec // Only one will be set, both are positive; this provides the maximum.
+		if base == 16 && f.sharp {
+			// Also adds "0x".
+			width += 2
+		}
+		if f.unicode {
+			// Also adds "U+".
+			width += 2
+			if f.uniQuote {
+				// Also adds " 'x'".
+				width += 1 + 1 + utf8.UTFMax + 1
+			}
+		}
+		if negative || f.plus || f.space {
+			width++
+		}
+		if width > nByte {
+			// We're going to need a bigger boat.
+			buf = make([]byte, width)
+		}
+	}
+
+	// two ways to ask for extra leading zero digits: %.3d or %03d.
+	// apparently the first cancels the second.
+	prec := 0
+	if f.precPresent {
+		prec = f.prec
+		f.zero = false
+	} else if f.zero && f.widPresent && !f.minus && f.wid > 0 {
+		prec = f.wid
+		if negative || f.plus || f.space {
+			prec-- // leave room for sign
+		}
+	}
+
+	// format a into buf, ending at buf[i].  (printing is easier right-to-left.)
+	// a is made into unsigned ua.  we could make things
+	// marginally faster by splitting the 32-bit case out into a separate
+	// block but it's not worth the duplication, so ua has 64 bits.
+	i := len(buf)
+	ua := uint64(a)
+	// use constants for the division and modulo for more efficient code.
+	// switch cases ordered by popularity.
+	switch base {
+	case 10:
+		for ua >= 10 {
+			i--
+			next := ua / 10
+			buf[i] = byte('0' + ua - next*10)
+			ua = next
+		}
+	case 16:
+		for ua >= 16 {
+			i--
+			buf[i] = digits[ua&0xF]
+			ua >>= 4
+		}
+	case 8:
+		for ua >= 8 {
+			i--
+			buf[i] = byte('0' + ua&7)
+			ua >>= 3
+		}
+	case 2:
+		for ua >= 2 {
+			i--
+			buf[i] = byte('0' + ua&1)
+			ua >>= 1
+		}
+	default:
+		panic("fmt: unknown base; can't happen")
+	}
+	i--
+	buf[i] = digits[ua]
+	for i > 0 && prec > len(buf)-i {
+		i--
+		buf[i] = '0'
+	}
+
+	// Various prefixes: 0x, -, etc.
+	if f.sharp {
+		switch base {
+		case 8:
+			if buf[i] != '0' {
+				i--
+				buf[i] = '0'
+			}
+		case 16:
+			i--
+			buf[i] = 'x' + digits[10] - 'a'
+			i--
+			buf[i] = '0'
+		}
+	}
+	if f.unicode {
+		i--
+		buf[i] = '+'
+		i--
+		buf[i] = 'U'
+	}
+
+	if negative {
+		i--
+		buf[i] = '-'
+	} else if f.plus {
+		i--
+		buf[i] = '+'
+	} else if f.space {
+		i--
+		buf[i] = ' '
+	}
+
+	// If we want a quoted char for %#U, move the data up to make room.
+	if f.unicode && f.uniQuote && a >= 0 && a <= utf8.MaxRune && strconv.IsPrint(rune(a)) {
+		runeWidth := utf8.RuneLen(rune(a))
+		width := 1 + 1 + runeWidth + 1 // space, quote, rune, quote
+		copy(buf[i-width:], buf[i:])   // guaranteed to have enough room.
+		i -= width
+		// Now put " 'x'" at the end.
+		j := len(buf) - width
+		buf[j] = ' '
+		j++
+		buf[j] = '\''
+		j++
+		utf8.EncodeRune(buf[j:], rune(a))
+		j += runeWidth
+		buf[j] = '\''
+	}
+
+	f.pad(buf[i:])
+}
+
+// truncate truncates the string to the specified precision, if present.
+func (f *fmt) truncate(s string) string {
+	if f.precPresent && f.prec < utf8.RuneCountInString(s) {
+		n := f.prec
+		for i := range s {
+			if n == 0 {
+				s = s[:i]
+				break
+			}
+			n--
+		}
+	}
+	return s
+}
+
+// fmt_s formats a string.
+func (f *fmt) fmt_s(s string) {
+	s = f.truncate(s)
+	f.padString(s)
+}
+
+// fmt_sbx formats a string or byte slice as a hexadecimal encoding of its bytes.
+func (f *fmt) fmt_sbx(s string, b []byte, digits string) {
+	n := len(b)
+	if b == nil {
+		n = len(s)
+	}
+	x := digits[10] - 'a' + 'x'
+	// TODO: Avoid buffer by pre-padding.
+	var buf []byte
+	for i := 0; i < n; i++ {
+		if i > 0 && f.space {
+			buf = append(buf, ' ')
+		}
+		if f.sharp && (f.space || i == 0) {
+			buf = append(buf, '0', x)
+		}
+		var c byte
+		if b == nil {
+			c = s[i]
+		} else {
+			c = b[i]
+		}
+		buf = append(buf, digits[c>>4], digits[c&0xF])
+	}
+	f.pad(buf)
+}
+
+// fmt_sx formats a string as a hexadecimal encoding of its bytes.
+func (f *fmt) fmt_sx(s, digits string) {
+	if f.precPresent && f.prec < len(s) {
+		s = s[:f.prec]
+	}
+	f.fmt_sbx(s, nil, digits)
+}
+
+// fmt_bx formats a byte slice as a hexadecimal encoding of its bytes.
+func (f *fmt) fmt_bx(b []byte, digits string) {
+	if f.precPresent && f.prec < len(b) {
+		b = b[:f.prec]
+	}
+	f.fmt_sbx("", b, digits)
+}
+
+// fmt_q formats a string as a double-quoted, escaped Go string constant.
+func (f *fmt) fmt_q(s string) {
+	s = f.truncate(s)
+	var quoted string
+	if f.sharp && strconv.CanBackquote(s) {
+		quoted = "`" + s + "`"
+	} else {
+		if f.plus {
+			quoted = strconv.QuoteToASCII(s)
+		} else {
+			quoted = strconv.Quote(s)
+		}
+	}
+	f.padString(quoted)
+}
+
+// fmt_qc formats the integer as a single-quoted, escaped Go character constant.
+// If the character is not valid Unicode, it will print '\ufffd'.
+func (f *fmt) fmt_qc(c int64) {
+	var quoted []byte
+	if f.plus {
+		quoted = strconv.AppendQuoteRuneToASCII(f.intbuf[0:0], rune(c))
+	} else {
+		quoted = strconv.AppendQuoteRune(f.intbuf[0:0], rune(c))
+	}
+	f.pad(quoted)
+}
+
+// floating-point
+
+func doPrec(f *fmt, def int) int {
+	if f.precPresent {
+		return f.prec
+	}
+	return def
+}
+
+// formatFloat formats a float64; it is an efficient equivalent to  f.pad(strconv.FormatFloat()...).
+func (f *fmt) formatFloat(v float64, verb byte, prec, n int) {
+	// Format number, reserving space for leading + sign if needed.
+	num := strconv.AppendFloat(f.intbuf[0:1], v, verb, prec, n)
+	if num[1] == '-' || num[1] == '+' {
+		num = num[1:]
+	} else {
+		num[0] = '+'
+	}
+	// Special handling for infinity, which doesn't look like a number so shouldn't be padded with zeros.
+	if math.IsInf(v, 0) {
+		if f.zero {
+			defer func() { f.zero = true }()
+			f.zero = false
+		}
+	}
+	// num is now a signed version of the number.
+	// If we're zero padding, want the sign before the leading zeros.
+	// Achieve this by writing the sign out and then padding the unsigned number.
+	if f.zero && f.widPresent && f.wid > len(num) {
+		if f.space && v >= 0 {
+			f.buf.WriteByte(' ') // This is what C does: even with zero, f.space means space.
+			f.wid--
+		} else if f.plus || v < 0 {
+			f.buf.WriteByte(num[0])
+			f.wid--
+		}
+		f.pad(num[1:])
+		return
+	}
+	// f.space says to replace a leading + with a space.
+	if f.space && num[0] == '+' {
+		num[0] = ' '
+		f.pad(num)
+		return
+	}
+	// Now we know the sign is attached directly to the number, if present at all.
+	// We want a sign if asked for, if it's negative, or if it's infinity (+Inf vs. -Inf).
+	if f.plus || num[0] == '-' || math.IsInf(v, 0) {
+		f.pad(num)
+		return
+	}
+	// No sign to show and the number is positive; just print the unsigned number.
+	f.pad(num[1:])
+}
+
+// fmt_e64 formats a float64 in the form -1.23e+12.
+func (f *fmt) fmt_e64(v float64) { f.formatFloat(v, 'e', doPrec(f, 6), 64) }
+
+// fmt_E64 formats a float64 in the form -1.23E+12.
+func (f *fmt) fmt_E64(v float64) { f.formatFloat(v, 'E', doPrec(f, 6), 64) }
+
+// fmt_f64 formats a float64 in the form -1.23.
+func (f *fmt) fmt_f64(v float64) { f.formatFloat(v, 'f', doPrec(f, 6), 64) }
+
+// fmt_g64 formats a float64 in the 'f' or 'e' form according to size.
+func (f *fmt) fmt_g64(v float64) { f.formatFloat(v, 'g', doPrec(f, -1), 64) }
+
+// fmt_G64 formats a float64 in the 'f' or 'E' form according to size.
+func (f *fmt) fmt_G64(v float64) { f.formatFloat(v, 'G', doPrec(f, -1), 64) }
+
+// fmt_fb64 formats a float64 in the form -123p3 (exponent is power of 2).
+func (f *fmt) fmt_fb64(v float64) { f.formatFloat(v, 'b', 0, 64) }
+
+// float32
+// cannot defer to float64 versions
+// because it will get rounding wrong in corner cases.
+
+// fmt_e32 formats a float32 in the form -1.23e+12.
+func (f *fmt) fmt_e32(v float32) { f.formatFloat(float64(v), 'e', doPrec(f, 6), 32) }
+
+// fmt_E32 formats a float32 in the form -1.23E+12.
+func (f *fmt) fmt_E32(v float32) { f.formatFloat(float64(v), 'E', doPrec(f, 6), 32) }
+
+// fmt_f32 formats a float32 in the form -1.23.
+func (f *fmt) fmt_f32(v float32) { f.formatFloat(float64(v), 'f', doPrec(f, 6), 32) }
+
+// fmt_g32 formats a float32 in the 'f' or 'e' form according to size.
+func (f *fmt) fmt_g32(v float32) { f.formatFloat(float64(v), 'g', doPrec(f, -1), 32) }
+
+// fmt_G32 formats a float32 in the 'f' or 'E' form according to size.
+func (f *fmt) fmt_G32(v float32) { f.formatFloat(float64(v), 'G', doPrec(f, -1), 32) }
+
+// fmt_fb32 formats a float32 in the form -123p3 (exponent is power of 2).
+func (f *fmt) fmt_fb32(v float32) { f.formatFloat(float64(v), 'b', 0, 32) }
+
+// fmt_c64 formats a complex64 according to the verb.
+func (f *fmt) fmt_c64(v complex64, verb rune) {
+	f.fmt_complex(float64(real(v)), float64(imag(v)), 32, verb)
+}
+
+// fmt_c128 formats a complex128 according to the verb.
+func (f *fmt) fmt_c128(v complex128, verb rune) {
+	f.fmt_complex(real(v), imag(v), 64, verb)
+}
+
+// fmt_complex formats a complex number as (r+ji).
+func (f *fmt) fmt_complex(r, j float64, size int, verb rune) {
+	f.buf.WriteByte('(')
+	oldPlus := f.plus
+	oldSpace := f.space
+	oldWid := f.wid
+	for i := 0; ; i++ {
+		switch verb {
+		case 'b':
+			f.formatFloat(r, 'b', 0, size)
+		case 'e':
+			f.formatFloat(r, 'e', doPrec(f, 6), size)
+		case 'E':
+			f.formatFloat(r, 'E', doPrec(f, 6), size)
+		case 'f', 'F':
+			f.formatFloat(r, 'f', doPrec(f, 6), size)
+		case 'g':
+			f.formatFloat(r, 'g', doPrec(f, -1), size)
+		case 'G':
+			f.formatFloat(r, 'G', doPrec(f, -1), size)
+		}
+		if i != 0 {
+			break
+		}
+		// Imaginary part always has a sign.
+		f.plus = true
+		f.space = false
+		f.wid = oldWid
+		r = j
+	}
+	f.space = oldSpace
+	f.plus = oldPlus
+	f.wid = oldWid
+	f.buf.Write(irparenBytes)
+}