forked from xi2/xz
/
dec_xz.go
124 lines (113 loc) · 3.68 KB
/
dec_xz.go
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/*
* XZ decompressor
*
* Authors: Lasse Collin <lasse.collin@tukaani.org>
* Igor Pavlov <http://7-zip.org/>
*
* Translation to Go: Michael Cross <https://github.com/xi2>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
package xz
/* from linux/include/linux/xz.h **************************************/
/**
* xzRet - Return codes
* @xzOK: Everything is OK so far. More input or more
* output space is required to continue.
* @xzStreamEnd: Operation finished successfully.
* @xzUnSupportedCheck: Integrity check type is not supported. Decoding
* is still possible by simply calling xzDecRun
* again.
* @xzMemlimitError: A bigger LZMA2 dictionary would be needed than
* allowed by the dictMax argument given to
* xzDecInit.
* @xzFormatError: File format was not recognized (wrong magic
* bytes).
* @xzOptionsError: This implementation doesn't support the requested
* compression options. In the decoder this means
* that the header CRC32 matches, but the header
* itself specifies something that we don't support.
* @xzDataError: Compressed data is corrupt.
* @xzBufError: Cannot make any progress.
*
* xzBufError is returned when two consecutive calls to XZ code cannot
* consume any input and cannot produce any new output. This happens
* when there is no new input available, or the output buffer is full
* while at least one output byte is still pending. Assuming your code
* is not buggy, you can get this error only when decoding a
* compressed stream that is truncated or otherwise corrupt.
*/
type xzRet int
const (
xzOK xzRet = iota
xzStreamEnd
xzUnsupportedCheck
xzMemlimitError
xzFormatError
xzOptionsError
xzDataError
xzBufError
)
/**
* xzBuf - Passing input and output buffers to XZ code
* @in: Input buffer.
* @inPos: Current position in the input buffer. This must not exceed
* input buffer size.
* @out: Output buffer.
* @outPos: Current position in the output buffer. This must not exceed
* output buffer size.
*
* Only the contents of the output buffer from out[outPos] onward, and
* the variables inPos and outPos are modified by the XZ code.
*/
type xzBuf struct {
in []byte
inPos int
out []byte
outPos int
}
/* All XZ filter IDs */
type xzFilterID int64
const (
idDelta xzFilterID = 0x03
idBCJX86 xzFilterID = 0x04
idBCJPowerPC xzFilterID = 0x05
idBCJIA64 xzFilterID = 0x06
idBCJARM xzFilterID = 0x07
idBCJARMThumb xzFilterID = 0x08
idBCJSPARC xzFilterID = 0x09
idLZMA2 xzFilterID = 0x21
)
// CheckID is the type of the data integrity check in an XZ stream
// calculated from the uncompressed data.
type CheckID int
func (id CheckID) String() string {
switch id {
case CheckNone:
return "None"
case CheckCRC32:
return "CRC32"
case CheckCRC64:
return "CRC64"
case CheckSHA256:
return "SHA256"
default:
return "Unknown"
}
}
const (
CheckNone CheckID = 0x00
CheckCRC32 CheckID = 0x01
CheckCRC64 CheckID = 0x04
CheckSHA256 CheckID = 0x0A
checkMax CheckID = 0x0F
checkUnset CheckID = -1
)
// An XZ stream contains a stream header which holds information about
// the stream. That information is exposed as fields of the
// Reader. Currently it contains only the stream's data integrity
// check type.
type Header struct {
CheckType CheckID // type of the stream's data integrity check
}