1 files changed, 533 insertions, 0 deletions
diff --git a/src/pkg/fmt/format.go b/src/pkg/fmt/format.go
new file mode 100644
index 000000000..3cd492980
--- /dev/null
+++ b/src/pkg/fmt/format.go
@@ -0,0 +1,533 @@
+// 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 (
+	"strconv";
+)
+
+
+const nByte = 64;
+const nPows10 = 160;
+
+var ldigits string = "0123456789abcdef"  // var not const because we take its address
+var udigits string = "0123456789ABCDEF"
+
+/*
+	Fmt is the raw formatter used by Printf etc.  Not meant for normal use.
+	See print.go for a more palatable interface.
+
+	The model is to accumulate operands into an internal buffer and then
+	retrieve the buffer in one hit using Str(), Putnl(), etc.  The formatting
+	methods return ``self'' so the operations can be chained.
+
+		f := fmt.New();
+		print(f.Fmt_d(1234).Fmt_s("\n").Str());  // create string, print it
+		f.Fmt_d(-1234).Fmt_s("\n").Put();  // print string
+		f.Fmt_ud(1<<63).Putnl();  // print string with automatic newline
+*/
+type Fmt struct {
+	buf string;
+	wid int;
+	wid_present bool;
+	prec int;
+	prec_present bool;
+	// flags
+	minus bool;
+	plus bool;
+	sharp bool;
+	space bool;
+	zero bool;
+}
+
+func (f *Fmt) clearflags() {
+	f.wid = 0;
+	f.wid_present = false;
+	f.prec = 0;
+	f.prec_present = false;
+	f.minus = false;
+	f.plus = false;
+	f.sharp = false;
+	f.space = false;
+	f.zero = false;
+}
+
+func (f *Fmt) clearbuf() {
+	f.buf = "";
+}
+
+func (f *Fmt) init() {
+	f.clearbuf();
+	f.clearflags();
+}
+
+// New returns a new initialized Fmt
+func New() *Fmt {
+	f := new(Fmt);
+	f.init();
+	return f;
+}
+
+// Str returns the buffered contents as a string and resets the Fmt.
+func (f *Fmt) Str() string {
+	s := f.buf;
+	f.clearbuf();
+	f.clearflags();
+	f.buf = "";
+	return s;
+}
+
+// Put writes the buffered contents to stdout and resets the Fmt.
+func (f *Fmt) Put() {
+	print(f.buf);
+	f.clearbuf();
+	f.clearflags();
+}
+
+// Putnl writes the buffered contents to stdout, followed by a newline, and resets the Fmt.
+func (f *Fmt) Putnl() {
+	print(f.buf, "\n");
+	f.clearbuf();
+	f.clearflags();
+}
+
+// Wp sets the width and precision for formatting the next item.
+func (f *Fmt) Wp(w, p int) *Fmt {
+	f.wid_present = true;
+	f.wid = w;
+	f.prec_present = true;
+	f.prec = p;
+	return f;
+}
+
+// P sets the precision for formatting the next item.
+func (f *Fmt) P(p int) *Fmt {
+	f.prec_present = true;
+	f.prec = p;
+	return f;
+}
+
+// W sets the width for formatting the next item.
+func (f *Fmt) W(x int) *Fmt {
+	f.wid_present = true;
+	f.wid = x;
+	return f;
+}
+
+// append s to buf, padded on left (w > 0) or right (w < 0 or f.minus)
+// padding is in bytes, not characters (agrees with ANSIC C, not Plan 9 C)
+func (f *Fmt) pad(s string) {
+	if f.wid_present && f.wid != 0 {
+		left := !f.minus;
+		w := f.wid;
+		if w < 0 {
+			left = false;
+			w = -w;
+		}
+		w -= len(s);
+		padchar := byte(' ');
+		if left && f.zero {
+			padchar = '0';
+		}
+		if w > 0 {
+			if w > nByte {
+				w = nByte;
+			}
+			buf := make([]byte, w);
+			for i := 0; i < w; i++ {
+				buf[i] = padchar;
+			}
+			if left {
+				s = string(buf) + s;
+			} else {
+				s = s + string(buf);
+			}
+		}
+	}
+	f.buf += s;
+}
+
+// format val into buf, ending at buf[i].  (printing is easier right-to-left;
+// that's why the bidi languages are right-to-left except for numbers. wait,
+// never mind.)  val is known to be unsigned.  we could make things maybe
+// marginally faster by splitting the 32-bit case out into a separate function
+// but it's not worth the duplication, so val has 64 bits.
+func putint(buf *[nByte]byte, i int, base, val uint64, digits *string) int {
+	for val >= base {
+		buf[i] = digits[val%base];
+		i--;
+		val /= base;
+	}
+	buf[i] = digits[val];
+	return i-1;
+}
+
+// Fmt_boolean formats a boolean.
+func (f *Fmt) Fmt_boolean(v bool) *Fmt {
+	if v {
+		f.pad("true");
+	} else {
+		f.pad("false");
+	}
+	f.clearflags();
+	return f;
+}
+
+// integer; interprets prec but not wid.
+func (f *Fmt) integer(a int64, base uint, is_signed bool, digits *string) string {
+	var buf [nByte]byte;
+	negative := is_signed && a < 0;
+	if negative {
+		a = -a;
+	}
+
+	// two ways to ask for extra leading zero digits: %.3d or %03d.
+	// apparently the first cancels the second.
+	prec := 0;
+	if f.prec_present {
+		prec = f.prec;
+		f.zero = false;
+	} else if f.zero && f.wid_present && !f.minus && f.wid > 0{
+		prec = f.wid;
+		if negative || f.plus || f.space {
+			prec--;  // leave room for sign
+		}
+	}
+
+	i := putint(&buf, nByte-1, uint64(base), uint64(a), digits);
+	for i > 0 && prec > (nByte-1-i) {
+		buf[i] = '0';
+		i--;
+	}
+
+	if f.sharp {
+		switch base {
+		case 8:
+			if buf[i+1] != '0' {
+				buf[i] = '0';
+				i--;
+			}
+		case 16:
+			buf[i] = 'x' + digits[10]-'a';
+			i--;
+			buf[i] = '0';
+			i--;
+		}
+	}
+
+	if negative {
+		buf[i] = '-';
+		i--;
+	} else if f.plus {
+		buf[i] = '+';
+		i--;
+	} else if f.space {
+		buf[i] = ' ';
+		i--;
+	}
+	return string(buf[i+1:nByte]);
+}
+
+// Fmt_d64 formats an int64 in decimal.
+func (f *Fmt) Fmt_d64(v int64) *Fmt {
+	f.pad(f.integer(v, 10, true, &ldigits));
+	f.clearflags();
+	return f;
+}
+
+// Fmt_d32 formats an int32 in decimal.
+func (f *Fmt) Fmt_d32(v int32) *Fmt {
+	return f.Fmt_d64(int64(v));
+}
+
+// Fmt_d formats an int in decimal.
+func (f *Fmt) Fmt_d(v int) *Fmt {
+	return f.Fmt_d64(int64(v));
+}
+
+// Fmt_ud64 formats a uint64 in decimal.
+func (f *Fmt) Fmt_ud64(v uint64) *Fmt {
+	f.pad(f.integer(int64(v), 10, false, &ldigits));
+	f.clearflags();
+	return f;
+}
+
+// Fmt_ud32 formats a uint32 in decimal.
+func (f *Fmt) Fmt_ud32(v uint32) *Fmt {
+	return f.Fmt_ud64(uint64(v));
+}
+
+// Fmt_ud formats a uint in decimal.
+func (f *Fmt) Fmt_ud(v uint) *Fmt {
+	return f.Fmt_ud64(uint64(v));
+}
+
+// Fmt_x64 formats an int64 in hexadecimal.
+func (f *Fmt) Fmt_x64(v int64) *Fmt {
+	f.pad(f.integer(v, 16, true, &ldigits));
+	f.clearflags();
+	return f;
+}
+
+// Fmt_x32 formats an int32 in hexadecimal.
+func (f *Fmt) Fmt_x32(v int32) *Fmt {
+	return f.Fmt_x64(int64(v));
+}
+
+// Fmt_x formats an int in hexadecimal.
+func (f *Fmt) Fmt_x(v int) *Fmt {
+	return f.Fmt_x64(int64(v));
+}
+
+// Fmt_ux64 formats a uint64 in hexadecimal.
+func (f *Fmt) Fmt_ux64(v uint64) *Fmt {
+	f.pad(f.integer(int64(v), 16, false, &ldigits));
+	f.clearflags();
+	return f;
+}
+
+// Fmt_ux32 formats a uint32 in hexadecimal.
+func (f *Fmt) Fmt_ux32(v uint32) *Fmt {
+	return f.Fmt_ux64(uint64(v));
+}
+
+// Fmt_ux formats a uint in hexadecimal.
+func (f *Fmt) Fmt_ux(v uint) *Fmt {
+	return f.Fmt_ux64(uint64(v));
+}
+
+// Fmt_X64 formats an int64 in upper case hexadecimal.
+func (f *Fmt) Fmt_X64(v int64) *Fmt {
+	f.pad(f.integer(v, 16, true, &udigits));
+	f.clearflags();
+	return f;
+}
+
+// Fmt_X32 formats an int32 in upper case hexadecimal.
+func (f *Fmt) Fmt_X32(v int32) *Fmt {
+	return f.Fmt_X64(int64(v));
+}
+
+// Fmt_X formats an int in upper case hexadecimal.
+func (f *Fmt) Fmt_X(v int) *Fmt {
+	return f.Fmt_X64(int64(v));
+}
+
+// Fmt_uX64 formats a uint64 in upper case hexadecimal.
+func (f *Fmt) Fmt_uX64(v uint64) *Fmt {
+	f.pad(f.integer(int64(v), 16, false, &udigits));
+	f.clearflags();
+	return f;
+}
+
+// Fmt_uX32 formats a uint32 in upper case hexadecimal.
+func (f *Fmt) Fmt_uX32(v uint32) *Fmt {
+	return f.Fmt_uX64(uint64(v));
+}
+
+// Fmt_uX formats a uint in upper case hexadecimal.
+func (f *Fmt) Fmt_uX(v uint) *Fmt {
+	return f.Fmt_uX64(uint64(v));
+}
+
+// Fmt_o64 formats an int64 in octal.
+func (f *Fmt) Fmt_o64(v int64) *Fmt {
+	f.pad(f.integer(v, 8, true, &ldigits));
+	f.clearflags();
+	return f;
+}
+
+// Fmt_o32 formats an int32 in octal.
+func (f *Fmt) Fmt_o32(v int32) *Fmt {
+	return f.Fmt_o64(int64(v));
+}
+
+// Fmt_o formats an int in octal.
+func (f *Fmt) Fmt_o(v int) *Fmt {
+	return f.Fmt_o64(int64(v));
+}
+
+// Fmt_uo64 formats a uint64 in octal.
+func (f *Fmt) Fmt_uo64(v uint64) *Fmt {
+	f.pad(f.integer(int64(v), 8, false, &ldigits));
+	f.clearflags();
+	return f;
+}
+
+// Fmt_uo32 formats a uint32 in octal.
+func (f *Fmt) Fmt_uo32(v uint32) *Fmt {
+	return f.Fmt_uo64(uint64(v));
+}
+
+// Fmt_uo formats a uint in octal.
+func (f *Fmt) Fmt_uo(v uint) *Fmt {
+	return f.Fmt_uo64(uint64(v));
+}
+
+// Fmt_b64 formats a uint64 in binary.
+func (f *Fmt) Fmt_b64(v uint64) *Fmt {
+	f.pad(f.integer(int64(v), 2, false, &ldigits));
+	f.clearflags();
+	return f;
+}
+
+// Fmt_b32 formats a uint32 in binary.
+func (f *Fmt) Fmt_b32(v uint32) *Fmt {
+	return f.Fmt_b64(uint64(v));
+}
+
+// Fmt_b formats a uint in binary.
+func (f *Fmt) Fmt_b(v uint) *Fmt {
+	return f.Fmt_b64(uint64(v));
+}
+
+// Fmt_c formats a Unicode character.
+func (f *Fmt) Fmt_c(v int) *Fmt {
+	f.pad(string(v));
+	f.clearflags();
+	return f;
+}
+
+// Fmt_s formats a string.
+func (f *Fmt) Fmt_s(s string) *Fmt {
+	if f.prec_present {
+		if f.prec < len(s) {
+			s = s[0:f.prec];
+		}
+	}
+	f.pad(s);
+	f.clearflags();
+	return f;
+}
+
+// Fmt_sx formats a string as a hexadecimal encoding of its bytes.
+func (f *Fmt) Fmt_sx(s string) *Fmt {
+	t := "";
+	for i := 0; i < len(s); i++ {
+		if i > 0 && f.space {
+			t += " ";
+		}
+		v := s[i];
+		t += string(ldigits[v>>4]);
+		t += string(ldigits[v&0xF]);
+	}
+	f.pad(t);
+	f.clearflags();
+	return f;
+}
+
+// Fmt_sX formats a string as an uppercase hexadecimal encoding of its bytes.
+func (f *Fmt) Fmt_sX(s string) *Fmt {
+	t := "";
+	for i := 0; i < len(s); i++ {
+		v := s[i];
+		t += string(udigits[v>>4]);
+		t += string(udigits[v&0xF]);
+	}
+	f.pad(t);
+	f.clearflags();
+	return f;
+}
+
+// Fmt_q formats a string as a double-quoted, escaped Go string constant.
+func (f *Fmt) Fmt_q(s string) *Fmt {
+	var quoted string;
+	if f.sharp && strconv.CanBackquote(s) {
+		quoted = "`"+s+"`";
+	} else {
+		quoted = strconv.Quote(s);
+	}
+	f.pad(quoted);
+	f.clearflags();
+	return f;
+}
+
+// floating-point
+
+func doPrec(f *Fmt, def int) int {
+	if f.prec_present {
+		return f.prec;
+	}
+	return def;
+}
+
+func fmtString(f *Fmt, s string) *Fmt {
+	f.pad(s);
+	f.clearflags();
+	return f;
+}
+
+// Fmt_e64 formats a float64 in the form -1.23e+12.
+func (f *Fmt) Fmt_e64(v float64) *Fmt {
+	return fmtString(f, strconv.Ftoa64(v, 'e', doPrec(f, 6)));
+}
+
+// Fmt_f64 formats a float64 in the form -1.23.
+func (f *Fmt) Fmt_f64(v float64) *Fmt {
+	return fmtString(f, strconv.Ftoa64(v, 'f', doPrec(f, 6)));
+}
+
+// Fmt_g64 formats a float64 in the 'f' or 'e' form according to size.
+func (f *Fmt) Fmt_g64(v float64) *Fmt {
+	return fmtString(f, strconv.Ftoa64(v, 'g', doPrec(f, -1)));
+}
+
+// Fmt_fb64 formats a float64 in the form -123p3 (exponent is power of 2).
+func (f *Fmt) Fmt_fb64(v float64) *Fmt {
+	return fmtString(f, strconv.Ftoa64(v, 'b', 0));
+}
+
+// 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) *Fmt {
+	return fmtString(f, strconv.Ftoa32(v, 'e', doPrec(f, 6)));
+}
+
+// Fmt_f32 formats a float32 in the form -1.23.
+func (f *Fmt) Fmt_f32(v float32) *Fmt {
+	return fmtString(f, strconv.Ftoa32(v, 'f', doPrec(f, 6)));
+}
+
+// Fmt_g32 formats a float32 in the 'f' or 'e' form according to size.
+func (f *Fmt) Fmt_g32(v float32) *Fmt {
+	return fmtString(f, strconv.Ftoa32(v, 'g', doPrec(f, -1)));
+}
+
+// Fmt_fb32 formats a float32 in the form -123p3 (exponent is power of 2).
+func (f *Fmt) Fmt_fb32(v float32) *Fmt {
+	return fmtString(f, strconv.Ftoa32(v, 'b', 0));
+}
+
+// float
+func (x *Fmt) f(a float) *Fmt {
+	if strconv.FloatSize == 32 {
+		return x.Fmt_f32(float32(a))
+	}
+	return x.Fmt_f64(float64(a))
+}
+
+func (x *Fmt) e(a float) *Fmt {
+	if strconv.FloatSize == 32 {
+		return x.Fmt_e32(float32(a))
+	}
+	return x.Fmt_e64(float64(a))
+}
+
+func (x *Fmt) g(a float) *Fmt {
+	if strconv.FloatSize == 32 {
+		return x.Fmt_g32(float32(a))
+	}
+	return x.Fmt_g64(float64(a))
+}
+
+func (x *Fmt) fb(a float) *Fmt {
+	if strconv.FloatSize == 32 {
+		return x.Fmt_fb32(float32(a))
+	}
+	return x.Fmt_fb64(float64(a))
+}