Documentation
¶
Overview ¶
Package kanzi defines all the top level interfaces used in the kanzi data lossless compressor/decompressor
The implementation of these interfaces are available in sub-folders like bitstream, io, transform or entropy. In particular, the io package contains the implementation of the Writer and Reader used to compress and decompress data.
Index ¶
Constants ¶
const ( ERR_MISSING_PARAM = 1 ERR_BLOCK_SIZE = 2 ERR_INVALID_CODEC = 3 ERR_CREATE_COMPRESSOR = 4 ERR_CREATE_DECOMPRESSOR = 5 ERR_OUTPUT_IS_DIR = 6 ERR_OVERWRITE_FILE = 7 ERR_CREATE_FILE = 8 ERR_CREATE_BITSTREAM = 9 ERR_OPEN_FILE = 10 ERR_READ_FILE = 11 ERR_WRITE_FILE = 12 ERR_PROCESS_BLOCK = 13 ERR_CREATE_CODEC = 14 ERR_INVALID_FILE = 15 ERR_STREAM_VERSION = 16 ERR_CREATE_STREAM = 17 ERR_INVALID_PARAM = 18 ERR_CRC_CHECK = 19 ERR_UNKNOWN = 127 )
const ( EVT_COMPRESSION_START = 0 // Compression starts EVT_DECOMPRESSION_START = 1 // Decompression starts EVT_BEFORE_TRANSFORM = 2 // Transform forward/inverse starts EVT_AFTER_TRANSFORM = 3 // Transform forward/inverse ends EVT_BEFORE_ENTROPY = 4 // Entropy encoding/decoding starts EVT_AFTER_ENTROPY = 5 // Entropy encoding/decoding ends EVT_COMPRESSION_END = 6 // Compression ends EVT_DECOMPRESSION_END = 7 // Decompression ends EVT_AFTER_HEADER_DECODING = 8 // Compression header decoding ends )
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type ByteTransform ¶
type ByteTransform interface {
// Forward applies the function to the src and writes the result
// to the destination. Returns number of bytes read, number of bytes
// written and possibly an error.
Forward(src, dst []byte) (uint, uint, error)
// Inverse applies the reverse function to the src and writes the result
// to the destination. Returns number of bytes read, number of bytes
// written and possibly an error.
Inverse(src, dst []byte) (uint, uint, error)
// MaxEncodedLen returns the max size required for the encoding output buffer
MaxEncodedLen(srcLen int) int
}
ByteTransform is a function that transforms the input byte slice and writes the result in the output byte slice. The result may have a different size. The transform must be stateless to ensure that the compression results are the same regardless of the number of jobs (ie no information is retained between to invocations of Forward or Inverse).
type EntropyDecoder ¶
type EntropyDecoder interface {
// Read decodes data from the bitstream and return it in the provided buffer.
// Return the number of bytes read from the bitstream
Read(block []byte) (int, error)
// BitStream returns the underlying bitstream
BitStream() InputBitStream
// Dispose must be called before getting rid of the entropy decoder
// Trying to decode after a call to dispose gives undefined behavior
Dispose()
}
EntropyDecoder entropy decodes data from a bitstream
type EntropyEncoder ¶
type EntropyEncoder interface {
// Write encodes the data provided into the bitstream. Return the number of bytes
// written to the bitstream
Write(block []byte) (int, error)
// BitStream returns the underlying bitstream
BitStream() OutputBitStream
// Dispose must be called before getting rid of the entropy encoder
// Trying to encode after a call to dispose gives undefined behavior
Dispose()
}
EntropyEncoder entropy encodes data to a bitstream
type Event ¶
type Event struct {
// contains filtered or unexported fields
}
Event a compression/decompression event
func NewEventFromString ¶
NewEventFromString creates a new Event instance that wraps a message
type InputBitStream ¶
type InputBitStream interface {
// ReadBit returns the next bit in the bitstream. Panics if closed or EOS is reached.
ReadBit() int
// ReadBits reads 'length' (in [1..64]) bits from the bitstream.
// Returns the bits read as an uint64.
// Panics if closed or EOS is reached.
ReadBits(length uint) uint64
// ReadArray reads 'length' bits from the bitstream and put them in the byte slice.
// Returns the number of bits read.
// Panics if closed or EOS is reached.
ReadArray(bits []byte, length uint) uint
// Close makes the bitstream unavailable for further reads.
Close() error
// Read returns the number of bits read
Read() uint64
// HasMoreToRead returns false when the bitstream is closed or the EOS has been reached
HasMoreToRead() (bool, error)
}
InputBitStream is a bitstream reader
type IntTransform ¶
type IntTransform interface {
// Forward applies the function to the source and writes the result
// to the destination. Returns number of bytes read, number of bytes
// written and possibly an error.
Forward(src, dst []int) (uint, uint, error)
// Inverse applies the reverse function to the source and writes the result
// to the destination. Returns number of bytes read, number of bytes
// written and possibly an error.
Inverse(src, dst []int) (uint, uint, error)
// MaxEncodedLen returns the max size required for the encoding output buffer
// If the max size of the output buffer is not known, return -1
MaxEncodedLen(srcLen int) int
}
IntTransform is a function that transforms the input int slice and writes the result in the output int slice. The result may have a different size. The transform must be stateless to ensure that the compression results are the same regardless of the number of jobs (ie no information is retained between to invocations of Forward or Inverse).
type Listener ¶
type Listener interface {
ProcessEvent(evt *Event)
}
Listener is an interface implemented by event processors
type OutputBitStream ¶
type OutputBitStream interface {
// WriteBit writes the least significant bit of the input integer.
// Panics if closed or an IO error is received.
WriteBit(bit int)
// WriteBits writes the least significant bits of 'bits' to the bitstream.
// Length is the number of bits to write (in [1..64]).
// Returns the number of bits written.
// Panics if closed or an IO error is received.
WriteBits(bits uint64, length uint) uint
// WriteArray writes bits out of the byte slice. Length is the number of bits.
// Returns the number of bits written.
// Panics if closed or an IO error is received.
WriteArray(bits []byte, length uint) uint
// Close makes the bitstream unavailable for further writes.
Close() error
// Written returns the number of bits written
Written() uint64
}
OutputBitStream is a bitstream writer
type Predictor ¶
type Predictor interface {
// Update updates the internal probability model based on the observed bit
Update(bit byte)
// Get returns the value representing the probability of the next bit being 1
// in the [0..4095] range.
// E.G. 410 represents roughly a probability of 10% for 1
Get() int
}
Predictor predicts the probability of the next bit being 1.
Source Files
Directories
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| Path | Synopsis |
|---|---|
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Package io provides the implementations of a Writer and a Reader used to respectively losslessly compress and decompress data.
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Package io provides the implementations of a Writer and a Reader used to respectively losslessly compress and decompress data. |