README
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不同语言的压缩算法，只能保证兼容，而不能保证输出完全一直
Documentation
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Index ¶
- Constants
- Variables
- func Compress(input []byte) ([]byte, error)
- func Decompress(input []byte) ([]byte, error)
- func NewReader(r io.Reader) (io.ReadCloser, error)
- func NewReaderBuffer(r io.Reader, bufferSize int) (io.ReadCloser, error)
- type UnsafeByte
- type Writer
- func NewWriter(w io.Writer) *Writer
- func NewWriterLevel(w io.Writer, level int) (*Writer, error)
- func NewWriterLevel2(w io.Writer, level, method, windowBits, memLevel, strategy int) (*Writer, error)
- func NewWriterLevelBuffer(w io.Writer, level, bufferSize int) (*Writer, error)
- func NewWriterLevelBuffer2(w io.Writer, level, bufferSize, method, windowBits, memLevel, strategy int) (*Writer, error)
Constants ¶
const ( NoCompression = flate.NoCompression BestSpeed = flate.BestSpeed BestCompression = flate.BestCompression DefaultCompression = flate.DefaultCompression )
Constants copied from the flate package, so that code that imports czlib does not also have to import "compress/flate".
const ( Z_NO_FLUSH = 0 Z_PARTIAL_FLUSH = 1 Z_SYNC_FLUSH = 2 Z_FULL_FLUSH = 3 Z_FINISH = 4 Z_BLOCK = 5 Z_TREES = 6 )
Allowed flush values
const ( Z_OK = 0 Z_STREAM_END = 1 Z_NEED_DICT = 2 Z_ERRNO = -1 Z_STREAM_ERROR = -2 Z_DATA_ERROR = -3 Z_MEM_ERROR = -4 Z_BUF_ERROR = -5 Z_VERSION_ERROR = -6 )
Return codes
const (
DEFAULT_COMPRESSED_BUFFER_SIZE = 32 * 1024
)
our default buffer size most go io functions use 32KB as buffer size, so 32KB works well here for compressed data buffer
Variables ¶
var ( // ErrChecksum is returned when reading ZLIB data that has an invalid checksum. ErrChecksum = zlib.ErrChecksum // ErrDictionary is returned when reading ZLIB data that has an invalid dictionary. ErrDictionary = zlib.ErrDictionary // ErrHeader is returned when reading ZLIB data that has an invalid header. ErrHeader = zlib.ErrHeader )
Functions ¶
func Decompress ¶
Decompress returns the input decompressed using zlib, or an error if encountered.
func NewReader ¶
func NewReader(r io.Reader) (io.ReadCloser, error)
NewReader creates a new io.ReadCloser. Reads from the returned io.ReadCloser read and decompress data from r. The implementation buffers input and may read more data than necessary from r. It is the caller's responsibility to call Close on the ReadCloser when done.
func NewReaderBuffer ¶
NewReaderBuffer has the same behavior as NewReader but the user can provides a custom buffer size.
Types ¶
type UnsafeByte ¶
type UnsafeByte []byte
An UnsafeByte is a []byte whose backing array has been allocated in C and thus is not subject to the Go garbage collector. The Unsafe versions of Compress and Decompress return this in order to prevent copying the unsafe memory into collected memory.
func NewUnsafeByte ¶
func NewUnsafeByte(p *C.char, length int) UnsafeByte
NewUnsafeByte creates a []byte from the unsafe pointer without a copy, using the method outlined in this mailing list post:
https://groups.google.com/forum/#!topic/golang-nuts/KyXR0fDp0HA
but amended to use the three-index slices from go1.2 to set the capacity of b correctly:
https://tip.golang.org/doc/go1.2#three_index
This means this code only works in go1.2+.
This shouldn't copy the underlying array; it's just casting it Afterwards, we use reflect to fix the Cap & len of the slice.
func UnsafeCompress ¶
func UnsafeCompress(input []byte) (UnsafeByte, error)
UnsafeCompress zips input into an UnsafeByte without copying the result malloced in C. The UnsafeByte returned can be used as a normal []byte but must be manually free'd w/ UnsafeByte.Free()
func UnsafeDecompress ¶
func UnsafeDecompress(input []byte) (UnsafeByte, error)
UnsafeDecompress unzips input into an UnsafeByte without copying the result malloced in C. The UnsafeByte returned can be used as a normal []byte but must be manually free'd w/ UnsafeByte.Free()
func (UnsafeByte) Free ¶
func (b UnsafeByte) Free()
Free the underlying byte array; doing this twice would be bad.
type Writer ¶
type Writer struct {
// contains filtered or unexported fields
}
Writer implements a io.WriteCloser we will call deflateEnd when we set err to a value: - whatever error is returned by the underlying writer - io.EOF if Close was called
func NewWriterLevel ¶
NewWriterLevel let the user provide a compression level value
func NewWriterLevel2 ¶
func NewWriterLevel2(w io.Writer, level, method, windowBits, memLevel, strategy int) (*Writer, error)
NewWriterLevel let the user provide a compression level value
func NewWriterLevelBuffer ¶
NewWriterLevelBuffer let the user provide compression level and buffer size values
func NewWriterLevelBuffer2 ¶
func NewWriterLevelBuffer2(w io.Writer, level, bufferSize, method, windowBits, memLevel, strategy int) (*Writer, error)
NewWriterLevelBuffer let the user provide compression level and buffer size values
func (*Writer) Close ¶
Close closes the zlib buffer but does not close the wrapped io.Writer originally passed to NewWriterX.
Source Files