diff options
Diffstat (limited to 'libgo/go/compress/flate/deflate.go')
| -rw-r--r-- | libgo/go/compress/flate/deflate.go | 35 |
1 files changed, 22 insertions, 13 deletions
diff --git a/libgo/go/compress/flate/deflate.go b/libgo/go/compress/flate/deflate.go index 8505da706c9..20408409c8e 100644 --- a/libgo/go/compress/flate/deflate.go +++ b/libgo/go/compress/flate/deflate.go @@ -5,6 +5,7 @@ package flate import ( + "fmt" "io" "math" ) @@ -390,7 +391,7 @@ func (d *compressor) init(w io.Writer, level int) (err error) { d.fill = (*compressor).fillDeflate d.step = (*compressor).deflate default: - return WrongValueError{"level", 0, 9, int32(level)} + return fmt.Errorf("flate: invalid compression level %d: want value in range [-1, 9]", level) } return nil } @@ -408,17 +409,22 @@ func (d *compressor) close() error { return d.w.err } -// NewWriter returns a new Writer compressing -// data at the given level. Following zlib, levels -// range from 1 (BestSpeed) to 9 (BestCompression); -// higher levels typically run slower but compress more. -// Level 0 (NoCompression) does not attempt any -// compression; it only adds the necessary DEFLATE framing. -func NewWriter(w io.Writer, level int) *Writer { +// NewWriter returns a new Writer compressing data at the given level. +// Following zlib, levels range from 1 (BestSpeed) to 9 (BestCompression); +// higher levels typically run slower but compress more. Level 0 +// (NoCompression) does not attempt any compression; it only adds the +// necessary DEFLATE framing. Level -1 (DefaultCompression) uses the default +// compression level. +// +// If level is in the range [-1, 9] then the error returned will be nil. +// Otherwise the error returned will be non-nil. +func NewWriter(w io.Writer, level int) (*Writer, error) { const logWindowSize = logMaxOffsetSize var dw Writer - dw.d.init(w, level) - return &dw + if err := dw.d.init(w, level); err != nil { + return nil, err + } + return &dw, nil } // NewWriterDict is like NewWriter but initializes the new @@ -427,13 +433,16 @@ func NewWriter(w io.Writer, level int) *Writer { // any compressed output. The compressed data written to w // can only be decompressed by a Reader initialized with the // same dictionary. -func NewWriterDict(w io.Writer, level int, dict []byte) *Writer { +func NewWriterDict(w io.Writer, level int, dict []byte) (*Writer, error) { dw := &dictWriter{w, false} - zw := NewWriter(dw, level) + zw, err := NewWriter(dw, level) + if err != nil { + return nil, err + } zw.Write(dict) zw.Flush() dw.enabled = true - return zw + return zw, err } type dictWriter struct { |