Imported Upstream version 1upstream/1

1 files changed, 65 insertions, 35 deletions

diff --git a/src/pkg/compress/gzip/gzip.go b/src/pkg/compress/gzip/gzip.go
index 8860d10af..3035dfffc 100644
--- a/src/pkg/compress/gzip/gzip.go
+++ b/src/pkg/compress/gzip/gzip.go
@@ -6,10 +6,11 @@ package gzip
 
 import (
 	"compress/flate"
+	"errors"
+	"fmt"
 	"hash"
 	"hash/crc32"
 	"io"
-	"os"
 )
 
 // These constants are copied from the flate package, so that code that imports
@@ -21,9 +22,9 @@ const (
 	DefaultCompression = flate.DefaultCompression
 )
 
-// A Compressor is an io.WriteCloser that satisfies writes by compressing data written
+// A Writer is an io.WriteCloser that satisfies writes by compressing data written
 // to its wrapped io.Writer.
-type Compressor struct {
+type Writer struct {
 	Header
 	w          io.Writer
 	level      int
@@ -32,28 +33,43 @@ type Compressor struct {
 	size       uint32
 	closed     bool
 	buf        [10]byte
-	err        os.Error
+	err        error
 }
 
-// NewWriter calls NewWriterLevel with the default compression level.
-func NewWriter(w io.Writer) (*Compressor, os.Error) {
-	return NewWriterLevel(w, DefaultCompression)
+// NewWriter creates a new Writer that satisfies writes by compressing data
+// written to w.
+//
+// It is the caller's responsibility to call Close on the WriteCloser when done.
+// Writes may be buffered and not flushed until Close.
+//
+// Callers that wish to set the fields in Writer.Header must do so before
+// the first call to Write or Close. The Comment and Name header fields are
+// UTF-8 strings in Go, but the underlying format requires NUL-terminated ISO
+// 8859-1 (Latin-1). NUL or non-Latin-1 runes in those strings will lead to an
+// error on Write.
+func NewWriter(w io.Writer) *Writer {
+	z, _ := NewWriterLevel(w, DefaultCompression)
+	return z
 }
 
-// NewWriterLevel creates a new Compressor writing to the given writer.
-// Writes may be buffered and not flushed until Close.
-// Callers that wish to set the fields in Compressor.Header must
-// do so before the first call to Write or Close.
-// It is the caller's responsibility to call Close on the WriteCloser when done.
-// level is the compression level, which can be DefaultCompression, NoCompression,
-// or any integer value between BestSpeed and BestCompression (inclusive).
-func NewWriterLevel(w io.Writer, level int) (*Compressor, os.Error) {
-	z := new(Compressor)
-	z.OS = 255 // unknown
-	z.w = w
-	z.level = level
-	z.digest = crc32.NewIEEE()
-	return z, nil
+// NewWriterLevel is like NewWriter but specifies the compression level instead
+// of assuming DefaultCompression.
+//
+// The compression level can be DefaultCompression, NoCompression, or any
+// integer value between BestSpeed and BestCompression inclusive. The error
+// returned will be nil if the level is valid.
+func NewWriterLevel(w io.Writer, level int) (*Writer, error) {
+	if level < DefaultCompression || level > BestCompression {
+		return nil, fmt.Errorf("gzip: invalid compression level: %d", level)
+	}
+	return &Writer{
+		Header: Header{
+			OS: 255, // unknown
+		},
+		w:      w,
+		level:  level,
+		digest: crc32.NewIEEE(),
+	}, nil
 }
 
 // GZIP (RFC 1952) is little-endian, unlike ZLIB (RFC 1950).
@@ -70,9 +86,9 @@ func put4(p []byte, v uint32) {
 }
 
 // writeBytes writes a length-prefixed byte slice to z.w.
-func (z *Compressor) writeBytes(b []byte) os.Error {
+func (z *Writer) writeBytes(b []byte) error {
 	if len(b) > 0xffff {
-		return os.NewError("gzip.Write: Extra data is too large")
+		return errors.New("gzip.Write: Extra data is too large")
 	}
 	put2(z.buf[0:2], uint16(len(b)))
 	_, err := z.w.Write(z.buf[0:2])
@@ -83,16 +99,28 @@ func (z *Compressor) writeBytes(b []byte) os.Error {
 	return err
 }
 
-// writeString writes a string (in ISO 8859-1 (Latin-1) format) to z.w.
-func (z *Compressor) writeString(s string) os.Error {
-	// GZIP (RFC 1952) specifies that strings are NUL-terminated ISO 8859-1 (Latin-1).
-	// TODO(nigeltao): Convert from UTF-8 to ISO 8859-1 (Latin-1).
+// writeString writes a UTF-8 string s in GZIP's format to z.w.
+// GZIP (RFC 1952) specifies that strings are NUL-terminated ISO 8859-1 (Latin-1).
+func (z *Writer) writeString(s string) (err error) {
+	// GZIP stores Latin-1 strings; error if non-Latin-1; convert if non-ASCII.
+	needconv := false
 	for _, v := range s {
-		if v == 0 || v > 0x7f {
-			return os.NewError("gzip.Write: non-ASCII header string")
+		if v == 0 || v > 0xff {
+			return errors.New("gzip.Write: non-Latin-1 header string")
+		}
+		if v > 0x7f {
+			needconv = true
+		}
+	}
+	if needconv {
+		b := make([]byte, 0, len(s))
+		for _, v := range s {
+			b = append(b, byte(v))
 		}
+		_, err = z.w.Write(b)
+	} else {
+		_, err = io.WriteString(z.w, s)
 	}
-	_, err := io.WriteString(z.w, s)
 	if err != nil {
 		return err
 	}
@@ -102,7 +130,9 @@ func (z *Compressor) writeString(s string) os.Error {
 	return err
 }
 
-func (z *Compressor) Write(p []byte) (int, os.Error) {
+// Write writes a compressed form of p to the underlying io.Writer. The
+// compressed bytes are not necessarily flushed until the Writer is closed.
+func (z *Writer) Write(p []byte) (int, error) {
 	if z.err != nil {
 		return 0, z.err
 	}
@@ -122,7 +152,7 @@ func (z *Compressor) Write(p []byte) (int, os.Error) {
 		if z.Comment != "" {
 			z.buf[3] |= 0x10
 		}
-		put4(z.buf[4:8], z.Mtime)
+		put4(z.buf[4:8], uint32(z.ModTime.Unix()))
 		if z.level == BestCompression {
 			z.buf[8] = 2
 		} else if z.level == BestSpeed {
@@ -153,7 +183,7 @@ func (z *Compressor) Write(p []byte) (int, os.Error) {
 				return n, z.err
 			}
 		}
-		z.compressor = flate.NewWriter(z.w, z.level)
+		z.compressor, _ = flate.NewWriter(z.w, z.level)
 	}
 	z.size += uint32(len(p))
 	z.digest.Write(p)
@@ -161,8 +191,8 @@ func (z *Compressor) Write(p []byte) (int, os.Error) {
 	return n, z.err
 }
 
-// Calling Close does not close the wrapped io.Writer originally passed to NewWriter.
-func (z *Compressor) Close() os.Error {
+// Close closes the Writer. It does not close the underlying io.Writer.
+func (z *Writer) Close() error {
 	if z.err != nil {
 		return z.err
 	}